Hello everyone. I am new to this fourm. I have a question that I haven't seen answered using the search function, although i'm certain it has been asked. I am probably not searching correctly. I want to build a bass amplifier and separate cabinet. I would like to go with 350- 500 watts. If this is dumb i'll just step back off this. The safe bet is SS, I don't want to try tubes, well , because I enjoy life, and i dont own a O'scope. First are their kits available for something like this, that you are aware of? I'm not too worried about the cabinet, l'll most likely go with one of the fearful designs if you are familiar with those.
300/500W is doable, but not suggested as a first project.
Rather than *electronic* problems, the "mechanical" problems will arise finding a suitable big heavy chassis to hold it all, the big power transformer, big cooling fins plus probably adding some cooling fan, etc.
Notice the repeated use of the word "big" and not by chance.
Cost may easily add up.
I would start by building a nice Bass preamp, your choice, plus a 50/70W chipamp.
You can use it with a 15" speaker or a 2x10" cabinet.
You are not wasting your time, that amp will be kept for rehearsals and recording, plus being easily portable anywhere.
Later on you can either build a 300/500W kit, if available (remember the "mechanicals" I mentioned, just the PCB and a transformer which is what kits offer is far from a practical working amp) or plain get a cheap 300/500W rack amp and building a suitable cabinet 2x15" at least or 2 of 4x10" style.
Forget a single 8x10", impossible to carry.
Also forget a "500W" single 15" ; they promise but do not deliver.
You need a lot of cone surface to move air.
I forgot: you drive your rack amp frrom your 50/70W amp, which you still keep and use.
As I said, you do not waste it :tu:
Thank you for the quick reply. I really like the idea of building a bass pre, and a 50/70 chipamp.
Are threads here that cover these? I'm using a 90w combo at the moment. It just sounds like junk to me. I like the sound of the old Ampeg b-15. The Motown sound is good to me. I'm a bottom end guy.
Is a 50/70 chipamp kit out there? Please point me in the right direction. My electronic background is from a trade school called R.E.T.S., pretty good 2yr. trade school in it's day. I worked as a field service tech in the copy machine industry for a while. If you have ever worked repairing things in the field you know i was more likely to snatch a board, and install a reworked one in its place. Component level work in the field was a no-no for me. I can adapt though. Thanks again for the reply.
I think JM is being kind. I'm an experienced builder and I would have a long hard think before attempting a build of this class. Just re-creating an Acoustic 361 at the (genuine) 160 watt level took the best part of a year.
I'd also suggest that while brute force is popular with bass guitarists, my own experience strongly suggests that cunning beats brute force every time. I have built some horn-loaded speakers for bass and found that they can more than deliver in a moderately sized, powered, and priced package.
I can vouch for the fact that this guy's designs are not hyped but realistic, and deliver what is claimed;
http://www.billfitzmaurice.com/ (http://www.billfitzmaurice.com/)
The Fane back-loaded J-horn design looks good too.
The basic point is not watts but dBSPL, and when you discover that you can get more dB with 50 watts and a good horn, you are going to wonder about others flogging 8x10's with 500 watts for fewer dB Front of House.
Dont know about your spanish skills, but, here something that looks promises...
http://www.construyasuvideorockola.com/proy_prebass.php (http://www.construyasuvideorockola.com/proy_prebass.php)
What you think?
Thanks for the reply Roly. I have seen Bill on other fourms. He has boatloads of knowledge. I did spend a lot of time looking at his designs. I want that Motown like sound. From what I have seen so far he likes the mid-range sound. It does cut through better though. I think Jm was telling me the samething you are saying in a very tactful manner. I love his idea but I haven't seen those as kits.
Polo thank you also. I'm a single language guy, and i don't always do so great with that one.
I'm in bed on a tablet pc so i had to save the page and i will try and use google translate shortly.
Thanks again and if you guys come across plans for jm's suggestions please post them.
I cut my teeth on Tamla-Motown the first time around (I'm still gigging this stuff in my 60's).
400 Watt Columbian bass rig. Yes, very impressive.
So is this;
(http://news.cnet.com/i/bto/20070117/mclaren_nose_540x306.jpg)
...but you would be nuts to try and learn to drive in one.
Quote from: http://www.construyasuvideorockola.com/proyect_amp_mono_400w_1.php
IMPORTANT: This project is not for beginners. The voltage and current management are quite high, not counting the cost of components. For this reason you should have good knowledge and experience in electronics assembly projects of this magnitude. If you have no experience in the assembly of electronic projects, we recommend starting with a simple amplifier, such as the 40W amplifier. Otherwise any mistake can cost you money. {my emph.}
To be blunt, these amps are for
advanced builders only. The preamps, sure, but the main amps are serious engineering.
It also has to be said that these are adaptions of stereo amps to guitar service, and as such are not intended to deliver their rated output continuously as is required of stage gear.
There is nothing wrong with the idea of getting high power by running several lower power amps in parallel, in fact there is a lot to be said for it, but how ever you do it you have to deal with some very serious questions of component capacity and sufficient cooling.
The power transformers, big as they are, are only for intermittent output at these power levels. Rack amps designed for concert use have power transformers twice this size for the same power, and look more like welders than amplifiers.
The multi-amp method has a couple of real advantages; one is that lower powered amp modules make use of more commonly available components, thus they are cheaper and easier to build and to repair, and they also give you diversity in that if one amp blows up at a gig you still have the other(s), all your performance eggs are not in one basket.
As a keyboard player who uses a homebrew Twin-50, and as a soundie who has used multiple amps, I can tell you this diversity has saved the show on more then once occasion. Even the classic
Acoustic 360/361 used a single preamp, but independent power modules in each W-bin - and I would strongly suggest to you that they knew what they were doing going this way.
A speaker in a direct-radiator cab is about 3% efficient in converting electricity into sound. In a J- or W-bin that jumps to 25 to 30% efficient; in other words it makes 50 watts sound like 500 watts - without having to use a genuine 500 watt driver. Bill's "Siamese", one of his earlier designs I modified a bit, has ample slap thanks to having tweeters, but I wouldn't call it "mid-range" by any means, going down flat to the low-E on a four string bass it makes your guts shake.
So it looks like the consensus is "keep it simple stupid"!!!??? I'm very interested in everything that has been said. Roly what would you suggest as a start .... can you point me in a good direction for a buildable ( <---- is that a real word? Aww you know what i mean. ) amp for bass? I love the idea of less watts, but better sound. I've looked around the net for some of the things mentioned here, and it's kept me busy. Here's proof.
(http://i47.tinypic.com/29vjotc.jpg)
I can get one of these Peavey series 300 things for about $40 but it reads Musicians where this one reads bass. It reminds me more of a preamp than a amp though. It yells a minute when you turn it on.
Good idea? Bad idea. Please help!!!
(http://i49.tinypic.com/29n9j5c.jpg)
That Peavey Musician, if working properly, is an excellent Bass amp too.
Just don't use its reverb of Fuzz !!!
*Many* old amps e+were designed that way: same big PCB where for Bass "ffects" were simply not fitted.
And for $40 each ...... *I* would buy a dozen, and I'm not kidding.
Real difference between Bass and Guitar versions, besides effects, was speakers, as in 2 or 4 x 12" instead of 1 or 2 x 15".
And 10" were for Guitar ;) .
Check old Kustom, Acoustic, Randall, etc. catalogs (and schematics).
Yeah, "buildable" is certainly a word, and not a bad concept if you want to actually finish something and use it. ;)
Ah, so you found my Siamese. The amp just happened to be what was around at that time and it has been driven by all sorts of things since it doesn't really have an amp of its own. It's nominally a couple of hundred watt 15-inch Etone driver but normally gets driven with about 50 watts (and I dread to think what would happen to the back wall if I drove it with 200 watts).
Like most of my stuff this was build mostly out of scrounge, the cloth covering and corners were bought but most of the rest were scraps gathered from here and there. I did an earlier, smaller Mid-Ranger that was built entirely from wood that had been pile up to burn in a bonfire, warped ply and the like.
A criminal amount of good ply &c gets thrown out at building sites as "offcuts" or used formwork that has a bit of cement residue on one side, and for a bit of dumpster diving after quitting time, and a bit of cleaning, you can have all the materials you need to build guitar speaker cabs - leaves more money to spend on the actual driver(s).
While I'm not unhappy with the Siamese W-bin I'm now keen to try one of the Fane J-horns which I think may give just as good results with less building effort (and weight).
Any box with knobs you can get for $40 has to be worth serious consideration - all the better if it's actually working. :dbtu: If it doesn't suit your needs, or you can't adapt it, you can always flog it again (to JM :cheesy: ).
http://OzValveAmps.org/cabinets.htm#fane (http://ozvalveamps.org/cabinets.htm#fane)
Get 01-11, and 34-41 bass horns.
attach: Fane-rear-J-15
This thread is making me want to build a W-bin or a J-horn cabinet for my old 60-watt Univox tube bass head! Off to follow links...
Any ideas as to why this peavey musician is screaming when it is turned on??? It stops after it's been on a few minutes.
Quote from: oleskool on June 15, 2012, 03:01:12 PM
Any ideas as to why this peavey musician is screaming when it is turned on??? It stops after it's been on a few minutes.
Is it a high pitch whine, a low pitch rumble, some other noise?
Here's an Audio Engineering Society J-horn for 12, 15 or 18 inch driver, similar to the Fane.
I'm posting this one here because it's out of my private stash (not on-line) and the book is way out of print now.
If you look closely at the response curves the main difference as the diameter goes up is you get that extra bit just above 50Hz, but at the expense of some top end roll-off. I'm considering a pair of these with 12-inch drivers, and maybe a low-reach tweeter horn in each for use with synth/keys.
Circuits for the Musician 300 series appear to be available here;
www.audio-circuit.dk/schematics_o-r.php (http://www.audio-circuit.dk/schematics_o-r.php)
re: Peavey Musician screaming
Q: Do any of the controls have any influence, louder, softer, change tone or pitch?
1. Have J-bins or W-bins been built that use 10" bass drivers? I'm wondering how a single- or dual-10" compact folded horn arrangement might work with a low-wattage head like mine...or does that compactness/small driver approach begin to negate the efficiency benefits of a design like that?
2. Does the "screaming" of the Peavey Musician occur even if nothing is plugged into the input? Or does it only happen when you plug in an instrument or just a cable? If the latter, does plugging something else into it still make it scream?
I have an old Valco tube amp that screams like crazy if I plug my lap steel into it, but it doesn't act up with my guitar. My lap steel is fine plugged into other amps. I haven't traced this problem down and dealt with it yet.
Well you can put a horn on anything, or anything in a horn, but horn or not there are a few physical realities that must be recognised and paid due homage.
Big speakers are used because they pump more air for a given cone throw. They are also used because they normally will have lower mechanical self resonance frequencies, and once you come below the driver resonance the output starts to drop like a rock.
From my discussions with bass players it seems that groups of 10's are favored for two reasons, one is that some players like the more trebly "ga-dang", but it also seems that many bass players are willing to compromise on real fundamental "ommph" for the sake of portability. I remember one discussion that ended on me asking if they were a bass player first, or a driver first, and if they were a bass player first then maybe they needed a bigger vehicle.
As a keyboard/synth player I have a foot in this camp because I want real bass from my left hand, and smaller speakers simply don't cut it.
There is a thing that all small speakers such as "bookshelf" and computer speakers depend on, and it's called the "replaced fundamental".
If you present the human ear with a group of third harmonics it is possible to fool the brain into thinking that it is hearing not harmonics but the fundamental note, even though there may be no fundamental there at all.
If you do a sinewave sweep (no harmonics) of typical computer speakers you won't hear anything until you get above 100Hz, perhaps well above, yet if you play music through them you will get an impression of the bass line. This is an example of the "replaced fundamental", and to some degree this is what you are getting with 10-inch speakers. But no matter what you do you are never going to get that feel-it-in-your-chest thump of a genuine fundamental.
If we compare two 10's with a single 18, the cone area for a single 10-inch is about 78 sq inch so two are about 157 sq inch. A single 18 has a cone area of about 254 sq inch, so already a pair of 10's will have to throw nearly twice as far to move the same volume of air.
When we look at the driver free air resonance we find that a 10-inch has a typical resonant frequency of about 60Hz, while an 18-inch will be down around 30Hz, so the ten is starting to roll off even before we get to the open bottom E on a four string bass (41Hz).
If that were not enough, as soon as you put any speaker in a cab its resonant frequency is pushed right up. You can minimise this effect by making the cab very large, but you then end up with a cab that is as big as a family fridge (or bigger) and the loading on the driver cones is reduced to the point where they are easy to turn inside out.
When it comes to bass the basic physics is not kind, and there is no such thing as a free lunch.
What horn loading does (for any speaker) is it creates an acoustic impedance transformer (or gearbox if you like) between the stiffness of the cone and the floppy compliance of the air at the horn mouth, and provided it is big enough for the desired low frequency cutoff it loads the cone and limits the throw for a given SPL output - it couples the speaker to the air better; and that is where the big increase in efficiency comes from. (for a given cab volume a J should produce a "better", less compromised, horn than a W)
The other way to go is to put your drivers in a way undersized box and flog the living daylights out of them with huge power (e.g. most commercial bass rigs). You end up with a rig that is fairly small and transportable, but terribly inefficient (i.e. most of those watts go into heating up your speaker voice coils instead of into the air).
This really only scratches the surface of what is a major and interesting problem in physics. The key word (unless you have a very large truck) is "compromise", and no matter what the salesman tells you, the old saying is still true - "There ain't no substitute for cubic feet".
"Doof" boxes, so-called sub-woofers, are a whole other nasty topic all of their own.
{I sometimes wish I had taken up the flute}
This is very interesting and is presented in a condensed-enough form for me to grasp; thank you for taking the time to write this. I have probably experienced a lot of the "replaced fundamental" phenomenon without knowing it! Maybe I need to get some time in playing my bass and listening through some larger speakers to get a feel for what some real fundamental feels/sounds like.
My pleasure, because it has long been a special interest to me as a key player and soundie/mixer.
We are all boiled frogs. About the only time you actually hear real fundamental bass these days is at big arena rock shows with rows of W-bins the size of double beds along the front edge of the stage, and you can actually feel the kick drum in your chest - fooom!
My son is typical of the iPod and doof generation, and you should have seen his face the first time I played him some Toto through the Siamese. "Never mind you don't like the naff music - listen to the bottom end". Once you have the illusion explained, and actually experience real fundamental bass guitar bottom-E, sound systems never sound the same again. ;)
Actually, it's been years since I've been a gigging musician, but after reading and re-reading your post it got me thinking about nights when my band lucked into playing some of the bigger clubs around here (like, when two or three bands in front of us on the list were sick or something, and we eventually got the call).
Hearing the familiar sound of our drummer's kick and low tom and the bassist's Peavey TNT combo suddenly booming through a row of subs and nice monitors, out into a mostly empty club, was pretty exciting.
I meant to say in my last post that your likening the horn to a gearbox was helpful to me; also, in another thread here I mentioned recently picking up a little Line 6 Lowdown 110 bass amp cheap and used. I think that would be a good example of "flogging the living daylights" out of a small (10") speaker in a too-small box (12" x 12" x 12" cube, plus subtract however much the chassis cuts into the internal volume...probably reduces the internal depth by at least 1-1/2" or 2").
To me that little amp sounds pretty good on at least two or three of the models, but I wonder how hyped the models are in the lows to partially overcome the acoustic limitations of the amp's physical configuration? It would be interesting to use the amp to drive a larger, more "neutral" enclosure and drivers and see what that sounded like.
Well, *my* customers go the big box, high power route.
As in 4 Ampeg 8x10" boxes driven by 4 of my 300W heads or same cabinet setup with 2 of my tube rackpreamps driving an AB Systems 1500 into 2 cabinets, plus a QSC900 (later replaced by an AB1000) driving other 2.
Of course, they play Stadiums and have armies of Roadies, forklifts, the full Monty.
My heads are the white front ones, with the very visible HP bright red Leds.
http://youtu.be/LpGu0XscQ-o <-- click to see the You Tube video.
(http://farm2.staticflickr.com/1191/728742371_33c063ac00_z.jpg)
These are the silver and light blue Tube Preamps driving the Rack Power Amps:
(http://farm2.staticflickr.com/1301/729418210_ec91a14ddf_z.jpg)
and
(http://farm2.staticflickr.com/1308/729418154_e462126021_z.jpg)
In case you wonder, the unconnected Rack mount Ampeg SVT400 you see in the middle, is the "backup amp".
Well, to be frank @mexicanyella, I consider any speaker for any use in a 1 foot cube to be a practical joke. The 15 that is in the Siamese came out of a commercial vented enclosure, intended for bass, that I came to call its "carry crate" 'coz as a speaker cab it was a bust, and as a bass cab doubly so.
Let me quote some actual numbers to hand. A Dai-1Chi "instrumental" 10-inch (94dB/W, 400Wmax) has a free-air resonance Fo of 63Hz. From a different table, a 10 with an Fo of 52Hz has a resonance of 105Hz in a 1 cu ft enclosure.
That's roughly the open-G or top string, leaving the rest of the bass guitar down a mineshaft (and that's before you scale it up 20% or so).
This is about the same size as the Roland Cube series, and I know from painful experience that they start to roll off about Middle-C, or 250Hz odd - and these get sold as "keyboard" amps cor blimy! Computer keyboard maybe, 'cause they are totally bloody useless as synth amps - shreeking lead guitar is the only thing they are good for (and door stops).
(Counts up on fingers...) I make that 32 drivers and 1.2 (or 2.5) kilowatts for the backline bass alone.
I think I rest my case. :-X
{should we ignore the mike in front of the bass bins and the rather large bins behind which I assume are only part of the on-stage foldback - what do the FoH bins look like JM? :o And we're not fooled by you using dwarfs to make the bins look bigger either. :lmao: }
Of course all this depends on the playing style and desired effect. If the bass player uses a popping and gar-dang style then the fundamental may be a lot less important.
But for those bass guitarists who;
- are not frustrated lead guitarists
- are not rich
- are not (yet) famous
- don't have a road crew that gets mistaken for a small invasion force
- don't play stages that are so high they need oxygen
- play venues where the majority of the audience are still in the same State, and
- want actual fundamental bass notes
...some compromise and cunning are required. ;)
Good points all, and in general a great thread that has affected how I look at things.
Now, taking a brief break from bass amps, I think I've left my "tube amp snob" days far and long behind me, but check out that green Matchless head on that check-fronted Marshall cabinet. If a guy was going to play through a half-stack, I bet that'd be a pretty nice-sounding one to play through!
We used to split gigs with a band whose guitarist ran a Matchless Clubman head through a Fender Bandmaster cab, and and it really sounded great. Ahh, memories...
Well, these guys play LOUD. http://en.wikipedia.org/wiki/La_Renga
The guitar player uses 6 100W tube heads into 4x12" Marshall cabinets.
Heads being a mix of Marshall, Matchless and Mesa Boogie.
(http://farm2.staticflickr.com/1261/730355172_f6d52280af_z.jpg)
So against 600 guitar tube watts , 2500 Bass watts are proportionate.
Which is not unreasonable when playing outdoors, in a 48000 seat Football (USA "Soccer") Stadium.
Which actually held 74000 people because the Football field was chock full, besides the actual seats.
The still empty River Plate (Buenos Aires) Stadium, the night before:
(http://img7.imageshack.us/img7/6140/image11ac.jpg)
Same, slowly filling up, 4 hours to the actual concert.
(http://img513.imageshack.us/img513/315/image04j.jpg)
Ah !!! , the "midgets" are my kids ... and the right size for their age.
As you see, I take them everywhere (if possible), to see what "Dad's work" is about.
Quote from: J M Fahey on June 17, 2012, 12:25:08 PM
Ah !!! , the "midgets" are my kids ... and the right size for their age.
As you see, I take them everywhere (if possible), to see what "Dad's work" is about.
I would love to be "uncle polo" :P also to see what "dad´s work" is about.
Yeah, going to work with Dad under those conditions would have to be pretty interesting!
Does the guy blend all those amps for a composite tone, or switch between them for certain things, or all of the above?
This is a basic Rock'nRoll band, they just plug, turn everything up and go.
No keyboards, nothing.
A basic trio plus a sax player on some songs.
Problem is, they draw so much people that they can not play for less than, say, 5000 people (usually over 10000).
Now , to be able to pack more inside a stadium, they build a large circular rotating stage in the middle of the fiels, some 40 meters diameter.
In such a huge stage, amps get lost, because they are spread all around:
http://youtu.be/lV5Jlcn_v-I <--- click for a video
http://youtu.be/lMxZoAdRWWU <--- similar in another Stadium.
EDIT: please do not think I sell these big amps every week, or that I recommend you to follow such path, let's get back to the original idea behind this thread.
My "bread and butter" amps , the ones which have paid for my house, car, Family, whatever during the past 43 years have been good and simple 100W, 2x12" Bass and Guitar amps.
Why 100W? : easy to get in SS; loud enough with power to spare to play along any normal drummer, who is the guy who really sets the sound volume reference onstage.
And they have no volume pots !!! ; they play as they play.
For me, roughly equivalent to, say, 50/60W amplifiers.
So in my experience, 60W is the minimum onstage; 100W can easily be turned down, of course; 50/60W is just on the drummer's level, some guitar players may get by with 40W (or 25/30W but *very* good speakers).
I see *lots* of kids lately trying to play onstage with 15W amps (Orange Tiny Terror/Vox Night Train/Marshall Haze 15/etc) but they have no dynamic range, always at the edge of overdrive, no reserve power left for *clean* sound, so ......
They usually have to play into a Marshall 4x12" cabinet to be heard, so, what you save on amp you spend (lots more) on the cabinet.
While guys with around 50W and a 12" speaker play hgappily.
We are talking guitar here.
For Bass, 100W is better, driving a good 15".
Yet I use 2x12" Why?
I make my own speakers: when I started with this over 40 years ago, tried the classic 1 x 15" against 2 x 12" in similar cabinets: 2 x 12" won hands down so ......
These are my standard heads:
(http://farm2.staticflickr.com/1392/730546838_5368176040_z.jpg)
these the standard 2x12" cabinets
Front:
(http://farm2.staticflickr.com/1288/729861731_e2139ddfd7_z.jpg)
and back (showing the Bass tuning port)
(http://farm2.staticflickr.com/1114/729861797_9a8f25f0df_z.jpg)
The 2x12" cabinets are light and easy to carry in any car, either in the trunk or, worst case, in the back seat.
As I said, I live thanks to the *regular* Musicians, Pro or advanced enthusiasts; big Stadium packing bands are cool, but not that many, and can't sustain me.
Of course, they polish my name and help bring in the regular folks !!
Back to what you want to build: a 50/60W chip amp, a good speaker and any preamp you fancy will carry you a long distance.
Start by building a simple SS preamp like the one Rodd Elliott recommends for guitar, but pull the clipping diodes.
You will have a "Fendery" sound, not bad at all.
Build it, use it, play a lot , you will soon know what it can and what it can not do, your own practical experience.
Later, if you wish, you may build a hybrid: a tubed "Ampeg fliptop" (B15N) preamp, driving your chipamp and speaker.
You'll have quite a good chunk of "Motown sound", still you won't have power tube compression ... but not bad for a homemade project.
Good luck.
JMF, I really like the clean, simple looks of your 2 x 12" cabinet. I'd love a chance to try one of your amps out someday. I don't think a trip to Argentina is in my budget right now, but never say never...
Thanks for the La Renga clips too. That big circular stage is pretty wild.
Re: power levels, amp features and bass...I am only just learning to play bass, on a P-bass copy, but what I've found is that I'm happiest with a clean, uncompressed and fairly bright tone, which I can darken "to taste" with the bass guitar's tone knob. I set the amp loud and try to play fairly softly and evenly with my hands, fingerstyle that is, and "compress" myself by managing my "attack" on the instrument. I am a ways from mastering this, but when it works it's a lot of fun, and one thing about this approach that really appeals to me is that I don't seem to need any pedals or anything special from the amp. Just loud, clean and no special EQ features.
I realize that my own idea of what sounds good with bass might not apply to others, but I think it's a valid point that a simple, clean-toned and fairly neutral amp can sound decent with bass, good enough to have some fun with, if my experience is any indication.
Quote from: J M Fahey
As you see, I take them everywhere (if possible), to see what "Dad's work" is about.
I think that's brilliant JM; they will grow up with some great memories, and understanding how shows are put together, all the background work required. :dbtu:
After my son was born I often had to combine work with child minding, so I would take him on jobs such as office computer repairs and mixing gigs wherever possible, but I would also take him to visit nearby small factories and ask to show him around, so he got to see glass works, sheet metal, various textiles, and an iron foundry that was a favorite - and never got knocked back once.
Quote from: J M Fahey
and they have no volume pots !!!
But what is "volumen"? Are we evolving to a guitar amp that just has a switch marked "off" and "11"? :cheesy: Nice looking gear.
Quote from: mexicanyella
a clean, uncompressed and fairly bright tone
I agree with JM, a fairly basic amp of 50/60 or 100 watts, and I would suggest the AES rear-loaded J-horn with a suitable 15 inch speaker will cover both a rich bottom end and still allow brights from the front, and be practically portable.
I would either build your amp as two units, preamp and main amp, or at least include Fx send and return. Even if you don't intend to include Fx this is still the place you can experiment with external graphic or parametric EQ's and such.
Apart from cost I see two important advantages in building your own gear; satisfaction that "my" rig really is my creation; and when it needs repair (as they all do at some time), or you feel you want to modify it in some way, you are fully in charge, you know exactly what is inside the boxes and the compromises are all yours to own or to change.
Rod's amp designs are as good as you will find anywhere, but two important points, don't skimp on the power supply, or the heatsink - it is hard to have too much heatsink in a gigging amp (and you always seem to need more than you initially think).
Quote from: Roly on June 18, 2012, 12:41:57 PM
... it is hard to have too much heatsink in a gigging amp (and you always seem to need more than you initially think).
I managed to do it:
(http://www.thatraymond.com/imagehost/overkill_heatsink.jpg)
That is a single LM3886 on there btw.
Nope, looks about right to me (as long as it also has a fan somewhere out of sight) :lmao:
@ joecool: nice build !!
@Roly:
Quoteand they have no volume pots !!!
refers to *
drummers* !!! ;)
And they have the volume switch stuck on 11 anyway !!! :lmao:
That's why I said : "they define the volume level onstage".
Part of mine being considered "good" amps comes from the fact that I do not make small amps.
50/60W minimum.
So many times a brand-oriented guy buys a "famous" amp, such a 30 to 60W Hartke/Laney/Peavey/Marshall/whatever , shows up with it at the rehearsal room, and one of my 100 watters (which by the way costs less than his imported stuff) blows them off the water.
I also avoid combos and go for "real" cabinets as you see.
As you mentioned before, Acoustic Laws can't be beaten.
Quote from: Roly on June 18, 2012, 01:58:23 PM
Nope, looks about right to me (as long as it also has a fan somewhere out of sight) :lmao:
Yeah, funny. No fan and running it full tilt in a 75F room for an hour brought the heatsink up to about 90F on the end with the chip and 85F or so on the other end. I'd say it won't be an issue :-)
**edit**
I should note that at normal volumes I was unable to get the heatsink to raise more than 5F above room temp no matter how long I played it.
Quote from: J M Fahey on June 18, 2012, 02:40:12 PM
@ joecool: nice build !!
Thanks. It used a 330va transformer as well. WAY more than necessary, but I had planned on adding a second channel (never did though) and wanted to make sure at full tilt it would have enough. I'd rather build it once and do it such that I can upgrade later. Who knows, my brother has it now and I may get it back some day and choose to through another channel or 3 in there.
Oh, drummers, yeah, I forgot about them (easy to do).
Still, I rather like the idea of a guitar amp with minimalist controls...
(http://www.ck-supplies.com/uploads/ImageRoot/detail/13000/hVuAb95V.jpg)
Yeah Joe, looks like you could turn that into a bridge with little trouble.:tu: Where did you score the chassis metalwork?
Quote from: Roly on June 18, 2012, 08:57:26 PM
Oh, drummers, yeah, I forgot about them (easy to do).
Still, I rather like the idea of a guitar amp with minimalist controls...
(http://www.ck-supplies.com/uploads/ImageRoot/detail/13000/hVuAb95V.jpg)
Yeah Joe, looks like you could turn that into a bridge with little trouble.:tu: Where did you score the chassis metalwork?
Old (dead) CB base station radio.
Also, I have a guitar amp I made that has no controls but gain (on or off). It is an LM386 based deal and it clips onto my belt, I built it into a pocket radio that I gutted for that purpose. It turns on when you plug in. There is also a green LED where the antenna use to be that lights when the circuit is powered. Runs on 3 x AA and it's had the same batteries in it for years now. I don't play it much now, but for a while I used it frequently.
Quote from: Roly on June 16, 2012, 06:14:32 AM
There is a thing that all small speakers such as "bookshelf" and computer speakers depend on, and it's called the "replaced fundamental".
If you present the human ear with a group of third harmonics it is possible to fool the brain into thinking that it is hearing not harmonics but the fundamental note, even though there may be no fundamental there at all.
As a brass player (tuba and trombone) I'm well acquainted with that effect.
Firstly it's used for what we call a "false partial", that allows playing notes that don't exist on the horn. Handy in a pinch, but they never sound quite right.
Also I've seen similar effects where you play one note of a triad, sing the another (not the easiest thing to do), and the horn natural harmonics cause the ear to fill in the missing note and hear the full triad. (only works when all 3 notes play with the same "fingering")
Really freaky the first time you hear it.
Quote from: Roly on June 17, 2012, 12:46:30 AM
About the only time you actually hear real fundamental bass these days is at big arena rock shows
Live performances of unamplified music. Nothing like the bass (i don't mean guitar either), tuba, tympani on a proper stage in a hall with good acoustics.
Or stand in front of 20+ sousaphones playing a grove at fff.
Quote
{I sometimes wish I had taken up the flute}
You and me both.
Quote from: Roly on June 14, 2012, 10:34:28 PM
While I'm not unhappy with the Siamese W-bin I'm now keen to try one of the Fane J-horns which I think may give just as good results with less building effort (and weight).
http://OzValveAmps.org/cabinets.htm#fane (http://ozvalveamps.org/cabinets.htm#fane)
Get 01-11, and 34-41 bass horns.
attach: Fane-rear-J-15
Roly, I looked through the Fane speaker book--cool stuff--from your links and in looking at the cross-section of that rear-horn-loaded "J-bin" 15" enclosure...it looks like the speaker cone radiates directly through the round hole at the top, while the rear of the cone is radiated out through the folded "J-horn." Am I seeing this correctly?
If so, is the idea that by "delaying" the sound coming off the back of the cone by the length of the horn, the sound reaches the mouth of the horn in time to be "in phase" with the direct-radiated sound coming off the front of the cone? So the extra efficiency comes partly from the horn-loading effect you described, but also from harnessing the sound off the rear of the cone more effectively?
STDog, I think I've experienced something like that "false partial" effect when trying to play lap steel in a tuning that didn't lend itself to minor chords without fancy hand moves that were out of my reach at the time. You could play part of the minor triad without abusing your inexperienced hand, and even if the other instruments were'nt covering the note you left out, sometimes it would still seem to be there. So it wasn't just wishful thinking, huh?
Quote from: mexicanyella on June 20, 2012, 02:01:42 AM
STDog, I think I've experienced something like that "false partial" effect when trying to play lap steel in a tuning that didn't lend itself to minor chords without fancy hand moves that were out of my reach at the time. You could play part of the minor triad without abusing your inexperienced hand, and even if the other instruments were'nt covering the note you left out, sometimes it would still seem to be there. So it wasn't just wishful thinking, huh?
The false partial is a bit different. It's cheating the natural harmonic series on the horn and using the overtones to mimic the note.
Say you have a Bb horn. open partials are Bb, Bb, F, Bb, D, F, etc..
That octave jump between the bottom 2 is the issue. With 3 valves (or a 7position slide) you can play down to the E between them, but no lower. You need 4 valves to get all of that octave. But, you can fake an Eb between them that has zero fundamental and is all overtones. And, many can fake all the way down to the B.
On a stringed instrument, you can play two strings and sympathetic vibrations will sound the third if you have the chord fretted properly. That's similar to the effect I mentioned, in that the missing note has to fit in the tube as played. Say you play Bb, sing F, and the D magically sound in the head. That because if the interactions of the overtones of the 2 real notes, the horn characteristics, and the human ear.
Not sure about other effects on strings. Whatever you are playing would need to emphasize enough of the right harmonics to trick the ear.
Interesting @STDog, didn't know that. I actually used to roadie a double bass player, but sousaphones are pretty thin on the ground in Australia, the occasional Trad Jazz band, never mind in massed swarms (or whatever the collective is for sousaphones). Do people still go to orchestral performances any more? I was sorta thinking of massed German basses when I wrote that, but I thought that most readers wouldn't know what I was talking about. In my misspent youth I used to go around playing pipe organs and 32 foot Diapasons spoil you for real bass.
@mexicanyella - yes, that's right, the upper frequencies are radiated from the front of the speaker cone, and the rear is loaded by the J-horn.
No; what happens is that the radiation crosses over. Down to the acoustic crossover all the radiation comes from the front of the speaker because the inertia of the mass of air in the horn makes it effectively a sealed box, but as the efficiency of the front radiation starts to drop off so the air mass behind (by arrangement) starts to respond and as the frequency comes down the whole cab acts like a horn, with little radiation from the front of the speaker cone.
It is effectively a combination of both a mid frequency direct radiator and a low frequency horn. {The Siamese 'tho does have some internal vents and makes use of the radiation from them to augment its bass output, but then it's rather more complicated inside.}
Because the replaced fundamental is all in the mind you could actually call it wishful thinking. ;) I was talking to a techno mate about this topic who pointed out that MP3 encoding makes heavy use of this subjective effect.
This stuff goes some way to explaining why chord inversions, 'tho nominally the same, actually sound a bit different.
Quote from: Roly on June 20, 2012, 08:07:52 AM
Interesting @STDog, didn't know that.
A lot of horn players don't understand it either. They just know those false partials sound bad.
Quote
Do people still go to orchestral performances any more? I was sorta thinking of massed German basses when I wrote that, but I thought that most readers wouldn't know what I was talking about. In my misspent youth I used to go around playing pipe organs and 32 foot Diapasons spoil you for real bass.
Some do. Not nearly enough.
Speaking of the land down under, I'd really like to go to the Sidney Opera House and hear that organ.
In the States you can always find a good college marching band on Saturday during football season. That's the best place to find lots of sousaphones.
Catch them practicing, inside, for the best effect :)
And drum corps is still pretty good, though the switch to Bb horns has hurt the bass. The old horns in G have/had a lot more punch.
Quote
Because the replaced fundamental is all in the mind you could actually call it wishful thinking. ;) I was talking to a techno mate about this topic who pointed out that MP3 encoding makes heavy use of this subjective effect.
And OGG Vorbis relies on it even more than MP3.
Gotta love how easily the human mind can be tricked.
Motion pictures rely on that effect (multiple stills looking like motion).
Even our displays (monitor, TV, etc) as you have 3 distinct color points (RGB) that the mind blends into a color.
QuoteDo people still go to orchestral performances any more?
Thanks God many still do, specially in Europe.
In Austria , Germany and Czechoslovakia (or what they became now) open air Classical Music concerts rival Rock Festivals in popularity and attendance.
In Buenos Aires , at least once a year, I dress up and go to listen some real music at our Teatro Colón, our Opera House.
It's *incredible* the transparence, brilliance, depth, separation, dynamic range you can hear there.
Back home, I want to smash all Hi Fi equipment with a hammer.
Not even the *best
* Hi Fi equipment even approaches that.
I have friends with as-expensive-as-their-home equipment: still no dice.
Which isn't surprising, their listening rooms are a shoebox compared to the real thing.
So far I have only listened to 2 very believable reproductions (meaning I close my eyes and "they are there"):
1) string quartets and
2) small Jazz ensembles, meaning, say, a singer accompanied by a piano, double bass, small drum set, maybe a horn or two.
Or, what's about the same, some Classical or Flamenco guitar players.
*Recording* is very important too, best I've heard is music captured in one take, no processing, just 2 mikes (often in an "X-Y" setup), direct to disc or digital recording.
I took some audio recording classes in school, and before we were turned loose in the multitrack studio, we had to do some field recordings of acts we'd find for ourselves, using the school's two-track field kits (TASCAM portable DAT, small Mackie mixer--better mic preamps than the DAT had--a stand with a clever stereo X-Y mount on it and a pair of Shure SM81 small-diaphragm condenser mics). For the small-ensemble assignments we were supposed to use the mics in the crossed 90-degree XY formation to reduce the variables and ease the grading process. It was very exciting to hear how accurate and spatially defined a recording could be using that arrangement. In the assignment my partner and I turned in, we recorded a electric guitar/upright bass/drums jazz trio in a pretty noisy bar, and while the ice-grinding machine was pretty intrusive every time someone ordered a frozen drink and the upright bass wasn't picked up as loudly as I'd have liked, it was remarkable how you could hear EVERYTHING and it was positioned realistically in the stereo spread when you'd close your eyes and concentrate on it.
Before turning the equipment back in some friends and I messed around with comparing XY formation at 90 degrees, ORTF formation at 110 degrees or something like that and also the spaced pair approach, in a basement, recording a couple of acoustic guitars playing together. I recall the ORTF being even more pronounced stereo, maybe a little more lush, but it seemed a little "hyped" to me somehow. Spaced pair recording in a basement-sized space didn't sound bad but it wasn't as focused and crisp as the XY setup.
Later on we had to record a large classical ensemble in a pretty good-sized hall, using a spaced pair of omnidirectional mics and I think a more distant filler mic...I can't remember the details of that as well but I do recall that it took some experiments in spacing the mics and blending them different ways at the mixer to approach the huge actual acoustic sound we were hearing in the actual space. The final recording seemed to sound pretty good, but nowhere near the real thing! I think it was supposed to be a humbling experience...clearly a long afternoon of moving three mics around and running cables and taping things down to the floor was not enough to really do it right, and while we were borrowing some pretty expensive mics and gear, we were really on the low end, gear-wise, for that kind of thing.
My step-father got to a point where he decided it was better value for money to buy concert tickets than Hi-Fi gear. As a kid I was allowed to have any LP I wanted - as long as it was classical. So in my youth I was playing in rock bands and also a subscriber to Melbourne Symphony Orchestra and Australian Opera seasons, and catching chamber recitals of Bach, Vivaldi, &c. Never been mad on modern composers, or classical dance as an art form, but a good symphony orchestra in a good venue (and Melbourne is lucky to have both) is really an experience.
I've also done a lot of live recording, but never with the kind of equipment I'd like to have, but I've found that if you are prepared to put in the effort to squeeze the best out of what you've got you can still make some pleasing recordings.
I have a group of favorite recordings that I listen to just for pleasure, and they are almost all live recordings of performances in front of an audience, and even though there are the "ice grinder" moments there is also an energy that you simply don't get with studio recordings; there is no chance of a second take here, get it right first time or die live on stage in front of thousands. That risk seems to lift performers and performances.
So yeah, when I'm talking fundamental bass I'm thinking of a bunch of orchestral basses, or the biggest Diapason on a big pipe organ - that's the sort of chest-vibrating bottom end that a bass guitarists should have at their disposal.
Quote from: Roly on June 21, 2012, 07:23:18 AM
So yeah, when I'm talking fundamental bass I'm thinking of a bunch of orchestral basses, or the biggest Diapason on a big pipe organ - that's the sort of chest-vibrating bottom end that a bass guitarists should have at their disposal.
I think that's what any bass player really wants. Bass should be felt as much (more?) as heard.
And on the very bottom end the human ear doesn't hear the fundamental very well either. While the nominal is 20Hz, that best case in a lab. The low A on a piano is 27.5Hz (just below a 16' C pipe), compared to the 41.2Hz E on a 4 string bass. Tuba parts regularly go down to 24.5Hz G, and at least one piece has 16.3Hz C (32' pipe).
Reproducing anything below 50Hz just takes a lot of air movement, and really needs to be felt.
That's just not easy, never mind trying to do it with small drivers and low power.
Guys, thanks for sharing your personal experiences, that's what I was referring to, the "real" sound of Music.
Nowadays vey little people knows what I'm talking about.
Not usual finding guys with the same kind of experiences I've had, lots of Forums filled with people with *strong* (borrowed) opinions but little to back them with.
:dbtu:
Quote from: J M Fahey on June 21, 2012, 12:32:39 PM
Nowadays vey little people knows what I'm talking about.
Not usual finding guys with the same kind of experiences I've had, lots of Forums filled with people with *strong* (borrowed) opinions but little to back them with.
I think you would be pleasantly surprised with the public as a whole (not to be confused with those on internet forums).
Forums, especially "music" forums can be very selective. But go to other forums and try the off-topic areas and I think you'll find a different perspective.
The real trick is for the now older generations (I'm only 40 mind you) to ensure the younger generations experience real music and gain an appreciation. And that means taking time out from other activities and going to the symphony, finding a chamber performance, a concert on a real organ, etc. Start them early. Drag them kicking if we must. It will sink in.
I was forced to listen to/ perform a lot of music I didn't like. Then years later I was able to appreciate it. Had I not be forced I don't know that I'd have ever made the leap myself.
Now, where did oleskool run off too?
What are your current plans?
Did you buy that Peavey?
I didn't runaway. I have been trying to decide my next moves. I think the speaker part has been decided. When this started I was thinking one of the fearful designs by green boy. As it progressed I am leaning heavily in the direction of Bill Fitzmaurice's jack 12 design. I will not be moving this cabinet around a lot, so I will not try the lighter version of the cabinet with all the bending wood. The Elliott sound (mkll I think ) looks like a good place for me to start with amp builds. I may try something smaller first though haven't made up my mind for sure yet. I did find this interesting, http://www.albertkreuzer.com/preamp.htm#faq but looking at things briefly you will need a o'scope to complete the project. This is my first attempt at building something other than in school. I was quickly in the field repairing copy machines using a foolproof repair manual. ie... place red lead of volt meter on pin 12 place black lead on pin 16 if it doesn't show 24v replace board and bring old board for repair. I will be relying on you guys help if you don't mind. I didn't buy the peavey but it's probably still there.