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Messages - syndromet

#31
Amplifier Discussion / Re: Class D Amp Recommendations?
February 27, 2008, 06:43:51 AM
I have tried a few tests with Class D, but have never gotten any good results.

You should however check out Class T chips, like the ones found over at www.41hz.com

I built one of their AMP-5 kits, and tested it with guitar. sounds absoloutly wonderfull with a good preamp. They seem to be even better than class D when it comes to heat and power consumption. I also saw that you were building a Butique amp, and I think Class T have a way better reputation than class D. I also think it would be kind of hard getting a good reputation if you use the same chips as most cheap SS amps use, and I belive that is quite often Class D.
#32
The Newcomer's Forum / Reposting my encyclopedalia
February 27, 2008, 06:20:06 AM
I have had quite a few requests for this lately, so I thought I should repost it her. Quite a usefull tool for beginners and transistor swappers....
It is still a work in progress, and any tips on other stuff to be in here is welcome. I'm working on transelating the mm drill sizes to inches for you weird Americans.
Admins, feel free to add a link to the FAQ if you feel like it.
Encyclopedalia
#33
The Newcomer's Forum / Re: Hello!
February 25, 2008, 08:27:16 AM
I second the LM1475. Use this as a poweramp, with a good tube pre, and you should get grest distortion st sny volume. i have also had success running my Lm1475 with the FET emulation pedals found at runoffgroove.com. Very tube like. Even the Little gem, wich looks very simular to your mintyamp, sounds superb.
#34
Just a quick comment.

The volume the speakers put out are not directly a result of the speakers watt rating. You should look at the speakers efficiency rating. That gives how many db the speaker output at 1watt at a certain frequenzy in a given distance. The higher the efficiency, the higher the volume. A speaker rated with an effiecency at 100db and 2 watt will play way louder with the GEM than a 50 watt speaker rated at 95 db at the same impedance.

http://everything2.com/index.pl?node_id=1523585
#35
Quote from: syndromet on September 14, 2007, 07:45:50 AM
I found this
http://toroid-transformer.com/
Might be usefull for others too.
Just wanted to tell you that I have bought a couple of transforners from these guys, and the transformers are really great, and high quality. Fast shipping, great prices and a good selection. Check 'em out the next time you need one.
#36
Amplifier Discussion / Re: ADVANCED Troubleshooting
January 17, 2008, 08:39:34 AM
I'd spend a few dollars, and try to change the chip or transistors. If that doesn't help, I'd rip out the guts, and build a Lm3886 with a krank pre.....
#37
Preamps and Effects / Re: preamp for LM3886?
January 15, 2008, 06:23:22 AM
Preamp questions are kind of hard to answer without a little more info. We need to know what kind of sound you are looking for. A lot of stompboxes have more than enough gain to serve as a preamp, so you should look into some of those. I'm using a SansAmp clone with my LM1875, and it sounds superb. Can't beat that for versatility and sound quality, but they are kind of hard to build There are a lot of great preamps/stompboxes with a three band eq that are not overly complicated, and I suggest you look into the JFET circuits at runoffgroove.com.
Here are a few suggestions for distortion-preamps:
http://www.runoffgroove.com/englishchannel.html for a VOX AC30 like circuit.
http://www.runoffgroove.com/thor.html For a high gain Marshal like overdrive
http://www.runoffgroove.com/eighteen.html For a classic rock Marshal like overdrive
http://www.runoffgroove.com/umble.html For a dumble-like sound
http://www.runoffgroove.com/professor.html for a fender like-sound
http://gaussmarkov.net/wordpress/circuits/dr-boogey/ For a Mesa Boogie high gain distortion

I've buit all of theese myself, and they all sound great. I have also used a few as preamp, running on 9V, and they work perfectly.

All of theese are JFET based, and could be run of higher voltages (18v is ideal) for a little more head room.
You could also try the Krank Distortion Maximus. I havent tried it yet, but from what I've heard it sounds great for high gain distortion. It's based on a highgain bjf transistor and a LM386, and should be able to run of higher voltages too.

I would recomend you using one of these for the dirty channel, and a single inverted Lm072 as the clean channel. I'm using that myself, and it gives a perfect, sterrile sound, much like the infamous cleansound of the Roland Jazz Corus. It could also be cool to add a blend pot between the two channels, for a wide array of sounds.

Just my 2 cents of advice.


#38
Schematics and Layouts / Re: high power amp
December 21, 2007, 09:41:15 AM
All you need here is a poweramp. Stereo lm3886 from chipamp.com should give you what you need. Or you could try one of the higher power amps from 41hz.com
#39
Hi, and welcome. High quality cables and shielded, well grounded guitars is where I would start. Since the amp is silent when unplugged, there is probably nothing wrong with the amp.
#40
Amplifier Discussion / Re: Good source for transformers?
September 14, 2007, 07:45:50 AM
I found this
http://toroid-transformer.com/
Might be usefull for others too.
#41
Amplifier Discussion / Good source for transformers?
September 12, 2007, 05:06:12 AM
I'm looking for a 2x24V secondary, 230V Pirmary transformer with a rating of 300VA, and I can't seem to find anyone else than elfa.se who will ship internationaly. On elfa, the trafo costs around 100$ without shipping, wich I find a little to expensive. Anyone know of a good source for cheap trafos? I used Apexjr.com the last time, and they were great, but I don't think they have what I'm looking for this time. The trafo will be used for a 41hz.com AMP5.
#42
Amplifier Discussion / Re: Battery Powered Class-D Amp
September 08, 2007, 12:59:59 PM
From the bands you mention, I think both the english channel and the eighteen would sound great. My guess would be that the Eighteen fits a littlebit better. You should breadboard them both, and let you buscker decide.
#43
Amplifier Discussion / Re: Battery Powered Class-D Amp
September 07, 2007, 03:59:47 PM
When it comes to amplifying acoustic guitars, I'm no expert, so I wont comment on that. Talking about electrics I think my oppinion might be interesting enough to share. My current setup consist of a stereo LM1875 amp, running different DIY stompboxes as preamps, most of the time with success. Most of the time I use a Behringer GDI-21 as my preamp, simply because it sounds great on the high gain settings. The GDI-21 is really just a Sans amp copy, and sounds very much like the original. I think the clean sounds are ok, but you'd probbably be better of with something else if your friend is playing using mostly clean or slightly distorted sounds. When I record clean sounds I use my trusted LM1875 with a Professor Tweed at low gain settings or any transarent booster. I also use the english channel when I need that clean/overdrive VOX-sound.

I would suggest something like this: give the amp two switchable preamps, one for acoustics and one for electrics. Depending on the pickups, a piezo equipped guitar usualy have a lot higher impedance than a guitar with magnetic pickups. For the acoustic preamp, I would suggest something as simple as a tl072 running close to its max power, followed by some sort of tree band eq. I have a piezo equipped strat, and it sounds very natural running through my microphone pre, wich is just a tl072 tunning on +/- 12V. Check http://www.syndromet.com/sounds/piezo.mp3 for proof. I use the piezo throuh the GDI-21 at times to, and it sound
ok too, but far from as good as the tl072 thing.

For the electric guitar-preamp, I  wouldn't bother to build the sans amp, as most buskers don't need high gain settings (I remember seeing this guy sitting in the middle of the streat in Oslo playing Sepultura and Pantera on one of those mini-marshalls. Sounded great!). If your friend plays country or bluesy stuff, I'd recomend the Professor tweed, and if he plays rock I would sugest the English channel. You might even consider the Eighteen, as it sounds great on clean settings as well. I have tried my amp with most of the ampsims over at runoffgroove.com, and they all sound a lot like what they are moddeled after. When it comes to powering the thing, I would suggest Gel Cell batteries, like they use on motor bikes. I use that for my stereo Ruby, and have been doing that for a year without recharging. Lightweight, reliable, quickly charged  and hold the power for ages.
#44
Amplifier Discussion / Re: Pictures
August 05, 2007, 01:45:03 PM
Damn, momo and jpm83! Those are some seriously nice builds! Did you make the cabinett yourself, Janne?
#45
Amplifier Discussion / Re: Fender Frontman 15G
July 24, 2007, 09:06:56 AM
That might solve your problem