Hay, I want to build a peavey bandit 112 redline or a Randall RX120D
I build a couple of stompboxes but never an amp. I am looking for the PCB and the schematic but can't find one (for both). If anybody can help with the schematic and the pcb and also give some instructions I'll be very greatful.
Oh and for the randall a 60-80 watt ver will be good too.
You can get the schematic and layout for any Peavey product from customer service at the factory.
You can ask the PV parts folks if they still have boards for that model, but it won;t be an empty board if you plan to build your own.
Hi Kin.
You will find *many* schematics, a few layouts and *no* boards available.
The first is usually provided as a service to repair technicians, in case of trouble, but the last would be akin to shooting their own foot, commercially speaking.
Google "Rod Elliott", he kindly provides many schematics, including a guitar preamp and many power amps.
He sells the boards for most of them.
You might get a dead or sick Bandit for peanuts (there are millions of them everywhere) and repair/rebuild it.
It's a problem for me to get a broken Bandit cause I don't leave in the US. Also I am not sure I would be able to design such big pcb (I mean not small as a stompbox). Also what about the randall cause I like it's sound better.
I found some schematics and pcb but I am not sure if it is the preamp or the whole amp.
http://www.about-guitar-amps.com/guitar_amps_schematics/Peavey/Peavey_Bandit_112-2.pdf (http://www.about-guitar-amps.com/guitar_amps_schematics/Peavey/Peavey_Bandit_112-2.pdf)
Also how can I erase the parts from the pcb so I can use it
(the username is:amp and the pass schematics)
QuoteI am not sure I would be able to design such big pcb
Me neither, and have been doing it for over 30 years.
Truth is, boards this complex usually are designed by some PCB suppliers, who have people who do this everyday , even nominally "for free" , but who expect to get your 20000 boards a month order.
You *may* print that board image 4x the real size, then very carefully trace over it with India ink, some technical pens, a fine artist's brush, etc. , on vellum (transparent drawing paper) and "extract" the copper-only image , but even so it's a lot of trouble.
You can build a commercial power amp from a kit , that's 90% of the job, and ,say, a Dr Booget or Dr Tweed or something like that to drive it.
Even a Guv'nor, for which you do find boards and layouts, is in fact the distortion channel of some Marshalls.
Start with that, in the future you can add another channel, effects loop, reverb, but go step by step, playing along.
Those 50W LM3886 kits sound very good and are loud, only asking you to use a good speaker.
As a curiosity, where are you writing from?
Maybe we can suggest you something else, based on that.
I am writing from Israel.
I decided to build the randall rg80\100 es preamp (with both clean and dist channels) with poweramp kit (by the way which one do you recommend. I want it to be good for gigs\home\and to be able to play with drums).
I found a schematic but it is very complex and I can't isolate the preamp.
Also I don't know how to power up the power amp+preamp from one saurce?
Oh and how can I cancel the reverb (but leave the fx loop).
Oh and can I build the preamp with the rg100\80 dist channel and the clean channel from another amp with better clean (more fender clean for blues and funk mostly).
OK, search what amplifier kits (50 to 120W) you can find locally and post a couple links to the most promising ones.
If you can order from US or Europe/UK say so, it's easier.
Post the Randall schematic (I have one but let's all use the same version) and I'll draw a colored box around what you'll need.
It can be split in various modules, so you can build, say, the dirty preamp and start playing quickly, then add the loop, later the clean channel and switching, then the reverb (if you can get a reverb tank).
Tell me about the possibilities for an electronics hobbyist there.
I know that for Defense purposes the highest level electronics are available, we used Israeli Dagger jets, Shafrir missiles, etc. in the Falklands War, but that's a Government to Government deal, don't know what the regular guy on the street , like you or me, can get on a regular shop.
Anyway you'll need PCB making materials, to roll your own, plus getting some experience on the software.
Express PCB is quite user friendly.
If it proves complicated or takes too long, I suggest you build one of the Marshall pedals /Guv'nor, Shredmaster, Jackhammer) for which you get a PCB design on some Forums.
They are the distortion channel from a Valvestate, minus the tube, and sound very good.
Once you decide on what power amp to build, it's easy to get the +24V or +9V to feed the Randall preamp or one of the pedals.
Good luck.
PS: I suggest you make an aluminum chassis with a lot of pot and jack holes, plus a few switches, where you mount the power amp and supply and any preamp you want to test.
You'll be able to play live with it, and modify it at will.
Well the possibilities suck. The components aren't really great quality and there no different types (there is only ceramic resistors) and they are pretty expensive. I usually order kits and components from the US (but to order an amp is much harder and you pay a lot of taxes for it). I can't find any lm3886 kits (from USA) so if you have a good one (the cheaper the better) and I also prefer a 80-100 watt power amp (cause it is ss it it is not need to be at high volume for gain so I can use a high watt amp at home too right?) . Oh and I think I'll build it at one shot but in pieces because it will be easier to debag (I never debagged anything caues til now I got lucky).
I added a schematic
Okay I found a kit: http://www.chipamp.com/lm3886.shtml (http://www.chipamp.com/lm3886.shtml)
1. which one should I buy (mono kit/stereo kit/dual mono kit)
2. How much watt is it?
3. in this pic http://www.briangt.com/gallery/lm3886amp/proto_amp_5 (http://www.briangt.com/gallery/lm3886amp/proto_amp_5) there is alot of other stuff. Do I need to buy it or does it comes with the kit (Also what does each one of them do? (I only recognize pcb and one pot)
Oh and what about the two channels form different amps (U thought of tech21 trademark 60 cause I am not sure if the clean channel of the randall with a ts is good enough for SRV blues )
Thanks for your info on the average experimenter there.
Starting with the power amp kit, it looks that it will work.
Read many times the assembly manual, look at the pictures, etc.; every time you read it you will understand something new.
I think your best bet will be the dual mono.
You can build a very loud 2x12" combo, or a 1x12" (still quite loud) and later an extension speaker; everyday you use the 1x12 combo on its own, and in larger places, both.
I think you have 220V; state so to the kit provider so he sends you the correct transformer.
On the picture you show, I can see 2 mono boards, bolted to the chassis as heatsinks, a PSU board, a transformer and assorted hardware (switches, jacks, etc.)
You will still need to get a chassis, suitable heatsinks, and build some kind of preamp.
You might want to start with an intermediate 10/15W amplifier to hone your skills, which can be powered by a *very* common 12V transformer, and drive surplus car-type speakers, which you may even get for free from some junkyard or friendly mechanic.
Take it as a practice lesson, you get to keep and play it, and will have less doubts when building the larger one.
You can still drive it with a Guv'nor clone, which is easily powered "free" from the main power supply.
This way it will be much easier and cheaper (not to mention the Customs hassle) to get everything locally.
You'll feel good after building it.
Okay I chose to use a shred master as a dist channel and I need to find a clean channel (I though about the tonemender but some say it pretty sucks). Also I need ideas for power amps (If it is not kit it will be better cause the kits are expensive).
There are several China/Honkong based outfits with high ratings that have 7293/4 and 3886 amp boards kit and finished. I have bought a few of these boards for TDA20x0s without problems Have also bought bulk resistors etc also.
Just search TDA7294 or LM3886 on ebay
Hi Kin.
The suggestion above is good.
Anyway I will post a link for a TDA2003 based 8W power amp kit, (European made, 15U$S) which has the added advantage that it can be powered by a 12V wall wart which you can find there for peanuts, saving moving transformers by mail which is relatively expensive. It will also power your preamp.
You can also use any speaker you find, and put it in any enclosure without feeling ashamed, be creative and have fun, it's an experiment!!
Build it, (with the ShredMaster as a preamp) and annoy your neighbours, you will have power enough for that.
With that experience, in a short time you can build a larger one.
I'm not at home now (still Sunday night here) but tomorrow I'll post.
I looked for lm3886 and tda7294 kits and all are 80w plus. I want it too be at least 15watt so I think I'll go with higher volt power supply (but I have no ideas how to build it and how to adjust it to 220 volt which we use in Israel. I understand in America you use less). For preamp I will go with shredmaster and tone mender and maybe later I'll add an fx loop. Still I don't know which power amp to build and what to do with the power supply. I prefer cheap stuff cause I am a teen and I don't have a lot of money (But lots of resistors and capatitors).
To get 18volt biopolar power supply can I first use this to get form 9v a 18v http://www.geofex.com/circuits/+9_to_33.htm (http://www.geofex.com/circuits/+9_to_33.htm)
and then use this to make it bipolar http://gaussmarkov.net/wordpress/circuits/bipolar-9v-power-supply/ (http://gaussmarkov.net/wordpress/circuits/bipolar-9v-power-supply/)?
Hi kin.
Those power supplies are not enough, they are very low power, only suitable for pedals.
You will need a "real" transformer, with 220V primary.
I suggest you buy that in Israel, becuse they are heavy and bulky and postage will be a significant part of the cost, not forgetting Customs.
Yesterday I had suggested this:
http://www.vellemanusa.com/us/enu/product/view/?id=350529
which costs U$15 and can be powered by a wall-wart, which you can even get for free or very low cost (SEGA or Car Stereo power supply, etc.)
Don't know why they call it 4 or 5 W RMS; The original datasheet calls it 10W and you can even get 12W :
http://www.google.com/url?sa=t&source=web&cd=1&ved=0CBkQFjAA&url=http%3A%2F%2Fwww.st.com%2Fstonline%2Fbooks%2Fpdf%2Fdocs%2F1449.pdf&rct=j&q=tda2003&ei=u6nYTNmTC8ewngffvcHPCQ&usg=AFQjCNFbVnZKkk9l2OdV0jn7m45Wq3UZGw&cad=rja
the beauty of it is that in the Velleman instructions they even show how to add an input volume control, how to hook the Power Supply and the speaker:
http://www.vellemanusa.com/downloads/0/illustrated/illustrated_assembly_manual_k4001.pdf
You can use it as is, without preamp, as a practice amp.
You can advance your electronics building skills , have fun, later add the Shredmaster and in the future, replace the power amp with a louder one, such as:
http://www.vellemanusa.com/us/enu/product/view/?id=522104
It's 100W RMS into 4 ohms, a *very* serious amplifier, louder than the Bandit, in the same class as the Randall.
What I like about Velleman is the excellent assembly manual they provide, and all of them are written in a similar style; you learn one and have half-learnt the next.
Good luck.
Okay I'll build this preamp (the small one) but do I need a heat sink for the preamp, and how much ohm does is produces (can I use it with the speaker of an mg15cd). Also is the tone mender a good preamp? The channel switching will be a 3pdt and two will switch between the input and output of the preamps and the third one will select to which preamp the power will go. Do you know how can I add a footswitch (and the regular switch on the amp)?
Oh also the kit needs 15volt not 12. Oh and where can I get a 12V power supply which will work with 220v (I can't find any good one in Israel)
Hi kin:
1) DO you have an mg15? ... or just a leftover speaker? The MG preamp is very good, its 15W amp is louder than the small Velleman kit.
If you only have the speaker, build the kit.
2) those "12V" are nominal. As you see, it can work from 9 to 18V, power varies of course.
If you have a ready made PSU, use it. 12V (nominal) is a very common voltage, that's why I suggested getting a salvaged or second hand one.
Or you can use one of those cheap chinese "1A" multivoltage power supplies, available everywhere and often sold by street vendors.
If you use a 12VAC transformer, a bridge rectifier (or 4 diodes) and a 4700uFx25V capacitor, you will have around 16V , excellent.
Do you live in a very small town or some faraway place? Because in any reasonable size city, there *must* be some electronics suppliers; worst case mail order ones.
Post some link to electronic suppliers you have easy access too.
Maybe most of us can't read the pages (unless there is an English version too), but sure can look at pictures and labels and suggest you something.
Good luck.
I have an MG15 and I pretty like it's clean preamp. I don't want to use it only the speaker. I have a store (+in the web site there is no products) but the Power Supply are pretty harshy (in FX pedal some power supplies work quieter then other so I think in the amp is the same).
What about the tone mender, the switching and cooling for the whole amp (is it needed)?
Here is links to the store http://www.talmir.co.il/main_category.asp?c_id=427 (http://www.talmir.co.il/main_category.asp?c_id=427)
http://www.talmir.co.il/main_category.asp?c_id=66 (http://www.talmir.co.il/main_category.asp?c_id=66)
Hey !! That store is better than I thought !!
It should be, Haifa is a very important port.
Maybe very expensive, of course, that's a different problem.
From what they have there, you can use those cheap chinese Minwa transformers.
1) 2X6V 1000MA 0202091 (12VA) Good for a 8/10 W amplifier.
Those 12VAC@1A are fine for your TDA2003 amplifier and your Shredmaster.
You'll have 16V DC main, and auxiliary 9V.
It will have less power than your MG15, but if you want to experiment and learn, it will be excellent to start, I suggest you do it.
2) 2X18V 2000MA 0202097 (72VA)
This is a serious one, good for a 50/60W amplifier, much more than what your MG15 speaker stands.
You will have +/-25V rails, an LM3886/7294 chipamp will provide up to
30W RMS into 8 ohms, and around 50W rms into 4 ohms.
If you buy an excellent and not too expensive Jensen MOD1270 in 4 ohms or 2 MOD1050 (8 ohms each) you will be LOUD, in the same class as the Bandit65, and with a heavier sound.
I suggest you build a powered box, with the 12" or 2x10" in it, and drive it from your MG.
I have made tons of powered boxes for guys who have good but small amps.
2xEL84 amps in a metal band, what were they thinking?
The MG is not bad, it only sounds "small" , because, well, it IS small.
Driving external 50W into a big box, it becomes a fire eater.
Good luck.
Fine I'll go with the 2x6v minwa. Is it the power supply or do I need anything else? Also you haven't answered me if the tone mender is a good clean preamp and do the amp need cooling (another heat sinks or whose fans like in computer power supply (I use one for a box).
Hi kin
In Page 7 of http://www.vellemanusa.com/downloads/0/illustrated/illustrated_assembly_manual_k4001.pdf
you have the power supply: transformer, diode bridge and 2200x25 capacitor.
I suggest 4700 x 25 for better filtering.
You can buy everything at your supplier.
The TDA2003 needs a small heat sink.
If you buy the Velleman kit, Im *think* it includes the heat sink; if it does not, bolt it to a piece of aluminum which in turn gets bolted to the chassis.
¿Clean preamp? I don't like the tone mender very much, I do like the one used in Rod Elliott's Project27
(http://sound.westhost.com/p27-f1.gif)
but it needs a split supply, easy to get in larger amps but not in the TDA2003.
Really you do not even *need* a clean preamp there, try your guitar straight in the TDA2003 as on page 8 and 9 of the assembly manual.
NVM I think I still will go with tone mender. My last question is how to get a 9v- from the same supply that goes to the power amp? Oh and how can I built a regular channel switch+foot switch that I will connect to a jack (but at least for this project it is optional)
Hi kin.
If you look at the tonemender schematic and Rod Elliott's (draw them side by side on the same (large) sheet of paper), you'll see that they are practically the same, (Op Amp -> Tone control -> Op Amp) with the big difference that in Rod's the first one does provide some gain (15x) *and* switchable Bright control, then passive tone control, which you might consider having a 10x loss, and then a second Op Amp, again with 15x gain. This is a professionally designed preamp, equivalent to what you'll find on most commercial guitar amps.
In Tonemender, the first Op amp has no gain (1x) , it's set as a buffer, then it passes through the passive tone control, where it is attenuated to 1/10th its original value, becoming very weak, and then it's strongly amplified (100x) by the 2nd Op Amp, together with internal noise plus any hum or interference it may pick along the way.
This is an amateurish design, the kind you'll often find in non-professional Forums, hardly on Commercial products.
Mind you, *both* will probably seem to have the "same result" ... in simulation ....
In real world design, along the way you must try to keep your signal between certain limits: not so high as to clip, not so,low as to having to pay the penalty of hiss and hum when recovering.
Careful grounding, filtering and shielding can take care of hum, but noise is built-in , we must avoid getting it into our signal.
Being so similar, probably the tonemender board design can be modified somewhat to accomodate Rod's .
Google "zener regulated supply" to see how they work and how to get regulated 9V from an unregulated 16V supply.
Go step by step, build the basic amplifier first, plug your guitar straight into it, enjoy, feel proud (you deserve it), show it to everybody, then go the next step.
My first amplifier was a Class A, 2W single transistor power amp, the kind used in car radios way back then (1968), I was 15 y.o.
In 1969 I built my first guitar amp, a 4 or 5W Gibson GA5 , 1 12AX7 + 1 6V6. 1 jack, 1 volume control, on/off switch.
Boy, was I proud !!!
Then took the plunge and built a point to point wired (no board) Fender Bassman clone, later an Ampeg BT15 clone, fully on Veroboard, and so on.
Just don't hurry too much and enjoy along the way.
Good luck.
Okay so I'll leave the tone mender Idea and maybe later add a tone controls to the clean channel : ). Thanks for help.
I looked for the zenner regulated supply but haven't found any thing that tells me how to design it or how to make it -. Only what it does.
http://www.reuk.co.uk/Zener-Diode-Voltage-Regulator.htm
Vsource is the input in volts (16v) right? And I have no idea how much mA the shredmaster uses how can I check it before building it.
Hi kin.
Step by step:
1) Google TL072 datasheet . You'll get:
2) http://www.datasheetcatalog.com/datasheets_pdf/T/L/0/7/TL072.shtml
3) you choose anyone there. I chose the ST one, because it's smaller:
http://www.datasheetcatalog.org/datasheet/SGSThomsonMicroelectronics/mXrxvrt.pdf
4) there, on the "electrical characteristics" table, I see:
Icc (supply current per amp, no load)= 1.4mA typical , 2.5mA maximum.
Just for safety I assume I may get a "hungry" Op Amp, so I take 2.5mA.
I have 4 OpAmps( 2 per package) so my pedal will eat, 4x2.5mA= 10 mA. I add 5mA so the Zener passes some current, or it will not "Zene", as Enzo would say, I will calculate for 15mA consumption.
I will also consider that on loud volume the supply "raw" voltage will drop, after all it's not regulated at all.
Don't know how much and lack some data for calculation, but from previous experience to consider a loss of 2V is reasonable, so I consider I'll have 14V when loud.
5) The voltage dropping resistor will be: (14V-9V)/0.015A=5V/0.015A=330 ohms.
330 ohms is a standard value.
What power dissipation should it support?: 5Vx0.015A=0.075W so a 1/4W one will be more than enough.
6) How much will the zener dissipate if I have power "on" but pull the distortion board out for any reason? (as to tweak it): 9Vx.015A= 0.135W. A 1/2W Zener will do nicely.
In actual use it will dissipate much less, because most of the current will be absorbed by the 2 TL072.
7) What if I add , say, a clean channel with 1 TL072?: calculate adding 2x2.5mA extra, for a total consumption of 20mA.
If the LED is fed from the 9V, add its consumption too; personally I would feed it straight5 from the 16V unregulated.
Good luck and please re-do calculations yourself, so you can use this knowledge in other, future projects.
Good luck.
Okay, I finally got all the parts except the fuse. I just can't find one in my country. Can I use other fuses or just this? Are this good http://cgi.ebay.com/T1A-1A-20mm-5mm-Slow-Blow-Fuses-250V-RoHS-UL-VDE-x-10-/?250488788457?pt=BI_Electrical_Equipment_Tools&hash=item3a524b95e9 (http://cgi.ebay.com/T1A-1A-20mm-5mm-Slow-Blow-Fuses-250V-RoHS-UL-VDE-x-10-/?250488788457?pt=BI_Electrical_Equipment_Tools&hash=item3a524b95e9)?
Hi kin.
I understand you are building the TDA2003 power amplifier plus a couple 9V pedals as preamps.
Since you have 220V, use the 500mA fuse (not 1A) that your supplier carries, the most common one.
Don't worry about slow, fast, timed, whatever, just what's available.
The transformer have 5 wires while there is only 4 in the drawing in the instructions. It has 2 red, 1 white and 2 black. Which goes where?
here is the pic of the parts that I don't know how to connect.
(http://img29.imageshack.us/img29/9170/12894342.png) (http://img29.imageshack.us/i/12894342.png/)
Uploaded with ImageShack.us (http://imageshack.us)
Does the transformer have any labels? Where? What do they say?
Measure the DC resistance Black/Black; Red/Red/ amd both Grey/Red
Remember to short your test probes and substract that value from the reading.
Oh I now found that it is written
Black-PRI 220V 50Hz
Red-SEC 6VAC X2 1A
GREY-C.T
Can I get more than 12V out of this?
Hi Kin:
Then you have to turn that transformer 180º (referring to your drawing): both blacks to the left, one straight to one side of 220V, the other to the other side, but through the switch and the fuse holder.
Both reds to the right, to the AC pins of the bridge rectifier.
The 2200x25 electrolytic capacitor will charge to the peak voltage of 12V: 12VACx1.4142=16.97V DC. (in theory)
Substract from that a little over 1V because of diode losses, you'll end with almost 16V DC, perfect for that Velleman Kit (or anyone similar to it).
The grey wire goes unconnected, insulate its free end with some electrical tape.
Good luck.
If I put the + (form the zener regulator) to the circuit I put the - to the ground? If it is right do I have to put the + or the - in the shredmaster
In single supply amplifiers, as this one, "-", "black" and "ground" are all the same.
The "-" from your power supply (PSU) goes to the - of the Velleman and to the - of the Shredmaster.
The +16V from your PSU goes to the + of the Velleman and, through a dropping resistor to the + of the shredmaster.
To make *sure* that the shred receives 9V and no more, you have a 9V Zener from + to ground.
OK, I build the power amp kit and it works fine. I got shocked once then I was turning it off but I'm just fine. The problem is that the resistor in the zener regulator got burned. Is this because I haven't connected the 9V circuit or because something else, and how to fix it.
0) Congratulations on your build. :tu: :tu:
1) Did you use a 330 ohm, 1/4W (or higher dissipation) resistor?
It should be warm to the touch, but not burning or smoking.
2) Do you measure 9V there?
*If* you put the Zener the wrong way, it will drop only less than 1 V; the resistor will dissipate (worst case)= (15x15/330) W=0.7W=700mW; way too much for a 1/4W resistor=smoke and burn.
Use a 330 ohm 1W resistor, it will support even a shorted preamp.
Good luck.
I used 120 OHM 1\2 W and a 5W 9v zener. I haven't checked the voltage but there was smoke and the resistor turned black. I need about 50mA cause I use barber LTD as the clean preamp and the shredmaster as the dist.
Also which switching is better:
(http://up350.siz.co.il/up2/lx5zzwywmvcn.bmp) (http://www.siz.co.il/)
any help?
I didn't read the whole thread, is the switch just for switching between 2 channels on the amp or something?
Yes, it switches between channel 1 (barber ltd) and channel 2 (marshall shredmaster)
Best is the middle one, which switches inputs and outputs.
Do not switch the +9V or any power, it will pop a lot or give you very funky sound for quite a few seconds, until voltages stabilize, or both.
You might also join inputs permanently, switch outputs only, and if the shredmaster injects some faint buzz in the background, use the now spare contact to kill its gain when unused.
and what about the zener rgulator
I used 120 OHM 1\2 W and a 5W 9v zener. I haven't checked the voltage but there was smoke and the resistor turned black. I need about 50mA cause I use barber LTD as the clean preamp and the shredmaster as the dist.
Well, do check the voltage.
Check that you have those 9V and alsothe real voltage across the 120 ohm resistor, to calculate the power it's actually dissipating
W= V*V/R
Up to the rated dissipation, it will be hot but not toasting or burning.
but the resistor have already been burned
Maybe you have *another* spare resistor? :)
but won't it burn again?
Quote from: kin0 on December 23, 2010, 11:50:16 AM
but won't it burn again?
Have you made any changes to the circuit since the last one burned? If no, they yes it will probably burn and you should figure out why it burned before firing it up again.
It's why I asked. I HAVE NO IDEA what is wrong.
QuoteI HAVE NO IDEA what is wrong.
And you won't, unless you measure. ???
Put a new one, have your multimeter ready on the 20VDC scale, turn it on and quickly measure *if* you have +9V across the Zener and *what voltage* you have across the resistor.
It should take less than 10 seconds each.
Maybe your resistor survives that long, maybe not , but now you'll know someting.
Based on that, you'll find a problem and won't burn the third one .
Good luck.
OK I fixed it. The zener was the wrong way. Thanks anyway. Now I am working on the pcbs.
December 19th:
Quote*If* you put the Zener the wrong way, it will drop only less than 1 V; the resistor will dissipate (worst case)= (15x15/330) W=0.7W=700mW; way too much for a 1/4W resistor=smoke and burn.
Ahem !!! Cough cough !!! 8|
Quote from: kin0 on December 25, 2010, 07:00:56 AM
OK I fixed it. The zener was the wrong way. Thanks anyway. Now I am working on the pcbs.
Excellent. Good to hear you got it working.