How about a high gain amp kit?

novosibir · Post by **novosibir** » Mon Jan 16, 2006 7:36 am

joshwilson3 wrote:Do you think more than 4 gain stages would be needed?

Billy Batz wrote:I havent done much 2203 modding. Brentsp has but he doesnt post anymore. Larry has but maybe he doesnt want to give away any secrets

Nobody needs five gain stages! You won't get more gain out of five gain stages, the only what you'll get more is noise - hiss and hum - and an enhanced chance to build an oscillator

In the early 90's all my high gain mods have had 5 gain stages, also the "Scream" sound of my first DINO heads.

Already back in the mid of the 90's I've found out, that I could get the same amount of gain out of 4 gain stages, but less noisy, with more dynamics by using the guitar's volume control, with more balls and warmth - and with a better touch sensitivity.

A high gain sound out of 5 gain stages is sounding like flooding hot oil w/o any dynamics, the sound already doesn't "live" and "jump" - those kind of sounds you can hear on some fusion stuff from the past.

Larry

bmf5150 · Post by **bmf5150** » Mon Jan 16, 2006 8:03 am

Bainzy wrote:
Necrovore wrote:
bmf5150 wrote:do you have a schematic for this mod,sounds cool!
Yeah this sounds pretty interesting. Is it switchable on the fly?
Totally switchable on the fly. I don't have a schematic, but I've got a modified diagram that I did where I took Dan's 1959 diagram and I added the extra circuitry onto that. The mod totally transforms the amp into a different amp, basically it runs on channel 1 but leaves it stock tonally when taken out. The gain control for the mod is channel 2's volume control, because when using channel 1 you won't be needing that, so by changing the single pot to a dual pot for channel 2's volume, the pot changes it's function when used with the mod but keeps everything stock tonally. It's pretty neat if I don't say so myself

With the mod disengaged the amp looks and sounds normal, with the exception of the DPDT switch I've fitted. However, if you change one of the other pots at the front to one with the same value BUT that has a DPDT push-pull switch in it, you could have the amp 100% stock looking from the outside!

With the mod engaged and the Rk=2.7k, Ck=.68k, mids on 0-5 and G12T-75's, the amp is PERFECT for heavy metal in the vein of Slayer to Megadeth. Bump up the mids more and you're into Dokken territory, 80s hair metal. The sound of the amp still depends on the rest of the stock circuit (I've used it with a 12000 series circuit but it'd be closer to 80s he aclipair metal if you used a '69+ circuit).

I'll refer to the mod as the 'Bainzy Mod' in future so you guys know what I'm talking about. I think it's wired quite differently to the Caswell mod (on that you can't control the gain of the mod stage), so I'll try figure out still what he was doing aswell so you guys can have more options. I've been pretty reluctant to give this mod out as it took tons of research/trial and error/blueprinting/building/testing etc to design, but after seeing the way Mark gets blasted on PP for asking somebody just one component value in their amp, I'd hate to be like them.

Here's a picture of the Caswell mod, interesting to see it uses a Mustard cap for the signal cap for the mod. My guess is that will be a .0022uF because of the way that amp on AFD sounds.

sounds good!

bmf5150 · Post by **bmf5150** » Mon Jan 16, 2006 8:41 am

how transparent is the mod?

Bainzy · Post by **Bainzy** » Mon Jan 16, 2006 9:51 am

joshwilson3 wrote:Bainzy,

What do you think of this mod with a 100w Master Volume?

Does this mod add resistors and/or caps to the circuit?

I know a tube has two gain stages. Do you think using both sides of the tube would be too much for a 100w Master Volume? Cause I remember you talking about having two switches, one turned the extra tube on, and the other switch turned on both sides of the tube.

The mod adds resistors and caps to the amp, but does not change anything to the circuit path that was there before. I'll take pics of the mod in my 1959 for you guys when I get hold of a camera. I like to add the resistors and caps onto a small piece of circuit board material and turrets, but theres only 4 (5 if you use a mixer cap) components to the mod per extra gain stage so you could wire the parts straight to the tube or switch if you insulated them properly (see that Caswell pic, that's what he did with it).

Both sides of the tube could be too much for a MV - I get plenty of gain (more than I'd use) with both sides of the tube on a 1959. The thing is although you might not use both sides at once on a MV, you can have different cathode/signal cap/filter resistor/mixer cap values on each gain stage you add. So you could switch in V0a (V0 being the added tube), and have V0a as a low gain boost, or switch V0a off and switch v0b on - which could be wired for an extreme gain boost. There's so many options with this mod I haven't got round to trying out everything yet.

bmf5150 wrote:how transparent is the mod?

If you mean in terms of retaining the stock tone when off - it's totally transparent to my ears. Providing you wire it up properly (inc. lead dress), there's no reason why it should affect the stock sound.

If you mean in terms of looks, that depends on whether you use a toggle switch or a push pull pot for the DPDT switch. I drilled a hole in the back for the switch as I'm not bothered at all about harming the amps value (it's a reissue and is not getting sold), but another non-permanent method might be to replace the low input for channel 2 with a toggle switch.

Bainzy · Post by **Bainzy** » Mon Jan 16, 2006 10:22 am

novosibir wrote:A high gain sound out of 5 gain stages is sounding like flooding hot oil w/o any dynamics, the sound already doesn't "live" and "jump" - those kind of sounds you can hear on some fusion stuff from the past.

Larry

do you reckon that's why people find modern high gain amps as a bit sterile?

novosibir · Post by **novosibir** » Mon Jan 16, 2006 10:35 am

Bainzy wrote:do you reckon that's why people find modern high gain amps as a bit sterile?

No, I wouldn't say, that the 5-gain-stage-sounds are sounding sterile. If so, than it's due to other misdeeds in the circuitry or by choosing the wrong parts.

But the 5-gain-stage-sounds not seldom are more soundig as out of an organ than out of a guitar. Also the distinct characteristics of different guitars nearly get lost.

Larry

Bainzy · Post by **Bainzy** » Mon Jan 16, 2006 10:36 am

For people who've received the diagram from me, if I didn't explain how the mod works or how to add it twice or more, here it is:

Basically the mod does what Marshall tried to do when designing the 2203, but a lot more effectively and doesn't remove one channel to fit the extra gain stage. When the switch is off the switch sends the signal from channel 1's volume straight to the mixer resistor on the board, and it grounds the input of the extra tube. When engaged, the mod intercepts the signal between channel 1 volume and the mixer resistor, and sends it into the half of the extra tube you've turned on. Unlike the 2203 in this mod the gain is controllable. If you fix the gain stage's gain at a set value, you can free up the extra 3 lugs on channel 2's volume pot for making a preamp master volume, and switch it in and out by putting a push pull pot somewhere in the front of the amp (bass/mid/treble pots etc). So by doing that and changing the cathodes of the extra stage to 2203 values, you effectively make a 100% switchable 1959/2203 - how cool is that??

To make it truly exact copies of the two amps, the 1959 would have to be a 69+ circuit, but I prefer using a 12000 series circuit then running a 2203 on those values as it sounds great.

If you want to add the mod again for ANOTHER gain stage, just take the orange wire in the diagram (or whatever colour you used) before it touches that 470k mixer on the board, and replicate the mod again but using the other half of the extra tube. When you use the other half of the tube, pin 1 goes to the 100k/.022 or 100k/.0022 (blue wire in my diagram), pin 2 is the input (green wire), and pin 3 is the cathode (black wire). I'll have to construct a new diagram for adding the mod twice, as it might confuse people - but I think once you see it done twice it should make a lot of sense and become simple to do.

Billy Batz · Post by **Billy Batz** » Mon Jan 16, 2006 11:22 am

novosibir wrote:
Bainzy wrote:do you reckon that's why people find modern high gain amps as a bit sterile?
No, I wouldn't say, that the 5-gain-stage-sounds are sounding sterile. If so, than it's due to other misdeeds in the circuitry or by choosing the wrong parts.

But the 5-gain-stage-sounds not seldom are more soundig as out of an organ than out of a guitar. Also the distinct characteristics of different guitars nearly get lost.

Larry

That about sums up my SLO100. It does sound very good but theres so much compression and dynamic loos going on through the 5 gain stages that even when I have the master on 10 and the gain on 3 (which does a very good Super Lead impression) it still sound very soupy. But hell some people like it! People like 5150s they have what 6 stages?

Bainzy · Post by **Bainzy** » Mon Jan 16, 2006 11:30 am

Billy Batz wrote:People like 5150s they have what 6 stages?

wtf! 6 stages! No wonder EVH has lost his guitar tone!

bmf5150 · Post by **bmf5150** » Mon Jan 16, 2006 12:22 pm

Bainzy,could you send me the diagram for thw wiring of this mod or schmatic?does it just addg ain,but doesnt change your sound tone wise?
stan
bmf5150@yahoo.com

Bainzy · Post by **Bainzy** » Mon Jan 16, 2006 12:40 pm

Depends on what you want from it really. If you make the added gain stage the same values as everything you have on V1 (i.e. same tube type, same cathode values, etc) then yes it should be able to just add gain and not really change the frequencies when engaged. However, you can change the values on the extra gain stage so you can change the feel of the amp when it's engaged. Not only can you play about with those values, but when you have 2 different stages you can blend them in varying degrees with the 2 gain controls.

Sending diagram now...

Brentsp · Post by **Brentsp** » Mon Jan 16, 2006 2:03 pm

Hey guys just FYI:
Slash's amp that he rented was not the Caswell modded Tremlo SIR #39. In fact the amp he used wasn't even modded by Caswell himself. Caswell later left SIR and his replacment Glenn Buckley copied the Caswell mod #39 into a 70's metal panal Marshall and SIR labled it #36. This is the amp that Slash used for AFD. For what its worth its basically the same mod but different amp. Some of you might not have known that......its fairly recent info.

Bainzy · Post by **Bainzy** » Mon Jan 16, 2006 2:10 pm

I'd convert my plexi to metalpanel spec and figure out how to clone the Caswell mod on Slash's amp with the Bainzy mod, but it sounds so good right now I don't want to change a thing

If anyone wants to donate me their metalpanel 1959 for free I'll be sorted

Brentsp · Post by **Brentsp** » Mon Jan 16, 2006 2:13 pm

Bainzy wrote:I'd convert my plexi to metalpanel spec and figure out how to clone the Caswell mod on Slash's amp with the Bainzy mod, but it sounds so good right now I don't want to change a thing

If anyone wants to donate me their metalpanel 1959 for free I'll be sorted

I think your clip of it sounds great so I don't blame you. Did you have the 250uf on V2 also? I'd think it would be to fat/loose sounding but maybe not.

Bainzy · Post by **Bainzy** » Mon Jan 16, 2006 2:23 pm

To be honest I'm not quite sure about V2 - the amps changed so much (for the better) since that clip. I think at the time I had a DPDT switch that came free with my pickups, and I was using half of it to select different V2 bypass caps (up = 820ohm + 330uF, middle = 820ohm, down = 820ohm + .68uF). Unfortunately one night while working on the Bainzy mod the miniswitch broke. It was likely to be 330uF or .68uF as I used those most of the time, but that cathode change doesn't have as much affect as you might think - it's fairly subtle in the grand scheme of things, but it's a nice little switch to have. It definately wasn't 250uF on V2, I've never tried that. In fact, I've never even tried 250uF on V1

If your amp has a decent OT, caps and tubes you will get a much better sound from the Bainzy mod than is on those clips - in those clips I still had the crappy stock OT and tubes, and was running Mallory 150's (I couldn't even afford Sozo Mustard+ caps back then, but now I have those throughout). I'll record some clips of it with different V0 cathodes soon - I'll try 10k/0.022uF and 2.7k/.68uF again and compare. My recording gear is slightly better too so should be a bit better suited.

To put that clip into perspective, that was a 1959 with just one extra gain stage added. Channel 1 volume was on 6 and the extra stage gain was on 6. So 5 gain stages with everything on 6 would be a TON of gain.