Building a Mesa/Boogie Dual Rectifier

[ErikMiller]

I was told that the output transformer is the key to a cool distortion....

That would be merely the opinion of the person who told you that.

Here's my opinion:

For a Dual Rectifier output transformer to play a major role in the character of the distortion, you'd have to turn the amp up loud enough to peel paint off the walls. At normal playing levels, even in a full band rehearsal, you're probably not getting anywhere near saturation on the OT.

Yes, each stage of the amp affects the total sound, but in a Mesa, it's going to be the preamp (maybe some phase inverter) mostly responsible for the distortion tone.

In my experience, it's the preamp that has the most to do with setting the character of an amp, followed by the power amp section (including the phase inverter), then the power supply (how it responds to transients) and output transformer.

I used to believe, along with most of the rest of the world, that what gave Vox AC-30's their characteristic tone was the pair of cathode-biased EL84's. Now that I know more about amps, I believe that yes, an AC-30 would not sound quite the same with a different output stage, but the configuration of the preamp tubes and tone stack have a LOT more to do with it.

Those folks over at AX84 know a lot about getting good sounds out of home-built amps. Ask them about the importance of each component/stage in shaping the tone.

[william]

Most people seem to suggest getting the transformers from New Sensor.  The marshall replacment ones.  They will cost you about 150 us dollars I believe.  You might want to e-mail them to see what shipping would be and payment options.

[FeDomic]

Hola, veo que eres de Argentina.
Te invito a que participes en el foro de Plexilandia //www.plexilandia.cl, acá te podemos ayudar un tanto. Puedes comprar los transformadores acá en Chile. Como referencia, el par de trafos de poder y salida sale como 90 dólares acá. Y también puedes encontrar tubos baratos.

[Connoisseur of Distortion]

Most people seem to suggest getting the transformers from New Sensor.  The marshall replacment ones.  They will cost you about 150 us dollars I believe.  You might want to e-mail them to see what shipping would be and payment options.

why not just hunt down some hammonds?? i'm pretty sure the PT for the recto is under $100, for a brand new hammond.

[william]

I was just mentioning what most people suggest sounds best.  The final choice is up to him.  I was lucky and managed to get the Power transformer from a Dual Rectifier that was being converted from 120v to 240v.  I managed to get a deal on it.  I've spoken with mesa a few times about replacement parts, and the prices direct from them usually range in the 75-150 range.  But you might have to deal with a middle man, and their cost may be diffrent.  I worked at Guitar Center at the time so I could work directly with them.

[GFR]

There's another option I would consider before trying to build or mod a tube amp and dealing with high voltages etc.

Try a high gain pedal like the blackfire, BSIAB2, or one of the ROG amp-inspired pedals - it's easier, cheaper and safer to build. Even if in the end you decide that's not *exactly* the tone you're after and decide to build an amp, it doesn't hurt to have a nice sounding pedal around.

Meteoro, ame-o ou deixe-o...

Na verdade, eu gosto mesmo é do meu bom e velho Tremendão e do meu também bom e velho Palmer 200.

Mas a praia deles não é o som "muderno" que o mcorleone está procurando...

[Davide]

electritab's DR BOOGEY ?

[RedHouse]

Also go hang out at AMPAGE for a while, lots of good folks there too.

http://www.firebottle.com/fireforum/fireBB.cgi?cfg=ga&enter=go

IMHO the AX84 and AMPAGE forums are the best for decent DIY ampbuilders. [/url]

[GreenEye]

Just get a POD, a nice tube power amp, and use the Modern Gain or Rectifier channels.  They sound fine.

[object88]

Here's my uneducated, second-hand-knowledge perspective.  Nu-metal bands such as Korn really work the preamp, and hardly drive the power amp.  Given that, the OT probably doesn't matter as much as you think.  Futhermore, as has been said, 100W of tube power is freaking loud, seriously.  If you're playing in clubs, I suppose you're backed up by a house PA?  

I'd strongly consider a high-stage-count preamp (something like 4-6 stages, i.e., 2-3 tubes), a good ~18W push-pull power amp, a solid-state rectifier, and a matching OT.  Keeping your PT and OT sizes down will save you a lot of money, and make finding used parts easier.  Plus, if you're playing through an effecient 4x12, something as small as 6 watts can keep up with a moderate drummer.  (Ask Z.Vex about his Nano Head!)  

Even that configuration going to be tricky to handle as your first try.  If you can, get a large chassis, and leave lots of extra room to add a second channel later, but start off with just one, no switching.  Much easier!  You can psuedo-channel-switch with a boost, ABY box, and eq pedal, perhaps even in a simplified effects loop.

Good luck!!!

[JCM1959]

I found the PCB plus lots of pics. But i'm still finding the output transformer... now... of SLO 100....  

(I mean, the specs to get it done... can you pleaaaaase help me with that? thanks!!!)

You can use a power transformer and output transformer for a Marshall 100 watt amp.  I am not sure what you would need for the choke though.  

Soldano currently uses Mercury Magnetics transformers in their amps with the DeYoung transformers being an upgrade.  Mercury Magnetics, Obsolete Electronics, Heyboer trannys for a Marshall Super Lead amp will all work though.  Right now the Heyboer seems to be the tranny of choice for Marshall clones if you are looking for a strictly raock/metal amp.  They are also about half the price of MM trannys.  Check out www.metroamp.com for good prices on trannys and on their forum there is a quite a lengthy thread dealing with a DIY SLO clone.

Hope this helps you out.

[Connoisseur of Distortion]

Here's my uneducated, second-hand-knowledge perspective.  Nu-metal bands such as Korn really work the preamp, and hardly drive the power amp.  Given that, the OT probably doesn't matter as much as you think.  Futhermore, as has been said, 100W of tube power is freaking loud, seriously.  If you're playing in clubs, I suppose you're backed up by a house PA?  

I'd strongly consider a high-stage-count preamp (something like 4-6 stages, i.e., 2-3 tubes), a good ~18W push-pull power amp, a solid-state rectifier, and a matching OT.  Keeping your PT and OT sizes down will save you a lot of money, and make finding used parts easier.  Plus, if you're playing through an effecient 4x12, something as small as 6 watts can keep up with a moderate drummer.  (Ask Z.Vex about his Nano Head!)  

i really have to disagree about the volume issues. 100 watts isn't really all that much if you are playing in a band... though, admittedly, 18 watts in your bedroom amplifier can be overkill.

my experience in competing with drummers for sound has been very difficult. i was recently using a 60 watt tube half stack, but still i had to also split into a PA system for simply practicing! i recently upgraded to a 150 watt SS combo, which beats the half stack in volume by a long shot.

if 60 watts can fall behind, I don't think I'd even exist with a 6 watt amplifier... that's half the volume!

however, the idea of a multi-stage preamp and lower wattage output is definately a good idea, as you can always get mic'ed if you need the volume. This would also keep the cost down, and give you a much better chance of walking away without any bad shocks.

[ESPguitar]

Here's my uneducated, second-hand-knowledge perspective.  Nu-metal bands such as Korn really work the preamp, and hardly drive the power amp.  Given that, the OT probably doesn't matter as much as you think.  Futhermore, as has been said, 100W of tube power is freaking loud, seriously.  If you're playing in clubs, I suppose you're backed up by a house PA?  

I'd strongly consider a high-stage-count preamp (something like 4-6 stages, i.e., 2-3 tubes), a good ~18W push-pull power amp, a solid-state rectifier, and a matching OT.  Keeping your PT and OT sizes down will save you a lot of money, and make finding used parts easier.  Plus, if you're playing through an effecient 4x12, something as small as 6 watts can keep up with a moderate drummer.  (Ask Z.Vex about his Nano Head!)  

i really have to disagree about the volume issues. 100 watts isn't really all that much if you are playing in a band... though, admittedly, 18 watts in your bedroom amplifier can be overkill.

my experience in competing with drummers for sound has been very difficult. i was recently using a 60 watt tube half stack, but still i had to also split into a PA system for simply practicing! i recently upgraded to a 150 watt SS combo, which beats the half stack in volume by a long shot.

if 60 watts can fall behind, I don't think I'd even exist with a 6 watt amplifier... that's half the volume!

however, the idea of a multi-stage preamp and lower wattage output is definately a good idea, as you can always get mic'ed if you need the volume. This would also keep the cost down, and give you a much better chance of walking away without any bad shocks.

When i play with my drummer alone i use a 75watt Randall 1x12 combo it plays loud enough for that application..
But it "doesn't" play loud enough with 2 guitarists, 1 bassplayer and a drummer..

A couple of days ago i sold my rig (i'm going to buy me a new amp)
so now i use the Randall combo together with my Marshall 1960a cab at 4 ohms.. It plays loud as hell..

So it's a dilemma..

RB

[barret77]

when 75 watts  is not enough...

"-hey dude, I'm just like Pete Towshend"
"-why, you kick ass and play really well?"
"-nope. I just got a good old tinnitus"

[ESPguitar]

when 75 watts  is not enough...

"-hey dude, I'm just like Pete Towshend"
"-why, you kick ass and play really well?"
"-nope. I just got a good old tinnitus"

I said>

the "internal" speaker is'nt enough.. It kicks ass with the 1960 cab, sounds waaay better too...

RB

[Mojah63]

Here's my uneducated, second-hand-knowledge perspective.  Nu-metal bands such as Korn really work the preamp, and hardly drive the power amp.  Given that, the OT probably doesn't matter as much as you think.  Futhermore, as has been said, 100W of tube power is freaking loud, seriously.  If you're playing in clubs, I suppose you're backed up by a house PA?  

I'd strongly consider a high-stage-count preamp (something like 4-6 stages, i.e., 2-3 tubes), a good ~18W push-pull power amp, a solid-state rectifier, and a matching OT.  Keeping your PT and OT sizes down will save you a lot of money, and make finding used parts easier.  Plus, if you're playing through an effecient 4x12, something as small as 6 watts can keep up with a moderate drummer.  (Ask Z.Vex about his Nano Head!)  

i really have to disagree about the volume issues. 100 watts isn't really all that much if you are playing in a band... though, admittedly, 18 watts in your bedroom amplifier can be overkill.

my experience in competing with drummers for sound has been very difficult. i was recently using a 60 watt tube half stack, but still i had to also split into a PA system for simply practicing! i recently upgraded to a 150 watt SS combo, which beats the half stack in volume by a long shot.

if 60 watts can fall behind, I don't think I'd even exist with a 6 watt amplifier... that's half the volume!

however, the idea of a multi-stage preamp and lower wattage output is definately a good idea, as you can always get mic'ed if you need the volume. This would also keep the cost down, and give you a much better chance of walking away without any bad shocks.

I've never had a problem with a 50 watt Marshall tube head keeping up with any drummer or in two guitar bands. Most of the time even on a big stage I never had to have it wide open. If you have really ineffiecient speakers or have way to much bass in your sound you would have a problem. Trying to compete with bass guitar and drum frequencies is really counter productive. Yeah chunk is nice but mud??

[ESPguitar]

It's a lot of bass in the Randalls..

RB

[GFR]

object88 said "100 Watts of TUBE power".

That's freakin' loud.

[scottosan]

Hello,

I know this forum is about effects... but i was wondering, maybe somebody here knows anything about this.

I want a Dual Rectifier. But i can't afford even a used one. I found the schematics in this page: http://www.tubefreak.com. I can't locate the PCB for this circuit, nor the specifications of the output transformer.

Can anybody help me? is there a website with this stuff ?.

Thanks a lot,

George

It will cost you more to source all of the parts than it will to buy a used mesa.  Furthermore, if you are trying to build a high-gain channel switching amp as your first build, you will fail.  No offence, butt there are many things the schematics will not teach you.

[JCM1959]

Hello,

I know this forum is about effects... but i was wondering, maybe somebody here knows anything about this.

I want a Dual Rectifier. But i can't afford even a used one. I found the schematics in this page: http://www.tubefreak.com. I can't locate the PCB for this circuit, nor the specifications of the output transformer.

Can anybody help me? is there a website with this stuff ?.

Thanks a lot,

George

It will cost you more to source all of the parts than it will to buy a used mesa.  Furthermore, if you are trying to build a high-gain channel switching amp as your first build, you will fail.  No offence, butt there are many things the schematics will not teach you.

True words.  Also take into concideration that there are bad DR schematics floating around the internet and would take knowledge of how the circuit is supposed to work to figure out what is bad.  It would probably be easier and less expensive for mcorleone to clone a Marshall 2203/4 and tweak on that.