# Adding a tube circut to a solid state amp?



## SinCron (Mar 2, 2006)

Is it possible?


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## Accept2 (Jan 1, 2006)

Wouldnt it just be easier to run a tube preamp in front of the solid state amp?..........


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## PaulS (Feb 27, 2006)

It would be easier to get something like the Tech21 TRI AC which is basically an analog preamp and does a fair job of emulating tube sound. The design differences between solid state and tube would prove to be a challenge. Most of the SS is on a pcb board .


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## SinCron (Mar 2, 2006)

That's the kind of feedback I need. So tell me about these differences. I dont want to go with something else. I want to mod an existing amp for a project.


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## Wild Bill (May 3, 2006)

*Tubing a solid state amp...*



SinCron said:


> That's the kind of feedback I need. So tell me about these differences. I dont want to go with something else. I want to mod an existing amp for a project.


Solid state amps usually use printed circuit boards - thin slabs of epoxy plastic with holes drilled to accept resistors, capacitors, transistors & IC's, or whatever.

Instead of wires running from part to part the board has traces of copper foil on the underside of the epoxy plastic.

How do you change the wiring or add parts for a tube stage? The short answer is - you don't!

A longer answer might be: Someone with great resources and patience and the facilities of a manufacturing shop might be able to do something but it would not be quick, cheap or easy. Also, I'd much rather it was you trying to do it than me! 

What's more, the power supply inside a solid state amp has NONE of the voltages needed to properly run a tube stage! You'd have to find room for a big transformer as well.

It's just not cost-effective, like putting a Tercel engine in a big Ford SUV. A lot of work and no real benefit.

Unless you're a bass player my advice is to dump the solid state amp and use the money to buy an old vintage Traynor tube amp. Traynors are still reasonably cheap and are great platforms for modding!

Don't waste your time with add-on preamps and such like ARP or whatever. They stick a 12AX7 preamp tube in a box and tell you it will make your solid state amp have "golden tube tone!"

It's just crap! Hype and marketing with no true technical theory to back it up. Tube amps sound so great because of the entire package of a string of preamp tube stages and the sweet thick distortion of a tube output stage running flat out! If you want that AC/DC Marshall sound you'll never get it with solid state.

If you decide to build and work on tube amps you're gonna have to learn some theory and some safety tips. Voltages in a solid state are kinda low but the high voltages and currents running around in a tube amp can hurt or even kill!

One of the best web sites for both newbies and "masters" is Ampage, at http://www.ampage.org

There's also http://www/ax84.com which is a beginner's site based on homebrewing an 18 watt Marshall style tube amp.

This is probably more info than you wanted but hopefully it's helpful...

---Wild Bill


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## SinCron (Mar 2, 2006)

No amount of info is too much. Thanks. Im doing it just for the sake of doing it.


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## Accept2 (Jan 1, 2006)

There are lots of preamps that use tube and solid state tech, so it can be done.................


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## Wild Bill (May 3, 2006)

*But why?*



Accept2 said:


> There are lots of preamps that use tube and solid state tech, so it can be done.................


True, but what do you have when you're finished?

I should fess up, I run an amp build and repair business. Most of the trade is tube amps but I take in the odd solid state amp if I'm feeling like experiencing some aggravation.  I built my first tube radio when I was 11 and I'm a geezer now. I've been at it more than long enough to have an informed opinion.

So my perspective is more "techie", although I have been playing since my teens, roadied for bands in the glory days when you actually got paid decent money and have fixed and built more amps then I can remember to count.

You can do almost anything if you don't care how long it takes, how much it costs and what it sounds like after you'e finished. The question was what can the original poster do with his solid state amp to add some tube stuff. I know exactly how much work is involved and while I'm not saying it's impossible I would never waste my time myself. Designing an amp that has a mix of tube and solid state in the first place is a helluva lot different than trying to retro-fit a solid state amp that's already built! Look inside one, try to imagine making major changes and see for yourself!

It could be possible to use the cabinet, speaker and chassis! Rip out the circuit board, throw it away and go all tube. You'd likely have room for a new power transformer after you chucked the solid state one.

I repeat, if you want good tube sound then go all the way and make it a total tube amp. Putting in just one preamp tube won't do it.

Whatever you do, you'll have to embark on a learning curve. There's just too much involved for any one to give you some quick instructions in a forum or over the phone.

The upside is that after you get into it you will have a LOT of fun building some AWESOME tube amps!

---Wild Bill


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## SinCron (Mar 2, 2006)

My main goal is to learn. I love learning. Any extra pointers and whatnots you can give would be great. Im looking to mod a Peavey Pacer and its pretty much a compact head in a 1X12 cab. I just want to expiriment and learn. Its all so fun for me.


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## SinCron (Mar 2, 2006)

If I can find a place around here to order them, I will. How much would it cost to get a heavy ass sound?


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