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DIY Valve Amp


markytbass
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[quote name='pete.young' post='7793' date='May 27 2007, 08:24 PM']You need to have a chat with that nice Mr. Torres![/quote]

the link is [url="http://www.torresamps.com/index.htm"]here[/url], I've been looking at this site a lot myself lately. I want to build backup for my pignose to the same spec but I've other jobs pending

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I made a little 5W valve amp (mainly for guitar), and hunting out the parts was fun, to say the least. I think it's more economic to find a kit - this guy does a couple - [url="http://www.ampmaker.com/index.asp"]http://www.ampmaker.com/index.asp[/url] - but he's currently not taking orders due to ill health, unfortunately. If he'd have been doing those kits when I made my amp I'd have jumped on it.

As I understand it, to get an amp with decent volume means you will need to spend a fair bit on transformers (as well as lots of power amp valves, of course). Maybe a valve preamp might be worth consaidering as a first project? There was a thread either here on maybe on basstalk where someone had built a preamp froma kit that seemed very reasonable in price.

www.ax84.com and www.18watt.com are good resources - there is discussion of bass amps on the ax84 forum.

Finally, don't do it to save money (IMO). A secondhand valve amp will probably keep it's value should you resell - a DIY amp will certainly not sell for the price of the build.

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[quote name='steve' post='8489' date='May 29 2007, 10:12 AM']the link is [url="http://www.torresamps.com/index.htm"]here[/url], I've been looking at this site a lot myself lately. I want to build backup for my pignose to the same spec but I've other jobs pending[/quote]

Hi,

I work with Barry at Torres UK and can recommend their kits, in fact the Super Boxers are my design.

They are guitar amps but I would be happy to help Torres with the re-design required for bass.

Dave

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[quote name='DHA' post='8537' date='May 29 2007, 11:42 AM']Hi,

I work with Barry at Torres UK and can recommend their kits, in fact the Super Boxers are my design.

They are guitar amps but I would be happy to help Torres with the re-design required for bass.

Dave[/quote]

Hi Dave, what are the differences between a valve guitar head and valve bass head? I've often wondered whether they're interchangeable

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[quote name='steve' post='8574' date='May 29 2007, 01:10 PM']Hi Dave, what are the differences between a valve guitar head and valve bass head? I've often wondered whether they're interchangeable[/quote]

Hi Steve,

A lot of the early valve heads were the same design for bass and guitar. The first Marshall Plexi's were in fact a copy of the Fender Bassman and the only difference between a Marshall super lead and a Bass was one 500pF cap on the SL.

But, the new high gain amps for guitar lose all the bottom end required for bass.

The design in layout is very much the same but it's the decoupling caps that change in value and some reduction in gain is also needed in the bass versions so that motorboating does not occur.

So to answer your question yes they are interchangeable but a guitar will sound better on a bass amp but not so good the other way round.

Dave

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I'd add that to work well for Bass, a modern valve amp needs to have a seriously hefty, well-wound output transformer, capable of faithfully transferring all that LF power. On most guitar amps (and - as Dave pointed out - many so-called "bass" amps from the vintage years), the OPTs simply aren't designed to do this.

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[quote name='Oxblood' post='8618' date='May 29 2007, 02:47 PM']I'd add that to work well for Bass, a modern valve amp needs to have a seriously hefty, well-wound output transformer, capable of faithfully transferring all that LF power. On most guitar amps (and - as Dave pointed out - many so-called "bass" amps from the vintage years), the OPTs simply aren't designed to do this.[/quote]

Very true. 4 string basses could probably get away with it, but in the modern age of 5 and more string basses, older style valve amps just won't cut it.

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I recently received a Brownnote D'lite kit to build. Looking forward to getting started.

The other company I considered for kits was Ceriatone. Although based in Malaysia I've heard fantastic reports about Niks stuff and he has about 30 kits to choose from, all clones of classic valve amps from Fender Champs to Matchless DC30s to Trainwreck Express kits.

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[quote name='presoulnation' post='9924' date='May 31 2007, 03:03 PM']Surely there is a lot of money to be made from hand built amps? Luthiers are fighting for custom in a saturated market all the time, but no bugger builds amps :)[/quote]

Don't bet on it!

I tried for years to get my amps off the ground without any real success. A handbuild valve amp takes many hours to build and when it's done you then have to tune the components to make it sound right which can take longer than the build. The way the big boys get around this tuning is to design a circuit that is working well within it's limits and hence not at it's best, a bit like a rally car and the production model version!

Then theres the cost of the parts, cheap ones might work for a while but will effect tone.

Maybe it's just a UK thing as in the US there is a good handbuilt amp market but over here very few want to pay the real value. Most of the amps I have built have gone to mates or pros that know what they want.

I would add a note of warning about building valve amps, the voltages involved will kill so there are not many second chances :huh: Also if anyone builds and sell such an item you will have to CE mark it, if anyone is hurt or killed when not doing something silly then the builder will be to blame and we are not talking just a fine here.

You will need a good range of test equipment to do the job correctly.

I think building an amp for yourself is a great idea but building for profit, well that's another thing.

Dave

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Whilst on the subject of voltages and electrical equipment I think (though I will have to confirm this) that if you were to sell a 2nd hand amp/combo etc that you have to provide a Portable Appliance Test certificate (PAT). I know when I was a sparkey we used to do a lot of business with a local auction house testing anything with a 3 pin plug on. Also some venues won't let you use untested equipment because of health and safety laws.

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[quote name='acidbass' post='8636' date='May 29 2007, 03:44 PM']Very true. 4 string basses could probably get away with it, but in the modern age of 5 and more string basses, older style valve amps just won't cut it.[/quote]

Um. My Burman guitar combo has exactly the same transformers as my Burman bass head, and they both
definitly cut it when it comes to 5 string basses. Generalise at your own risk.

As far as Mr. Torres is concerned, I have nothing but praise for him. I had a long and interesting
chat (well , for me it was interesting) with him at the London Guitar Show . DBA, I think you're
fortunate to work with him.

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[quote name='pete.young' post='10138' date='May 31 2007, 08:09 PM']Um. My Burman guitar combo has exactly the same transformers as my Burman bass head, and they both
definitly cut it when it comes to 5 string basses. Generalise at your own risk.[/quote]
Ah now let's be fair, I did say [i]many[/i] vintage amps, not all. :) No flies on Greg Burman. He was a no-compromise merchant all the way: top quality gear with a price tag to match.

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[quote name='pete.young' post='10138' date='May 31 2007, 08:09 PM']Um. My Burman guitar combo has exactly the same transformers as my Burman bass head, and they both
definitly cut it when it comes to 5 string basses. Generalise at your own risk.[/quote]

LOL, you beat me to it!

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