DIY Amp Building - A 5W Tube Amp

[aj633]

I have been thinking about tinkering around with building a guitar amp. I'd like to try a 5W head with an EF86 and EL84. What are some good resources for learning and buying parts?

[Prattacaster]

http://www.freewebs.com/valvewizard/

I like the stuff of Merlin's website, most of it isnt not relevant to your specific 5w head, its all great info tho.

http://www.ampbooks.com/

Another great one.

And I like: http://tubedepot.com/
http://www.tubesandmore.com/
http://www.justradios.com/

[Blues_N_Rock]

For learning you have come to the right site. But there are other well respected sites such as: http://ax84.com/.

Good luck with your build.

[gashford]

I just went through building a 5 Watt amp and I have to say it was one of the most rewarding diy projects I've been through. I obsessed about it for months, reading ax84 and a set of books by Merlin Blencowe (http://www.freewebs.com/valvewizard/).

I decided on converting an Epiphone Valve Junior to a "Plexi SE" using a PCB and build guide found here: http://guitaramplifierpcbs.com/PlexiSE.aspx. You basically rip everything out of the VJ re-using only the case, chassis, transformers, and a couple of switches and connectors. There is an option to either build a pre-amp resembing a Plexi (beautiful clean with little crunch) or JCM800 (cascaded gain stages / high gain). It runs a solid state rectifier, 2 x 12AX7 pre-amp tubes, and a 1 x 6V6GT single ended power section. FWIW, I tried both pre-amps and preferred the cascade option. The same site above also sells an 18W Marshall conversion.

It was a great way to get my feet wet in amp building without being too difficult. With a PCB, you miss out on some steps (turret/eyelet board layout) which may be a either a good or bad thing, but the result was a noise-free, great sounding amp.

There are lots of people shipping complete kits. Check out:
https://taweber.powweb.com/store/kits.htm
http://triodeelectronics.com/ampsandgear.html
http://www.ceriatone.com/index.htm
http://www.trinityamps.com/Product_Parts.htm

For parts:
http://www.tubesandmore.com
http://www.tubedepot.com
http://www.mouser.com

Good luck and stay safe

[gashford]

I should also mention that a 5W amp is not by any means a quiet amplifier, especially through a 4x12 cab

[Keyser Soze]

Originally Posted by Blues_N_Rock

For learning you have come to the right site. But there are other well respected sites such as: http://ax84.com/.

Good luck with your build.

This. Specifically the P1 theory document, which explains the operations of a single ended amp quite well.

Using a pentode in the pre-amp is going to raise the level of difficulty, and for that Merlin's website (or even better his pre-amp book) is going to prove useful.

[gashford]

Originally Posted by Keyser Soze

Specifically the P1 theory document, which explains the operations of a single ended amp quite well.

I agree! A great read. The P1-ex theory document is a little newer than the P1 (more like a version 2 of the P1 doc):
http://www.ax84.com/p1x/p1-ex-theory.pdf

[5992]

If you're just starting out, I'd suggest buying a kit. You can scratch build, but no one vendor seems to have all the parts you might need.

I'd suggest the 5F1 Tweed Champ circuit. There are a few kits out there, and you'll have a nice looking, great sounding amp when you're done, if you take your time and do it right.

When I started out, I went the scratch building route. It took me a long time to get to the point where I had most everything I needed to build an amp. Sadly, most of the local places that I used to source parts have now gone out of business. So that leaves the Internet for mail order. And shipping costs have gone way up. They really start to add up when you source parts from different vendors.

If you're set on scratch building an amp with an EL84 output and EF86 preamp, check out this thread on the Vox AC4 build:

http://music-electronics-forum.com/t10311/

Hope it all works out for you.

[smolder]

Dave Hunter's book (I think there may be one in the emporium) is an excellent read prior to building an amp. It explains the fundamentals quite well. It even walks you through the stages of building a specific amp. You can use it as a reference in parallel with your build.

[ReginaldBisquet]

I agree with 5992. Kits are definitely the way to start out. I built a 5x3 kit from Ceriatone that was very interesting, a lot of fun and highly rewarding.



I took that experience and switched out the transformers... THAT was frustrating, but still very enlightening on matching up transformer specs with amp circuits.

I then built a 5F1 kit from Weber...



... and began to truly appreciate the difference between a well designed kit and a poorly designed kit. The circuit from Weber was fine, but the parts and kit components were very poor... especially compared to the Ceriatone kit.

The other thing I learned about small kits (independent of my opinion on the Weber kit) is that building a circuit in a small chassis is like building a ship in a bottle. There's a lot of little things that need to be assembled and cramming it all in there (for a novice like me) can be frustrating and deflating.

I'd recommend finding a local amp tech that you can turn to that will double-check your work when you run into a brick wall... which happens to all of us when starting out.

My sources for parts:

Watts Tube Audio
http://www.turretboards.com/

Hoffman
http://www.hoffmanamps.com/

Antique Electronic Supply
http://tubesandmore.com/

... and your local Radio Shack.

[ugameus]

http://www.sewatt.com/

[aj633]

Thanks for all the links and info. I've been tied up the last two days and didn't check for responses. Was kinda surprised to come back and find so many!

[ReginaldBisquet]

I don't mean to thread-jack, but now I have a parts question:

Has anyone ordered from Amp Parts Direct?
http://shop.amppartsdirect.com/

I was going to pick up some transformers from ClassicTone and was recommended to use Amp Parts Direct for my order.

[Marshamps]

Originally Posted by ReginaldBisquet

I don't mean to thread-jack, but now I have a parts question:

Has anyone ordered from Amp Parts Direct?
http://shop.amppartsdirect.com/

I was going to pick up some transformers from ClassicTone and was recommended to use Amp Parts Direct for my order.

I haven't ordered from them, but that's John of ValveTrain Amps a very reputable guy in So. FL.

BTW, What is that extra cap doing on the first stage plate circuit in the 5F1 doing?
Thanks,
Mike

[ReginaldBisquet]

You wouldn't believe (okay... maybe you will) the noise I was getting with the 5F1 build from Weber. I had to do something to cut back on the oscillation I was hearing when the amp was turned up. I suppose the amp's a little darker in tone than normal, but at least I can turn it up without getting a bunch of squealing.