Newcomer, where to start?

[peterpan188]

Well, I am not a total newbie, but it would be the first time I work with tube amps. I have worked with other solid state designs, and this time I would like to try something new with tubes.

What I want to build is a simple power amplifier for a pair of bookshelf speakers. Don't need a lot of power, so 10W is about enough. It can be a pair of monoblocks. Is there any design that I can get a hand on with these requirements? What tube is a good place to start off from? EL34?

Thanks in advance,
Peter

[andRookie]

When I was adviced about a newbe project Claus Byriths projects where recommended. 8W SE design
I am building his 30W pp amp, going on 1/2 year now.

[ErikdeBest]

Hi Peter Pan

You make a big chance to receive lots of replies, so much that you will feel dizzy choosing one among them.

I am working (parallel at least another 5 projects...) on the baby huey, a design by Gingertube. It uses EL84 and puts out about 10W
EL84 Amp - Baby Huey

May I recommend a good book? Valve amplifiers, third edition by Morgan Jones

Good luck

Erik

[ray_moth]

What tube is a good place to start off from? EL34?

EL34 is not a bad place to start but EL84 might be better for your first amp, because it operates with 100v less B+ and is extemely easy to drive, i.e. the driver doesn't need to provide much current or swing much voltage. The fact that EL84 sounds very good in ultralinear push-pull (PP) connection doesn't hurt either.

PP is probably your best bet, because it's easier to achieve success than single-ended (SE) and the output transformer is smaller and less expensive for the same power handling. You can build two monoblocs if you want to, of course, but with EL84s it's not really necessary. A single stereo unit is perfectly feasible and more cost-effective.

[Eli Duttman]

Peter,

TOOT! TOOT! (Sounding my own horn.)

Check out "El Cheapo" here. "El Cheapo" is a MODEST cost "integrated" amp in the power range you want.

[Sherman]

Lots of choices out there! I can recommend Mikael's SE KT88 as a very good sounding and easy to build amp. Power output on mine is 7.5 WPC. Search the forum for 'Mikael's KT88'.

That said Ray is right about OPT size and cost for PP vs. SE. Plus PP designs delivering 10WPC or more are common.

[grhughes]

Also the 6GM5 is a good candidate if you can find them. There is a host of schematics and ideas. I would lean toward the octal tubes as drivers; much lower distortion. The book VALVE AMPLIFIERS by Morgan Jones is a good start, but requires some knowledge of electronics. He or his publisher doesn't believe in connection dots on his schematics. Also some of his solutions are esoteric. THE AUDOCYCLOPEDIA , a book long out of print but published by Howard Sams and edited by Howard Tremaine is an excellent book and in it are a multitudes of schematics.

[peterpan188]

Thanks guys. Well, although this is a first time project on tubes, it isn't necessary to be cheap. I am looking forward to something that sounds different from SS, while giving me a good impression on tube amps.

andRookie: I took a look at the paper, very well written indeed. 8W version looks great, and the 30W PP version looks very nice too. Have you finished the 30W one? How does it sound?

ErikdeBest: Do you think the baby huey would be a little too many compliated for PTP wiring? This will the first time I do PTP wiring, still got some skill to learn on that.

Thanks again guys!!

[peterpan188]

Any other suggestion or advise?

Peter

[scott_m]

I'd just add that I've built Eli's 'El Cheapo' PP amplifier from the linked schematic and thread. I did upgrade the output transformers to Dyanclone z 565s, which added an extra 100 dollars or so to the total cost. What I wanted to say was don't let the name fool you. It's a great sounding amp, and a reasonably straight forward build. That it comes at a relatively low cost is a bonus.

Scott.