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    Building, troubleshooting and testing of these amplifiers should only be
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    the safety precautions around high voltages.

Building first tube power amplifier, reccomendations?

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Hi everyone,

Im ready to build my first tube power amplifier. I would like to keep it simple and not too expensive, but a fair amount of output power. (10wpc?). Any recommendadtions of an amplifier that can be buit fairly cheaply (iron).

Rhys
 
Ha3!

I'm halfway through the re-built this circuit into a bargain chinese EL84 amp, delay by my day job and now stuck with layout in confine space.

A friend built one for a listen and he said and I quote " I found 300b mid-range in this amp".

Now should you stop reading and start collecting parts?

Cheers

Ken
 
rhysh said:
Just a 370HX in the cupboard so far.


The 370HX is perfect for a stereo baby huey, I built mono baby hueys with the 270EX which is 275-0-275 @ 100ma with a CLC PS. That's exactly half of your 370HX.

The 370 series have a convenient bias tap so you could later modify your BH to the fixed bias variant (or build that first if you have the skills, it's a little more complex)

If you haven't done so already, download PSUDII from duncan amps and model your supply. As mentioned above, you can dial in your B+ voltage (target for BH is around 320+/-) with the first cap when using a CLC
 
rhysh said:
Would the simple SE not be a better choice?


The simple SE is single-ended (one output tube per channel), yielding a few watts total output depending upon the output tube chosen.

The Baby Huey is an EL84 ultralinear wired push-pull output (two output tubes/channel) yielding 10-12 watts/channel.

Another similar amp is SY's Red Light District, also an El84 Push Pull (wired as a pentode) for about 15W output.

If you want 10W+ output, push-pull is the most cost effective way. SE 10W+ gets expensive quickly.
 
Thanks for the replys, after looking into the single ended option more, the $/W ratio isnt really worth it.

I am just not too confident with my p2p wiring, and i dont really know what i am doing.

Do you think it would be more simple to build the red light district or the baby huey, with my p2p skills in mind?

I can read and draw schematics, i think its just going to be the p2p wiring thats the problem.
 
My first amp project was a baby huey.

The point-to point part isn't too tough. What I found a little challenging was breadboarding (on proto PCB board) the CCS bias blocks. Overall a very satisfying learning experience.

I believe SY's RLD will be similar, since you'll need to build the LED CCS.

Both design are very well documented.

You can always consider starting with a breadboard, literally a 16" square or so piece of plywood, add some feet, and bolt everything to the top. Wire it up using solder tags or screw type barrier strips. It's easy and fast to make changes on the BB. Once you've got it dialed in, buy/build a chassis. Drilling holes in your shiny chassis and then deciding your layout is sub-optimal can be discouraging.

You can get experimenter's tube sockets to make breadboarding P2P a breeze, see these links

http://www.diyaudio.com/forums/showthread.php?s=&threadid=129780&highlight=

http://www.diyaudio.com/forums/showthread.php?s=&threadid=132348

Steve at apex jr also sells octal sockets for breadboarding, but if you build a BH or RLD you will only need nine pin sockets unless you want to use an octal rectifier.
 
rhysh said:
Thanks, i will go with the baby huey, instead of breadboarding i will just make some DIY PCB's :D Sound good?

If you can DIY the CCS and bias block PCB's, you're almost done.

In the past some folks here have made vanilla PCB's for CCS's, possibly as a group buy IIRC. I would like to pick up a few but I don't know if anyone has any left.

Download (and play with) PSUDII if you haven't already. It's free, and extremely useful. You can start by modeling your power transformer in the SS baby huey PS circuit.
 
boywonder said:


If you can DIY the CCS and bias block PCB's, you're almost done.

In the past some folks here have made vanilla PCB's for CCS's, possibly as a group buy IIRC. I would like to pick up a few but I don't know if anyone has any left.

Download (and play with) PSUDII if you haven't already. It's free, and extremely useful. You can start by modeling your power transformer in the SS baby huey PS circuit.


Okay, i have created a layout for the CSS and Bias blocks. should the remaining p2p wiring be a breeze?

I have been playing around with PSUDII, very intresting!
 
rhys - baby huey!

I am delighted with mine. The build isnt hard (if you read the f'ing datasheet for the transistor right!!! red plates arent pretty)


bluebello audio for supplies - the chap that runs it is super helpful.

Use 6p14p instead of the el84s. I think they sound superb.
 
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