New Amp Photo and Schem

[DougH]

http://www.aronnelson.com/gallery/v/DougH/TenWattWonder/

Haha... I just realized I *still* need to replace that temporary plastic washer on the power switch with a metal one. Oh well...

Thanks to John Lyons for instructions on how to finish the wood.

[BRingoC]

Is that the normal input channel from the ac15?  If so, where did you sorce the parts, on your own ie mouser, or an amp parts site? Pics of the insides?  What are the dimensions?

[DougH]

Is that the normal input channel from the ac15?

I don't know if it's "normal" or not. Look up an AC15 schematic and compare.

If so, where did you sorce the parts, on your own ie mouser, or an amp parts site?

Most of them I had lying around my bench. The OT is custom. The rest I got surplus and from my local tube guy.

Pics of the insides?

Nope, I'm not taking it apart. It looks great but I don't feel like disassembling it.

What are the dimensions?

Sorry, I'm too lazy and don't feel like answering all these questions. Thanks for your interest.

[John Lyons]

What are the dimensions?

Sorry, I'm too lazy and don't feel like answering all these questions. Thanks for your interest.

You crack me up doug!
The amp looks good. I'm sure it sounds great as well.
If you get a wild hair and want to make some sound clips I'll listen to them...

John

[DougH]

Hey John, thanks! I'll get around to some clips sooner or later. I just wanted to get the pics up first.

Thanks again for all your help with the finish. I'm really happy with the way it turned out. Puts my other amps to shame.  

And yes, I'm glad I used the paste wax...

[John Lyons]

No problem Doug, glad to help.
The wood finishing thing is a bear to do, and adding one more step isn't something to look forward to.
The wax buffing is the thing that makes the finish though.

John

[Johan]

interesting mastervolume..is it actually shanging the gain in the P.I, ( booth the cathode resistance going up and also grid bias going more negative in relation to cathodes) or is there something else going on?...that's a new one to me, never seen anything like it...good work.
j

[DougH]

Thanks.

The master volume basically biases the PI colder as you turn it down. So as it reduces drive to the power tubes, it increases the amt of distortion from the PI. It tends to compensate for the lack of power tube drive and keep the distortion level more consistent. I got the the idea from a thread at ax84 about "power scaling for cheapskates". The tradeoff is that as you turn it down, you lose headroom. It's not that significant down to about 50% but below that you really notice it.

In all honesty I don't really use the master volume or top cut control much with this amp though. I thought they would be a good idea when I was getting the design together, but in practice they are not needed very much.

[petemoore]

  Dreamy !
  Vunderbahr schematic, the B+'s layout at the bottom made it easier for me to envision..exactly how B+'s work, info I may find quite useful in the very near future [when my PT shippings and sort-outs are complete..I recieved/opened and tested a 'top shelf' PT with the wrong taps yesterday [Ughhh], then packed/labeled shipped it back.
  Sorry, I'm too lazy and don't feel like answering all these questions.
  Aplenty, I have...[lol] having accumulated Irons and parts...all this, with a few more pieces and more info, could easily become another fine amp or two.
 
 
 
 
 

[MartyMart]

Nice work Doug and thanks for posting your design
MM.

[DougH]

Thanks Pete.

If you have questions, ask away. I just felt like I was getting pounded back there...

If you want to get started building amps, the best place to get the basics is ax84. Hang out there in the forum, read the intro material, and build a simple one to start with.

[DougH]

Thanks Marty!

[DougH]

Just wanted to mention that I found a couple mistakes on the schematic. The corrections have been uploaded. It should be fine now.

[Dragonfly]

Doug...

  You never cease to come up with things that interest me. Thanks. Seriously cool amp. Now get off your ass and post some soundclips !

AC

[MartyMart]

If you want to get started building amps, the best place to get the basics is ax84. Hang out there in the forum, read the intro material, and build a simple one to start with.

Exactly what I did, but at 18watt.com
I built an "Ampmaker" SE-5a kit which sounds fantastic BTW
I have about 70% of a JTM45 parts including the chassis/control panels ... just need a free week or so to build it !!

[DougH]

I started with amps about 7-8 yrs ago by modding the crap out of an Electar 10.

[MartyMart]

I started messing with amps two years ago by modding the crap out of a couple of Epi VJ's 
The large voltages still give me the "heebee geebee's" - probably a good thing to not get complasent about that !

[petemoore]

  Bought a kit, Dan sent two, I built both.
  5e3's they are, and basket cased AC 30 I snipped the PT out, compared V's with the new one...nope, [packed up and shipped yesterday for one with correct would Vtaps for my 'non rectifier SS reverb' amp], have to wait till [hopefully next week] that arrives.
  I think a power amp with 2x EL84's and pre-amp of tubes/jfets/mosfets would be pretty cool.
  I wonder what about the original VOX RI transformers makes them substandard IMO when compared to MM tranny's theory wise, and what could be built to fascilitate less transformer influence on tone in general, or some design which lends itself to working with less than state of the art iron to good result in some other way.
  Sacrificing total output for very clean type of tube amp feels like it might have good mileage, merely a suggested topic...merely an ~uneducated hypothesis about the PS might not matter much if it's over-rated and not intended for sag or other.
  An 'Un-tweeked' design as it were, certainly better quality transformers could take just about any tube amp and tweek it, something circuit that is particularly less concerned with the transformers, or uses the 'less expensive' irons to some benefit.

[birt]

hey Doug, i just saw your amp popping up on another forum: http://www.el34world.com/Forum/yabb2/nph-YaBB.pl?num=1194663583

[alfafalfa]

Nice work Doug,

What OT did you use ?  10 K , is it Hammond ?

If you  have different 6BM8-P tubes , you could split the bias arrangement and tweak it to get a good (better) balance.  ( See TUT 3 )

Does the Ef86 celan up when you turn down the guitar volume ?

Alf