Pee Wee Hammond

[sluckey]

Last week while organizing the shop I ran across this little chassis. So I took it to the bench just to fire it up again, and several days later I had Pee Wee. I had originally planned to put the AO-44 in a 5E3 cab and use it as a dedicated reverb amp. Really sounded good having a separate cab that could be placed anywhere. But after building the Revibe I lost interest. So now I have just one more amp! And the shop is still a mess... 

I just added an AB763 preamp to the AO-44 push/pull cathode biased 6GW8 power amp. This thing really has a big Fender sound with plenty of volume. Much better than the AO-44 conversions you see on youtube where the guitar is sent directly to the power amp.

Schematic and pics in the attached pdf

[smackoj]

nice Wee SL.....looks pretty darn Rockabilly

 

[Platefire]

Great Job! about the same size chassis as my Hoffman Record Player amp-little bit different layout. I like your tone stack over a tweed type 5E3 tone stack I was considering. I'm thinking that stack would allow you to dial in a lot more bottom than the tweed type? Plate







<-----BTW-Read-U2!

[sluckey]

There's plenty of bottom thump, especially with my 15" Big Ben. I actually removed the typical Fender 25µF cathode caps to reduce the bass. Plenty of ice pick on tap too. It's very much like a blackface but only lower power.

[terminalgs]

Awesome!     nice job sliding that Noval socket in there.  Looks as if Hammond did themselves! I see you have to remove a tag strip too (looks like it had the unwanted transistor preamp circuit tag strip)

The PI/power circuit is very close in component values and voltages, and identical in basic circuit layout to the little M2 and M4 amps Magnatone made in 1963/64.   Either the Estey engineers used the same suggested circuits from the manufacturer or... they used a Hammond circuit to begin with (they were using the Hammond patented reverb tanks and I imagine the tanks came with some engineering papers; with those tanks, like Hammond, Estey sometimes used a transistor for recovery).

Just like you found, the Estey engineers decided the circuit needed a couple of 12AX7 gain stages ahead of it for guitar.

I've got some 6GW8s,, I'll have to see if I can get them into a build some day.

[eleventeen]

I just got one of those in a pile of junk I bought!

I had never heard of those output tubes (that meaning nothing in particular) and was pondering switching to EL34s. The OT looked pretty darn beefy for that power level and that, I suspect, shares a lot of the blame for the good bass resp.

I edged into the same thought you had, that feeding a guitar signal into the output tubes was a guaranteed loser; but I didn't think to shove in a preamp tube.

[sluckey]

identical in basic circuit layout to the little M2 and M4 amps Magnatone made in 1963/64.

Do you have schematics for the M2 and M4? If so, I'd love to get a copy.

[tubenit]

Sluckey,

That is a VERY cool build!!   Thanks for sharing it.

With respect, Tubenit

[kagliostro]

Hi Steve

Despite your Final approach was on: November 10, 2012, 12:16:39 pm

This is a very nice conversion 

Franco

[sluckey]

Despite your Final approach was on: November 10, 2012, 12:16:39 pm

I had to do a "go around". 

[Slimtim]

Very nice conversion.Are you going to make it into a head,put it in a combo or just leave it be as is?

[sluckey]

I'll leave it as is.

[Platefire]

Well, I would recomend a bottom plate and four rubber feet to dress/close the bottom up and make it compatable to sit on any of your speaker cabs. And a couple of handles makes it easy to move around. That's just me!    Plate  

[sluckey]

Well, I would recomend a bottom plate and four rubber feet to dress/close the bottom up and make it compatable to sit on any of your speaker cabs. And a couple of handles makes it easy to move around. That's just me!    Plate  

OK. Thanks.

[DummyLoad]

very cool conversion and nice work.  

i was going to convert germanium x-istor to depletion MOSFET and add a second MOSFET with one-knob tone stack & vol.

got tired of moving it around to make room in the lab, so i farmed the iron and tubes, put them in storage, then tossed the chassis. :-(  

--pete

[sluckey]

got tired of moving it around to make room in the lab

I really know what you mean. This is an easy chassis to put on the back burner. I did the same. But I was surprised with the potential of this little amp. I still have another. Wonder what will become of that! 

[jojokeo]

got tired of moving it around to make room in the lab

I really know what you mean. This is an easy chassis to put on the back burner. I did the same. But I was surprised with the potential of this little amp. I still have another. Wonder what will become of that! 

Maybe a pentode EF86/5879 follow-up???

*nice work Steve! I love to see this kind of stuff. Especially from you - your work and thoroughness are terrific.

Echambley was looking for ideas for a 10w or so "mini-Twin" and this was something similar (using these power tubes) I was contemplating as a possibility. Do you think it could pass for something like what he's looking for?

[sluckey]

I think the AO-44 would be a good candidate for a small "twin" amp. I had to do a lot of head scratching to be able to shoehorn one extra tube into that tiny chassis. Putting two extra tubes and 6 pots in that chassis would be very difficult. Maybe impossible. If I was gonna do that, I'd just use a larger chassis.

[jojokeo]

I don't know if he needed extra functionality like Tremolo & Reverb so therefore it wouldn't be a "scaled Twin", just a clean Twin type of sound at around 10watts is what I think he was after? Maybe Ed will chime in when he sees it?

[Ed_Chambley]

I don't know if he needed extra functionality like Tremolo & Reverb so therefore it wouldn't be a "scaled Twin", just a clean Twin type of sound at around 10watts is what I think he was after? Maybe Ed will chime in when he sees it?

Been watching this.  A portion of the idea I have used.  I am just collecting info as I still have far too many amps to get sold before my next build.