New 2ch Ac30ish build finished

[randalp3000]

Started this last weekend. Very similar to an amp I built a couple months ago that's been getting a lot of gig time. Really enjoying the parallel single gain stage but I'm going to try split cathodes and grids this time. Also trying a little bit bigger power trans this time with 288ma at 300-0-300. I'm going to try a switched pot for the cut control to take it out of the circuit as well. I'm building it on a small 6.5x12.5" chassis so I'm going to mount some filter caps under the board to save space.

[randalp3000]

Here's where I left off last night

[Blackburn]

Nice MM OT I see in that schem you got there....

Looks real good, buddy! Can't wait to see her all done up. You gonna use new or old glass?

[randalp3000]

Is that your old transformer? I forgot where I got it.

Probably all new tubes except I have NOS ef86's, JJ el84's most likely.

[Blackburn]

Maybe. The code looked kind of familiar. I dig the JJs for Voxy stuff.

[randalp3000]

Turret board is now ready and some other stuff wired.

[M Fowler]

Randal if you don't stop building amps your going to catch up to my inventory.

[randalp3000]

Ha, this used to be the home office and now it's an amp shop with a computer in it.

Awhile back I told my wife we should pull out the carpet and we could get matching work benches and some shelves for crafts and activities. I have a serious problem....and yes amps are stacking up. I really need to start building some head shells so I can take more than one to my gigs.

[Reeltarded]

Mark had to incorporate as a township. Yep. His amps can be seen from space.

[M Fowler]

I told myself that unless I have a faceplate I can't start on a new project.

It's just me I don't like a naked amp.

I did sell my Fowler HRP yesterday, beer money- errr I mean tube money bought Preferred Series 7025 / 12AX7 and Tung-Sol EL34B for my Express.

Mark

[dcribbs1412]

Cool build Randal
maybe build one large cab/shelf on wheels and put all the amps in it.
maybe a small motor and steering capabilities...

I'm with Mark...no more faceless/headless amps for me.
BTW how many amps constitutes a problem?
I'm thinking of expanding my shop.

Darin

[randalp3000]

Thanks,

Got it working and it sounds amazing,

However I have a hum that seems to be coming from the PI. If I get any where near the grid wires or the .047 feeding the PI it will buzz like crazy. The hum is also worse with the cut bypassed.

I have a gig in a few hours and I might just throw this in a head shell from my Morgan and give it a shot.

If anyone has any suggestions I would really appreciate them.

[M Fowler]

When I had that hum issue it was a poorly built Heyboer PT causing the problem.

Where is that black ground wire from the PPIMV going to since there is no turret on the board for the 220K/220K ground it should ground along with the center taps.

Mark

[randalp3000]

thanks for looking Mark.

It's grounded to the filter cap for the PI right in front of the pot. The preamp filter caps are mounted under the board.

[Blackburn]

Man, that came together nicely! Very clean build, Randall.