*New Build Thread* 2nd Gen Hybrid 50w footswitchable FET

[telentubes]

Can't wait to hear your impressions of this one. I'm going to have to change out some new parts for old in my 50 watt. Sounds like it will make a big difference. Nice job!

[amplifiednation]

Just put some serious time into this. I think i logged over 4 hours into the amp tonight!

Got the relay board wired up, the power tube sockets done, finished up the IEC/Fuse/PWR switch. Then I did the heaters and got the FET relay wired in. Man that was a tight squeeze!!

No coax coming the input...any thoughts on that?? I thought i could always add it later, there is a convenient ground point right on the relay board. Input jack to relay seems is so short I don't know if it would matter.

The 3 button footswitch I got from CE dist is not the same as the jack i have on the amp...uggh. No footswitch, no FET.

I still need to wire in the FET trimmer, the OD coax runs from the board, and then figure out what goes in this big square hole. Oh, and waiting for some dynamite CF's for the preamp grids. I have some CC if they don't arrive.

Hope to have this powered up for my b day on Tuesday. It's kind of like a present from amp garage!

[amplifiednation]

That amp is gonna rock, congrats Taylor.

Ange

Thanks Ange! It's been a long fun road since you helped me build my Rocket!!

[boldaslove6789]

Build looks great so far Taylor. You're really gonna dig the 70's voicing.

You should try some 6V6's in that amp too fo sho. 6V6 Pwr amps seem to fit perfect with the 70's era amps preamp, mucho compression and sustain.

[ToneMerc]

You should try some 6V6's in that amp too fo sho. 6V6 Pwr amps seem to fit perfect with the 70's era amps preamp, mucho compression and sustain.

10-4, I love my 004 and my next one will be quad 6V6 build as well, mostly like an HRM.

TM

[amplifiednation]

I am behind schedule....I got the PT and the rest of the amp wired up today....powered up, voltages look good, but no signal...I got some work to do.

[amplifiednation]

Once I have this up and running I'll post some more pics.

I've confirmed signal passing up to V1...voltages all check out nicely, I missed a connection at the cliff jack and still need to wire in the FET trimmer before I really start to troubleshoot

mains 122
secondaries 737
heaters 6.7

B1 483
B3 453
B4 288
B5 279

V1 183/190
V2 195/194
V3 289/312

plates 480
bias 35ma

[amplifiednation]

Alright...I need some help.

Voltages seem good, I can't get the bias as positive as I would like, but I want to get the amp making music before i mess with the power supply, because it seems to be working properly.

I am not getting signal to pass through the amp. I've got a very faint hiss and I'm getting pops and crackles when I test the plates of all preamp tubes and power tubes. If I plug a guitar in I can just barely hear it coming through my test speaker...very faint.

I don't know anyone else thats used this layout...I'll check with Jason to see if he's revised it in anyway.

I went through the amp and continuity seems to be checking out everywhere...I'm thinking this is going to be something silly...or a misconnect.

I am wondering about the OD relay wiring.

Here are some pics and the layout again...I realize these are tough amps to find fault from pictures, but if you have troubleshooting advice, I'm all ears!!!

[amplifiednation]

here's the layout again

[dcribbs1412]

Hi Taylor
you might have updated your build, I don't see speaker jacks in the pics?

Darin

[amplifiednation]

Haha, yeah you don't see them in the pics, you are correct!! My OT is a 1964 Bassman with a 4 ohm tap...so i didn't put the impedance selector in, nor the secondary jack..

the jack is wired up normal right to the OT with the NFB off the +.
i'll snap a pic.

[martin manning]

Maybe the first thing to try is loop send to another amp, and another amp into loop return- see if either the pre-amp or the power amp is working.

[ToneMerc]

Alright...I need some help.


I went through the amp and continuity seems to be checking out everywhere.

Taylor, i'm blind here at work and can't see files or layout, but verify that you have a jumper from your first plate resistor to the treble cap. I had the exact same issue with my first early build and didn't find it until I shot signal through it and traced it with the O scope. Once I raised the board I could see that the jumper wasn't there. I had marked off the wrong jumper as being placed when I built the board.


TM

[amplifiednation]

Martin,
Great idea.

Preamp is not working. Power amp is working, but "power amp" controls on the amp do not work...is that the way it's supposed to go?? Excellent!! Halfway there..

TM,
I'll check the jumper.

Here's the speaker jack/power tubes.

[martin manning]

Preamp is not working. Power amp is working, but "power amp" controls on the amp do not work...is that the way it's supposed to go?? Excellent!! Halfway there...

The loop return goes straight into the PI so it's downstream of the volume controls. Presence should work, though.