Fender deluxe point to point clone

[pappajoe]

I have hard wired a version of a Fender deluxe. This is a modified philco tube amp that I have added a 12ax7 and have used only 1/2 half of the triode. On powering up I get motorboating kind of static sound. No input/sound from the jack/guitar. Please look at the attached drawing and see if there is something I'm missing. Also on th OT there is a white wire in addition to the Black/green wire that goes to the speaker, it is tied to a lug but no hookup to the rest of the amp. I'm stumped?!?!?! Thanks in advance for any input. Ok....... I can't seem to attach a jpeg file. I will email jpeg to antone that is willing to help. Or if someone wants to enlighten me as to the method of attaching a jpeg image I'll update this post. Regards, Pappajoe

[pappajoe]

Atttached diagram for revious post

Hope this is legible enough.

[imaradiostar]

looks like it should work OK. Maybe you could try posting a picture of the inside of the amp.

jamie

[Bruce / Mission Amps]

He's right we'd need to see what you actually made, not what you drew.
You don't need an 820 on the cathode of the 12AY7, 1500 is good.
The input jack looks like it isn't draw right... but it could be just the way you drew it 'cause you have the 68K wire grounded with that line across after the jack... stuff like that makes it hard to help as you might not have actually built it that way.. see my point?

[pappajoe]

Post pics of build

Thanks guys! I'll post a pic of what I built. won't get to it till Friday! It's real packed in there but as Bruce said.....needs a new pair of eyes. I did use the original terminal strips and tried to always use common ground when possible. The input jack has a 1meg resistor tied to ground. Again thanks, Joe

[pappajoe]

Photos of amp

It's jammed pretty tight in there. Hope it helps. Also, thank to anyone for taking there time to look at this.

[pappajoe]

Original schematic

This is the original schematic. Thought it may be helpful.

[imaradiostar]

what is the blue wire (unshielded) from the tube socket to the pot? Looks like it's not connected correctly at a glance.

jamie

[pappajoe]

blue wire reply

The blue wire fromthe 1 meg pot goes to the grid of the 2nd 12ax7. The red going into the pot is coupled with a .1 cap goes to the input of the volume pot.

[imaradiostar]

it looks like you've got the middle and hot lugs of the pot swapped- is there a reason you did this?

jamie

[imaradiostar]

Like you said, it's tough to tell what's going on from pictures.

Would you mind posting pin voltages for the tubes?

jamie

[pappajoe]

Pin voltages

Voltages on V1 12ax7
pin6 - 150v
pin7 - .3v
pin8 - .3 low?!?!

voltages on v2 12ax7
pin1 - 275v
pin2 - .6v
pin3 - 21v
pin6 - 230v
pin7 - 20v
pin8 - 43v

voltage on V3 V4 6v6's
pin2 - H H
pin3 - 339v 339v
pin4 - 321v 321v
pin5 - .05v .1v
pin6 - X X
pin7 - H H
pin8 - 19v 19v

[RWood]

A couple of things I would do:

• Lose the phono jacks and install the 1/4" jack right on the chassis
• Run shielded cable on those long runs too and from the volume control
• Move the on/off switch away from the volume control

RWood

[imaradiostar]

major things are wrong at V2a- there should only be a few volts at most difference between the grid and the cathode. Check for a bad tube, bad solder joints, resistors with incorrect values, etc.

I would swap the two non-ground lugs of the volume pot. You want full signal from the previous stage coming into the end of the pot and the wiper to form a variable resistor between the plate signal and ground.

jamie

[imaradiostar]

I would swap the two non-ground lugs of the volume pot. You want full signal from the previous stage coming into the end of the pot and the wiper to form a variable resistor between the plate signal and ground.

I just took a look at the original 5E3 schematic- I guess it was wired that way so it won't hurt anything. I still prefer the other way but it shouldn't matter much. Maybe someone else that knows 5E3's well can chime in as to why they're built that way.

jamie