The Amp Garage

martin manning wrote: ↑Tue Jan 16, 2018 1:09 am Rats. It's really fighting you! I'm sure that was the problem with the filters. At this point I'd look for where the signal is lost with a scope or a listening probe.

I agree, I'm going to step back for a day or so, clear my perspective

Just tolexed the cabinet.

I got all the repairs done.

Unfortunate, when I power up the only signal that is coming through seems to be the reverb return. The amp is only working at a fraction of its volume and the tone control seem ineffective. I'm wondering if I have a stray wire clipping shorting something out ???

The switch tests OK. Can you see anything I'm missing in the wiring?

Hello, cool amp. I was just inside a 1969 Bassman and it had the same hookup wire. I don't think running 6L6 power tubes in a Deluxe should damage it. At least Neil Young doesn't think so. :D You wont get much more wattage out of the amp but it does thicken the sound. That probably was the mod. Fir...

I think I found the hum origin. It had started to come and go. The hum changed as I manipulated the bias pot. Then I found weak connection on pins 6 and 4 on the right power tube. I got the connection to stay strong then measured the following voltages, while there was no hum: All in in volts DC Bia...

Cool, thanks for the responses. The filter caps are shot, last power up = smoke. The stock caps are all 16uf I was going to replace those with 20uf. Any value in going higher for the first two in series, like 40uf for a little more headroom? After those I was going to change the board electrolytics ...

Have any of you seen a fender with this skinny wire?

better pic

I friend of mine brought this over today. Serial # dates it to 1969. My friends mother used to work for the Grateful Dead in the early 70's. Apparently about 1972 he was starting to play guitar and the mom asked Jerry if he had and old amps and guitars that her son could have. He gave her this Delux...

The OT on these are fantastic! I've built 3 amp with them and they are great. "Girth" to the max.

I really appreciate you making these videos, raising the bar!

Good luck with the build.

Yes, much better. Now what voltages do you have on the power tubes and how closely do the cathode currents match? Measure pin 3, 4, 5, and 8 voltages, and also measure VAC on pin 5's to see how much ripple is in the DC bias. Any luck on the high filter and presence? I did a quick test with the new ...

Ok, I think I see what you have now. Looks like a blue wire goes from each pin 8 to a red jack, and a black wire goes from both pin 8's to the black jack, and a 1R goes from the black jack to ground, yes? That means the red and black jacks are all tied together, and you have a common cathode voltag...

martin manning wrote: ↑Wed Jan 10, 2018 5:26 am So you have a 1R to sense current on each power tube? That should be fine. Does the idle current on the two sides match reasonably well? How about the DC bias voltages at the CF cathodes? Are they close?

No just the wire from pin 8 to the ground banana jack / 1 ohm 5 watt.

Great! Does the hum persist with the PI tube pulled? I’d want to rule out the power stage as the source right away. I pulled the PI tube (V5) and the hum stays the same. Turning the master volume has no affect on how loud the hum is. The only thing different I did from your wiring on the power tube...

No matter how many amps I build I'm always amazed when the thing works with the first try. No smoke! Initial observations: I've got some significant AC hum. I'll change out the 12AX7s and I think go with a 12AT7 to drive the reverb. Hopefully that will reduce the hum. It is loud; but more than loud ...