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[Valvehead]

Did you check the DC going to V1's filament ? It's on that last page of the schematic.

v1

pin4 -2.6vdc
5 -2.6vdc

9 +2.6vdc

[loudthud]

Seems like DC is on the low side. Does pulling V1 make those Voltages pop up to +/- 3 or higher ? I see you mentioned it killed the hum in the first post. How do those 1N4007 diodes look ?

I wonder if the hum is just leaking into the signal path because of a hummy heater supply. Any way you can put DC from a 6V battery or a floating DC power supply on V1's filament ?

Note: If one side of an external power supply is grounded, it will short one side of the +/- 3V and damage the diodes or the power transformer.

[Valvehead]

Those diodes test good . I dont have a 6v supply to try

[loudthud]

Can you put together 4 fresh D-cell batteries ? They can power a 12AX7 filament long enough to see if it kills the hum.

Those two 6800uF 6.3V caps might be bad. Do you have any way to test them ?

[Valvehead]

Can you put together 4 fresh D-cell batteries ? They can power a 12AX7 filament long enough to see if it kills the hum.

Those two 6800uF 6.3V caps might be bad. Do you have any way to test them ?

ill see if i have any 6800 .

[Valvehead]

Swapped 6800 uf caps . No change

[loudthud]

Check the AC feeding those diodes and the 6800uF caps. Does that AC have to go through any of those connectors like the one that turned brown in post 13 ? Give any of those Molex type connectors a little drop of contact cleaner and move them around to clean off any oxides on the pins. Don't touch the pins with your fingers.

[The Dude]

Ok, the low voltage supplies use half-wave rectification, so some 60Hz ripple is normal.
But the ripple level from your scope pics (over 4Vpp) is excessive. Check the 220µ filter caps. When replacing observe polarity.

^^^^ This. 4Vpp AC on a -13VDC supply is way too much. I know you subbed caps on that supply, but something is still wrong here. Maybe the caps aren't grounded/you lost a ground, maybe leaky rectifier, etc.? At any rate, I 'd concentrate on this until you can get that supply cleaner.

[Valvehead]

Check the AC feeding those diodes and the 6800uF caps. Does that AC have to go through any of those connectors like the one that turned brown in post 13 ? Give any of those Molex type connectors a little drop of contact cleaner and move them around to clean off any oxides on the pins. Don't touch the pins with your fingers.

only 1 molex , it has been removed. i have 3vac where it should be at the diodes

[Valvehead]

^^^^ This. 4Vpp AC on a -13VDC supply is way too much. I know you subbed caps on that supply, but something is still wrong here. Maybe the caps aren't grounded/you lost a ground, maybe leaky rectifier, etc.? At any rate, I 'd concentrate on this until you can get that supply cleaner.

I just texted the owner and asked if he wants all electrolytics replaced . Im betting he says yes (he loves the amp)

the noise doesnt change when switching from tube rect to diodes

[The Dude]

You could recap the entire amp and still have the problem. Personally, I'd troubleshoot the problem first rather than just shotgunning all the caps. It could be a connection/ground problem, rectifier problem, etc. and may not even be faulty caps. The problem with your low voltage supply (too much AC on -13V rail) has nothing to do with tube or SS HT rectifier switching. The low voltage supply is always the same. I'd highly recommend finding the problem before just wholesale replacing caps.

[Valvehead]

Owner said go for it. Im pulling the board. In the immortal words of Corrado Soprano " God f... it all . "

[Valvehead]

Just an update....I threw in the towel after many hours . New tubes , all new electrolytics, all voltages ok , chop-sticked it , etccc. Now its developed a new , intermittent buzz noise to join all the other hum and buzz. . Im out. Owner is grabbing it Saturday and shipping it to Mesa. No one around here will work on it ! !

[DrGonz78]

If someone sends me the Boogie I think hmmmm…

I think we should all go on a mission to gut out these amps and put in an actual repairable circuit.

[The Dude]

Personally, I wouldn't buy a Boogie. I think they are overpriced, difficult to service, and the sound doesn't justify the price. That said, I'm not opposed to working on them. As I've said before here, you just have to charge for the extra hassle. Further, a customer who can afford a Boogie should expect to pay more for service.

Edit: I am curious though, Did all the work done on this amp ever correct the 4VAC on the -13V DC supply?