classic 50

[mikejanbohn]

Ok here's another one...I have a Peavey Classic 50 and it was new in 74'
I replaced the 6l6s and it sound "hummy-like"........whats the most likely thing thats wrong???? jmb ps thanks for the help.

[WholeToneMusic]

hum

Are the Filter caps original?

[mikejanbohn]

yes ...what are filter caps..???

[WholeToneMusic]

The filter caps filter out the DC ripple current after the rectifier converts AC signal to DC signal. They are the largest capacitors in the amp, They dry up after 10 to 20 years. You should bleed them before you poke around in your amp. they hold deadly amounts of voltage. I usually use a 1.5k wire wound (when the amp is off) with alligator clips on both ends across the first filter cap, If you do not have one you can use an insulated screw driver if your brave and touch the + end of the cap to the chassis with the screw driver, If your startled by large pops then I would use a Hook up wire with alligator clips on both ends and hook it from pin 1 of V1 to ground and leave it for 30 seconds. Anyway you can usually tell if the filter caps are done by checking visually for any signs of leakage or bubbling on the sides of the caps.

[Enzo]

ANd I would point out that your amp is a "Classic" not a "Classic 50." Classic 50 is a current model and is nothing at all like the Classic.

[Amp Kat]

Aren't those can caps in there Enzo or is that the Musician ? That would be the main cause in that amp after only 35 years.

[Enzo]

Oh hell, I don't remember. I'm lucky if I remember lunch anymore.

COme to think of it I haven't had any... I'm off to the gas station for hot dogs.

[mikejanbohn]

so ...do you think its the filter caps??? what about the tranformer.???( I'm pulling this out of mt ass...you know...)
I have a friend who might be able to do the work , it I can come up with the probable cause. thanks for you kindness....

[WholeToneMusic]

I would replace all the Electrolytic capacitors (Polarized- the ones with + and - on them) even if they are cans they can dry up, the electrolyte dries up from age. Your should also replace the coupling capacitors while your at it. Hey Enzo could you pick me up some nachos while your at the station?

Hum can come from 60 hZ which is the A.C. line or heater filament or 120 hZ which is the D.C. power supply of the amp.

The most common cause of amp hum is from faulty filter caps, bad output tube, or a loose ground connection. You can check all the voltages that the Power Transformer should be supplying to see if they are correct to rule out the Power Transformer.
I would visually inspect the + sides of the Electrolyic capacitors and look for leakage or bubbles first.

[clintronics]

Schematic PV Classic

Im looking for the schematic for a PV classic. Ths one with 2 6L6s and all transistor preamp.

[TD_Madden]

call or email Peavey...they will more than likely provide a schematic....and probably for free.