Re: Tube Amp Troubles


"Ryan Stalter" <ryangobie@xxxxxxxxxxx> wrote in message
news:Xns96FD923419FA3ryangobiehotmailcom@xxxxxxxxxxxxxxxx
>
> Hello. This is my first time posting to this group and I hope some of you
> might be able to provide me with some direction. I'm a college kid who's
> trying to learn as much as I can about tube amps and after so much reading
> I wanted to get my hands dirty. I've fixed a few amps for my friends and
> one of them had a broken Ampeg V4 that was giving him extremely low
> volume.
> Needless to say, I took it off his hands to see if I could get it up and
> running. First I just played it to see what was happening. On 10 it wasn't
> at all uncomfortable to listen to. Maybe slightly louder than a
> television.
> Both channels were doing this so I figured it was after the channels
> converged. Then I took this Sunn Coliseum I have and ran the preamp out
> into the power amp in on the Ampeg. No appreciable difference in volume. I
> opened it up and took voltages and everything was within a few volts of
> the
> schematic I have so I swapped the tubes out. No change still. I found some
> resistors that drifted so I swapped them out and still nothing. I don't
> have a scope yet but I tested the AC across the primary of the output
> transformer and got a reading of about 20 volts which according to one
> books power table is about right for a 100 watt amp into a 4 ohm load. So
> just the other day I had some free time on my hands so I went through and
> heated up some joints in the power amp and it seemed to get a little bit
> louder so I played for a minute and just looked at the tubes and while
> idling, the power tubes have a normal blue glow about them but when I hit
> a
> note and hold it the plates start to turn red and when I let go they go
> back to that blue glow. I'd really just like to get this thing up and
> working and back to my friend. Any suggestions? I'd really appreciate it.
> Thanks!
>
> -Ryan

Do you really mean primary ??

20 volts on the Primary is very low.

20 volts on the Secondary is correct for 100 Watts into 4 ohms. If it does
not sound loud then there is something wrong with your speaker. ( or your
hearing )



.

Relevant Pages

  • Tube Amp Troubles
    ... This is my first time posting to this group and I hope some of you ... into the power amp in on the Ampeg. ... schematic I have so I swapped the tubes out. ... books power table is about right for a 100 watt amp into a 4 ohm load. ...
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  • Re: Tube Amp Troubles
    ... This is my first time posting to this group and I hope some of you ... > into the power amp in on the Ampeg. ... > schematic I have so I swapped the tubes out. ... > books power table is about right for a 100 watt amp into a 4 ohm load. ...
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