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Old 07-21-2007, 02:52 PM   #1
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Help with Ampeg V2

I just posted this in the "Vintage Amp" section before realizing that this might be a better place to get help:

I just bought a V2 and the Reverb is not working. When I hit the side of the cab I get the reverb "crash" sound. I have pulled the tranny and taken a look at the reverb tank. The only visible problem is that the cable plugged into the "output" jack has a a big dent in it from being pinched or tighten against some thing. The dent goes through about 1/2 of the cable but it is not broken or showing any exposed wiring. I didn't think to check continuity before putting the amp back together.

My question is: if I can here the reverb "crash" when I hit the side of the cab(when powered up) , does that mean that it is most likely not this cable since it is on the "output " side? Any thoughts would be appreciated. Thank you.

Regards,

Tom
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Old 07-21-2007, 04:49 PM   #2
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Quote:
Originally Posted by Dr.Tom View Post
...My question is: if I can here the reverb "crash" when I hit the side of the cab(when powered up) , does that mean that it is most likely not this cable since it is on the "output " side? ...Tom
If you mean "Output" from the tank then, yes, that cable is good. It is then likely that you have a problem in the drive part of the circuit (Check the tube, input cable etc.) or the input wiring to the reveb tank. It is common to find broken wires that connect the tank connectors to the internal spring transducers. Next time you are inside check the continuity of all the wires at the tank connectors. For an Ampeg, you sould get around 200 Ohms DC resistance when you measure the tank transducers. If the drive (Input side) is open, look for a broken wire inside.

BTW when you say you "pulled the tranny" did you men the chassis? Here, we take tranny to mean transformer.

Regards,
Tom
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Old 07-21-2007, 05:19 PM   #3
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Quote:
Tom Phillips

BTW when you say you "pulled the tranny" did you men the chassis? Here, we take tranny to mean transformer.
Tom,

Thank you for the reply. It is very helpful. Yes I did mean chassis rather than tranny.

Regards,

Tom
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Old 07-21-2007, 05:23 PM   #4
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Tom,

Which tube is the reverb tube ? Thank you,

Tom
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Old 07-21-2007, 05:52 PM   #5
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Reverb driver is the 6CG7, looks like a 12AX7 but taller. sits next to the 6K11 triple triode
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Old 07-21-2007, 09:21 PM   #6
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Dr Tom,

A few other ideas.
1) You can temporarily wire the tank backwards by hooking the output cable to the input. If you still get the crashing sound then you know that both transducers are working. (Still need to verify that it's the correct tank for an Ampeg. A tank designed for a classic Fender will not work in a V2.

2) Since the reverb was not working when you got the amp you should consider the possibility that the tank may not be original. In that case it may not have been replaced with the correct part. Are their any numbers printed on the reverb tank? An example would be 9FB2A1C but a lot of the OEM tanks don't have those numbers so it's not conclusive if you don't find that number. There will also be date code format numbers which can allow us to tell how old the tank is.

Have you verified that the input reverb cable is good yet?

Regards,
Tom
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