Epiphone Valve Jr. AC in.

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Curtis70
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Epiphone Valve Jr. AC in.

Postby Curtis70 » Wed 05/08/19 4:38 pm

Hello. I have acquired a Epiphone Valve Jr Head V2 and it has a Hammond OT installed so I opened the amp up to take a look at the inside to see if anything else was changed. There were a few resistors and caps that were replaced but the thing that throws me off is the BROWN wire that runs from the AC in to the power switch. There is a 25 watt 20 Ohm sand block resistor installed in line. Can any one tell me why they would do that? Thank you.

More Info: I got to try the amp out today and it was dead quiet till about half way then there was some volume. Cranked all the way up it's clean and not loud at all. So I replaced the (El84) that is labeled 6BQ5 USA GM DELCO with a JJ EL84 and the amp is louder than my other head. I couldn't find much info on the GM tube. Any thoughts? Thanks.
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Daviedawg
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Re: Epiphone Valve Jr. AC in.

Postby Daviedawg » Thu 05/09/19 2:20 am

Welcome.

The effect of the incoming power line resistor is to reduce the voltage arriving in the amp. So my guess is that someone had higher than standard supply voltage at the wall and wanted to reduce it without modding the amp. I can think of no other reason just now.

6BQ5 and EL84s are close to equivalents so should not account for the big volume difference. So something else was in play like dirty pins or a faulty valve.

Dd
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Curtis70
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Re: Epiphone Valve Jr. AC in.

Postby Curtis70 » Thu 05/09/19 6:24 am

Thank you for the reply Dd. The bottom of the tube is fairly brown but the socket looks fine. It could of been something they just put in when they sold it but then why leave the JJ ECC83S? Luckily nothing blew up. My thought on the resistor were either a damper or an attempt at a slow warm up like a standby or something. Well everything works and sounds good. Thank you.
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zuceno
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Re: Epiphone Valve Jr. AC in.

Postby zuceno » Sun 06/02/19 7:04 am

Curtis70 wrote:
Wed 05/08/19 4:38 pm
I replaced the (El84) that is labeled 6BQ5 USA GM DELCO with a JJ EL84 and the amp is louder than my other head. I couldn't find much info on the GM tube. Any thoughts? Thanks.
GM as in General Motors, Delco as in auto-electrical supplies. The tube was originally supplied for use in a car radio. They didn't actually make tubes, they bought them in from large manufacturers and had them labelled up, as did Motorola (Motorola tubes are mostly relabelled RCA).

Other markings can help identify the actual maker - a "stop sign" 6BQ5 mark would likely be RCA, a rectangular box around a 6BQ5 mark might be Raytheon or Tung-Sol. Sometimes they come with RETMA codes that indicate the manufacturer - for example, 188 would be GE.
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roaddawggie
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Re: Epiphone Valve Jr. AC in.

Postby roaddawggie » Thu 06/20/19 9:21 am

Hello all,

I am new to the forum. I have just obtained an epiphone Valve Junior. I would like to modify it to a marshall 18w.

My question is, where might I obtain this information? Am I in the correct forum.

Thanks for your help I look forward to learning a lot and eventually contributing some relevant / usual information .

Thanks
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crgfrench
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Re: Epiphone Valve Jr. AC in.

Postby crgfrench » Thu 06/20/19 10:31 am

roaddawggie wrote:
Thu 06/20/19 9:21 am
Hello all,

I am new to the forum. I have just obtained an epiphone Valve Junior. I would like to modify it to a marshall 18w.

My question is, where might I obtain this information? Am I in the correct forum.

Thanks for your help I look forward to learning a lot and eventually contributing some relevant / usual information .

Thanks
This might help:
http://www.wattkins.com/files/wattkins/ ... 20v1.0.pdf

also

http://www.wattkins.com/projects/junior-chassis
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roaddawggie
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Re: Epiphone Valve Jr. AC in.

Postby roaddawggie » Wed 07/03/19 2:38 pm

Thanks for the Watkins documents I have a new OT so this will help a lot. Thanks again I will keep y'all posted as I progress.
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