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Ampeg V4 Club

#921
Thanks for the replies.
The original Magnavox tubes still look and sound like new, but I would like a spare set. I'll look into your suggestions.
Is it worthwhile to add a variable resistor for the bias circuit? As far as I can tell, I would just need to replace one resistor (R49). The bias resistor is 75k, I think. Would a 100k linear variable resistor give enough adjustment range? I haven't done any measurements yet, but I think the amp is biased pretty cold as is.
Thanks!
 
#922
Eric_Allard said:
Thanks for the replies.
The original Magnavox tubes still look and sound like new, but I would like a spare set. I'll look into your suggestions.
Is it worthwhile to add a variable resistor for the bias circuit? As far as I can tell, I would just need to replace one resistor (R49). The bias resistor is 75k, I think. Would a 100k linear variable resistor give enough adjustment range? I haven't done any measurements yet, but I think the amp is biased pretty cold as is.
Thanks!
Click to expand...

I set mine up with a marshall style 22K pot and a 68K resistor in place of the 75K bias resistor. Having the bias pot in series with a resistor helps guarantee that if the pot fails or moves you've got something keeping the tubes close to the right range, at least in theory. Anyways, when I got my amp all set and adjusted the bias to a good range I checked the resistance across my pot/resistor pair - read 74.5K. It might be a little cool but that's not a bad thing in a bass amp and helps with tube life.
 
#927
Eric_Allard said:
I looked at that same listing. He's asking for $25 shipping to Canada, which is ridiculous. I've sent him a message asking for a better shipping quote.
Click to expand...

Email Brent Jessee at Audiotubes.com, he's got 6K11s listed for $24 and anything I've bought from him in the past has been good. Not sure what his shipping to Canada would be. http://www.audiotubes.com/bjtubes.htm
 
#930
JN8642 said:
Would love to join this club! If anybody knows anybody selling a 70's V4 in the New England area(or anywhere) I'm interested.
Click to expand...

There is a clean V4 I see on the local to me North Jersey Craigslist for $900. It's a bit high but you may be able to get the price down, it's been listed for awhile. I cannot copy and paste from my phone but I saw it earlier if you are close enough to NJ.
 
#932
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Its been a while since ive played this set-up. Its a pretty kick-@ss and take names type of rig. Hoisting it up on the flight case makes a pretty large difference in the amount of volume thats needed, which wasnt even close to half power last night. Its got a much more focused low end characteristic over the B15 215, but still cant dish out the overdrive like the B15. The volume necessary for the nice dirt in the V4 its high enough to catch looks from the band leader in certain clubs. Hopefully tonight at a venue with better monitors ill be able to hit the sweet spot!

cheers!
 
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#933
Hello. Quick question. Suppose someone didn't have or download a manual and ran two 8ohm cabs together through only one 4ohm output for 2 gigs and a few hours of home use. Would that have done any damage?
Both 4ohm outputs seem to be working, now and the output is tremendous but should I get it checked out?
Guess I was used to my 70s V4. Thanks.
 
#935
gerrywarwick said:
Hello. Quick question. Suppose someone didn't have or download a manual and ran two 8ohm cabs together through only one 4ohm output for 2 gigs and a few hours of home use. Would that have done any damage?
Both 4ohm outputs seem to be working, now and the output is tremendous but should I get it checked out?
Guess I was used to my 70s V4. Thanks.
Click to expand...

Doesn't sound like you did anything wrong. Two 8 ohm cabs daisy-chained together is a 4 ohm total load. That should be run off of the 4 ohm tap.
 
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#936
Hey, thanks!
20151001_224805.jpg
Felt right to me too but I happened to see a video that made me download the manual. It says, if connecting two, 8ohm cabs, use both 4ohm jacks and to use only one, if connecting only one 4ohm cab. Something about parallel wiring?
Thanks again.
Pic of my 70s and my reissue.
 

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#939
Tried again and it seems louder with the cabs seperated. Hmmm, could be just me. Guess it doesn't matter, since either way the cabs reach their limit way before the amp. SWR Goliath sr. is my gigging cab anyway.
Did my last 10 summer gigs with it and I still can't believe this 100w head is pushing a 1000w cab. And I'm in a Reggae band.
Thanks for your patience!
 

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