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Vibrate in 62 Fender VL

corpse

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Vibrato in 62 Fender VL

Works great at higher settings but pretty undramatic at 2-4. Is it the tube (I hope)?

I hope autocorrect doesn’t start a nuclear war. I meant Vibrato.
 
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Wally

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Corpse, Leo got the wrong word, so it is no problem if you misspell it!!!
That circuit is a bias vary tremolo circuit and therefore depends on the biasing of the power tubes to be set 'properly' in order to assure maximum strength. IF the bias is set for to much current draw, the trem can even stop functioning completely.
OF course, my first question would be....are the electrolytic capacitors fresh? IF not, then that needs to be addressed.
 

corpse

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Thanks guys. Let me check which one Sonar and that won’t happen until next weekend as I am headed north in a couple of hours.
It is time for a trip to the bench I guess.
 

corpse

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Hey Sonar
The speed works fine- it is the intensity that cuts off at five or six.
 

LeonC

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Assuming it isn't the oscillator tube, and that the power tubes aren't WAY mismatched, there's a good chance it's one or more caps in in the oscillator circuit...particularly if they're the yellow Astrons...by now most of those are passing direct current... Yeah, take it to your tech. These things are generally pretty easy to diagnose, once you have the amp on the bench.
 

oldog

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I the amp is biased hot the Vibrato will sound weak. You have to bias amps with power tube bias vary style Vibrato fairly conservatively to have a strong Vibrato.
 

El Gringo

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This reminds me of my Brown 62 Fender Super which has the Vibrato and it is nice .
 

corpse

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It is going for a spa visit in Chamblee- Jeff Andrews will get it singing sweetly again.
 

deytookerjaabs

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When I recapped my '61 BandMaster most of those yellow astron caps were kaput and I've talked to techs who've said the same thing. That said, it wasn't exactly well cared for and I'm not sure if they used those caps into '62. At first I did the big caps but I could tell the sweep on some of the pots was too weak just on common sense alone. With each yellow cap replaced the amp just came to life. Vibrato/vibe sound went from wee eee wee to wooohshoooshooooshoooowwww, the bass/treble pots went from a tiny sweep to a big sweep etc..etc. My buddy got around to measuring the old caps and said "you could have just built the amp from random parts." When I sold the amp the new owner was saliviting over the bag of yellows even after I reassured him they're dead.

Yeah, I'm sure your tech will get some numbers and decide who stays..and who goes!
 

corpse

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Wally the caps are new looking- three blue and two black all new.
 
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corpse

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So the postop is interesting. The yellow Astrons were leaking- oddly the power tubes were badly mismatched and the V2 12AX7 was weak. I have some NOS stuff, incl a NIB set of matched GE 6L6GCs. But getting back to the original issue, it turns out the intensity knob in the 6G11 is different from the 6G11A. It worked fine but has the wrong sweep- it was factory original. Picking it up today. How is the intensity sweep in your early 60’s Vibrolux?
 

Wally

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There ya go! Nothing like a good tech, eh? I checked the schematics, and sure enough...the 6G11 used a 250K audio taper while the 6G11A calls for a 250K linear taper.
 

corpse

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Wally- he is decidedly unsentimental about original parts- esp ones that leak. So I got a new pot, a lamp, a bag full of caps, (my) new tubes and a killer amp. Now the sweep goes from 2.5- max on the intensity but it is there and in yo face when it is on. And with properly matched GE 6L6GC's (hey Big Al) it spits nails. Thank you for your help Wally, Dey and all.
Total bill was $200.
 

Wally

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Corpse, just to clarify for my future reference... Is your amp a 6G11 or a 6G11A? Can you take a look at the pot he removed to see if it is a linear or an audio pot? Much appreciation......
 

corpse

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Hey Wally- the tag is printed 6G11 with an "A" in blue ballpoint after. The Pot says 250K AUD.
The amp sounds great.
 

Wally

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Hey Wally- the tag is printed 6G11 with an "A" in blue ballpoint after. The Pot says 250K AUD.
The amp sounds great.

Thnaka for the feedback, corpse.
So, if that audio taper pot is what was pulled the. The amp was NOT a fully-developed 6G11A as the 250k audio taper pot was spec’d in the first 6G Vibrolux...the 6G11. Thanks for the reply.....I will make notes for future reference.
 

Wally

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Interestinglygly, the 6G9 and 6G9A Tremolux schematics call for the audio taper while the 6G9B calls for the linear taper. The 6G3 Deluxe has one schematic, and that calls for the linear taper. I suppose the Deluxe was correct from the beginning, right? The 6G2 Princeton always used the linear pot there, too.
 

Professortwang

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Hello all

Just thought that I would add some information. I have a 62 Brown Vibrolux. The tube chart says that the amplifier is a 6G11A however the chassis matches the 6G11 schematic. The most significant difference between the two is the taper of the intensity pot as mentioned earlier in the thread. There are also a couple resistors that are different values one of which is in the bias supply. Here is a youtube video of Simo playing a SG junior into a Vibrolux that sounds fantastic!

 
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