Biasing VH4S...

  • Thread starter Thread starter GtarLover
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GtarLover

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So, I have read the info on matched quads for the VH4 and readings from 80ma - 100ma for the 2 pairs, I am installing new =C= 6550's :D Anyway, I am curious if there is any difference between the VH4 and VH4S, in terms of the pairing. I read Mark2C's comments about outer and inner pairing for the VH4 and was just wondering if things were any different for the VH4S because it's stereo. Maybe this makes no difference and I am guitarded, well I am, fine :doh:

Would appreciate any guidance, as the Diezel web site doesn't say anything about biasing VH4S, only VH4. By the way, my VH4S is 2002 model, if that matters. Thanks in advance.
 
No difference. There is only one bias pot so it should bias the same way as the VH4. Inner pair and outer pair at 80mA or so.
Since they are on the same bias supply you will have to use a "close enough" reading between the pairs as there is never a perfectly
matched quad. Generally a 5mA difference is normal so wherever you bias the inner or outer pair will be a few mA higher or lower.
I bias the =C= 6550's at 70mA per pair in the VH4. To my ear it's perfect, but you can easily try 80-100ma.
 
Hey Mark 2C,

Thanks for the info, I suspected, yet never hurts to ask. Now the unthinkable has happened, I replaced the preamp AND poweramp tubes and I get a fizzy, crackle, very little tone at all :no: What happened!!! Advice, HELP!!!

OK, I tried a different preamp tube in V1 and it's all good now. I frickin' HATE when a new tube is crap, right out of the box :gethim:
 
I have had more than enough bad pre's out of the box or ones that last ten minutes to fill a shoe box.
I usually burn my tubes in for four hours after biasing then I re-check before putting the chassis back in the head shell.
You never know how the tubes will react until they are settled in. Just for good measure check your bias again in a few
days to make sure it did not drift too far from where you set it and re-adjust of necessary.
 
MARK2C":2o7ki3ja said:
I have had more than enough bad pre's out of the box or ones that last ten minutes to fill a shoe box.
I usually burn my tubes in for four hours after biasing then I re-check before putting the chassis back in the head shell.
You never know how the tubes will react until they are settled in. Just for good measure check your bias again in a few
days to make sure it did not drift too far from where you set it and re-adjust of necessary.
Click to expand...

Pop, fizz and crackle are more than likely pre's.

V.
 
Yeah, it was a bad pre in V1, right out of the box!! I will be sending it back,let's see what happens.

I think you are right Mark2C, I will let these settle, as you mentioned and check again to see how things are set.

Anyway, new =C= 6550's are in!!!! New pre tubes as well...we'll see how she roars :D

Anybody know a good place to get the Ruby HG+ pre tubes Papa has been recommending? I can't seem to find any :(

Peace + Rock :rawk:
 
Well Goose, the pain of it is, I had to leave town this morning, early. So, I am sitting here on the damn computer with NO VH4S. I will have to give you the full skinny after I get home. Won't be for 10 days :doh:

I have a feeling though :D
 
ok plz let me know :thumbsup:
77FZ4_DiezelVH4Shead20april2010klein.jpg
 
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