Tube rolling in a Custom Vibrolux Reverb

Discussion in 'Amp Central Station' started by Mike H., Jul 17, 2019.

  1. Mike H.

    Mike H. Tele-Afflicted Silver Supporter

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    I've owned a '95 Blonde Custom Vibrolux Reverb for quite a while. I always liked it as a gigging amp, but it got a little too dirty too quick on the volume knob for my taste. I moved on to a '63 Vibroverb Reissue and a 1967 Blackface Vibrolux Reverb because I wanted more clean headroom. The CVR has been in my practice space for years. It recently got a rip in the grill cloth, so I brought it home to replace it with an oxblood cloth, something I always wanted to do, but never got the motivation.

    While I had it at home, I started doing a few tube substitutions to see how it would alter the sound.
    After a few experiments, I think the amp is sounding better than it's ever sounded. It has more clean headroom than before, and it's dead quiet.

    I replaced V1 and V2 with some JJ 5751's to slightly lower the gain. I replaced the V3 reverb driver with a NOS Mullard 12AT7, and swapped out the phase inverter 12AX7 in V6 with a JJ balanced 12AT7.
    The amp just came alive with this combination. There's really no other way to describe it.

    I just wanted to share my experience with anyone else who has a CVR, and wants to get a little more clean headroom with less noise without doing the Moyer Mods.
     
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  2. archetype

    archetype Fiend of Leo's Silver Supporter

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    Thanks for posting the specifics. Have you considered converting to '63 VVRI specs? My understanding is that it's just changes to the values a few small components. Same circuit, tubes, and transformers.
     
  3. Mike H.

    Mike H. Tele-Afflicted Silver Supporter

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    I have a real '63 VVRI, so I don't want to molest the CVR.
     
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  4. dannyh

    dannyh Tele-Afflicted

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    Op...what speakers are in your CVR? Some of the early blonde ones came with the blue frame alnicos iirc. Just curious...
     
  5. Mike H.

    Mike H. Tele-Afflicted Silver Supporter

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    The original speakers were replaced by the previous owner with Mojotones. One of the Mojotones died and I replaced it with a Jensen P10R.

    I'm thinking about replacing both speakers with the Eminence Legend 1028K. I have those in my '63 VVRI and they sound great.
     
    Last edited: Jul 18, 2019
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  6. dannyh

    dannyh Tele-Afflicted

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    I have 1028Ks in my VVRI, I agree.

    I was asking as I’d seen Fender promo pics showing the CVR with blue frames but never saw one with them in person, wondered if that was just a prototype pic I’d seen...thanks!
     
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  7. Wally

    Wally Telefied Ad Free Member

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    The CVR was introduced in 1995. Sometime not long after that, Fender stopped using those Eminence speakers and began using the Jensen’s.....cosmetics, I suppose??? They liked having a label that loosely resembled the Jensen’s of old????
    I don’t find it necessary to do the Moyer mods in the CVR. I do like to establish a negative feedback loop with a potentiometer for adjustment, and I like to install a bias adjustment pot. The lack of negative feedback is the reason for the noise, ime. One can take the feedback back to stock VVRI values or heat it up by increasing the resistance with the pot. There is a point beyond which imho there is no reason to increase the resistance....so the lack of a NFB loop causes noise that need not be there....ime and imho. There is a great place for the bias adjustment on the back of the chassis to the left of center. There is already a hole in the chassis underneath the pack panel....just put a hole in the panel and there you are.
     
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  8. tweedman2001

    tweedman2001 Tele-Afflicted

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    Wally is right. I have a Blonde 95 with the blue frame Eminence speakers.
     
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  9. swampyankee

    swampyankee Tele-Holic Gold Supporter

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    I had both a modded CVR and A VVRI for a bit. My CVR came with P10R's. My VVRI came to me with a mix of ceramic and alnico speakers. I liked the P10Rs better so I swapped them into the VVRI and sold the CVR with the mixed pair.
    If I had kept the CVR I was thinking of making it my "hotter" amp by giving it back its original circuit for less headroom, along with a pair of ceramics.
     
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