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Post by rockman627 on Oct 9, 2021 21:32:46 GMT -5
I have a Deluxe Reverb that was Mike Marsh's prototype for his Clifton Reverb line. As a prototype, he was obviously trying this and that and it is a bit of a rat's nest in there. It's currently not working and I'm thinking of rebuilding it to a more straightforward DR. Then it occurred to me that in a few times I gigged with it, it wasn't loud enough. I wondered what Fender amp was in the 30 watt region and it seems the VibroLux Reverb fit the bill at 35 watts. So I think that will be my project: to turn a Deluxe Reverb to a Vibrolux Reverb.
A preliminary investigation of the DR layout (AB763) and the Vibrolux layout (AA964) shows the circuit boards to be the same. Can someone confirm this for me, please?
And it looks like a Hammond 290CX is correct for a VibroluxR and will drop right in. My original output transformer measures 3.125 in. screw to screw. A Hammond 1760J output transformer measures 3.56 in but I think that leaves me enough room to drill a new hole. It looks like the other transformers can stay.
So it would seem you can take a deluxe reverb, put in more powerful transformers, change to 6L6's, and you have the more powerful vibrolux reverb (with 1 speaker). That seems too easy. Please point out any errors in my thinking before I start ordering parts.
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pdf64
Wholenote
Posts: 556
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Post by pdf64 on Oct 10, 2021 4:51:56 GMT -5
I eventually did that to a DR build, after wrecking the PT and OT by cranking it using 6L6.
I used a Mojo Vibrolux PT, 776 I think, which needed the chassis opening up a bit. Easy enough to do with a nibbler tool, but somewhat irreversible.
It all worked fine but I kinda regret it now. The amp seems a lot heavier with the beefier iron, and I’d quite like a DR.
It was loud enough as a DR with 6V6 if using an EV speaker, which sounded great.
But no, I had to try it with 6L6, doh!
So I suggest get your amp working right as a proper DR, and verify that the previous perceived lack of SPL couldn’t be rectified by a more sensitive speaker. If necessary, buy an EVM12L secondhand to check. You can always sell it on if it doesn’t work out, so it shouldn’t cost much to experiment.
Also, it’s a bad idea to do mods and repairs at the same time. The amp’s fault needs chasing down and a definite identification of the root cause making, otherwise you risk putting a lot of work into it and it still doesn’t work right.
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Post by Peegoo 🏁 on Oct 10, 2021 7:32:59 GMT -5
I agree ^^^
It's generally considered to be "throwing money off the back of a train" when converting an amplifier into something it wasn't intended to be.
BUT if it's a hobby thing and you love to tinker (like I certainly do), by all means go for it. Just make sure you seriously consider all your motivations for doing so.
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Post by rockman627 on Oct 10, 2021 12:50:22 GMT -5
Yes, this is a tinkering situation. I have a 1962 Fender Concert that wasn't working and I built a new circuit with a turret board and it worked out well and now I have a bug for tinkering. The Deluxe (actually, a Marsh Amps Clifton Reverb)has a bunch of mods that I ended up not caring for: a fixed/self bias switch, a gain boost knob in the back, reverb dwell and tone in place of vibrato. Those mods also make the circuit board indecipherable to me. So I'm going to get a Deluxe Reverb turretboard and fill it with overspecd components (1 watt resistors instead of 1/2 watt, etc.) following the AA964 layout. I have an easier time using turret boards. Hopefully I'll have a 1 speaker Vibrolux Reverb that should meet most of my jamming/gigging needs.
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Post by rdr on Oct 11, 2021 14:22:05 GMT -5
A smart guy at the old site spoke about converting a DR to 6L6. Other than beefing up the OT, he also increased the size of the filter caps and used a Weber Copper Cap (I think WS1) with no voltage drop.
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Post by rockman627 on Oct 12, 2021 20:57:22 GMT -5
Hey, I've noticed something on the layouts that confuse me. The layouts on the DR and the VR look almost identical except for the tubes, power and output transformers; yet nearly all the voltages on the DR are higher than the VR. I would have thought the VR would have higher voltages so the 6L6's could deliver 35 watts.
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pdf64
Wholenote
Posts: 556
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Post by pdf64 on Oct 13, 2021 4:51:02 GMT -5
The HT supply may be stiffer, better regulation on the HT winding. The schematic voltages are at idle, not at full power output. Those are very different conditions in an AB amp.
And the OT may have a lower primary impedance, probably around 4k rather than 6k6 of the DR. Thereby making use of the 6L6’s higher cathode current capability.
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