I appreciate the info and re-assurance about running wires above board.
Thanks
Deluxe Reverb Build
Moderators: pompeiisneaks, Colossal
Re: Deluxe Reverb Build
Woah, That is NOT a Deluxe output transformer !NickC wrote:[img1728]http://homepage.mac.com/swamptone/DeluxeReverbTop.jpg[/img]
1728]What kind of tubes are going in there ?
rd
Re: Deluxe Reverb Build
Fat Stack?
Re: Deluxe Reverb Build
OPT is a Mercury Magnetics Toneclone Fatstack for Deluxe Reverb. It is much larger than the stock OPT. 8 ohm output.
There will be a standard consort of preamp and reverb/vib driver tubes: preamp V1 & V2 = 7025, V3 = 12AT7, V4 = 7025, V5 = 12AX7, V6 = 12AT7, GZ34 rectifier . Power tubes can be 6V6 or 6L6; the amp will support either with a bias reset. I intend to run it with a pair of 6V6 initially.
There will be a standard consort of preamp and reverb/vib driver tubes: preamp V1 & V2 = 7025, V3 = 12AT7, V4 = 7025, V5 = 12AX7, V6 = 12AT7, GZ34 rectifier . Power tubes can be 6V6 or 6L6; the amp will support either with a bias reset. I intend to run it with a pair of 6V6 initially.
Re: Deluxe Reverb Build
I've not see the PS board on top (outside the chassis) like that before. This doesn't cause any problems with the EMFs from the trannies?
Re: Deluxe Reverb Build
surfsup wrote:I've not see the PS board on top (outside the chassis) like that before. This doesn't cause any problems with the EMFs from the trannies?
The power supply (filter cap) board is covered by a metal cover (a.k.a. doghouse). The metal cover helps shield against EMF. It also contains potential damage in the event of exploding electrolytic caps. It protects the main board from molten cap innards. In the photos above, the doghouse has not yet been installed.
That topology is typical of many Fender amps including Deluxe Reverb, Bassman, Twin Reverb, Super Reverb, Bandmaster, etc.
I guess it's a trade-off. In exchange for protecting the main board, you make some concessions for lead routing; a slightly more difficult layout to work with.
Re: Deluxe Reverb Build
I know that Mercury transformers are great but I don't understand the needd to fatstack a Princeton or Deluxe.
I would do that for a Marshall Plexi 100w to get the bass response up where I need it and push some air.
I would do that for a Marshall Plexi 100w to get the bass response up where I need it and push some air.
Re: Deluxe Reverb Build
M Fowler wrote:I know that Mercury transformers are great but I don't understand the needd to fatstack a Princeton or Deluxe.
I would do that for a Marshall Plexi 100w to get the bass response up where I need it and push some air.
I got a good deal on eBay. Even so, I might have been better going with a suitable Heyboer, Edcor or Hammond.
Research reveled the MM would allow a switch to a pair of 6L6s down the road (as per Aiken Deluxe Reverb mods). I like that flexibility.
Re: Deluxe Reverb Build
Love it!
Hard to beat a good BFDR.
You gotta let us know how it sounds.
Hard to beat a good BFDR.
You gotta let us know how it sounds.
<i> "I've suffered for my music. Now it's your turn."</i>
Re: Deluxe Reverb Build
I guess I didn't realize how much bigger the Fatstacks were, not having used one yet $$$NickC wrote:OPT is a Mercury Magnetics Toneclone Fatstack for Deluxe Reverb. It is much larger than the stock OPT. 8 ohm output.
There will be a standard consort of preamp and reverb/vib driver tubes: preamp V1 & V2 = 7025, V3 = 12AT7, V4 = 7025, V5 = 12AX7, V6 = 12AT7, GZ34 rectifier . Power tubes can be 6V6 or 6L6; the amp will support either with a bias reset. I intend to run it with a pair of 6V6 initially.
I've seen the large core Deluxe option that's offered by David Allen but those use the 2 screw mounting, not 4 like what you've got there.
If you get some power readings on it I'd like to see how much increase there is with just a 6L6 swap and bias.
Is it the stock B+ voltage ?
looks good
rd
Re: Deluxe Reverb Build
I was looking at the pics you posted (nice build, btw) and had a few observations.
1) I see that you've grounded the screen supply separately from the preamp supply (as you should do), but Fender did not. They tied the screen cap ground to the preamp cap grounds. Gerald Weber surmised (and I have more or less confirmed in practice) that they did this because by sourcing the reverb driver voltage from the screen supply yet grounding the reverb driver tube's cathode with the rest of the preamps, it creates enough potential difference between the grounds to (sometimes) induce oscillation in the oh-so-sensitive reverb circuit. If you get any weirdness in the reverb, the fix is to move the ground of the 2K2/bypass cap to the screen ground. You can just run a wire down into the doghouse. You'll need another turret though. If it isn't a problem, don't sweat it; I mention it just in case.
2) When you finalize the lead dress, the B+ wires that run from the doghouse between the circuit board and the backs of the Reverb Channel pots can be enormously hummy. You want to bundle those wires and dress them as close to the circuit board as you can and keep the reverb and tone control wires as far away from them as you can. The tremolo intensity leads carry the switching noise from the neon lamp and cause the "ticking effect" so these want to be dressed away from everything else too. Kind of a tall order for an inch and a half of real estate, I know.
3) Once everything is together, you might want to experiment with carbon comps for the PI plate loads and maybe the third mixing stage. I think it was Randall Aiken who suggested that the beneficial distortion characteristics of CCs are most pronounced where you have high voltage and large signal swings. Just something to fool around with.
Very cool amp (everyone should have one). And it's neat that you've designed for the 6V6/6L6 swap. 5881s are an especially nice alternative.
1) I see that you've grounded the screen supply separately from the preamp supply (as you should do), but Fender did not. They tied the screen cap ground to the preamp cap grounds. Gerald Weber surmised (and I have more or less confirmed in practice) that they did this because by sourcing the reverb driver voltage from the screen supply yet grounding the reverb driver tube's cathode with the rest of the preamps, it creates enough potential difference between the grounds to (sometimes) induce oscillation in the oh-so-sensitive reverb circuit. If you get any weirdness in the reverb, the fix is to move the ground of the 2K2/bypass cap to the screen ground. You can just run a wire down into the doghouse. You'll need another turret though. If it isn't a problem, don't sweat it; I mention it just in case.
2) When you finalize the lead dress, the B+ wires that run from the doghouse between the circuit board and the backs of the Reverb Channel pots can be enormously hummy. You want to bundle those wires and dress them as close to the circuit board as you can and keep the reverb and tone control wires as far away from them as you can. The tremolo intensity leads carry the switching noise from the neon lamp and cause the "ticking effect" so these want to be dressed away from everything else too. Kind of a tall order for an inch and a half of real estate, I know.
3) Once everything is together, you might want to experiment with carbon comps for the PI plate loads and maybe the third mixing stage. I think it was Randall Aiken who suggested that the beneficial distortion characteristics of CCs are most pronounced where you have high voltage and large signal swings. Just something to fool around with.
Very cool amp (everyone should have one). And it's neat that you've designed for the 6V6/6L6 swap. 5881s are an especially nice alternative.
Re: Deluxe Reverb Build
I've hear that there's no point in using CCs in this type of PI. however, earlier in the circuit can be nice
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Re: Deluxe Reverb Build
Found the article; it wasn't Aiken (who deals only noise of the various types), it was R.G. Keen: http://www.geofex.com/Article_Folders/c ... oncomp.htm
The issue with using CCs in the PI is the feedback loop, which dimishes the effect.
The issue with using CCs in the PI is the feedback loop, which dimishes the effect.
Re: Deluxe Reverb Build
Thanks Firestorm!
Your observations, and the Keen reference, are very helpful. I've revisited the wire-dress and made some adjustments, using cable ties to bundle and control wire orientation .... paths crossed at 90 degrees. As you noted, there's not a lot of real estate to work there.
I was close to installing a GZ34 and testing some voltages with the remainder of the tubes out. But thought first I'd drill holes in the cab for the chassis straps (easier and safer while tubes are out) by lining up the chassis in the cab and marking where to drill. In that process I hit an unexpected snag. That nice, big output transformer ran smack into one of the speaker posts .... it doesn't clear by about an inch. I can't cut off the post enough and still have clearance to mount the speaker. Looks like I'll have to remove the baffle, remove the cloth and rotate the orientation of the studs 90 degrees ..... or mount T-nuts to the face rather than the posts (I'd rather the posts, since they aren't as prone to vibrating loose). Then reattach the cloth.
Oh well, onward and upward.
I appreciate the information and advice. Thanks again.
Update / Correction:
The speaker itself doesn't clear the OPT either.
My choice is to swap the OPT for a standard size or build a new baffle board for the cab with the cut-out about 1.5 inches to the left.
I have a Heyboer Deluxe Reverb OPT (but I'd have to pull it from another project .... no big deal).
I wish I'd foreseen this, and am reminded of the old axiom .... measure twice, cut once.
Your observations, and the Keen reference, are very helpful. I've revisited the wire-dress and made some adjustments, using cable ties to bundle and control wire orientation .... paths crossed at 90 degrees. As you noted, there's not a lot of real estate to work there.
I was close to installing a GZ34 and testing some voltages with the remainder of the tubes out. But thought first I'd drill holes in the cab for the chassis straps (easier and safer while tubes are out) by lining up the chassis in the cab and marking where to drill. In that process I hit an unexpected snag. That nice, big output transformer ran smack into one of the speaker posts .... it doesn't clear by about an inch. I can't cut off the post enough and still have clearance to mount the speaker. Looks like I'll have to remove the baffle, remove the cloth and rotate the orientation of the studs 90 degrees ..... or mount T-nuts to the face rather than the posts (I'd rather the posts, since they aren't as prone to vibrating loose). Then reattach the cloth.
Oh well, onward and upward.
I appreciate the information and advice. Thanks again.
Update / Correction:
The speaker itself doesn't clear the OPT either.
My choice is to swap the OPT for a standard size or build a new baffle board for the cab with the cut-out about 1.5 inches to the left.
I have a Heyboer Deluxe Reverb OPT (but I'd have to pull it from another project .... no big deal).
I wish I'd foreseen this, and am reminded of the old axiom .... measure twice, cut once.
Re: Deluxe Reverb Build
It's times like this that a head cabinet is in order especially when going with non-stock iron.