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Post subject: 80-81 Deluxe Reverb: Silverface with black faceplate.
Posted: Sat Aug 24, 2013 6:41 am
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I just bought an 80-81 Deluxe Reverb. According to the Fender Amp field guide, it's exactly the same as a Silver Face Deluxe, with only the faceplate changed from silver to black. It seemed like a good deal. Does anyone have any experience with the 80-82 "silver" faces? Any thoughts appreciated. I think I got a great deal. If it's the same set up as the 70s silver faces, I got a killer deal. Go ahead, break my heart. Who's played one?


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Post subject: Re: 80-81 Deluxe Reverb: Silverface with black faceplate.
Posted: Sat Aug 24, 2013 6:57 am
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I believe this amp is basically the same circuitry as an AB763 (blackface circuit) with a pull boost volume control.

The cab maybe made of MDF, rather than plywood. Seems like a good deal.

http://www.webphix.com/schematic%20heav ... _schem.pdf


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Post subject: Re: 80-81 Deluxe Reverb: Silverface with black faceplate.
Posted: Sat Aug 24, 2013 9:52 am
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The chassis configuration is based on the A1270 revision but with the pull-boost volume control added to the vibrato channel's circuit. They're solid amps -- I have a '78 silverface edition, installed in a custom-built 1 x 15 cab. If you paid less than a grand you got a deal indeed.

Rawk on!

8)

Arjay

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"Here's why reliability is job one: A great sounding amp that breaks down goes from being a favorite piece of gear to a useless piece of crap in less time than it takes to read this sentence." -- BRUCE ZINKY


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Post subject: Re: 80-81 Deluxe Reverb: Silverface with black faceplate.
Posted: Sat Aug 24, 2013 2:04 pm
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Yeah Arjay... if you look at the circuit of the Deluxe Reverb A1270, it's very close to the AB763. To these old, tired eyes --- the rectifier type and the added pico-farad snubber caps on the 6V6GTs is different. And a hotter grid-to-ground load onto the phase inverter. All stuff easily reversed.

The amp seem to have same tone stack and phase inverter setup. Plus, bias pot.


http://www.webphix.com/schematic%20heav ... _schem.pdf

http://www.webphix.com/schematic%20heav ... _schem.pdf


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Post subject: Re: 80-81 Deluxe Reverb: Silverface with black faceplate.
Posted: Sat Aug 24, 2013 3:18 pm
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BMW2002Ti wrote:
Yeah Arjay... if you look at the circuit of the Deluxe Reverb A1270, it's very close to the AB763. To these old, tired eyes --- the rectifier type and the added pico-farad snubber caps on the 6V6GTs is different. And a hotter grid-to-ground load onto the phase inverter. All stuff easily reversed.

The amp seem to have same tone stack and phase inverter setup. Plus, bias pot.


I never even bothered with it for my '78 chassis -- merely inspected it, replaced one tired bottle (12AT7 phase inverter), fine-tuned the idle bias, then it was off to the races. It sounds nearly as tasty as my silverface '68 AB763.

Arjay

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Post subject: Re: 80-81 Deluxe Reverb: Silverface with black faceplate.
Posted: Sat Aug 24, 2013 5:52 pm
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Retroverbial wrote:
It sounds nearly as tasty as my silverface '68 AB763.Arjay



This is interesting as the difference between sf and bf has always been underlined on this forum, and now you are saying the above :?: :?:


Memphidelity, it would be good if you can post a photo .. not many 80-82 sf are seen on this forum lately.

:arrow:


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Post subject: Re: 80-81 Deluxe Reverb: Silverface with black faceplate.
Posted: Sun Aug 25, 2013 6:46 pm
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Thanks, y'all. I'll try to post something.


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Post subject: Re: 80-81 Deluxe Reverb: Silverface with black faceplate.
Posted: Sun Aug 25, 2013 6:48 pm
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We'll be watching.

Arjay

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Post subject: Re: 80-81 Deluxe Reverb: Silverface with black faceplate.
Posted: Sun Aug 25, 2013 6:55 pm
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My guess is the swing voltage on the 12AT7 phase inverter is the biggest difference maker in tone. Between the AB763 and the A1270.

The 330K-ohm grid-to-ground loading resistors on the A1270 will have much less swing and POTENTIALLY keep the output more linear than the 1 meg-ohm load in the AB763's PI. This move has "CBS" written all over it. As overdriving the PI is what gives a guitar amp some of the characteristic "clipping" tone.

Couple this treatment of the PI with the 2000 pico-farad grid-to-ground stubbers on the 6V6GT -- you can see someone was really worried about instability & linearity in the output stage.

My guess is the stock A1270 will sound much less aggressive, esp at volume, than the AB763.


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Post subject: Re: 80-81 Deluxe Reverb: Silverface with black faceplate.
Posted: Sun Aug 25, 2013 11:13 pm
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BMW2002Ti wrote:
My guess is the swing voltage on the 12AT7 phase inverter is the biggest difference maker in tone. Between the AB763 and the A1270.

The 330K-ohm grid-to-ground loading resistors on the A1270 will have much less swing and POTENTIALLY keep the output more linear than the 1 meg-ohm load in the AB763's PI. This move has "CBS" written all over it. As overdriving the PI is what gives a guitar amp some of the characteristic "clipping" tone.

Couple this treatment of the PI with the 2000 pico-farad grid-to-ground stubbers on the 6V6GT -- you can see someone was really worried about instability & linearity in the output stage.

My guess is the stock A1270 will sound much less aggressive, esp at volume, than the AB763.


+1

All in the quest for louder, cleaner, and more headroom per CBS's insistence, while ironically those same boardroom suits mandated cutting corners on production costs by supplanting the beloved Blue Molded tone caps with shapeless blobs of lesser grade, speeding up the assembly-line time resulting in sloppier lead dress, only cursory fine-tuning of the idle bias at the checkout bench, etc etc etc. But the smaller "student" amps remained relatively unscathed throughout their production runs and an A1270 Deluxe Reverb *can* sound just as sweet as a blackface with some modest tweaks.

Arjay

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Post subject: Re: 80-81 Deluxe Reverb: Silverface with black faceplate.
Posted: Tue Aug 27, 2013 9:22 am
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"The 330K-ohm grid-to-ground loading resistors on the A1270 will have much less swing and POTENTIALLY keep the output more linear than the 1 meg-ohm load in the AB763's PI."

Is this fix as simple as changing out resistors?

Also, how to you deal with this?:

2000 pico-farad grid-to-ground stubbers on the 6V6GT

Thanks


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Post subject: Re: 80-81 Deluxe Reverb: Silverface with black faceplate.
Posted: Fri Sep 06, 2013 6:58 am
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Thanks again for y'all's input.

Well, it's here. My ears are ringing like church bells, but I love it.

I had been playing my Tele (Bardens) and Jag (Lollars) through a gussied-up Music Master Bass. The Deluxe tube rectifier is something else. Another world.

One problem: The vibrato does not work. I think I just need to replace tube V5, right? It was billed as working. I love the 'verb and sag so much I haven't even tried to fix it!

Is there anything I can do with the output tubes to break it up at lower volume? It's loud as hell. I have a small studio/rehearsal room and it is blasting into a baffle now. Still loud. Anything I can do? [I have an attenuator, but am not sure about using it on this amp.]

Thanks again!

Tube Compliment:

- New Russian, Chinese preamp tubes (EH)
- New, matched EH 6V6GT output tubes
- Original Fender-Stamped, G.E. 5U4GB rectifier

http://www.ebay.com/itm/1980-81-Blackfa ... AQ:US:1123


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Post subject: Re: 80-81 Deluxe Reverb: Silverface with black faceplate.
Posted: Fri Sep 06, 2013 9:41 am
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The "vibrato" (actually, it's a tremolo effect) requires a footswitch or a shorting plug inserted into the footswitch jack to operate. Do you have either?

Arjay

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"Here's why reliability is job one: A great sounding amp that breaks down goes from being a favorite piece of gear to a useless piece of crap in less time than it takes to read this sentence." -- BRUCE ZINKY


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Post subject: Re: 80-81 Deluxe Reverb: Silverface with black faceplate.
Posted: Fri Sep 06, 2013 10:47 am
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Can I just short an RCA plug?


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Post subject: Re: 80-81 Deluxe Reverb: Silverface with black faceplate.
Posted: Fri Sep 06, 2013 10:59 am
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" 2000 pico-farad grid-to-ground stubbers on the 6V6GT. "

OEM should be 1200 pico-farads. In any event. I'd keep them in the circuit. Change the grid load on the phase inverter to 1meg-ohm resistors. See how the amp sounds like. You will need a good 12AT7 is this position with the 1-meg ohm resistors. I'd opt for a nice NOS Sylvania 12AT7WA. Have it check for balance across the triode sections. And low-noise.

If it sounds ok.. unsolder one end of the pico-farad resistors on the 6V6GTs. See if the bias becomes unsteady. If not... try the amp out. Any change in tone? If not.. solder the the caps back in place. They are there to help stop high-frequency induced instabilites. Which may cause problems with the 6V6GTs.

If the tone does change, for the better, without the caps. Try the amp out for awhile and see if the 6V6GTs seem ok. No red plating or overheating. If all is ok. leave the caps out. If you are using good 6V6GT (like RCA, GE, or Sylvania) --- you'll prolly be ok. As this is what most ppl used in this amp, back in the AB763 days. If you are using some modern Chinese or Russian made 6V6GT, the lack of pico-farad caps MAY reduce life of the tubes.

Good luck!

http://www.webphix.com/schematic%20heav ... _schem.pdf


EDIT: yes you can just use a shorted RCA plug.


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