NAD...1966 Fender Pro Reverb. Circuit Questions

[SoK66]

It

iirc, G. Weber’s recommendation back in the ‘90s was to take it to the car wash and spray it down. I always laugh about that one. I have it in an old VG somewhere if I did not throw it away. That old newsprint doesn’t hold up very well. The stack is yellowed…and dirty…but it is there.

Those were great sources of info in the day, now somewhat overlooked and often disputed. They all got compiled into one of his books. I chuckled at the car wash recommendation, a bit much for a vinatge amp. But the grill cloth idea works.

 

[ravindave_3600]

I have one. No opinions on replacement parts but you just bought a heckuva amp.

 

[bigben55]

I had a 1966 that I tried MANY speaker combinations in. I settled on this: a Celestion A type and a Mojotone(Eminence made) 35 watt alnico that's been discontinued for a while. AWESOME combo, not too heavy, not extra loud.

 

[David Barnett]

Fender Amp circuit numbers are 'somewhat' unique to the amps they inhabit.

Lots of BF Fenders are AB763 but have different components such as tube compliment and transformers. Those circuit numbers mainly refer to the dates they were designed - AA165 is from January (1) of 1965 (65).

Really, you need to include the model with the circuit number. A Bassman AA165 is not at all the same as a Pro Reverb AA165. A Pro Reverb AA165 has more in common with a Twin Reverb AB763 than it does with any Bassman.

Precisely. And the reason why the Pro Reverb is an AA165 instead of AA or AB763 is that there were no Pro Reverbs before 1965. For the last half of '63 and all of 1964, the Pro-Amp was a 1x15" non-reverb combo.

 

[Wally]

I had a 1966 that I tried MANY speaker combinations in. I settled on this: a Celestion A type and a Mojotone(Eminence made) 35 watt alnico that's been discontinued for a while. AWESOME combo, not too heavy, not extra loud. View attachment 979630

Eminence called that 12” Alnico the ALP122…(paper former)…or ALK122…Kapton former back in the day. Stablemate to the ALP10/ALK102. Thirty years ago they built them both in 8 and 16 ohms.
I have been running ALK1028s in various amps for almost 30 years.

 

[KeepItSimpleTele]

I had a 1966 that I tried MANY speaker combinations in. I settled on this: a Celestion A type and a Mojotone(Eminence made) 35 watt alnico that's been discontinued for a while. AWESOME combo, not too heavy, not extra loud. View attachment 979630

Nice. I do like the A type and V type speakers both from Celestion. Glad to hear your thoughts on it.

My 66 Pro Reverb with the Jensens c12Q speakers is just 48 lbs. These speakers are just over 4lbs each. They are basically the weight of a Neo actually. I really like how the amp is actually a 2x12 that is packable. A Twin with heavy mag speakers and the bigger transformers can be 69lbs and up. Huge difference in practice.

 

[bigben55]

Wally is correct. Live this low watt Eminence alnicos in multi speaker old Fender amps. I "think" Eminence still makes that 12". The Mojotone model I had was the MP12RHD. Probably out of production for 20 years.

 

[nickmm]

Eminence George Alessandro GA-SC64 12 if you want Blackface tones.

 

[Dana Rudd]

Congrats on the new amp. Will look great once it's cleaned up. Enjoy and HNAD.

 

[wstrnswingster]

Wally, Weber also suggests swapping the output transformer with one from a BF Bassman. Have you, or anyone, tried it?

Here’s before and after grille cleaning shots. Some like the funky look, not me I like the "after" look. That’s up to you.
I used a vacuum to get the loose stuff first. Amazing how much crap gets in the backside of a baffle! Sprayed some 409, simple green should be ok, brushed it and rinsed it with a hose. I didn’t go crazy with the hose just enough to fully rinse it. Then let it dry in the sun.

With only a few exceptions Amps are what I regret selling. This is one in the regret file! Recently I found out a tech pal used to own one of Gatton's VR and had recorded all the circuit mods!

FWIW, this amp had no Tube Chart and no evidence it ever had one. 64 parts, Jan 65 Oxfords.

 

[Wally]

Wally, Weber also suggests swapping the output transformer with one from a BF Bassman. Have you, or any one, tried it?

Swapping these smaller OTs in VR, Bandmaster, Pro, Pro Reverb, and Vibroverbs amps
was a popular mod back when people were wanting more headroom, less saturation, and more articulation. I always liked what these smaller OTs did. In today’s world; that lower output with earlier breakup and saturation might be desirable. I would never change a VRs OT. Ommv. The VR is a special amp in my opinion….my favorite Bf/SF 6L6 reverb amp. They run lower voltages and do something a little bit different from the others.

 

[Wally]

@wstrnswingster, kudos on the great job cleaning that grille cloth.

 

[wstrnswingster]

The Weber mod was for the Pro Reverb. Had a super clean 66 and almost tried it, got a BF Bassman to rob the OT, back when the heads were cheap. But both got sold to fund something else, IIRC a move at the time. I didn't dig the PR with my main steel so it got sold.

 

[Wally]

The Weber mod was for the Pro Reverb. Had a super clean 66 and almost tried it, got a BF Bassman to rob the OT, back when the heads were cheap. But both got sold to fund something else, IIRC a move at the time. I didn't dig the PR with my main steel so it got sold.

Well, for steel, there are things one could do to the Pro Reverb make it a better amp. Yes, a Bassman OT would stiffen things up..better articulation. So would increasing the first stage capacitance. One could go to a solid state rectifier…straight solid state not an emulator. That would do two things….up the voltage and allow one to go beyond that 50-60mfd limit in that first stage of filtering.
One could plug into the #2 input to decrease the signal to that input gain stage, or one could change the gain characteristics of that first stage itself.
or…one could get a Dual Showman Reverb head and a small cab with an EV speaker????

 

[KeepItSimpleTele]

Swapping these smaller OTs in VR, Bandmaster, Pro, Pro Reverb, and Vibroverbs amps
was a popular mod back when people were wanting more headroom, less saturation, and more articulation. I always liked what these smaller OTs did. In today’s world; that lower output with earlier breakup and saturation might be desirable. I would never change a VRs OT. Ommv. The VR is a special amp in my opinion….my favorite Bf/SF 6L6 reverb amp. They run lower voltages and do something a little bit different from the others.

I'm with you about liking what these smaller output transformers do. I was firmly in the "bigger tranny massive sound" camp before as I really like my pedal board....but the benefits of the smaller sized tranny is clear when you play them back to back. The tone is just "there" already without much EQ.

 

[KeepItSimpleTele]

Wally, Weber also suggests swapping the output transformer with one from a BF Bassman. Have you, or anyone, tried it?

Here’s before and after grille cleaning shots. Some like the funky look, not me I like the "after" look. That’s up to you.
I used a vacuum to get the loose stuff first. Amazing how much crap gets in the backside of a baffle! Sprayed some 409, simple green should be ok, brushed it and rinsed it with a hose. I didn’t go crazy with the hose just enough to fully rinse it. Then let it dry in the sun.

With only a few exceptions Amps are what I regret selling. This is one in the regret file! Recently I found out a tech pal used to own one of Gatton's VR and had recorded all the circuit mods!

FWIW, this amp had no Tube Chart and no evidence it ever had one. 64 parts, Jan 65 Oxfords.

View attachment 979813

I'm liking the "after cleaning" look better myself! I'm intending to get at mine this weekend hopefully!

 

[plexi69]

My ‘65 Pro has a pair of Utah speakers from 1971. I quite like them and suggest looking for a pair of vintage speakers from the ‘70’s as they would be less expensive than either speakers from the ‘60’s or newer ones. I believe the main reason for the tone of these amps is the fact that they are tube rectified. Fender amps with tube rectifiers always sound great.

 

[luthierwnc]

If it isn't dead quiet, check the filter caps. Simple but dangerous so get help if you need it.

I had good luck in a 2X12 combo with a Warehouse G12C and a G12C/S together. That was for an amp that didn't have the Fender mid-scoop, though. For even more to ponder; it will be hard to get that amp to break-up without the club owner throwing you out the window. Consider what you'll stomp on for solo-boosts and how that affects the frequency range. Nice score, sh

 

[Timbresmith1]

Swapping these smaller OTs in VR, Bandmaster, Pro, Pro Reverb, and Vibroverbs amps
was a popular mod back when people were wanting more headroom, less saturation, and more articulation. I always liked what these smaller OTs did. In today’s world; that lower output with earlier breakup and saturation might be desirable. I would never change a VRs OT. Ommv. The VR is a special amp in my opinion….my favorite Bf/SF 6L6 reverb amp. They run lower voltages and do something a little bit different from the others.

Yep. Vibrolux reverbs are magic

 

[fushifushi]

About two months ago I picked up a mostly stock '66 Pro Reverb that had been rehoused in a head cabinet. Lots of people online love the Eminence GA-SC64 12" speakers because they're close the original sound of the amp, so I ordered two of them. Put them in a 2x12 cab, and they do sound great. I can't compare them to anything else though, so my perspective is limited.

I've since added a negative feedback control pot (in place of the ext speaker jack) and a mids control pot (in place of the courtesy AC outlet). Both are easily reversible mods in case I want to return it to stock. These mods both help bring out the mid-range in the amp in different ways. But I suppose selecting more mids-forward speakers might have achieved the same thing.

In any case, it's a wonderful amp. Have fun!

Jason