Virgin 66 Pro Reverb

[Voxbox]

Hi All, Been a while since I posted here.
I have a rare beast - a 1966 Fender Pro Reverb that has NEVER been removed from its chassis, until now that is. There is only one set of marks from the mounting bolt's star washers on the chassis.
The amp is 99.9% mint as it has spent its entire life in a studio in the UK with a cover on. There is hardly any dust in or on it and it is 100% original apart from a couple of pre-amp tubes.
The power tubes are Amperex - are these original? One is slightly microphonic, so if I replace them, what are the good 6L6GCs these days?
Likewise with the 7025s, a couple are microphonic, so what are the brands worth considering?

I have a dilemma as I know I really should change all the electrolytics, but I'm finding it hard to bring myself to do it!
The amp's (new) owner just wants a working amp and isnt bothered about collectibility or resale value, though he does want me to keep the old parts just in case he does sell.
None of the anode caps are leaking dc.
None of the electrolytics are swollen or leaking.
Speakers are intact.
There is a very slight ghost-note effect around the 12th fret on the G string when the amp is driven hard. (I know.... change the caps, but the effect is slight.)

As I'm in the UK, and the amp is wired for the USA with a 2 core cable, I've added a three core power cable and made an earth connection to the side of the chassis and also removed the wiring to the ground switch. The chassis would have either 120Vac or 6Vac on it depending on which way the "ground" switch was set. Or is that the "death" switch? 
Also wired the live circuit through the fuse followed by the power switch. Its being powered through a auto transformer with the earth carried through.

I'm going to do the heater circuit phasing and add the 2  x 100R resistors to the heater circuit too.

Also I've got the Weber book, so I'll try his mods too, as the customer is oddly keen to try some of the well-known mods out. I say "oddly" as he has only had the amp for one day before he brought it around. I'd live with it first, but anyway.

How does it sound?....Well I have to admit I have never even seen one of these in the flesh before - they are rare as hen's teeth in the UK.
Sounds like a bright Fender! Crunches around 4 on the vib channel.
I'm pretty envious of you guys in the US having so many nice old amps to play with.

So, my questions are -
Do I replace the electrolytics? With Spragues?
What is a good replacement for electrolytics in the cap can?
Power and pre-amp tubes - what's worth considering? (I know it's a personal choice, but I'd like to weed out the duff tubes from the good) JJ's? Winged Cs?

Any other things I should be thinking about?
Disconnecting the trem circuit?

Thanks a million.

Cheers

[floyd]

C'mon.. please don't add 100 ohm resistors to an already C-tapped grounded heater winding.. this guy needs someone who knows what he's doing.

[PRR]

I would check for smoke or horrible rattle (6L6 can't rattle bad), fix the grounding (as you did), then tell him to break it in a while (it *is* nearly virgin).

It will come back sooner or later, with a better idea of its virtues and flaws; THEN do what needs to be done.

I would NOT "mod" it (aside from safety). As-is, it isn't a despised amp, some folks like it (a lot).

[six el six]

Change out the electrolytics.

Now not later.

[Willabe]

The amp's (new) owner just wants a working amp and isn't bothered about collectibility or resale value, though he does want me to keep the old parts just in case he does sell.
None of the anode caps are leaking dc.
None of the electrolytes are swollen or leaking.
Speakers are intact.

I'm going to do the heater circuit phasing and add the 2  x 100R resistors to the heater circuit too.

Also I've got the Weber book, so I'll try his mods too, as the customer is oddly keen to try some of the well-known mods out.

If that amp is in as great of condition as you say it is, and I believe it is, it is definitely NOT an amp to be trying mods on!

That amp being all original in mint condition and being as rare as you say it is in the UK, is probable worth a small fortune to a collector or pro player.

I wouldn't change a thing to sell it for as much as possible.

Not even the power cord and I would not put the amp back in the chassis so you don't add any star washer marks.

I would not play through the original speakers either. There old and you WILL either drop the voice coil because the glue is so old, or just blow them up. All it could take is as little as 15 minuites or so and I'm not exaggerating! Collectors are very fussy about any and every change made to the point of even a solder joint. Every single thing you do to that amp will drop the value to a buyer. I'm not saying that I agree with them but that's what their willing to pay the big money for.

If your friend wants to try mods on an amp that's fine but just not a mint condition vintage Fender Pro. Tell him to sell that amp and buy 2 or 3 or 4 beater used amps that are not in collector condition. Then he can mod away to his heart and ears delight. It's fun and a great way to learn.

I'll say it again, That amp is not an amp to be used as a test bed for mods. Why would anyone want to mess up it's mint condition when many a collector or pro player would love to own it?

Every day that goes by mint condition vintage amps get harder and harder to find. Leave that thing alone and sell it to someone who will take care of it like it was their own child.


                Brad    

 

[eleventeen]

I'm pretty envious of you guys in the US having so many nice old amps to play with.

This has changed massively over the past "XX" years (pick a number) On a per capita basis, you in the UK probably have a roughly equivalent numbers of old Marshalls and Oranges and Hiwatts and 20 other brands. I *will* acknowledge that very few of the Euro combo-style amps are as friendly to work on or mod than old Fenders...we also have that issue with older Gibson and Supro amps...but *anything* with tubes [valves, to you!] in it is automatically holy grail material.

Old ones are very scarce and are priced to the moon. Sure, once in a while one turns up, but there are very, very few bargains what with ebay alerting anyone and everyone what the last one sold for.

[HotBluePlates]

The power tubes are Amperex - are these original?

I wasn't aware Amperex made 6L6GC's, though I suppose it's possible they're Amperex USA and/or an American brand relabeled.

... 1966 Fender Pro Reverb that has NEVER been removed from its chassis, until now that is.

...

I'm going to do the heater circuit phasing and add the 2  x 100R resistors to the heater circuit too.

It is my opinion that "heater phasing" is pure myth. I've tried rewiring amps back this way when I was first learning, and I've built amps where I paid no particular attention to heater wiring other than routing. Neither way had more or less hum.

Also I've got the Weber book, so I'll try his mods too, as the customer is oddly keen to try some of the well-known mods out. I say "oddly" as he has only had the amp for one day before he brought it around. I'd live with it first, but anyway.

Talk him out of it. This is a great amp exactly as it is. I'd love to have a Pro Reverb, probably more than a Super Reverb (and I used to own a '67 Super Reverb).

Also, Weber's books and mods were written back at a time when tweed amps were rare and expensive, but blackface amps were relatively cheap. Why do you think so many of the mods apply to blackface and silverface Fenders, but there's no mention of mods for tweed amps (except for converting 1-wire heater circuits to 2-wire).

I've tried them, and the little bit of gain boost you might get from disconnecting the trem or dropping the 3.3MΩ reverb resistor to 1MΩ could just as easily be gotten with a decent clean boost pedal (and the pedal could give a lot more gain if needed).

So I'd try to convince him to leave the amp as stock as possible, or possibly replacement speakers only in the interest of preserving the originals.

Do I replace the electrolytics? With Spragues?
What is a good replacement for electrolytics in the cap can?

Spragues are nothing special. I used to be brainwashed otherwise, but have since come around. Any modern axial cap with the necessary voltage rating probably will have better performance for less cost than Spragues or the original caps.

[alerich]

Spragues are nothing special. I used to be brainwashed otherwise, but have since come around. Any modern axial cap with the necessary voltage rating probably will have better performance for less cost than Spragues or the original caps.

And long enough leads. I was under the impression that the only reason that Sprague continues to manufacture the blue Atom series capacitors is to provide a like physical package for restoration purposes to those customers for whom it matters. Manufacturing a cap inside of another cap is going to be more expensive, hence part of the reason for the higher prices. While I agree that there are several other very good choices out there that will perform just as well as Atoms (I have used Illinois caps in the past and currently I have been using MIEC caps) I can certainly see the visual appeal of Atoms for those who like that sort of thing even though they are hidden under the doghouse.

[Danskman]

As of electrolytic filter caps, use F&T, they are HiQ and have the right leads length. Or Illinois if you are on a budget, but please, not these huge Atom caps, there's no interest at all using them inside a doghouse...
For cathode caps in pre-amp, reverb, tremolo circuit and bias filter caps, I usually use Sprague ones (25/25 and 100/100).
I would never change anything else in this kind of amps, expect 2-prongs mains cable, death cap suppression, tubes sockets cleaning or re-tensioning, if needed. As already said, please don't add a virtual center tap when a real one exists in the heater circuit..... Oh, and forget the heaters "phase" operation, too.  These amps were built, sold and used for decades without any need to get the filaments aligned.
Regards,
Danskman

[Ed_Chambley]

I am a collector of Fender amps.  What Brad said is absolutely correct.  There is the thought of what good is an amp if it has some noise and ghost notes.  Collector amps and player amps are 2 different things.  As good as this amp looks from the few photos I would stop and get it appraised.  Since I cannot see the back or tolex, reverb tank and bag, I cannot say what I would pay for it.

As it is, I promise I would give you all the parts to build any combo the guy wants since he is wanting a players amp.  All you will end up doing is getting this anyway if you begin modding the amp.  Check the logo closely.  It looks as if it is at a slightly turned left.  May just be the photo.

To answer your questions on tubes, the 7025 is needed in v1 and v2.  You can get some RCA Grayplates reasonable.  The 12At7 is usual a JAN, but the new Tung-Sol will work fine in the PI and reverb but fit very tight, but I would bet the ones in there are fine.  The 6L6 that was in most were sylvania clear tops.  The RCA Blackplates have gotten too expensive and are not as great as the price demands.  Personally, I would not put a new production tube in it, but I would not use it as a players amp.

The "average price" for this amp is $1400 US.  This is average.  On a scale of 1 to 10, would you give it an 8 or better?  If so, this is not an average amp.  If this one has the Jensen C12N and not the oxford, even better.  Is the black footswitch and cover with the amp?  It will really fool you what a guy like me will pay for an amp like this if everything is there and has never been messed with.

The paper covered Mallory caps usually will show blisters on the ends, but I have a couple of amps with small blisters and sound fine.  It should weigh 24kg and the tilt-back legs (16") should be showing a little pitting, but not much to be an 8 or above.  In the photo I cannot even see any scratches at the input jacks.

Get all the numbers off everything, PT, OT and pots and chassis.  If everything is 67 or earlier and there are no tears in the tolex and no accessories missing, your friend has quite a find.  It is just too easy to make a AA165 with 2, 12" speakers to modify an original.  There is no telling what this amp is worth, but I can assure you these old amps are some of the best investments you can make.

[smackoj]

I don't have an opinion about what the collectibility of the '66 Pro would be. I'm sure you have gotten sage wisdom regarding that aspect of this fella's amp. I do have an opinion on tubes though. Here are my picks:

Sovtek 6L6WXT in the power slots. they produce lots of power and can, with the right speaker and circuits, sound a lot like a blackface amp from the 60's.

JJ preamp tubes are good and dependable.

I mostly mix and match my preamp tubes out of a box full of vintage one's I've collected over time. I think that is where I hear the most
difference when seeking that 'special' tone that I like.

cheers     

[Voxbox]

What can I say?
Many thanks for all your helpful posts.

Thats a good point about it being a collectors amp. On the other hand, these are so rare here its not so easy to pick up players amps either so keeping it is the really the only practical option. ( I could always build one ....)
It will be used professionally though.

The point is that this amp is going to be used, so it has to be safe, it has to work, and it has to sound as good as it can be. To me that means doing the ground connection, changing the electrolytics (and keeping the originals), replacing defective valves.
The original power tubes are Amperex 7851s, not 6L6GCs. I'll try a set of Winged Cs and JJs, simply because I have them.
I've photographed absolutely everything except the pots.

Thanks for the tips on the pre-amp valves Ed and smackoj.

There are NO blisters on ANY electrolytics.

On a scale of 1-10, I'd give it 9/9.5. There are some jack marks around the "1" input on the Vib channel, there is the original covering  on the springs. The amp cover probably is not original. The footswitch seems original and has had some, but not a lot of use. There are a couple of minor dents on the top panel, but the tolex is 100% intact.
Speakers have the blue Fender label and are marked 022954 and 328610 on both magnets and on one speaker only there is B609 66 on the rim.

What make are they?

I doesnt need the 2 x 100Rs on the heater circuit as it is centre-tapped already. Just an assumption I made before really looking into it.

I can post more pics if you like.

Thanks for everyones help so far.

Cheers

[HotBluePlates]

Thats a good point about it being a collectors amp. On the other hand, these are so rare here its not so easy to pick up players amps either so keeping it is the really the only practical option. ( I could always build one ....)
It will be used professionally though.

The point is that this amp is going to be used, so it has to be safe, it has to work, and it has to sound as good as it can be.

Then he needs to sell this to a collector, and have the same amp made from scratch. He'd have money left over afterwards, and wouldn't have to worry about altering the value.

If the player's name is Keith Richards or Eric Clapton, then the rules don't apply. If the guy has somewhat less money or a less extensive collection, it just doesn't make sense to gig with this amp. It's like saying a guy has a 1959 Les Paul Standard, but really likes Jeff Beck so he wants to put a Floyd Rose on it.

The original power tubes are Amperex 7851s, not 6L6GCs.

Then 99.9% chance these are G.E. 7581's relabeled as Amperex. G.E. may have been the only manufacturer of this tube until the late 70's when PhilipsECG in the US also made them.

Speakers have the blue Fender label and are marked 022954 and 328610 on both magnets and on one speaker only there is B609 66 on the rim.

What make are they?

022 = Jensen.

Check the other numbers. The "9" after "022" should be the last digit of the year of manufacture; blue labels weren't used in 1959, so this would likely indicate 1969 (or possibly 1979, if a late replacement speaker). But the final 2 digits don't make any sense; these are the week of manufacture, and there are only 52 weeks in the year, so "54" is an impossible marking.

328 = Utah.

"6" probably means 1966 (especially if this speaker looks older than the other, and if the rest of the amp dates to 1966). Probably your original speaker, and lending credence to the Jensen being a replacement. "10" = 10th week of 1966, so this amp was likely assembled in the first half of 1966.

[Willabe]

On the other hand, these are so rare here its not so easy to pick up players amps either so keeping it is the really the only practical option.

I don't believe that.

( I could always build one ....)

Yes you can.

It will be used professionally though.

Apples to oranges. One mans ceiling is another mans floor. Not to challenge but what defines used professionally?  

Collector amps and player amps are 2 different things.  

There is no telling what this amp is worth, but I can assure you these old amps are some of the best investments you can make.

Then he needs to sell this to a collector, and have the same amp made from scratch. He'd have money left over afterwards, and wouldn't have to worry about altering the value.

If the player's name is Keith Richards or Eric Clapton, then the rules don't apply. If the guy has somewhat less money or a less extensive collection, it just doesn't make sense to gig with this amp. It's like saying a guy has a 1959 Les Paul Standard, but really likes Jeff Beck so he wants to put a Floyd Rose on it.

Ed and HBP, YES, YES, YES!

Voxbox, I understand you guys are thrilled to have found this amp, we all would be and get to play through it and open it up BUT NOT MESS WITH IT!

BUT, YOU 2 REALY NEED TO SLOW DOWN AND THINK THIS THROUGH, REALY!

Think about this, another way to up this amps value in a very real and fair way to collectors is.....

Since this amp spent it's life in a studio....

If you can get signed documentation of what studio, who recorded there and the gold ring would be if you can get people there to confirm exactly who recorded with that amp and even better what album and best yet what song.

Each 1 of those things could/would make the value sky rocket!

It would well be worth taking a month, 2 months, 6 months, a year or more to research this amps studio history! It's been done before and has paid off handsomely and then some.

Think about this, IF your friend plays his cards right and can get the amps studio history documented, the more the better, when he sells it for big money and the sale comes out in the press, he'll say....

"My amp tech, from what I told him about the amp, advised me, not to do any thing to it before I research on the amps history and not change any thing until then."

Now your golden in England as a vintage tube amp tech. That will set you on the map as a "vintage amp tech" who won't mess up your classic vintage amp or it's value. You think I'm kidding, but I'm not!    

It's like people who inherit or find at a garage sale old coins, old firearms or swords. Then they "clean" them up and KILL the vale of them!

The added wheels will hurt some and putting the chassis back in the cab, thus adding extra star washer marks is also gonna hurt the value. By doing that you just killed your evidence that it was never taken out of the cab. Which to a collector is a VERY BIG DEAL!

I'd bet your friend could get $4K/$5 as is now in the UK, even more if he spends the time researching it's history in the studio. Could be HUGH difference in value!

I REALY THINK YOU 2 ARE MAKING A HUGE MISTAKE! YOU 2 NEED TO STOP AND THINK THIS THROUGH!

HBP and ED are right, with the money your friend could get if you guys stop devaluing the amp any more and taking the time to get solid documentation you could build him 1, 2, 3 or 4 amps.

The guys here would help you build him a new amp, you know that.

1. You would gain a great deal more of experience than messing with a pristine vintage amp.

2. Your friend will be MUCH happier too!

3. A piece of history will be preserved.

4. Some one who will respect, cherish and take care of that amp will be the guardian of it.

PLEASE, PLEASE, SHOW THIS WHOLE THREAD TO YOUR FRIEND. SINCE IT"S HIS AMP, HE NEEDS THIS INFORMATION FOR HIM SELF DIRECTLY TO HELP HIM MAKE A DECISION ON HIS OWN ON WHAT TO DO.



                  Brad    

[Voxbox]

Brilliant, everyone's passion over this amp is wonderful, heart-warming.

DON'T PANIC!

I'm not about to do any mods apart from add the earth connection. Collect-ability comes second place to safety IMHO.

I've advised the owner that all I am prepared to do at the moment is change the valves. Then he should go live with it before making any changes, and that he would be better off having one built (by me of course - I build amps) if he can't find a players-amp. I await his response.

Regarding the star-washer marks, that's an easy one to get round as all I have to do is place a hard fibre washer or two between the star-washer/combined nut thing and the chassis, so the single set of washer marks will remain.

Great point about the provenance of the amp, Brad. That is definitely worth checking out. Unfortunately it wasnt from a London studio, but from a city in the regions where there is less likelihood of "name" players using it. You never know though.
Let you know.

[Willabe]

Regarding the star-washer marks, that's an easy one to get round as all I have to do is place a hard fibre washer or two between the star-washer/combined nut thing and the chassis, so the single set of washer marks will remain.

Yes! Brilliant!   

Then he should go live with it before making any changes, and that he would be better off having one built (by me of course - I build amps) if he can't find a players-amp.

Well yes, built by you of course.     

That is definitely worth checking out. Unfortunately it wasn't from a London studio, but from a city in the regions where there is less likelihood of "name" players using it.

Well they had enough money and the desire to buy it. Maybe even finding out the story of how the amp even ended up in their studio in the first place would be interesting. 

You never know though. Let you know.

Please do.


                   Brad     

[Ed_Chambley]

From the photo I would bet the tolex is original because the grill cloth looks original and the corners at the chassis look great.  This is the hardest thing to get right.  Also, you can look at the tolex overlap on the top and bottom.  The top should look the same on both sides, but the bottom overlap is usually a little different from side to side.  I cannot be sure, but most times when someone puts new tolex on an amp the also use new grill cloth.  Not always and both could have been replaced.

As so far as the star washer marks.  Just put the amp upside down and put the washers in-place and then put the chassis bolt in while holding the washer/nut.  Hopefully you cannot see where the philips screwdriver removed them.  Putting a piece of electrical tape on your wrench and screwdriver tip will keep anything from getting scratched showing the chassis has been messed with.

Collectors are nuts, I know and I look at everything.  If it is a 9 or 9.5, are you considering normal age.  To be a 10 does not mean new.  There is absolutely no way for an amp not to show some age.  If it does not, I will immediately pass on buying it.

Great find.  I would love to have it since I do not have a BlackFace Pro Reverb.  I have actually been looking for a nice one and this looks like it could fit the ticket.  Try to find another speaker or a pair of Jensens dated 65 or 66.  The mismatched replacement is a big deal.  The jensens may cost what seems like a lot, but it will add more to the amp value than they cost.

[Willabe]

Brilliant, everyone's passion over this amp is wonderful, heart-warming.

DON'T PANIC!

In a time where things are designed and manufactured to be used for only a year or two and then thrown in the garbage, it's important to preserve things that were built to last.

It's already gotten to the point in this world of not being able to buy good fine instrument grade wood. The world has also gone the way of low voltage electronics, so it gets harder and more difficult to find good quality high voltage parts let alone tubes.

Yes these things are really only "tools" to make music with but do you want the best tools or cheap tools for your craft?

I'm a carpenter and the better the tools I have to work with the better of a job I can do.

It's been said many times by people who knew and worked with Leo Fender that he felt very strongly that he had a calling to build these musical tools so musicians could make music for the world.

And he did.


                   Brad    
 

[HotBluePlates]

It's already gotten to the point in this world of not being able to buy good fine instrument grade wood. ...

Yes these things are really only "tools" to make music with but do you want the best tools or cheap tools for your craft?

'Round about 1995, Taylor decided to build a guitar from a shipping pallet to prove it was the skill of the builder, not the fine woods, which was largely responsible for the sound of a guitar.

Nail holes filled with aluminum, the "3-piece back" is really 5 pieces from a pallet, and the top is 6 pieces of 2x4 "mystery wood" whose species they were unable to determine.

In a way, this makes me want to get the crappiest modern-production tubes to design an amp around, cause if it sounds good with them, I wouldn't have to rely of relatively expensive out of production stuff which is destined to disappear.

[Willabe]

That's a cool looking guitar.


            Brad     

[alerich]

In a way, this makes me want to get the crappiest modern-production tubes to design an amp around, cause if it sounds good with them, I wouldn't have to rely of relatively expensive out of production stuff which is destined to disappear.

That's one approach. To me the 'pallet guitar' example would be more valid in your analogy if you collected really cheap examples of tube making materials and were able to construct tubes from it that rivaled NOS performance.

[Voxbox]

surprised no-one has mentioned the Amperex 7581s (KT66s?) vs 6L6GCs?
I'm going to post more pics in a while, especially of the speakers as there has been some work done there.

[HotBluePlates]

surprised no-one has mentioned the Amperex 7581s (KT66s?) vs 6L6GCs?

I already did.

7581 is an American tube number; Amperex (Holland manufacturer under the Philips umbrella of companies) would never have made this tube. As far as I can tell from looking up NOS examples for sale, G.E. seemed to be the only maker (EDIT: the earliest data sheet I can find for it is from Tung Sol, a couple years before G.E.'s 7581A).

Tung Sol's data sheet says this is a 6L6GC with a "controlled zero bias characteristic and a low loss base."

First picture at this vendor's website shows an Amperex-labeled G.E. 7581A, also marked "KT66" on the box. It's an import, so KT66 would help local buyers know what they're getting, just as your Sovtek 6L6 doesn't say "6Π3CE". This happened in the old days, too; I have RCA-labeled "5AR4's" which are really Mullard GZ34's (complete with batch codes and Philips factory code for Mullard).