1974 Fender Silverface Pro Reverb Questions

[Matt Haugen]

Hi all. A friend has offered to sell me a 1974 Fender proreverb amp. All of the tubes seem to be working, but when they are all heated up, one of them glows quite a bit dimmer than the other two. I am speaking of the largest tubes housed in the amp.

I assume that all tubes have to be in good working order for a tube amp to work. This might seem like an idiotic question, but I just want clarification on that.

I looked around at the ebay to get an idea of value, but can't seem to come up with a comparable amp. I have seen 2 in the completed listing. Both amps had all new tubes installed. One had upgraded speakers, and both had the foot pedal included in the auction. They sold for approx 750 and 650... The amp I might buy is all original and has the dust cover which is in pretty poor condition and no foot pedal.

I was told that I would get a 'friend' discount, but I was given the task of finding a fair price, I could use a little help here as to what this amp might sell for. What might a shop owner pay for this amp? I will post some photos if there are requests, but it is an all original 74 silverface pro reverb. The image I posted was pulled off of the net, but is identical to the one I might buy.

[Russell Vance]

Hi Matt,

Difficult to definitely price the amp in question without seeing it and playing it but a genuine foot-switch is around $40 and a new set of valves (all of them) is around $115.   So in the absence of anything else take the low EBAY price of $650 and subtract $155 which gives $495 - take off 10% for a "friends price" which is $49.50  and you end up with around $445.   A dealer would give him one third to one half of the going rate (one half if he was trading it and one third if he was selling it) less the pedal replacement cost and "we'll also need to change out the tubes and rebias it - $200".........so if you offer $450.00 you are doing him a favor.  

The rules are simple - "vintage collectors" and their money are easily parted - "all original" just means "old" and practicing musicians should not bother with making allowances and spending heaps just because some breed of human bower-bird like spending heaps of money to buy old stuff and just look at it.  Offer what it is worth to you which is $450.  If the seller does not want to sell it at that price then don't buy it.

Rusty.

[Matt Haugen]

Thank you Russell. I was hoping to hear from you as I always enjoy reading what you have to say. You truly know your craft.

[Mark Pollock]

No, all the tubes do NOT have to be working for the amp to work. In your case, you have two 6L6 tubes, the same as what is in a Super Reverb or old Bassman amp. They are working together in AB configuration. It's possible (though unlikely) that one is working and one is not.

But they are both probably working. This amp is 38 years old, and was manufactured with parts that, when new, had 10% allowable tolerances. Those parts have since drifted significantly in value. One tube is probably getting very different amounts of voltage than the other. The bias is probably nicely off. AND NONE OF THAT MATTERS, unless one tube is just glowing red all over. As long as it sounds fine, and isn't broiling the tubes, you are okay.

Now, if it were mine, I'd have a couple of things fixed up, such as the polarity "death switch", which is capable of turning your guitar into a 120 volt power supply through your heart, and I would make sure that the fuse is the correct value and not some insane 20 amp fuse tossed in because "the stupid amp kept blowing fuses". The transformers should be as rust free as possible, the cables should not be frayed, the nuts should be tight, the "vibrato" should work, as should the reverb, blah blah blah. I wouldn't sweat the footswitch, unless you seriously switch the reverb or "vibrato" on and off while you are playing, and nobody does that.

This amp is from Fender's worst years, and has some majorly stupid design flaws, most noticeably, a "bias balance" pot. In a nutshell, bias is the negative voltage sent to the big power tubes, and it affects how they perform their job. Setting the bias correctly is a big part of shaping the amps sound, how soon it breaks up, how clean it plays, etc. A good amp has a pot that lets you set the voltage, and a pot that lets you balance the voltage. You can't set the voltage on this amp, just the balance. There are lots of ways of converting this to better function, but again, if you are happy, don't worry about it. At least this doesn't have the dippy "Master Volume" control, which was really a mislabeled "sound like crap" dial.

Actually, here's a better approach to the problem - do you like the sound and playability of this amp? If so, go for it. If not, you could go nuts trying to make it something it is not. If you like it, then ignore everything I said and play the amp until it smoulders. Rusty is pretty good on his value estimate, and I have nothing to add to that.

Last thought - not sure if you want to tackle repairs, but those big capacitors under the metal pan are waiting to kill you if you open up the amp. If you ever open it up, first Google how to drain the capacitors and how to approach repairs safely. 400 volts will do plenty of damage if you are careless. There are plentiful parts available for repair and improvement, so don't hesitate.

[Steve Williams]

Maybe it goes without saying that those big caps can kill you even if its not plugged in. But it always seems important to me that we remind people of that.  Old tube type TVs used to kill people a lot. 

[Paul Verticchio]

Hello Matt.

The only thing I can add to Rusty's spot on advice is: This amp WILL need new filter capacitors in it's power supply. That'll probably run $75-$125 USD.

1974 40 watt non-master volume Pro Reverbs are superb amps.  [even the master volume models are great amps....with a bit of work]  They weren't produced in the same quantities as most of Fenders other amps like the Twin Reverb, Super Reverb or Deluxe Reverb. They excel at he classic 'Fender clean" sound at a loud volume.  Ripping overdrive is not their strong suit but...they play well with EFX pedals.  Essentially, they have all the very best features of Fender amps.

We had two master volume models in the shop over the past year. Neither lasted longer than a week before our "hippest' customers snatched them up.  They were in good & very good condition and sold for about $800 USD @ with original tubes & no foot switches or covers.  BTW: The only folks that get picky about foot switch originality are high end collectors. Personally, it's a non issue and aftermarket switches work just fine.

To give you an idea of how good a value this is: a 1974 Fender Deluxe Reverb goes,on average, for about $1200 UDS.  It has one 12" speaker and is rated at 22 watts RMS.  You'll be getting twice the amp for half the price and that's what we'd all call a GREAT deal.

Nowadays, the 'hottest'  black tolex vintage Fender amps are the Vibrolux Reverb (40w-2x10) and the Pro Reverb (40w-2x12).  The Vibrolux's are selling in the $1750-$2500 USD range. It wouldn't surprise me if the Pro Reverb's hit the $1500 range very soon.

In summary: The Pro Reverb is a fantastic all around amp.

Best of luck with the auction,

Paul

[Matt Haugen]

Thank you all for the input and advice. I have to admit that the comments about electricution got me a little scared, I will most certainly not be tinkering with this amp on my own. I really appreciate all of you.

[Mark Pollock]

DIY on tube amps is fun and rewarding, but you first need to spend an hour learning good discharge technique.

http://www.instructables.com/id/Tube-Amp-Rebuild-and-Mod/step4/DISC...

My favorite book on the subject is Dan Torres "Inside Tube Amps". Dan is a tinkerer, and has a lot of detractors because he has a habit of modifying old amps to make them playable. His reverb kit for improving the reverb on a Fender amp is fantastic - I have one in my Super Reverb. The best thing about that book is the charts and clear explanation of how to bias an amp - I made quite a few friends really happy when their amps were properly biased.