Silverface tone question

[Shawnobi]

I have a '79 silverface Pro Reverb (Master Volume A993658 circuit). I got it cheap as it wasn't working, which was an easy fix.

I'm curious though, these amps are known for being 'hard' sounding and not 'warm' which it is. But why is this? Is it down to the tone stack? Or the choice of filter caps between stages? Or is it the fact that being cleaner there are less harmonics?

[eschertron]

So what does "hard" mean. Is it 'ice pick in the ears hard' or something else?

JM2C a really clean amp will have very little compression and a huge amount of output stage headroom, so each transient can go many dB above the RMS value of the sound level. This raises the chance of the 'ice pick' experience. Is that what you were suggesting?

[Justin Thomas]

Being THAT late in the Silverface run, it's acquired all the cumulative changes over 10+ years of yes, trying to get louder and cleaner. I don't know if the Master is one of the models that advertised "any desired degree of distortion," but it's probably got a pull boost which I think turns the verb into a "distortion" knob? Can you post a schematic? I bet it's also got an ultralinear output section, stiffer filtering, the cabinet construction is either chipboard or particle board instead of solid or plywood. Speakers probably not as good, glued in baffle... wacky bias circuit, all kinds of things to reduce hum due to quality control issues. Crappier lead dress jeeding parasitic suppression caps...

It's not just one thing or the other. It's a lot. These amps CAN sound great, just undrrstand they may never sound "like a blackface." That's fine. It can certainly bs greatly improved, without having to Marshallize it. IOW, gotta turn it into a distortion machine. I bet it's pedal-friendly, too. Whip it into the best shape you can without too much radical brain surgery, and if you still don't like it or want to work with it, pass it on.

Justin

[g1]

This is the 135W UL w/master version which is probably the correct schematic:

[Justin Thomas]

I think the Pro is the 70W version, but all the same things apply. Just add two 6L6s.

Justin

[g1]

Oops, thanks Justin, don't know how I saw Twin there instead of Pro .

[Alan0354]

I took a quick look at the schematic, the front end is very similar to the 73 and later Twin Reverb that I had with MV. The tone stack is very close to the older Fenders. From my experience, my Twin sounded very much like the old ones except a little softer in sound ( not the volume, just a little smoother sounding). I think the difference is in the power amp with UL tapping. That should give a very different distortion characteristics compare with the older amps.

Without looking deeply into the bias and all, my wild guess it's the UL that makes the difference in the sound. The distortion profile of the UL design is very different from the simple power amp of the older ones. I would first reverse the screen back to a fixed voltage like the old ones to start and see how it sounds.

[Shawnobi]

It's not just one thing or the other. It's a lot. These amps CAN sound great, just undrrstand they may never sound "like a blackface." That's fine. It can certainly bs greatly improved, without having to Marshallize it. IOW, gotta turn it into a distortion machine. I bet it's pedal-friendly, too. Whip it into the best shape you can without too much radical brain surgery, and if you still don't like it or want to work with it, pass it on.

Justin

Yes it's an ultralinear circuit that G posted. I don't want to Blackface it, in the same way I wouldn't want to Tweed a blackface. I think they are great amps in their own right. Yes, take pedals well and great for surf rock, country. I play post-rocky stuff so silverfaces are much better suited than Blackfaces. I was just wanting to understand, tonally, what makes them different. Coming from the angle that sound is just about EQ, right? Boosting/ subtracting frequencies. The width of 'Q' etc.

I've got a 74 Silverface twin as well. I've got to do a bit of servicing to both next week. Then I want to do a side-by-side comparison.

Incidently Justin "Whip it into the best shape you can without too much radical brain surgery" I think you've hit the nail on the head with what I want there.

[Shawnobi]

Well, I spent tonight recapping the pro and fixing the mains on the twin. Decided to have a quick comparison. Normal channel with all knobs set to 5. Twin sounding lovely as ever. But man, when I switched to the pro it blew it out of the water! It just had more of every thing. The highs almost shimmered at the low end was warm. I think I must have been letting the internet jade me after not hearing it for a while. She's a keeper for sure!

[Jazz P Bass]

Thanks for the post.

[Alan0354]

Ha, why are people keep thinking the late 70s UL Pro/Super etal do not worth the money. I never own or try one, I have no comment on the sound, but you definitely see the UL Fenders sale lower price than the earlier 70s SF without MV. Is it psychosomatic again?

[pdf64]

'Normal channel with all knobs set to 5'

That means nothing really.
Track end to end values are generally specified to be within +-20%, but along the track the accuracy to nominal taper / law of the pot is unspecified.
The amps could well have been fitted stock with different taper pots to each other.
My experience is that the bass and middle control taper of late 70s Fenders is much steeper than earlier models, eg ~30% c.f. 10%.
So electrically, setting them to '5' would provide differing results.
And with old amps, parts get replaced, and pot tapers are poorly understood and its difficult to identify / source the OEM type.

If the Pro Reverb master volume isn't at max then there's a treble boost from a bright cap.

And then the speakers in amps are probably different.

A fairer comparison that's simple for the user would be to set all the tone controls to max and put both amps through the same cab.

[Justin Thomas]

I would just like to say: I think the takeaway from this thread is that the late-70s UL Fenders don't necessarily deserve the bashing they get.
There's at least ONE player that likes them, and that therefore justifies their existence. Shawnobi gave it a shot, actually played it, and liked it.

Let's say we were actually comparin a 66 Pro Reverb, a 79 Pro Reverb, and a 2012 theoretical RI Pro Reverb that was at least as faithful as the 65 TR & SR. I think to compare the '12 & 66 is fair, as they were designed to be close approximations of each other, circuit & tone wise. But the late 70s UL Fenders were never really meant to sound or feel like the BF amps. How many car models never evolve, often radically, to meet the (perceived) needs of the day? And isn't it only fair to compare like with like, if we're going beyond mere aesthetic favoritism?

Given the knowledge we have today, parts quality, and "anything goes" attitude, I think we can leave these amps as they were now. Sure, they may not sound just like XYZ, but do they have to? To disgruntled owners (or potential owners) - If you don't like it, sell it & buy the parts for your own! Shawnobi, enjoy your UL PR!

All that said, pdf64 is correct about comparison criteria, esp. wrt tone controls & speakers. While it's still not a perfect test, given the passive & inconsistent parts builds, best to eliminate them as variables. Easiest way to do that is to crank all the tone controls on 10. And, $5 says both will sound equally grating and offensive when you do that! And that the amp with better speakers to your ears will make both amps sound better.

Justin

[J M Fahey]

these amps are known for being 'hard' sounding and not 'warm' which it is.

95% people posting that have never ever had both side by side to compare and just repeat blindly what they read.

Silverface amps can and do sound killer.

Twin sounding lovely as ever. But man, when I switched to the pro it blew it out of the water! It just had more of every thing. The highs almost shimmered at the low end was warm. I think I must have been letting the internet jade me after not hearing it for a while.

Funny thing is that the ones who would appreciate the difference most are those playing greasy smokey blues (which I love, shop music is Shoutcast 1.FM (Blues) or Belly up for Blues), which way back then might have been, say, 25% of players ; while Country, Surf, "commercial Music" , etc. were probably the statistical bigger percentage.

Today greasy smokey blues players may be , say, 1% of players, paunchy 60 something graybeards (not complaining, me too ) while 99% others play "something else"

Just visit MF, GC, etc. any Saturday and listen to the licks they play to test stuff.

Yet this 99% who does not play the relevant music nor ever had one or the other , even less both together, endlessly repeat the mantras/suras/versicles by heart.

Oh well.

Back to Electronics: the difference should be based on "master volume amps vs non master ones" and that is the big difference.

If the amp has a Master volume and you use it, yes, distortion will be harsh/dry/brittle/cold/whatever; but set it to 10 (meaning out of the circuit) , set all other controls to 10 (he he, as pdf64 suggested ) and both sound very good.

Even JCM900 sound good that way

[Alan0354]

95% people posting that have never ever had both side by side to compare and just repeat blindly what they read.

Yeh, I just avoid it. But I never said anything bad about it because I don't know. I just know that it will sound different. I just like my old Vibrolux and even the 73 MV Twin.

Even JCM900 sound good that way

Well!!! I won't go this far!!! I own that little Dual Reverb for many years, never grow to like it. It's gutted already.


Anyway, one thing I have to say, the first generation MV Fenders was their first attempt in OD channel, that did not sound too good. I remember my Twin never sounded right in OD. But it's a real Twin in clean sound and when it's used as non Master Volume.