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Alligator Skin 1964 Fender Deluxe Reverb Effects Pedals, Units & Accessories
Old 4 weeks ago
  #61
Quote:
Originally Posted by Brian Ingram View Post

As I mentioned before, the speakers looked like 12" CTS alnicos, and after some more looking I believe they are CTS 7010 speakers with the whizzer cone. Someone gave them the "Krylon Touch" with some matte black, and appeared to get a little overspray onto the cone itself. Probably the same stuff they used for the inside of the cabinet & the attenuator box. See below for the original coloring:

https://i.imgur.com/U5WQuRI.jpg
https://i.imgur.com/FWAoLur.jpg
https://i.imgur.com/pJ3wwMo.jpg
Those speakers look like they have slightly smaller magnets and maybe voice coils than the one in the amp.
Old 4 weeks ago
  #62
Quote:
Originally Posted by kakao View Post
Put a pair of 6L6GC's in there, re-bias it, and enjoy .. the amp will sound punchier and fatter.


Er, no. You'd need a new transformer set to do it right. The PT doesn't have either the required current capacity or HV output and the OT can't really handle the power AND has the wrong primary impedance.

And it would mean screwing up a nearly pristine vintage chassis.
Old 4 weeks ago
  #63
Gear Nut
 

Quote:
Originally Posted by John Eppstein View Post
Er, no. You'd need a new transformer set to do it right. The PT doesn't have either the required current capacity or HV output and the OT can't really handle the power AND has the wrong primary impedance.

And it would mean screwing up a nearly pristine vintage chassis.

Nope. I have a pair of 6L6's in my 1966 DeLuxe Reverb for the last 20+yrs, original iron, years of gigging and recording, not a single issue, ever ... (The amps has been always re-biased with the new 6L6's, if need be).


Old 4 weeks ago
  #64
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norbury brook's Avatar
 

Quote:
Originally Posted by kakao View Post
Nope. I have a pair of 6L6's in my 1966 DeLuxe Reverb for the last 20+yrs, original iron, years of gigging and recording, not a single issue, ever ... (The amps has been always re-biased with the new 6L6's, if need be).


not everyone would be so lucky though, so John's right in saying beware of just fitting 6L6's with the standard transformer.


M
Old 4 weeks ago
  #65
Gear Head
 

Quote:
Originally Posted by Brian Ingram View Post
Why the continued insistence on "factory original"?

As I mentioned before, the speakers looked like 12" CTS alnicos, and after some more looking I believe they are CTS 7010 speakers with the whizzer cone. Someone gave them the "Krylon Touch" with some matte black, and appeared to get a little overspray onto the cone itself. Probably the same stuff they used for the inside of the cabinet & the attenuator box. See below for the original coloring:

I'm just relaying what I see. The black textured paint on the speaker doesn't appear to be painted over any other speaker finish. I don't see overspray on the cone. The cabinet paint is not the same as the speaker paint. The attenuator paint is not the same as the speaker paint.

The pics of the speakers you posted in comparison do look similar, though not exactly the same.
Old 4 weeks ago
  #66
Gear Guru
 
kafka's Avatar
Quote:
Originally Posted by John Eppstein View Post
It's called a L-pad, it's one of the most basic speaker attenuator circuits. That one was probably sourced from a hobbyist electronic source like Allied or Layfayette in the mid '60s and installed into a repurposed box. The big white rectangular thing is a 20 ohm wirewound resistor. To use it as a pad one side has had the insulating grout ground away so the wiper can contact the coil in the resistor. Such pads were sold for use a speaker level controls or frequency balance controls and mounted on the back plate of hi-fi speakers in that era. They were also commonly used in the crossovers of commercially sold Hi-Fi speakers. The dial would have been included in the package from the electronics supplier.

I'm not a big fan of speaker attenuators in general but this one probably isn't much worse than any other very basic 20 watt attenuator.
Yeah, now that you mention it, I remember seeing them at Radio Shack for 70V audio distribution systems.
Old 3 weeks ago
  #67
Gear Head
 

Ok now I'm getting into this. I put in the F&T filter capacitors. Started the electrolitics on the underside and checking resistor values. I'm finding over 80% resistors out of tolerance. Is it worth keeping the remaining 20%? If I were changing light bulbs I'd change them all. But whats the vintage amp protocol?
Old 3 weeks ago
  #68
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ponzi's Avatar
unless the dc voltages are way off, i personally would not mess with the resistors. do the rest and see how it performs
Old 3 weeks ago
  #69
Quote:
Originally Posted by tigerzilly View Post
Ok now I'm getting into this. I put in the F&T filter capacitors. Started the electrolitics on the underside and checking resistor values. I'm finding over 80% resistors out of tolerance. Is it worth keeping the remaining 20%? If I were changing light bulbs I'd change them all. But whats the vintage amp protocol?
Don't mess with the resistors unless you want to kill the tone and value of the amp. Only replace resistors if a circuit actually fails.

Only replace coupling caps if they fail or leak DC.
Old 3 weeks ago
  #70
Gear Head
 

Ok. You guys saved me! I lost one resistor that broke, otherwise left all. Amp sounds really good! Even with the wizzer cone speaker! Quite. No hum. Good tone. I still need to check voltages and play with tubes. Reverb changes tone to sound like a tin can but working. Tremelo works but seems weak.

Oops. Looking at the pics and I see I missed a cap. Tomorrow!
Attached Thumbnails
Alligator Skin 1964 Fender Deluxe Reverb-0123192214_hdr.jpg   Alligator Skin 1964 Fender Deluxe Reverb-0123192214b_hdr.jpg  
Old 2 weeks ago
  #71
Gear Head
 

I've made progress with amp. It does sound good! It's still on the bench until I get the tremolo intensity resolved. I tested it with the wizzer cone speaker and a new cannabis rex that I got for the 73 DR. I'm not finding any love for the wizzer. It buzzes on the low strings. I tried doping the cone perimeter and around the repair area, but not much improvement. I'm ready to ditch the speaker.

I tried the speaker attenuator. I'm not finding any love for it either. It sounds like a fuzz box with no volume or fullness. I think the amp sound much better with the amp straight to the speaker.

I ordered a new optocoupler for trem. Hopefully that will solve the week intensity. Now I'm off speaker shopping!
Old 2 weeks ago
  #72
Gear Head
 

Quote:
Originally Posted by kafka View Post
I'd leave the attenuator on it if it works. Bound to be useful, and just turn it all the way up if you don't want to attenuate.
Even with the dial turn all the way up it still attenuates. It certainly would be more useful if I could dial it off.
Old 2 weeks ago
  #73
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enorbet2's Avatar
Quote:
Originally Posted by 12ax7 View Post
If you're comfortable doing so, I'd replace all the electrolytics (just as a matter of general principle).

While I was in there, I'd also compare the values of all the components to the ones denoted in the schematic.

...Not that I'd necessarily replace them with the original values; I'd just wanna know what I had.
PLEASE! NO! I recommend not doing a knee-jerk, blind cap replacement "just because". For cryin' out loud, MEASURE! If the voltages are within spec then the only valid reason for replacing caps is hum. That ordinarily can be drastically reduced by replacing ONLY the first filter cap at the very start of the decoupling stages of the power supply.

The rest of the caps can be easily tested by temporarily soldering a known good cap in parallel with each one (one at a time is good) and listen for both hum reduction and tonal response changes. Choose accordingly.

Things aren't good or bad just because they are old or because they are new. Don't just assume.

FWIW I personally prefer higher capacity than 16uf so my point is only so YOU can make the choice for what you like best. I'd opt for higher filtering capability and adjust bias and negative feedback to get back the flex, but that's just me.

The attenuator, being pure resistance, not reactive, does alter the response. I'd try it without and if I actually found 20 watts too loud I'd consider a modern reactive attenuator if I absolutely had to. I'd prefer not playing at venues that considered a cranked 20 watt amp too loud. That amp should be allowed to "breathe".

Last edited by enorbet2; 2 weeks ago at 07:50 PM..
Old 2 weeks ago
  #74
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enorbet2's Avatar
Regarding the Tremolo circuit it is fairly unlikely the optocoupler is bad. It is far more likely that the caps that create the oscillation (2 x .01s and 1 x .022 )are leaky assuming the supply voltage is correct and the tube itself isn't weak.
Old 2 weeks ago
  #75
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enorbet2's Avatar
Quote:
Originally Posted by John Eppstein View Post
Er, no. You'd need a new transformer set to do it right. The PT doesn't have either the required current capacity or HV output and the OT can't really handle the power AND has the wrong primary impedance.

And it would mean screwing up a nearly pristine vintage chassis.
That's not quite so, John. That the PT will only produce around 400-420vdc at reduced current just means a shift in operation. It wouldn't just suddenly morph into a Super or a Bassman but It will work and be reliable... and respond a bit differently.

The OT impedance mismatch is slight and will also only shift operation parameters. It's power handling capacity will be unaffected because you can't get more power out without putting more power in. 6L6's aren't substantially more efficient than 6V6s. The power supply determines output almost entirely regardless of output device.

Substituting 6L6s for 6V6s in Deluxe amps is utterly common and requires only bias adjustment and ZERO effect on a pristine chassis since there is ZERO need to replace the transformers. It works and is one of the many values of tube amplifiers that they adjust nicely to a wide range of operating conditions. Who cares if the actual output drops or increases by a lousy 5% when the voltages are specced at plus or minus 20%?
Old 2 weeks ago
  #76
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12ax7's Avatar
 

Quote:
Originally Posted by enorbet2 View Post
[...]Things aren't good or bad just because they are old or because they are new. [...]
Sure they are!

...For instance, things like scrambled eggs and electrolytic capacitors don't quite last as long as we'd like.

Electrolytic caps WILL go bad over time just sitting around (even in a climate-controlled environment in its original packaging).

Other types of caps are a different story, but I will ALWAYS replace EVERY electrolytic in anything I own that's over 12 years old.

...And I have NEVER been sorry for so doing.
-YMMV-
Old 2 weeks ago
  #77
Lives for gear
 
enorbet2's Avatar
Quote:
Originally Posted by 12ax7 View Post
Sure they are!

...For instance, things like scrambled eggs and electrolytic capacitors don't quite last as long as we'd like.

Electrolytic caps go bad over time just sitting around (even in a climate-controlled environment in its original packaging).

Other types of caps are a different story, but I will ALWAYS replace EVERY electrolytic in anything I own that's over 12 years old.

...And I have NEVER been sorry for so doing.
-YMMV-
While scambled eggs are perishable on a vastly shorter timescale (unless you freeze them) they are irrelevant to design and function of engineering.

I happen to agree with you for my personal equipment in that I much prefer modern caps with higher capacity and reduced ESR, BUT for those that value "Orig" it is simply silly to just assume that because they are old that they have gone bad. Odds may be that they are but why guess? Just measure and/or substitute and choose.

Frankly I replace electrolytics in the signal path on brand new amps with non-polarized as a matter of course but because they are non-symmetrical not because they have gone bad or are likely to, if they belong to me..
Old 2 weeks ago
  #78
Gear Head
 

Quote:
Originally Posted by enorbet2 View Post
Regarding the Tremolo circuit it is fairly unlikely the optocoupler is bad. It is far more likely that the caps that create the oscillation (2 x .01s and 1 x .022 )are leaky assuming the supply voltage is correct and the tube itself isn't weak.
The oscillator is working. I traced the circuit with my scope. I tried different tubes. The light in the optocoupler flashes. On the photo-resistor side of the optocoupler the signal has very little dip in volume. I'm working on a 73 DR that has similar symptoms but no dip in volume on the photo-resistor side. It's making me think the photo-resistor is not functioning properly on both amps.
Old 2 weeks ago
  #79
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enorbet2's Avatar
Quote:
Originally Posted by tigerzilly View Post
The oscillator is working. I traced the circuit with my scope. I tried different tubes. The light in the optocoupler flashes. On the photo-resistor side of the optocoupler the signal has very little dip in volume. I'm working on a 73 DR that has similar symptoms but no dip in volume on the photo-resistor side. It's making me think the photo-resistor is not functioning properly on both amps.
You may already know this but just to be sure, the operation of Tremolo on most Blackface amps is very simple. While some amps actually create tremolo by altering DC bias, most Blackfaces are a simple Master Volume control where the "Vibraoto" channel is isolated from the "normal channel" by a 220K resistor so only the one has a "Master control". It's just electronically controlled instead of mechanically controlled.

When the light goes "ON" the resistance of the LDR drops very low, usually less than 100 ohms, some nearer to zero. This is like having a Master on "0". So you can check the dc resistance of the LDR since it is completely passive and insure that it does swing down to very low levels. It is literally like measuring the effective resistance of a mechanical pot or variable resistor. Insure it "goes low".

If it does go low and still doesn't drop the output of the amp then it is likely there is some wiring issue, possibly in the channel isolation preventing the LDR from dropping the signal down. It shouldn't be difficult to discover what is keeping the signal far above ground despite the LDR going low.'

If the LDR doesn't go low, well.... look no further.
Old 2 weeks ago
  #80
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ponzi's Avatar
I had a fender amp where the tremelo did not work until you plugged a 1/4 inch plug in the back. It was shorted in an off position by the socket and inserting a plug opened it up so it started working. I can't recall if the plug needed to be shorted from tip to ring or not. Took me quite some time with the schematic as this was the last thing I expected. I also believe in replacing old electrolytics. Nobody has made me aware of what harm can come of this. Fact is, the new ones are better, and certainly better than 50 year old ones.
Old 2 weeks ago
  #81
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enorbet2's Avatar
As soon as we say "better" we are actually saying "different, and I like them more". As I've stated modern caps are better for what I want but I have met players who are willing to live with some hum in order to get the response of old, even tired old caps, and who am I to say they're mistaken? I just tell them few things are so simple as to be all good or all bad, that most are tradeoffs, and offer to temporarily substitute and let them decide. There are also some adjustments that can get back at least some of the "old" response.

Here, on an online forum, all I can do is warn people that they may very well feel and hear a difference and to measure and sub for themselves so they make an informed choice. However if the voltages are substantially off, there is no choice but to replace them if they are (and they are the most likely culprit) at fault. Something to consider is if a 50 year old cap still tests good then it is obviously a really good cap and shouldn't be tossed out without a good reason.

In my experience with Fender amps the filter caps were very solid and failed much less than those old Astron non-polarized caps. Those old yellow ones with green writing (really common in Tweed amps) for some reason are highly likely to leak as well as drift.

I heard a story that Leo Fender was asked "How do you get away with using a 25v electrolytic on a 40 volt circuit?" and his reply was , "Well, you have to buy good ones" :D
Old 2 weeks ago
  #82
Gear Head
 

Quote:
Originally Posted by enorbet2 View Post
It is literally like measuring the effective resistance of a mechanical pot or variable resistor. Insure it "goes low".

If the LDR doesn't go low, well.... look no further.

My Beckman meter shows resistance bouncing from 7k down to 6.5k and back. I wonder if the speed is not giving it enough time to drop resistance. The spead pot measures from 0 to 3.5M. 100k resistor is close tolerance.
Old 2 weeks ago
  #83
Gear Head
 

Quote:
Originally Posted by enorbet2 View Post
I happen to agree with you for my personal equipment in that I much prefer modern caps with higher capacity and reduced ESR, BUT for those that value "Orig" it is simply silly to just assume that because they are old that they have gone bad. Odds may be that they are but why guess? Just measure and/or substitute and choose.
The amp is really quite now. That's what I like. I don't have to worry about new noises showing up and having to constantly diagnose the next bad cap. I dont have time for that.
Old 2 weeks ago
  #84
Quote:
Originally Posted by enorbet2 View Post
Regarding the Tremolo circuit it is fairly unlikely the optocoupler is bad. It is far more likely that the caps that create the oscillation (2 x .01s and 1 x .022 )are leaky assuming the supply voltage is correct and the tube itself isn't weak.
Back in the day I saw a number of bad opto couplers. What I don't remember is what the symptom was.
Old 2 weeks ago
  #85
Quote:
Originally Posted by tigerzilly View Post
My Beckman meter shows resistance bouncing from 7k down to 6.5k and back. I wonder if the speed is not giving it enough time to drop resistance. The spead pot measures from 0 to 3.5M. 100k resistor is close tolerance.
Could be that the light bulb is weak.
Old 2 weeks ago
  #86
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enorbet2's Avatar
Quote:
Originally Posted by tigerzilly View Post
My Beckman meter shows resistance bouncing from 7k down to 6.5k and back. I wonder if the speed is not giving it enough time to drop resistance. The spead pot measures from 0 to 3.5M. 100k resistor is close tolerance.
Notice the Intensity pot is 50K- Reverse Audio taper. 7K is nowhere near enough resistance to ground to support anywhere near full volume. It should be at least 50K and iirc closer to 250K. I'll dig through my old parts to see if I still have a good LDR to check for certain but there is no doubt whatsoever that 7K is way too low. At full intensity Optocoupler Fender Tremolo has so much dynamic range it can sound positively violent.

UPDATE: OK I have a replacement unit which is not original so it could be different from old stock but still perfectly functional as it is new and never been used. It's dark resistance is over 6 megohm.
Old 2 weeks ago
  #87
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ponzi's Avatar
Quote:
Originally Posted by enorbet2 View Post
As soon as we say "better" we are actually saying "different, and I like them more". As I've stated modern caps are better for what I want but I have met players who are willing to live with some hum in order to get the response of old, even tired old caps, and who am I to say they're mistaken?...

I heard a story that Leo Fender was asked "How do you get away with using a 25v electrolytic on a 40 volt circuit?" and his reply was , "Well, you have to buy good ones" :D
My interpretation here is he was reducing parts cost, and some of the product may have been conservatively rated. There have been other interviews that also indicated to me Leo Fender was sourcing parts based on price--will lightening strike me as I say there was no magic here--no scouring the country for the best sounding parts, parts that were so special and unique that nothing today will ever sound as good?

To the extent people enjoy the sound of a tube amp with defective electrolytics, I can't deny their right to have what they like. But from a purist standpoint, when the amps were new, they sounded different as the caps were new and working better--although from what I remember using amps 40 years ago was plenty of 60 cycle hum even then. Much as I have nostalgia for songs released in the 1960s, I have absolutely no nostalgia for 60 cycle hum even though it pervaded all of my home electronics that had tubes back in the 60s-70s. Those little asian solid state home stereos were pretty clean, though. (pioneer, marantz, wood panels on the sides--you know what I mean).

Again, price point and we all know that in a power supply, more microfarads, more bass, less hum. Modern caps have more microfarads for a given cubic volume.

Point being, an all stock vintage fender may be more collectible, but its not likely to sound the same as it did when it was new. Same with a 50 year old speaker cone/spider.
Old 2 weeks ago
  #88
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enorbet2's Avatar
I agree Ponzi. especially about conservatively related products. Leo would only have known they were conservative by - yup, you guessed it - actually trying and measuring.

One important nit to pick is that you would be well-advised to discontinue referring to amplifier hum as 60 cycle. 60 cycle hum is 100% non-existent in SS amps and only a very small percentage of tube amps. The bulk of all audible hum by orders of magnitude, and 100% of it that can be improved by filter caps is not 60 cycle but 120 cycle post rectifier hum
Old 2 weeks ago
  #89
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ponzi's Avatar
Quote:
Originally Posted by enorbet2 View Post
...The bulk of all audible hum by orders of magnitude, and 100% of it that can be improved by filter caps is not 60 cycle but 120 cycle post rectifier hum
Pedantry is a truly thankless job, it feels good, but looks petty.
Old 2 weeks ago
  #90
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enorbet2's Avatar
Quote:
Originally Posted by ponzi View Post
Pedantry is a truly thankless job, it feels good, but looks petty.
You are regretfully mistaken . It didn't feel good (I'm far too old and experienced to seek approval) nor is it petty, especially for anyone designing, modding, or repairing an audio device.

Apparently you took it personally and it was not meant that way at all. That could be because you're possibly a musician who figures "an octave isn't a bad note" and not a designer, modder, or repair tech who needs accurate guidelines and numbers to do proper work..I didn't mean to trigger you. In fact I wasn't certain you were even aware of the difference and might've been glad for some clarity. .
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