Beautiful amp Terry and glad many are supporting you. You deserve it !!!!!! I still have my 59' bassman here for you when things lighten up :) thanks Ron
I like how there were grounded green wires wrapped around a bundle of wires, I assume, as a shield? You are a good man Terry. I can't tell you how much I have learned from your channel. Please keep the Kobbler, Troll, and Hammered Ham coming!
Later Supers (and other Fenders) will have those same ground wires wrapped around the wire bundles but they usually have 2-3x as many windings as you see on this amp. Really densely wound. That wiring is often called "Spaghetti" wiring.
Terry, you provide the tube electronics education I never had. My progress in understanding tube electronics in the last few years was due to you and Uncle Doug’s channels. Hope you and the family are safe. Thanks again!
I believe that the R/C combo on the power tubes was put there by Fender to help suppress oscillations caused by the poor lead dress on the Silverface amps. However, customers started complaining that they robbed high end.
Good ol' Fender bias balance/mixed bias circuit and one of the many CBS changes in 1968-69. Looking at the faceplate and seeing those black lines I would put money on this being a silverface drip edge model. I had a band master reverb with the same design. Most people have those cathode resistors and the bias balance circuit removed and converted back to blackface specs. I don't think it sounds much different and think its a cool design to be able to balance the bias between your tubes.
Hi, thanks for all the info. I have a vintage Fender Silver Face Pro Reverb which hadn’t been used for 20 years plus. Do not know the operational status , what can I do to check it out besides to bring it to the repair shop? Thank you!
Hi Terry, sorry to bother you but it seems as though the subtitles have been switched off on your last 2 videos. Sorry to be a bother, but I really enjoyed watching quite a few of your older videos over the weekend and now it seems that the new ones d0on’t have the option. Take care. Great channel!!
Always good to look at the innards of another Super Reverb! I guess I'm dumber than your average guitar player, 'cause I tried going to one of your pages and never could see how to send you any potato chips or dog bones or ... money, even ... But I'm not too swift with this Internet stuff ...
I have a fender 15g that had a broken volume pot, ive fixed the pot. The amp is making no sound on clean channel and overdrive channel sounds extra noisy and guitar tone sounds clean. Could the bad pot have damaged the ba4560 chip
Most guitarists dont care for the silver face grid resistors and caps, and many perform " Blackfacing" the amp by removing them, and a couple other small things to adjust the circuit closer to the older one.
Was gonna say exactly that. Judging by the stamped black numbers on the chassis, this is an AB568 (or later) Super with those 2000 pf caps and the 7 watt resistors. Most techs will yank those parts to take the amp to AB763, then consider whether to go GZ34 or 5U4GB rectifier.
Terry can you tell me what type of solder that you use I like using 63-37 a eutectic solder that is a two state solder. You dont get cold solder joints as the solder goes from liquid to solid direct
What year is this amp? Like 68-70ish? I had a 1973 Super Reverb and it had all PVC wiring in it, no cloth. This one seems to be a mixture. Mine also had those ceramic resistors on the power tubes.
Based on the blue molded Ajax caps and silverface with vertical black lines you can assume that it’s a late ‘67 or ‘68. I saw a ‘68 date stamp in the chassis, so I’d say a 1968.
Dear terry Thanks for sharing this video... For taming the tone of my fender super reverb ab68 silverface 1969 ( with no master volume) what is the best solution? Modding the amp and Add master volume to original circuit or only using variac ? What is the safest and most effective method? I'll apreciate if you answer my question.
@@AliKiani7887 The absolute simplest way is to replace the GZ34/5AR4 rectifier tube with a 5U4GB tube and try the amp that way. www.fourwater.com/files/fullrect.txt This will cut about 35 volts off your B+ voltage and *may* be enough. And it may not, but you don't even have to take the amp out of the cabinet to try that one.
If you notice closely in the beginning of the video as the camera sweeps by the front face plate by the name of the amp....you'll see 2 black lines framing the "super reverb".....like book ends. Those black lines were only used on carry over units in the transition to the silver face plates to denote that the guts were still black face guts.....it there was a cabinet present the tube chart in the cabinet would have 7-63 on it. When the silver face plate went into effect in the production line as a full on CBS model the black lines came off and the circuitry was the 5-68 designation.....meaning may of 1968. SO the black line amps were only made a few months into 1968 into the CBS silver face line to deplete the remaining black face parts in inventory. BUT IN THIS CASE......this is a bizarre transitional piece as it has black face components which are mainly the blue molded mallory caps which at a glance would suggest the full on black face circuit board and thus the 7-63 circuitry (including the black lines on the face plate)......BUT you also see the 5-68 changes on the power tubes and the power tube bias system. IT would be needed to examine the phase inverter resistors to see if the board is a true black face board out of a inventory bin that was combined with the chassis that was being set up as a 5-68 chassis as a unusual hybrid. WHEN you do a full on black face conversion, the phase invert circuitry also need to have the values of a couple resistors changed out as well as the power tube biasing system....AND the disk caps to ground on the power tubes. THIS is a truly weird Fender amp as this circuitry was not used long in production as the 5-68 version as those big cement power resistors on the power tube cathodes represent a bizarre CBS engineering interference in the design where the amp is a combination of fixed bias as it should be, all be it a wrong set up for the fixed bias as its a bias balance as opposed to an adjustable fixed bias as the older 7-63 versions......and a cathode bias system. SO to be clear...its a mix of fixed and cathode bias for the power tube section.......which totally sucks. CBS came to determine it sucked and deleted it in the next series in 1969.....without looking and reference I think they were designated the 3-69 models on the tube charts and schematics. So in effect, this weirdo system ran in production not even 10 months before the CBS engineering realized they screwed up and deleted it......but still didn't get it that they screwed up by deviating from the 7-63 design which was the tried and true design. SO as a point of doing service and being an expert.....the amplifier should have be proofed and restored to the 7-63 circuitry...when you know what you are actually doing in the service world. AS a generality, the blue molded Mallory capacitors tend not to be going bad as they age.......the really bad ones are the older era YELLOW ASTRONS used in the late 1950's in the tweed amps and carrying over into the early 1960's. They were all depleted out of inventory by the 7-63 reverb circuitry years.....but you might find a few hybrid circuit boards pre-1963 with both yellow Astrons and the Blue molded Mallory caps in the tolex covered amps between 1960 and 1962. Its not to say that a blue molded Mallory cap couldn't go bad and become leaky......its a very rare situation so far as with their age. Shortly in the evolution of the CBS years of fender......it was the circuitry and the signal caps they used which ruined everything......as these blue molded caps depleted in the inventory...they stayed on with Mallory but used a different series that had the chocolate color and a dull finish....they sound very thin and crappy compared to the blue molded series......and after they deplete the crappy chocolate color caps.....they still stayed with Mallory but used a dark blue drop type cap that do not sound too bad at all......these lasted into the late 70's and crossing over into the 1980's and the rivera era and the employee by out from CBS. SO in over all summation.....the silver face era and CBS association......the early silver face years....the amps really sucked as compared to the black faced amp. For the technicality, CBS took over in 1965 and still produced the black face amps till 1968 and the full on change in circuitry with the 5-68's. On a black face control plate, the Fender "electric" is pre-cbs....and the Fender "musical" is the CBS black face. Having a black face plate doesn't full mean non CBS as the generality is that just the silver face amps were CBS.
@@tiki_trash Yes. I believe this IS the circuit that gave Silverface amps a bad rep. This is not a bad thing because amps like these can be had for much less dough than the Blackfaces and easily converted to AB763.
Can I ask a question? I’m trying very hard to learn your trade and have been buying up dvds and books and studying. I’m happy to pay you for a consultation- kind of at my wits end with my current situation- last week I bought an all original 66 Super Reverb and it played great at the store- got home, the rectifier tube went, then the phase inverter.. no big deal, replaced, great sound again. I upgraded the cord to a three prong, no worries. Worked fine. Then decided to replace the filter caps, (FCK-4 kit from amprepairparts.com and took my time, one at a time, did a nice job (or so I thought) and now have a nasty hum that I can’t get under control. I also replaced the negative bias cap with the provided F&T 100uf/100v, haven’t done the tone stack caps because I wanted to sort this out first. I’m happy to pay you an over the phone consultation fee- any ideas what I did wrong here? No road case to ship and really want to tackle this on my own so I learn. I’ve also removed each filter cap and resistor and re-soldered. Definitely not there. Help!? :)
Check the resistors on the filter cap board you were working on, one or more of them has drifted in value. Replace the bad ones and see if that helps. Also, get an ohm meter and verify that the negative leads of your caps are in the right places.
First thing is to try to isolate the problem. I am going from your description...that the amp is just humming, however badly, and not emitting flames and smoke. Turn the amp on with the phase inverter tube out. If the hum goes away, the hum originates from the preamp section. If not, then the hum is in the power section. If it turns out the preamp stage(s) are the issue, then just pull tubes to see if you can locate it better. Hum can be hard to trace down, but it can also be stupid easy. For example, you say you blew up the original rectifier tube. This can blow up the dual 100 ohm resistors that create the so-called "synthetic center tap" on the heaters....usually soldered to the pilot light assembly. Check those R's. I will assure you, that ANY tube amp without a heater center tap will hum like a banshee. Not mild hum, crazy, violent hum....which sounds like what you said. Believe it or not; if the amp was all stock when you got it and it worked AND THEN you blew the rectifier tube, this is actually one of the more likely causes. Of course, you would jump for joy if your fix was 2 resistors. Point being, that fix is so easy you should for sure check it. And not just visually, see if those R's are cracked in half or burned and check their ohms. The hard part is describing in words the ten (guess) other possible sources of hum might be. But definitely check those R's first thing.
No offense, but these amps are so easy to convert to blackface specs. Those ceramic caps on the grids of the output tubes should have been clipped off at a minimum. I did an analysis back in the 90s on ampage.org as to why these caps were a design mistake. Your customer would have been so much more impressed if you had just clipped them out.
Stale humor, the basis of all Dad jokes. Keep 'em coming Terry!
This reminds me of a bygone time.... I miss you both and yet I don’t know either one of you.....yet I do. Thanks as always. I love Super Reverbs too!
Beautiful amp Terry and glad many are supporting you. You deserve it !!!!!! I still have my 59' bassman here for you when things lighten up :) thanks
Ron
D-Lab! Rock and Roll! Thanks for all of your videos.
I like how there were grounded green wires wrapped around a bundle of wires, I assume, as a shield? You are a good man Terry. I can't tell you how much I have learned from your channel. Please keep the Kobbler, Troll, and Hammered Ham coming!
Later Supers (and other Fenders) will have those same ground wires wrapped around the wire bundles but they usually have 2-3x as many windings as you see on this amp. Really densely wound. That wiring is often called "Spaghetti" wiring.
Terry, you provide the tube electronics education I never had. My progress in understanding tube electronics in the last few years was due to you and Uncle Doug’s channels. Hope you and the family are safe. Thanks again!
That is one clean amp. Great job Terry!!
Nice pair of Valiants on the bench back there...!!!
Great job on a very nice Super Reverb. I'm still playing the little single 6L6 amp you built for me several years ago.
Terry as always another nice video I learn so much in my own amp repairs and builds from your video's keep up the good work thanks!
one of my favourite youtube channels! keep going and thanks for all this great videos!
Bless you for sharing your wisdom with us!!!
I believe that the R/C combo on the power tubes was put there by Fender to help suppress oscillations caused by the poor lead dress on the Silverface amps. However, customers started complaining that they robbed high end.
Definitely get the wine!
Most excellent!
Hey Terry, at some point can you show what the underside of an eyelet board looks like. Thanks for the Videos.
Good ol' Fender bias balance/mixed bias circuit and one of the many CBS changes in 1968-69. Looking at the faceplate and seeing those black lines I would put money on this being a silverface drip edge model. I had a band master reverb with the same design. Most people have those cathode resistors and the bias balance circuit removed and converted back to blackface specs. I don't think it sounds much different and think its a cool design to be able to balance the bias between your tubes.
my toooooooooooooo..
Good stuff per the usual👍🏻 amp seem a bit noisy still at the test, perhaps the guitar, idk🤷🏻♂️ wasn’t overbearing though.
Hi, thanks for all the info. I have a vintage Fender Silver Face Pro Reverb which hadn’t been used for 20 years plus. Do not know the operational status , what can I do to check it out besides to bring it to the repair shop? Thank you!
Tony knows how to play
I’m curious as to what a refresh job like this would cost.
@Andrea Stelle I’ll check it out
Hi Terry, sorry to bother you but it seems as though the subtitles have been switched off on your last 2 videos. Sorry to be a bother, but I really enjoyed watching quite a few of your older videos over the weekend and now it seems that the new ones d0on’t have the option. Take care. Great channel!!
thanksss
I call them blue caps Blue Meanies from the Beatles' Yellow Submarine.
Hmmm I bought wine and amp components yesterday.
Had a Super Reverb for 25 years
Feel a thread in all of this
Need more wine
Always good to look at the innards of another Super Reverb! I guess I'm dumber than your average guitar player, 'cause I tried going to one of your pages and never could see how to send you any potato chips or dog bones or ... money, even ... But I'm not too swift with this Internet stuff ...
Go to google and type my name. All info is there
I have a fender 15g that had a broken volume pot, ive fixed the pot. The amp is making no sound on clean channel and overdrive channel sounds extra noisy and guitar tone sounds clean. Could the bad pot have damaged the ba4560 chip
Most guitarists dont care for the silver face grid resistors and caps, and many perform " Blackfacing" the amp by removing them, and a couple other small things to adjust the circuit closer to the older one.
Was gonna say exactly that. Judging by the stamped black numbers on the chassis, this is an AB568 (or later) Super with those 2000 pf caps and the 7 watt resistors. Most techs will yank those parts to take the amp to AB763, then consider whether to go GZ34 or 5U4GB rectifier.
Terry can you tell me what type of solder that you use
I like using 63-37 a eutectic solder that is a two state solder. You dont get cold solder joints as the solder goes from liquid to solid direct
What year is this amp? Like 68-70ish? I had a 1973 Super Reverb and it had all PVC wiring in it, no cloth. This one seems to be a mixture. Mine also had those ceramic resistors on the power tubes.
Based on the blue molded Ajax caps and silverface with vertical black lines you can assume that it’s a late ‘67 or ‘68. I saw a ‘68 date stamp in the chassis, so I’d say a 1968.
How important is it to change out the correct tubes 7025 and 12at7 instead of placing all 12ax7 on preamps?
Dear terry Thanks for sharing this video...
For taming the tone of my fender super reverb ab68 silverface 1969 ( with no master volume) what is the best solution? Modding the amp and Add master volume to original circuit or only using variac ? What is the safest and most effective method?
I'll apreciate if you answer my question.
I should mention that we use 220 volts in our country
@@AliKiani7887 The absolute simplest way is to replace the GZ34/5AR4 rectifier tube with a 5U4GB tube and try the amp that way. www.fourwater.com/files/fullrect.txt This will cut about 35 volts off your B+ voltage and *may* be enough. And it may not, but you don't even have to take the amp out of the cabinet to try that one.
Wow...I have never seen one that clean...Did you leave the old "Death Cap" in?
I believe that went when he installed the 3 wire cord.
Just a question, does the amp sound differ depending on what caps or filters that are put in? Does one brand sound better than the other? Thanks!
3:20 if you take them out its called a " blackface mod" those were added in the later cbs silver face era
If you notice closely in the beginning of the video as the camera sweeps by the front face plate by the name of the amp....you'll see 2 black lines framing the "super reverb".....like book ends. Those black lines were only used on carry over units in the transition to the silver face plates to denote that the guts were still black face guts.....it there was a cabinet present the tube chart in the cabinet would have 7-63 on it. When the silver face plate went into effect in the production line as a full on CBS model the black lines came off and the circuitry was the 5-68 designation.....meaning may of 1968. SO the black line amps were only made a few months into 1968 into the CBS silver face line to deplete the remaining black face parts in inventory. BUT IN THIS CASE......this is a bizarre transitional piece as it has black face components which are mainly the blue molded mallory caps which at a glance would suggest the full on black face circuit board and thus the 7-63 circuitry (including the black lines on the face plate)......BUT you also see the 5-68 changes on the power tubes and the power tube bias system. IT would be needed to examine the phase inverter resistors to see if the board is a true black face board out of a inventory bin that was combined with the chassis that was being set up as a 5-68 chassis as a unusual hybrid. WHEN you do a full on black face conversion, the phase invert circuitry also need to have the values of a couple resistors changed out as well as the power tube biasing system....AND the disk caps to ground on the power tubes. THIS is a truly weird Fender amp as this circuitry was not used long in production as the 5-68 version as those big cement power resistors on the power tube cathodes represent a bizarre CBS engineering interference in the design where the amp is a combination of fixed bias as it should be, all be it a wrong set up for the fixed bias as its a bias balance as opposed to an adjustable fixed bias as the older 7-63 versions......and a cathode bias system. SO to be clear...its a mix of fixed and cathode bias for the power tube section.......which totally sucks. CBS came to determine it sucked and deleted it in the next series in 1969.....without looking and reference I think they were designated the 3-69 models on the tube charts and schematics. So in effect, this weirdo system ran in production not even 10 months before the CBS engineering realized they screwed up and deleted it......but still didn't get it that they screwed up by deviating from the 7-63 design which was the tried and true design. SO as a point of doing service and being an expert.....the amplifier should have be proofed and restored to the 7-63 circuitry...when you know what you are actually doing in the service world. AS a generality, the blue molded Mallory capacitors tend not to be going bad as they age.......the really bad ones are the older era YELLOW ASTRONS used in the late 1950's in the tweed amps and carrying over into the early 1960's. They were all depleted out of inventory by the 7-63 reverb circuitry years.....but you might find a few hybrid circuit boards pre-1963 with both yellow Astrons and the Blue molded Mallory caps in the tolex covered amps between 1960 and 1962. Its not to say that a blue molded Mallory cap couldn't go bad and become leaky......its a very rare situation so far as with their age. Shortly in the evolution of the CBS years of fender......it was the circuitry and the signal caps they used which ruined everything......as these blue molded caps depleted in the inventory...they stayed on with Mallory but used a different series that had the chocolate color and a dull finish....they sound very thin and crappy compared to the blue molded series......and after they deplete the crappy chocolate color caps.....they still stayed with Mallory but used a dark blue drop type cap that do not sound too bad at all......these lasted into the late 70's and crossing over into the 1980's and the rivera era and the employee by out from CBS. SO in over all summation.....the silver face era and CBS association......the early silver face years....the amps really sucked as compared to the black faced amp. For the technicality, CBS took over in 1965 and still produced the black face amps till 1968 and the full on change in circuitry with the 5-68's. On a black face control plate, the Fender "electric" is pre-cbs....and the Fender "musical" is the CBS black face. Having a black face plate doesn't full mean non CBS as the generality is that just the silver face amps were CBS.
+1 on the stale humor ;)
3:00 My amp (ab568 circuit) already has those odd resistors.
Is that some sort of cathode/fixed bias circuit?
@@tiki_trash Yes. I believe this IS the circuit that gave Silverface amps a bad rep. This is not a bad thing because amps like these can be had for much less dough than the Blackfaces and easily converted to AB763.
@@tiki_trash yes, exactly
Can I ask a question? I’m trying very hard to learn your trade and have been buying up dvds and books and studying. I’m happy to pay you for a consultation- kind of at my wits end with my current situation- last week I bought an all original 66 Super Reverb and it played great at the store- got home, the rectifier tube went, then the phase inverter.. no big deal, replaced, great sound again. I upgraded the cord to a three prong, no worries. Worked fine. Then decided to replace the filter caps, (FCK-4 kit from amprepairparts.com and took my time, one at a time, did a nice job (or so I thought) and now have a nasty hum that I can’t get under control. I also replaced the negative bias cap with the provided F&T 100uf/100v, haven’t done the tone stack caps because I wanted to sort this out first. I’m happy to pay you an over the phone consultation fee- any ideas what I did wrong here? No road case to ship and really want to tackle this on my own so I learn. I’ve also removed each filter cap and resistor and re-soldered. Definitely not there. Help!? :)
As I am sure Terry is covered up, try music-electronics-forum.com, they help people out all the time and love a challenge on vintage gear.
Check the resistors on the filter cap board you were working on, one or more of them has drifted in value. Replace the bad ones and see if that helps. Also, get an ohm meter and verify that the negative leads of your caps are in the right places.
And remember to discharge your power supply caps before doing any work, safety first!
@@mendamp1715 I always do! Thanks for the advise. I’ll be digging in again in the morning.
First thing is to try to isolate the problem. I am going from your description...that the amp is just humming, however badly, and not emitting flames and smoke. Turn the amp on with the phase inverter tube out. If the hum goes away, the hum originates from the preamp section. If not, then the hum is in the power section. If it turns out the preamp stage(s) are the issue, then just pull tubes to see if you can locate it better.
Hum can be hard to trace down, but it can also be stupid easy. For example, you say you blew up the original rectifier tube. This can blow up the dual 100 ohm resistors that create the so-called "synthetic center tap" on the heaters....usually soldered to the pilot light assembly. Check those R's. I will assure you, that ANY tube amp without a heater center tap will hum like a banshee. Not mild hum, crazy, violent hum....which sounds like what you said. Believe it or not; if the amp was all stock when you got it and it worked AND THEN you blew the rectifier tube, this is actually one of the more likely causes. Of course, you would jump for joy if your fix was 2 resistors. Point being, that fix is so easy you should for sure check it. And not just visually, see if those R's are cracked in half or burned and check their ohms.
The hard part is describing in words the ten (guess) other possible sources of hum might be. But definitely check those R's first thing.
How much did you charge for this fix?
Anyone going to call Barry and tell him to watch this?
Already done
No offense, but these amps are so easy to convert to blackface specs. Those ceramic caps on the grids of the output tubes should have been clipped off at a minimum. I did an analysis back in the 90s on ampage.org as to why these caps were a design mistake. Your customer would have been so much more impressed if you had just clipped them out.