If a reverb tank in an amplifier is found to not have a piece of cardboard or masonite underneath it, I suggest adding one so that when you bag the tank the bag doesn't wrinkle up underneath the tank and contact the underside of the transducers, impeding their isolation and mechanically short-circuiting their suspension (the transducers are the lowest hanging fruit here, and are mounted to a spring-isolated subchassis in order to provide resistance against feedback). Sometimes the isolation springs have stretched a little bit and the entire subchassis, with it's transducers, might be hanging slightly lower than the bottom lip of the reverb tank; use 2 layers of cardboard as a bottom, with the uppermost cardboard layer having a cut out directly below the transducers so that they still "float" without bottoming out. It may be tempting to move the short isolating springs to the other unused holes in the shell of the tank, which are further apart, in order to increase their tension and lift the subchassis up a little higher, but I dont know if this would affect the resonant frequency of the tank and/or whether it would lessen the feedback isolation. I'd love to hear from anyone who has experience with this sort of thing.
Nice clean work! One thing I noticed... The black, hot wire from the power cord should be going to the gold screw and the white neutral should be going to the silver screw on the courtesy outlet. Even though the outlet isn't grounded, it does have polarity based on the size of the input slot.
Your bench looks like it was built from old-growth pine flooring pulled from a 1920's hardware store. At some point you may have to resist the temptation to build an amp cabinet with it!😉
I don't know if they still sell it, but the plastic tack they sold to hold up posters would work for holding wires in place. No 1970's dorm room would be complete without plastic tack holding up your Farrah Faucet poster (or Andy Gibbs, lol). Check your office supply store. Edit: that Accutronics Reverb tank is likely original, although both of my 1969 amps have a Gibbs 64063 tank. If you do need to replace the tank, MOD sells a good replacement. The proper tank for any vintage Fender amp is 4AB3C1B. You can find a table to see what each letter or number represents, on Stew-Mac or Ted Weber's websites.
Brad's Guitar Garage in Australia uses a blob of BluTack to hold wires down during his repair videos ---- but someone in the comments here recommends using Silly Putty because it's more resistant to soldering-iron heat than BluTack is.
I had a ‘66 Super Reverb and the Reverb was flat thin and lacking. I had a ‘79 Princeton Reverb that had the most luscious fat wonderful Reverb one could ask for.
They can be all over the place I guess, depending on how healthy the tank and circuit is. We'll hear how this accutronics tank from the reissue spring unit sounds soon 😊
Those reverb transducer usually can't be fixed. That brass pin is connected to a very thin wire if I recall. When it's pulled out, that's it. The MOD short decay tank is pretty dang good to my ears. 4AB1C1B is the part number from Antique Electronics Supply.
lmao blue tack is literally the stuff your teacher used to use in elementary school to stick crap to the walls. Magnetic tape is another option, in conjunction with cable management kits for PC builders. replace the double stick with magtape and you have every kind of clip/retainer you'd want, freely movable but will stay in place, and dont leave any residue. Also serves as a sort of litmus test - if they dont stick to the chassis you are working on, it's probably not worth working on.
It might have been instructive to set the wipers on both the original potentiometer and the replacement pot to their mechanical midpoint and then measure them from one side to the wiper and then the other side to the wiper to see if the taper of the two pots is similar or not. Newbies to this stuff may find it informative for learning the conceptual difference between linear and logarithmic pots, and how audio tapers may vary.
@@YeatzeeGuitar , By the way, I hate plastic shaft pots, primarily because they can get sheared off if banged into. They do have the advantage of not seizing up from galvanic corrosion, and the shafts ate easy to cut and shorten to length; but in the past I've encountered some cases where plastic shaft pots react with certain control cleaning chemicals and seize up almost immediately when sprayed.
If it was me personally, I wouldn't leave the death cap in place for "looks", I would remove it entirely; and although normally I'd give old parts back to the customer, I think I would throw that capacitor in the garbage. Considering that Ajax blue molded caps are "unobtainium", somebody might be tempted to use that cap in another amp repair or build, but it was under-rated and inadequate for the job, and has likely been severely stressed by AC wall voltage, therefore probably leaky (electrically) and not trustworthy. AC and DC ratings of capacitors are not directly comparable; modern "safety capacitors" are spec'd at 1000 volts and specifically designed to be self-healing and/or to fail "open", not shorted, in cases of an overload; but Fender used an ordinary 400 Volt DC rated capacitor as the death cap.
Check the next part of the series uploaded the other day, death cap was removed and they're actually 600v spec. I put it in the PI position tested for leakiness and it's fine 🤷♂️
@@YeatzeeGuitar , interesting ---- but I still wouldn't trust repurposing it as a coupling cap that has to block high DC voltage. The peaks and noise spikes of an AC power line are very rough on capacitors, although granted the amplifier was probably being played with the switch in the lowest-noise position that put the capacitor on the neutral side of the power cord and not on the hot side.....
Got to 40 minutes: broken reverb tanks usually stay that way, there's no reliable way to repair the transducers. The new MODs are way better than the present Accutronics.
@@YeatzeeGuitar If you put a Mojotone in a bag no one but you will know... Srsly, should you go new they've got 3 dwell lengths, choice of 2 or 3 springs, multiple ohm ratings and input output configs and they're $26 bucks. Sound samples on site, you'll find the shorter delay is brighter, longest is swampy and dark, pick your flavor. Iirc the bags are $9?
![[ENGSUB] UNPRODUCTIVE DAY ใช้ชีวิต (เปื่อยๆ) ด้วยกัน 1 วัน! | OUROAD CLOSEFRiEND SS2 EP.9](http://i.ytimg.com/vi/pyYKZ3kra9w/mqdefault.jpg)
If a reverb tank in an amplifier is found to not have a piece of cardboard or masonite underneath it, I suggest adding one so that when you bag the tank the bag doesn't wrinkle up underneath the tank and contact the underside of the transducers, impeding their isolation and mechanically short-circuiting their suspension (the transducers are the lowest hanging fruit here, and are mounted to a spring-isolated subchassis in order to provide resistance against feedback). Sometimes the isolation springs have stretched a little bit and the entire subchassis, with it's transducers, might be hanging slightly lower than the bottom lip of the reverb tank; use 2 layers of cardboard as a bottom, with the uppermost cardboard layer having a cut out directly below the transducers so that they still "float" without bottoming out. It may be tempting to move the short isolating springs to the other unused holes in the shell of the tank, which are further apart, in order to increase their tension and lift the subchassis up a little higher, but I dont know if this would affect the resonant frequency of the tank and/or whether it would lessen the feedback isolation. I'd love to hear from anyone who has experience with this sort of thing.
Nice clean work! One thing I noticed... The black, hot wire from the power cord should be going to the gold screw and the white neutral should be going to the silver screw on the courtesy outlet. Even though the outlet isn't grounded, it does have polarity based on the size of the input slot.
Your bench looks like it was built from old-growth pine flooring pulled from a 1920's hardware store. At some point you may have to resist the temptation to build an amp cabinet with it!😉
Yoooo! Thatnks for the shoutout, cuz. I owe you an ale.
❤️
Just have to say Man you pay a lot of a mind to everything, Well Done 🙂
Thanks! Can't turn that side of me off
When soldering, I use Silly Putty to hold wires in place.
Nice work brother!
I don't know if they still sell it, but the plastic tack they sold to hold up posters would work for holding wires in place. No 1970's dorm room would be complete without plastic tack holding up your Farrah Faucet poster (or Andy Gibbs, lol). Check your office supply store.
Edit: that Accutronics Reverb tank is likely original, although both of my 1969 amps have a Gibbs 64063 tank. If you do need to replace the tank, MOD sells a good replacement. The proper tank for any vintage Fender amp is 4AB3C1B. You can find a table to see what each letter or number represents, on Stew-Mac or Ted Weber's websites.
Brad's Guitar Garage in Australia uses a blob of BluTack to hold wires down during his repair videos ---- but someone in the comments here recommends using Silly Putty because it's more resistant to soldering-iron heat than BluTack is.
I had a ‘66 Super Reverb and the Reverb was flat thin and lacking. I had a ‘79 Princeton Reverb that had the most luscious fat wonderful Reverb one could ask for.
They can be all over the place I guess, depending on how healthy the tank and circuit is. We'll hear how this accutronics tank from the reissue spring unit sounds soon 😊
Those reverb transducer usually can't be fixed. That brass pin is connected to a very thin wire if I recall. When it's pulled out, that's it.
The MOD short decay tank is pretty dang good to my ears. 4AB1C1B is the part number from Antique Electronics Supply.
Originals would be long decay wouldnt they?
James @ rewind electric did a video where he was able to transfer a pin with its wire and hook over successfully, I maaaay give that a try for fun 😬
@@YeatzeeGuitar The original tanks have about a 2 second decay. The modern long decay tanks are approaching the 5 second area.
Try to fix it!
@@YeatzeeGuitarThe big Gibbs were in Hammond's like H100s and A100s, might be your best bet for a low mileage one.
@@matthewf1979 had no idea the modern ones are so different in specs!
lmao blue tack is literally the stuff your teacher used to use in elementary school to stick crap to the walls.
Magnetic tape is another option, in conjunction with cable management kits for PC builders. replace the double stick with magtape and you have every kind of clip/retainer you'd want, freely movable but will stay in place, and dont leave any residue. Also serves as a sort of litmus test - if they dont stick to the chassis you are working on, it's probably not worth working on.
It might have been instructive to set the wipers on both the original potentiometer and the replacement pot to their mechanical midpoint and then measure them from one side to the wiper and then the other side to the wiper to see if the taper of the two pots is similar or not. Newbies to this stuff may find it informative for learning the conceptual difference between linear and logarithmic pots, and how audio tapers may vary.
Fair point
@@YeatzeeGuitar , By the way, I hate plastic shaft pots, primarily because they can get sheared off if banged into. They do have the advantage of not seizing up from galvanic corrosion, and the shafts ate easy to cut and shorten to length; but in the past I've encountered some cases where plastic shaft pots react with certain control cleaning chemicals and seize up almost immediately when sprayed.
Oof! I've got some 1meg pots coming to replace it and see if that helps with the terrible taper
I sometimes burn my wires just to make a new wire sound old only cause I suck at soldering LOL
😂
Dude… batting 1000 on chassis grounds. 😘👌
🙏 I've worked hard on that skill!
@@YeatzeeGuitar it’s the parallel parking of amp repair. Some people got it. Some don’t.
@@YeatzeeGuitar, I'm an old dog who has somehow managed to learn a few new tricks from Psionic Audio and Brad"s Guitar Garage!
If it was me personally, I wouldn't leave the death cap in place for "looks", I would remove it entirely; and although normally I'd give old parts back to the customer, I think I would throw that capacitor in the garbage. Considering that Ajax blue molded caps are "unobtainium", somebody might be tempted to use that cap in another amp repair or build, but it was under-rated and inadequate for the job, and has likely been severely stressed by AC wall voltage, therefore probably leaky (electrically) and not trustworthy. AC and DC ratings of capacitors are not directly comparable; modern "safety capacitors" are spec'd at 1000 volts and specifically designed to be self-healing and/or to fail "open", not shorted, in cases of an overload; but Fender used an ordinary 400 Volt DC rated capacitor as the death cap.
Check the next part of the series uploaded the other day, death cap was removed and they're actually 600v spec. I put it in the PI position tested for leakiness and it's fine 🤷♂️
@@YeatzeeGuitar , interesting ---- but I still wouldn't trust repurposing it as a coupling cap that has to block high DC voltage. The peaks and noise spikes of an AC power line are very rough on capacitors, although granted the amplifier was probably being played with the switch in the lowest-noise position that put the capacitor on the neutral side of the power cord and not on the hot side.....
@@goodun2974 that's exactly my thought, and then this was already 3 pronged so 🤷♂️
Is the ground supposed to be longer than the hot, neutral on the three prong wall cable?
Yes
Thanks, wanted to verify.
So what happened with the "original" volume pot, you put it back in. Was it reading odd still or was that just because it was in the circuit? I
Just being weird in circuit 🤷♂️
@@YeatzeeGuitar Interesting to learn, I've never measured a pot in circuit. Good to know!
@@dyamariv3628 me either, not in that position
I would think when ever we change old stuff and then add new stuff they are not going to play well with one another...
As long as everything is in spec!
If you get an old tank fine but the new accutronics ones are junk
@@rayburn2007 yeah I got an old gibbs
Blue tac is that plastic putty your mom would make you use to stick posters to your wall instead of tape.
I used it only one time because the heat got to it and it was a nightmare to clean up lol
😂 Gotcha!
@@seanblythe9109 oof 😆 keep away from the big iron eh
@@YeatzeeGuitar I use a bigger flat fishing weight for chassis stuff
@@seanblythe9109 Silly Putty does not get disturbed by a bit of heat - if it worked for Apollo 8, it works for me :)
Got to 40 minutes: broken reverb tanks usually stay that way, there's no reliable way to repair the transducers. The new MODs are way better than the present Accutronics.
I kind of want to find a Gibbs 👀
If you can’t find one the MojoTone ones are awesome. Lyle recommended one for my 72 PR and it has a beautiful sound!
@@YeatzeeGuitar If you put a Mojotone in a bag no one but you will know... Srsly, should you go new they've got 3 dwell lengths, choice of 2 or 3 springs, multiple ohm ratings and input output configs and they're $26 bucks. Sound samples on site, you'll find the shorter delay is brighter, longest is swampy and dark, pick your flavor. Iirc the bags are $9?
@@oldasrocks9121 I've got a friend coming by next week with a couple tanks to test, we'll see how they fair!