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Discussion Starter · #1 ·
So I’ve been taking apart my amps to clean the pots and stuff for something to do. I have a tuxedo Princeton and I though about changing some caps for something to do. Do we have any preferred caps for vintage amps?
also, no these don’t have any good reason to be replaced, the amp sounds good as is, I’m just bored.
Electrical wiring Electronic engineering Electricity Electronic component Cable
 

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prepare for a lot of people to tell you “if it works and you love it, don’t bother”. But it does feel good to go over an amp and resolder and check values and “upgrade” or renovate caps. I’d focus on signal caps if you are going for some pricey paper in oil jobs.

Mojo Dijon’s are good caps.
Jupiter condenser would probably be a fun signal cap overhaul. I’ve had nice results with the Sozo blue caps. They seem to give off the old blue astron

I’d even order a nice lil Jupiter speaker to try while your at it.

The resistors all look like Allen Bradley’s which are great.

Wouldn’t hurt to go over it with a multimeter and make sure they are all within an acceptable tolerance.

It could be fun to play with the resistor value that controls the Trem speed. You can get some real slow deep tremolo.
 

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Don't change coupling caps unless they are bad. This is a valuable amp.
The only olds caps need to be new are the filter caps. They dry with time.

You want to drop the value of your amp 'cause you are bored !!!!
 

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Discussion Starter · #4 ·
Don't change coupling caps unless they are bad. This is a valuable amp.
The only olds caps need to be new are the filter caps. They dry with time.

You want to drop the value of your amp 'cause you are bored !!!!
The included picture is the amp.
these were already changed before I got it, and the amp was a good price.
changing caps to sozos or Jupiter’s won’t decrease the value.
 

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You are right.
These coupling caps don't need to be changed. Filters caps yes.

With fresh filter caps your amp may sound better, more than other coupling caps

You need to check output tubes bias and adjust if tubes are not the original one. Right bias = amp sound better= longer output tube life
 

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Sozo
 

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1965 Fender Mustang, Ampegs, anything to test an amp.
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You see something wrong with ground terminations ?
The solder connections to the chassis are not fully bonded. The heat source used was insufficient to create a proper bond...some may refer to it as a cold solder joint.
All the terminations are tacked to the chassis....there is no mechanical connection; the properties of solder does not allow a strong mechanical connection.
It may be acceptable for proto-type work but not for a commercial product.
 

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The solder connections to the chassis are not fully bonded. The heat source used was insufficient to create a proper bond...some may refer to it as a cold solder joint.
All the terminations are tacked to the chassis....there is no mechanical connection; the properties of solder does not allow a strong mechanical connection.
It may be acceptable for proto-type work but not for a commercial product.
Very interesting and educational. Thanks!
 

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prepare for a lot of people to tell you “if it works and you love it, don’t bother”. But it does feel good to go over an amp and resolder and check values and “upgrade” or renovate caps. I’d focus on signal caps if you are going for some pricey paper in oil jobs.
Yeah; there's a bloody good reason for that (like besides the vintage/value thing).

Also HELL NO - stay the F away from paper in (snake) oil caps. They are the worst. Mostly ancient (there is some new prod, but I think only lower voltage ones for guitar tone controls; even more expensive) so their value has drifted significantly from spec already and they are insanely likely to leak on you (ever been to e.g. A1 Electronics and looked in the PiO cap bins - fricken ew; you don't want that mess inside yer amp even if it is the holy grail of tone, which they aren't). Just don't. This is audio voodoo at it's worst. They are also rather large compared to other cap types (same value/voltage) so sometimes fitting them in can be an issue as well.


I'd be more concerned about the ground terminations than the brand of components.
Yes! Especially if the ground points are riveted to the chassis (or as Paul notices later - soldered - that's even worse; good catch); those loosen (or fail) over time and cause intermittent grounds as the amp's a rockin. Drill them out (or just litterally pry them off) and replace with screws and a terminal lug. Use a keps nut or if the lug is toothed reg nut is fine. Not sexy but actually makes a difference and can prevent a major issue in the future.





Do not crimp on a loop connector to the wire and put that on the screw (like car chassis grounds) or worse yet wrap the wire around the screw. Yeah it works (at least for a bit) but it's not as reliable, and robust. A proper terminal lug is also easier to work on later.
 

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Discussion Starter · #14 ·
i really appreciate everyone’s big long answers, detailing their knowledge of amps. I’m not attempting to undermine that, but for this post, I’m really just asking what is your favourite cap to use to put in old fender amps.
I’m thinking I may try some blue sozos.
 

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Ok, my $.02...
Any idea how old the electrolytic caps are -- there will be a date code on the Vishay/Sprague Atom 25Uf/25V caps on the board, ditto on the cap can. I usually replace electrolytics before 10 years. I also like to use 50V Atoms vs. the 25V. Nothing wrong with Mojo Dijons, but you might want to check for outer foil orientation in the circuit path. Most current cap brands don't mark the outer foil (Jupiter and Sozo are notable exceptions), so its DIY.
 

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I’m thinking I may try some blue sozos.
That's the best solution, keep trying until your satisfied, just make sure that they don't leak current.
Edit: try to find out where mojo sourced those Dions...they are likely a rebranded cap; it may not help if the replacements are the original manufacturers. ie. if they are rebranded TADs, source caps other than TAD which are probably rebranded too, appearances can be deceiving.
There are many electronic components that are rebranded. It's bad enough that you have to deal with counterfeits too. It may be a pessimistic attitude on my part but that the way it is.
 

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Wouldn’t hurt to go over it with a multimeter and make sure they are all within an acceptable tolerance.
Play around and experiment with types/brands all you like, but what he said ^^^^^.
Any differences will be measurable. Audible differences that are attributed to brand are often the result of a change in some value. It's nice to know exactly how you changed something rather than it just being different 'mojo'. :D

My own personal preference are the ones from a generic electronic component supplier at 1/10th the price of the same item re-labelled for the guitar amp market. But then you lose out on bragging rights or 'under the hood' photo-ops. ;)
 

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Yeah; there's a bloody good reason for that (like besides the vintage/value thing).

Also HELL NO - stay the F away from paper in (snake) oil caps. They are the worst. Mostly ancient (there is some new prod, but I think only lower voltage ones for guitar tone controls; even more expensive) so their value has drifted significantly from spec already and they are insanely likely to leak on you (ever been to e.g. A1 Electronics and looked in the PiO cap bins - fricken ew; you don't want that mess inside yer amp even if it is the holy grail of tone, which they aren't). Just don't. This is audio voodoo at it's worst. They are also rather large compared to other cap types (same value/voltage) so sometimes fitting them in can be an issue as well.




Yes! Especially if the ground points are riveted to the chassis (or as Paul notices later - soldered - that's even worse; good catch); those loosen (or fail) over time and cause intermittent grounds as the amp's a rockin. Drill them out (or just litterally pry them off) and replace with screws and a terminal lug. Use a keps nut or if the lug is toothed reg nut is fine. Not sexy but actually makes a difference and can prevent a major issue in the future.





Do not crimp on a loop connector to the wire and put that on the screw (like car chassis grounds) or worse yet wrap the wire around the screw. Yeah it works (at least for a bit) but it's not as reliable, and robust. A proper terminal lug is also easier to work on later.
There is no vintage value in Mojo Dijon Caps.
If I owned this amp, I would spend good money on replacing these modern Dijon caps with some fancy pants modern Jupiter paper in oil Caps. They do make mini mite and red and yellow Astron replicas for a pretty penny. It’s not a necessity to make and amps work, but a vintage amp is not a necessity either, it’s just sometimes it feels nice to tinker and upgrade something before it breaks.


I wouldn’t suggest gutting a completely stock vintage amp for shits and giggles. I myself have rebuilt an entire 1964 Princeton circuit with modern Sozo caps and Spragues as well as NoS Allen Bradley resistors and dropped it in to the chassis and it sounded very good, but then decided to stick with the the original assembly. I did however tidy up the wiring and alter the 3 prong so that the ground had a more mechanical connection. I also put in the effort to preserve the cardboard barrels from the mighty might caps and hide the new sprague atoms in them as well as pay extra for a CE cap can and then wrap it in aluminum tape and carefully etch the original cap can info onto it in order to preserve the original appearance of the amp as much as possible.

I then took the amp to a very reputable technician who went over the amp and made sure that it was perfect prior to moving it. I ended up keeping the Sozo’S and some of the unneeded NOS carbon comp resistors and have used them recently on a different amp.

If this were a blues junior I would wait until it’s broken and then head over to sayal and buy a 90 cents Chinese electrolytic and replace it on a need to replace basis. But what the OP is asking for us suggestions on which brand of modern caps built to “vintage” quality as a fun way to spruce up an already great amp.
 

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There is no vintage value in Mojo Dijon Caps.
If I owned this amp, I would spend good money on replacing these modern Dijon caps with some fancy pants modern Jupiter paper in oil Caps. They do make mini mite and red and yellow Astron replicas for a pretty penny. It’s not a necessity to make and amps work, but a vintage amp is not a necessity either, it’s just sometimes it feels nice to tinker and upgrade something before it breaks.


I wouldn’t suggest gutting a completely stock vintage amp for shits and giggles. I myself have rebuilt an entire 1964 Princeton circuit with modern Sozo caps and Spragues as well as NoS Allen Bradley resistors and dropped it in to the chassis and it sounded very good, but then decided to stick with the the original assembly. I did however tidy up the wiring and alter the 3 prong so that the ground had a more mechanical connection. I also put in the effort to preserve the cardboard barrels from the mighty might caps and hide the new sprague atoms in them as well as pay extra for a CE cap can and then wrap it in aluminum tape and carefully etch the original cap can info onto it in order to preserve the original appearance of the amp as much as possible.

I then took the amp to a very reputable technician who went over the amp and made sure that it was perfect prior to moving it. I ended up keeping the Sozo’S and some of the unneeded NOS carbon comp resistors and have used them recently on a different amp.

If this were a blues junior I would wait until it’s broken and then head over to sayal and buy a 90 cents Chinese electrolytic and replace it on a need to replace basis. But what the OP is asking for us suggestions on which brand of modern caps built to “vintage” quality as a fun way to spruce up an already great amp.
You misunderstand - I meant that one of the reasons is NOT the vintage amp value thing (that some others mentioned) - not my concern here at all. Personally I wouldn't be arsed to preserve the original cap cans as you describe (but valiant effort) because a) I have some vintage amps but nothing super valuable (if I sell the buyers are players not collectors, and they value proper working order above originality when it comes to consumables like filter caps and bias resistors), and b) it can be construed as misleading (if not disclosed) upon sale (and sure you may disclose but the next guy will probably forget - I'd put money on it actually). I am also not certain what that link to a cap selling site you included is for/trying to demonstrate.

Further, based on all the dfifferent caps I have used in various devices (not just tube amps - I'm newish to building those) I have serious doubts that anyone can hear any real difference between brands/types of the same actual value (especially if, as it appears you are now suggesting, you replace one or two here or there randomly in an uncontrolled fashion, in an amp with 10+ poly film caps in it). See also what @jbwelder said about value tolerances just above your last post - at the very least, if you want to have a valid experiment, control the variables that you can (measure the old cap after removing, and the replacement before you put it in - betcha they're not that close in value at all +/- 20% is a lot of swing - even 10% - how much makes a difference depends on what the cap is doing). Then there's the fact that they're all (minus PiO - which is a whole other problem) the same type of cap - Mallory, Orange Drops, Sozos (some of them - they have a few lines but you're not going to be using Micas as coupling caps), even vintage Mustards etc are all metalised polypropylene film (Orange Drops have a few types/product lines, but are all poly-something films; close enuf). The same thing (except in axial format and higher voltage rating) as those 40c box films in any guitar pedal. In fact Vishay (itself already an umbrella), Sprague (Orange Drops), Mallory (and a few others) are all brands owned by the same manufacturer - Cornell Dubliner. You think the boutique best-for-your-amp brands are rolled in house by the sole proprietor of whatever brand you care to look at (Sozo, Mojotone, Emerson etc)? The legacy of Mustards being awesome comes from the fact that they were one of the earliest precision mass produced NON PiO (or wax vs oil; same problems) caps - their true legacy is not tone so much as reliability (and tighter tolerances). That's why Marshall and Traynor etc used them so religiously. Same goes for Orange Drops in the US for Fender (Traynor is physically closer to the US, but at the time being part of the Commonwealth, British parts were sometimes easier/cheaper to get, Pete may also have just preferred Mustards - they were smaller). Eisenhower didn't give Sprague the exclusive military supply contract because they sounded better in their communications gear - it was all about tolerance and reliability (which can affect tone, eg 10% off a standard value tone cap will change the rolloff point of the filter a bit; some may notice).

If you really want to check the effect of different caps, build or buy (though if one can't build perhaps they're not qualified to run the experiment) a small uncomplicated device (a basic tube buffer or preamp only with no bells/whistles), buy a bunch of caps of each type desired to be tested and select the ones that are all closest in value (both to each other and to spec for the device ), put them on a multiway switch so it's not half an hour between tests, use a source that is consistant (recording or loop of you playing from a loop pedal). Don't just trust your ears (there's a reason proper experiments are double blind - not feasible here, fine, so do what you can), use the spectral analysis in your DAW. That's not a complete list. Otherwise you're just falling victim to various cognative biases, and, most likely simple variance in actual Farad values.... and especially with NOS or PiO stuff, significantly larger leakage resistance.

Lastly, rolling caps for fun when there are actual concerns with the amp (the grounds soldered to the chassis) is just ass backwards priorities (I really hope @RBlakeney is not dismissing that in post #14 above - little vague). The amp may have intermittent grounds (or variable resistance to ground if not cutting out all the way) and making those more solid will actually imnprove tone more (as well as prevent possible costly failures).

It is his amp and he can do what he wants, but the point is that if he does this, in such a wildly uncontrolled fashion (as so many already have - with the youtube vids to document it, no need to repeat) proves nothing - you can convince yourself of all sorts of things in the process though. All that will result in is an upwards price spiral for the 'special' stuff.
 

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Discussion Starter · #20 ·
You misunderstand - I meant that one of the reasons is NOT the vintage amp value thing (that some others mentioned) - not my concern here at all. Personally I wouldn't be arsed to preserve the original cap cans as you describe (but valiant effort) because a) I have some vintage amps but nothing super valuable (if I sell the buyers are players not collectors, and they value proper working order above originality when it comes to consumables like filter caps and bias resistors), and b) it can be construed as misleading (if not disclosed) upon sale (and sure you may disclose but the next guy will probably forget - I'd put money on it actually). I am also not certain what that link to a cap selling site you included is for/trying to demonstrate.

Further, based on all the dfifferent caps I have used in various devices (not just tube amps - I'm newish to building those) I have serious doubts that anyone can hear any real difference between brands/types of the same actual value (especially if, as it appears you are now suggesting, you replace one or two here or there randomly in an uncontrolled fashion, in an amp with 10+ poly film caps in it). See also what @jbwelder said about value tolerances just above your last post - at the very least, if you want to have a valid experiment, control the variables that you can (measure the old cap after removing, and the replacement before you put it in - betcha they're not that close in value at all +/- 20% is a lot of swing - even 10% - how much makes a difference depends on what the cap is doing). Then there's the fact that they're all (minus PiO - which is a whole other problem) the same type of cap - Mallory, Orange Drops, Sozos (some of them - they have a few lines but you're not going to be using Micas as coupling caps), even vintage Mustards etc are all metalised polypropylene film (Orange Drops have a few types/product lines, but are all poly-something films; close enuf). The same thing (except in axial format and higher voltage rating) as those 40c box films in any guitar pedal. In fact Vishay (itself already an umbrella), Sprague (Orange Drops), Mallory (and a few others) are all brands owned by the same manufacturer - Cornell Dubliner. You think the boutique best-for-your-amp brands are rolled in house by the sole proprietor of whatever brand you care to look at (Sozo, Mojotone, Emerson etc)? The legacy of Mustards being awesome comes from the fact that they were one of the earliest precision mass produced NON PiO (or wax vs oil; same problems) caps - their true legacy is not tone so much as reliability (and tighter tolerances). That's why Marshall and Traynor etc used them so religiously. Same goes for Orange Drops in the US for Fender (Traynor is physically closer to the US, but at the time being part of the Commonwealth, British parts were sometimes easier/cheaper to get, Pete may also have just preferred Mustards - they were smaller). Eisenhower didn't give Sprague the exclusive military supply contract because they sounded better in their communications gear - it was all about tolerance and reliability (which can affect tone, eg 10% off a standard value tone cap will change the rolloff point of the filter a bit; some may notice).

If you really want to check the effect of different caps, build or buy (though if one can't build perhaps they're not qualified to run the experiment) a small uncomplicated device (a basic tube buffer or preamp only with no bells/whistles), buy a bunch of caps of each type desired to be tested and select the ones that are all closest in value (both to each other and to spec for the device ), put them on a multiway switch so it's not half an hour between tests, use a source that is consistant (recording or loop of you playing from a loop pedal). Don't just trust your ears (there's a reason proper experiments are double blind - not feasible here, fine, so do what you can), use the spectral analysis in your DAW. That's not a complete list. Otherwise you're just falling victim to various cognative biases, and, most likely simple variance in actual Farad values.... and especially with NOS or PiO stuff, significantly larger leakage resistance.

Lastly, rolling caps for fun when there are actual concerns with the amp (the grounds soldered to the chassis) is just ass backwards priorities (I really hope @RBlakeney is not dismissing that in post #14 above - little vague). The amp may have intermittent grounds (or variable resistance to ground if not cutting out all the way) and making those more solid will actually imnprove tone more (as well as prevent possible costly failures).

It is his amp and he can do what he wants, but the point is that if he does this, in such a wildly uncontrolled fashion (as so many already have - with the youtube vids to document it, no need to repeat) proves nothing - you can convince yourself of all sorts of things in the process though. All that will result in is an upwards price spiral for the 'special' stuff.
Wasn’t dismissing, I just already knew it could use ground lugs, and was attempting to make a thread to find out what people’s favourite caps were. It’s kind of turned into someone asking for pickup recommendations, and people replying that it doesn’t matter what pickups you use, because you need to change your strings.
 
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