Techdeth
RESIDENT ROCK PROFESSOR
I’m never letting mine go . Stock. 78 2203 . Its a ripper
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skoora
Well-known member
It could even be a good sign if the FC’s test good because it probably means the amp was played a lot over the years ie. People dug firing it up,
FourT6and2
Well-known member
Even if old filter caps measure fine in-circuit, in terms of capacitance, it doesn't mean they're good. And it's hard to know if any amp actually sounds its best without replacing them. I've done five filter cap jobs on vintage Marshalls in the last month and each and every one of them sounded better AFTER replacing the vintage caps that still measured within 10-15% of nominal. The noise floor also comes down considerably. You don't know what a quiet amp sounds like until you've replaced 50-year-old filter caps and turned the amp back on. Instant night and day difference.
I've used both F&T and ARS with good results. I did get some ARS recently that didn't measure what they were supposed to, though. Got 220uF caps for a Hiwatt cap job that only measured 200uF. The entire reason I bought 220uF ones from ARS was because I didn't wan't the standard 200uF that everybody else sells. The ARS ones are just 200uF caps (two 100uF in parallel inside the can) with 220uF on the label. Disappointed. The F&T 220uF I sourced from Europe measure 220uF.
I've used both F&T and ARS with good results. I did get some ARS recently that didn't measure what they were supposed to, though. Got 220uF caps for a Hiwatt cap job that only measured 200uF. The entire reason I bought 220uF ones from ARS was because I didn't wan't the standard 200uF that everybody else sells. The ARS ones are just 200uF caps (two 100uF in parallel inside the can) with 220uF on the label. Disappointed. The F&T 220uF I sourced from Europe measure 220uF.
R
Racerxrated
Well-known member
I guess I go by my ears, and most if not all of my vintage Marshalls have sounded great and been very quiet. This 1980 2203 I just got, can't even tell it's running its so quiet. I hear a difference for the worse with F&T caps...hence whenever I've got an old Marshall with them, I order ARS. Strange I know but I'm not the only one who hears a difference with F&T caps in a Marshall. I won't use them.
If it ain't broke, don't fix it. No need. These old Daly and LCR caps, If I quote Larry have 'unnatural long life'. They just keep on ticking. Not one has ever blown up on me, and out of 60 Marshalls pre 1990 only one needed the caps changed due to leakage/crappy sound.
I actually did change a few of the Dalys in a 72 50w, just to experiment with different values that should affect the feel....used ARS, and the amp sounded the same as before but the feel did improve. So the new ARS didn't change the tone, or noise level at all. It was unnecessary in that amp to change them(other than experiment of course).
Bad Brain
Well-known member
Can try to describe the difference, or is it feel or what? Sometimes people only recognize subtle differences when you draw attention to it.
RedPlated
Well-known member
Agree. They never sound worse.
As far as A/B’ing them, forget about it. Unless you can put 6 caps on a switch and test them like that, you’ll never have a scientific result.
I use ARS exclusively.
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Racerxrated
Well-known member
The first example was a 2555 jubilee from 87. It had a strange 'decay' to the gain. Had newer F&T filter caps. At the time, I'd owned a bunch of Jubilees, 2555s, 2554s, 2550 and 2553. I was very familiar with their sound. This amp didn't sound like a Jubilee should...I thought it was modded but didn't look to be. I returned it to Guitar Center quickly. Some time later, I nabbed an 82 2204 with the white anniversary head shell. Same strange decay to the gain...and, same F&T caps. I ordered 3 ARS caps after talking with another RTer(he felt the same way about F&T in Marshalls) and swapped them in...BOOM there was the sound I'd expected. No strange decay to the gain. All was well once again.
Filter caps aren't supposed to make a tonal difference, but I heard what I heard. And didn't hear it anymore after swapping ARS caps in.
novosibir
Well-known member
The 'unnatural long life' of LCR and Daly filter caps is only guaranteed if the amp has not been stored unused for more than 6 months. If the amp has been stored unused for a longer period of time, the filter caps are de-formed and these must be formed before the first recommissioning.
If this does not happen, it will significantly shorten the life span of the LCR and Daly filter caps and it can also lead to unexpected failures (hum) or internal shorts (fuse is blowing).
In this case I recommend forming the filter caps first, before you fire up the amp again - after my method:
Forming filter caps
The ARS filter caps are produced (almost true to the original) according to the old LCR specifications including the right materials and therefore sound almost spot-on like old LCR or Daly filter caps.
Your Marshall amp sounds like before with the old filter caps, only after the change it is certainly a bit more stable and less ghosting.
I can't recommend the use of F&T filter caps, because although they are of very good physical and electrical quality, you won't have your usual 'old' sound with the right amount of 'British dirt' in the tone after the change.
After switching to F&T, your amp will sound at least 10 to 20 years younger, cleaner, brighter.
If that's what you want, then choose F&T's
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novosibir
Well-known member
It is the remaining ripple and its special characteristics that cause Daly, LCR and ARS filter caps, which modulates to the signal voltage via the supply voltages of the preamp tubes, which then creates this 'British dirt'.
F&T's are technically too good to be able to produce the same.
However, if you want to build a Hi-Fi amp, then don't choose ARS, but F&T or still better Mundorf filter caps.
R
Racerxrated
Well-known member
Thanks for chiming in!The 'unnatural long life' of LCR and Daly filter caps is only guaranteed if the amp has not been stored unused for more than 6 months. If the amp has been stored unused for a longer period of time, the filter caps are de-formed and these must be formed before the first recommissioning.
If this does not happen, it will significantly shorten the life span of the LCR and Daly filter caps and it can also lead to unexpected failures (hum) or internal shorts (fuse is blowing).
In this case I recommend forming the filter caps first, before you fire up the amp again - after my method:
Forming filter caps
The ARS filter caps are produced (almost true to the original) according to the old Daly specifications including the right materials and therefore sound almost spot-on like old LCR or Daly filter caps.
Your Marshall amp sounds like before with the old filter caps, only after the change it is certainly a bit more stable and less ghosting.
I can't recommend the use of F&T filter caps, because although they are of very good physical and electrical quality, you won't have your usual 'old' sound with the right amount of 'British dirt' in the tone after the change.
After switching to F&T, your amp will sound at least 10 to 20 years younger, cleaner, brighter.
If that's what you want, then choose F&T's
FourT6and2
Well-known member
I don't think I've ever seen someone tout the benefits of AC ripple on the B+ rail before haha
novosibir
Well-known member
It is undisputed that this is a technical inadequacy.
However, this is like salt & pepper in the soup and exactly what creates the 'British dirt' in the sound.
We all know that guitar tube amps do not amplify cleanly at any volume...
... and that's exactly what they're not supposed to do.
OTOH you would never want to play a CD-player in your Marshall amp and enjoy the music via your Marshall cab?
FourT6and2
Well-known member
Sure. I understand.
But isn't it a bit like using a "hot shield" method on a grid wire? Can you do that to create a low-pass filter in conjunction with the tube's Miller capacitance? Yes. But you have no way of intentionally tuning the cut-off. I'd rather use an actual capacitor, whose value I can change to get the exact high-end roll-off I desire, rather than relying on chance.
Same goes for filter caps, I suppose. And I use both ARS and F&T with good results.
novosibir
Well-known member
I don't see any connection between hot shield (what I would never do) and remainig ripple of filter caps and have no idea how you come to this comparison. For my understanding, this is like the comparison between apples and oranges.
However, there are actually many technical shortcomings in guitar tube amps that ultimately contribute to the desired sound and behavior of the amp and thus ultimately shape its character.
These are technical shortcomings that must be avoided at all for example, when designing a high-quality Hi-Fi tube amp.
However, there are actually many technical shortcomings in guitar tube amps that ultimately contribute to the desired sound and behavior of the amp and thus ultimately shape its character.
These are technical shortcomings that must be avoided at all for example, when designing a high-quality Hi-Fi tube amp.
shar-vell Dan
Well-known member
She was old & tired when i got her in 2009. Before & after caps and mods not even in the same realm of discussion.
I waited several years trying to decide who and what to do it. I heard from every self professed hair brained afficanado.
A bunch of hearsay and goobly gook. Even in this thread someone is trying to suggest F & T caps are less than stellar.
Finally lead Marshall Engineer Santiago Alverez talked sense to me and recomended Mr. Friedman as he knew him personally.
Its an amplifier not a Van Gogh, it makes guitars loud. FULL STOP.
Making this tired amp a fire breather is one of the best desicions ive made.
Despite the complex circuitry never had a problem in 14 years.
Have fun with your antique table ornaments.
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FourT6and2
Well-known member
I'm simply saying I prefer to be able to intentionally tune something rather than relying on chance/luck. I'm using the hot shield as an example to make my point.
novosibir
Well-known member
You can increase the miller capacity of a preamp tube by using a small capacitor on the preamp tube base between pin 1 & 2 or between pin 6 & 7 and vary it according to your ideas. So far clear.
But how can you influence the parameters (i.e. ripple) of an F&T filter cap in such a way that it then has the parameters of a Daly, LCR or ARS filter cap?
I don't know how and I don't see any way to change it.
If you have an idea, then tell me, because despite 41 years of experience with tube amps, I still like to learn something new.
And that's the point why I didn't understand your comparison.
But how can you influence the parameters (i.e. ripple) of an F&T filter cap in such a way that it then has the parameters of a Daly, LCR or ARS filter cap?
I don't know how and I don't see any way to change it.
If you have an idea, then tell me, because despite 41 years of experience with tube amps, I still like to learn something new.
And that's the point why I didn't understand your comparison.
FourT6and2
Well-known member
Right.
I can't. I'm saying I'd rather focus on other things that I can control. I've used and continue to use both ARS and F&T with equally good results.
G
GuitarManTim
New member
I appreciate all of your guys' help and opinions. I ordered yesterday, and I'm definitely excited. I might run it with my Headfirst Alta at the same time to see how that sounds, lol. And I really appreciate Jeremy responding, as one of the reasons I was looking for an old JMP was to possibly get the Moab mod, so it's good to know he thinks it looks good. Hopefully the caps are still good, but if not, I'll definitely buy some ARS caps. Oh, also I forgot to include pictures of it in the headshell, lol, but it's really pristine also. And for the added resistor, I guess I'll just see how it sounds unless y'all think I should remove it as soon as I get it?
novosibir
Well-known member
If you are in doubt where to get ARS filter caps and if you live in Europe, this is your address:
Watford Valves UK
And here ist the ARS 50+50/500V filter cap:
ARS 50UF+50UF/500V RADIAL