Filter Capacitor Replacement Axial vs Multi section (Sprague/JJ)

[volt9]

Hi there
 
I am building a Blackface Vibrolux, dont care much about how accurate aesthetic looks like.

My question is more about the power filter caps and options.

As we all know the Sprague filters are overpriced (and I wont start a discussion if they are the Caps Godness or not), as per my understanding there are other options F&T, etc. but I want to skip the Filter Can Tray and all the inside Board to house the 5 Axial Caps and explore the Multisection cap option. 

My questions in matter is it safe to replace the 5 @ 16uf 475V  caps with a single JJ Multisection 20/20/20/40 uf  500V ?

From what I read a 20% tolerance am I correct, just to confirm that this is a good option or should I just go for cheaper Axial Caps

Any thoughts?

[John]

Hi Volt, at the bottom of this page :

http://www.hoffmanamps.com/MyStore/perlshop.cgi?ACTION=enter&template&thispage=Capacitors&ORDER_ID=!ORDERID!

there is some good common sense info on caps/cans etc. I think you'll still want to add the additional 5th filter cap, or maybe finagle something with the 32/32 FT can along with the 40/20/20/20 from JJ. According to Doug, exact values are not critical.

You will want to watch the 1st filter cap (or "reservoir") cap value if you're using a 5Y3 rect. tube. I swapped the 1st cap -47uf- for a 22uf, so I've got 22, then 47, then back to 22 down the line. More really good info on Merlin's site too: http://www.freewebs.com/valvewizard/index.html

Hope this helps! And if someone else comes along and says I'm mistaken about something.... they're right!!!  I'm still learning all about this stuff too.

[jojokeo]

Is it safe - yes. Will it work - yes. Is it something you "should" do - no. Not according to people who write books and those that like to try to minimize any possibilities for lower noise floor, parasitic oscillations, ground loops, and other nasties - YMMV as to design, layout, lead dress, and budget considerations. In the old days this was a cheaper option to go w/ multi-section cap cans and it did save on room where things were tight w/ the layout.
You would be well served to read these two chapters before proceeding w/ your plan.

http://www.freewebs.com/valvewizard2/grounding.html
http://www.freewebs.com/valvewizard1/smoothing.html

[FYL]

I don't fancy multi section caps for new builds as their architecture - a single common ground - can bring unwanted noise. Two sections caps on two similarly grounded nodes are OK, for instance plates + screens or two preamp sections from the same dual triode.

You can consider using a couple of terminal strips holding the caps.



Or go for distributed filtering (best), either with the caps on board between nodes or connected between the board and chassis buss wire.



Pix from the Filter Caps page in Doug's library of info http://www.el34world.com/charts/filtercaps.htm

[volt9]

Hi Volt, at the bottom of this page :

http://www.hoffmanamps.com/MyStore/perlshop.cgi?ACTION=enter&template&thispage=Capacitors&ORDER_ID=!ORDERID!

there is some good common sense info on caps/cans etc. I think you'll still want to add the additional 5th filter cap, or maybe finagle something with the 32/32 FT can along with the 40/20/20/20 from JJ. According to Doug, exact values are not critical.

You will want to watch the 1st filter cap (or "reservoir") cap value if you're using a 5Y3 rect. tube. I swapped the 1st cap -47uf- for a 22uf, so I've got 22, then 47, then back to 22 down the line. More really good info on Merlin's site too: http://www.freewebs.com/valvewizard/index.html

Hope this helps! And if someone else comes along and says I'm mistaken about something.... they're right!!!  I'm still learning all about this stuff too.

Thanks for the advice, but If my electronics are correct the 20/20/20/40 will be enough since the Vibrolux requires 16/16/16 and 32uf (2 16uf wired in paralell) so I think the JJ will be the right replacement -

[John]

Gotcha. I just read the 5@16uf, didn't look at schematic. :)

[LooseChange]

Whenever I re-cap an old amp with multi-section caps I use individual caps and place them strategically along the B+ rail to eliminate excess hum. Works great.

[bluesbear]

I've used a JJ 40/20/20/20 in all new builds I've ever done. I didn't do any tricks to make it work, either; I just used them as intended. Never had a problem. Personally, I don't like the idea of high voltage on the outside of the amp like Fender did it but that seems to have worked okay. The cans save real estate! They've been used for decades; if they didn't work, we'd know.
Dave

[macula56]

I'm with Bluesbear on this one. I have never had any extar noise or hum when using the cap cans. I like the way they look too.

[stingray_65]

+1 to Blues Bear

It is common for amp builders (not manufactures making 1000 units a day) to go to every extreme and use the "best" construction technique possible.

This makes VERY reliable Very rugged and VERY great sounding amps.

this is not ALWAYS necessary, especially when servicing an old amp.

I'm in the middle of a conversion amp, taken out of an old Baldwin organ, cap can is the likely problem i'm having.

LOTS of 60hz hum and a slow metronome like ticking at all gain levels (goes away  when I pull the PI tube)

Any how, lead dress is awful in those point to point builds, Cap can, multiple grounding points, all sorts of things that a modern builder would avoid like the plague.

I'm pretty sure that with a cap can replacement all will sound great and I expect to see many years of service from this amp.

Baldwin had a reputation of quality to uphold, bad hum would not have been tolerated, I'm sure it will go away and give the quality performance they built their reputation on.

While cap cans may have some drawbacks, they will function as they are designed to do and perform well.

If your amp had one, put another back in (My opinion)

Ray

[volt9]

Thanks everyone for your input -

Just a comment (forgot to mention) - space is 1/2 of an issue,   I still have some space in my turret board for housing the 2 parallel F&T 16/475V caps or 1 Sprague 20/500V (for the Rectifier 32/475V section required)

so just to follow the Ground bible and avoid the 1 ground multi can for everything.....

What do you think of placing the 2 F&T for 16 or 1 20/500 and use a multi can cap for the remaining ones like a 20/20/20 @525V ?http://www.amplifiedparts.com/products/amp_parts/C-EC20X3-525  (Sorry Doug you dont have that part available)

or just save it and stick with the 1 single solution:

1 Multi can 40/20/20/20 @ 500V JJ  or CE (I expect the CE is better for heat dissipation due to its housing and heat transfer design)

Last question: will the 20% capacitance increase affect the tone of the amp? positive /negative way - I read something about bass response (my current design is kind of trebly at high volume) 

Thanks in advance
 

[volt9]

If your amp had one, put another back in (My opinion)

It is a new build so I don't need to follow any mechanical design -

[catnine]

Hi Volt, at the bottom of this page :

http://www.hoffmanamps.com/MyStore/perlshop.cgi?ACTION=enter&template&thispage=Capacitors&ORDER_ID=!ORDERID!

there is some good common sense info on caps/cans etc. I think you'll still want to add the additional 5th filter cap, or maybe finagle something with the 32/32 FT can along with the 40/20/20/20 from JJ. According to Doug, exact values are not critical.

You will want to watch the 1st filter cap (or "reservoir") cap value if you're using a 5Y3 rect. tube. I swapped the 1st cap -47uf- for a 22uf, so I've got 22, then 47, then back to 22 down the line. More really good info on Merlin's site too: http://www.freewebs.com/valvewizard/index.html

Hope this helps! And if someone else comes along and says I'm mistaken about something.... they're right!!!  I'm still learning all about this stuff too.

 So what was the result of using the 22uf reservoir cap instead if the 40 UF cap ? That site you listed even says that diode rectifiers short out more often than tube rectifiers. .

[catnine]

If your amp had one, put another back in (My opinion)

It is a new build so I don't need to follow any mechanical design -

 Sounds like space in your amp is the issue .

[John]

Catnine, with the 47 in first place, it "seemed" to me that I had discernible ripple in the sound coming out of the speaker, plus the transformer got pretty warm.. not so hot I couldn't hold my hand on it, but close to that. After swapping, the ripple "seemed" to much reduced, and the transformer ran cooler. Also, I do know according to the data sheet that 40 is absolutely max for a 5y3, and 20-30 is better. I also at the same time switched the NOS 5y3 for a Sovtek.

I say "seemed" because I know that sometimes we hear what we expect to hear. ;)

[catnine]

Catnine, with the 47 in first place, it "seemed" to me that I had discernible ripple in the sound coming out of the speaker, plus the transformer got pretty warm.. not so hot I couldn't hold my hand on it, but close to that. After swapping, the ripple "seemed" to much reduced, and the transformer ran cooler. Also, I do know according to the data sheet that 40 is absolutely max for a 5y3, and 20-30 is better. I also at the same time switched the NOS 5y3 for a Sovtek.

I say "seemed" because I know that sometimes we hear what we expect to hear. ;)

 I don't know what to say or what PT you are using . All I do know is after hours of playing at 7 my weber PT for a champ at 100 mA does not get more than warm . I can also say I heard nothing but quiet out of my speaker , no hum or anything else. I have playing in total darkness and never saw the rect 5Y3 do anything , no flash or fireworks at all. Who knows . I just built this amp based on what my good old 73 SF champ came with now granted the PT is not an old champ original and is rated higher , the Old 73 champ PT was 70 mA HT and this weber is 100 mA and has a 4 amp 6.3 heater and a 3 amp 5 volt for the rect . so who knows . so far it has worked as the old 73 SF that came stock with a 40/20/20 uf cap can and still had the original 5Y3 and 6V6 and 12 ax7 . I did build a 5F2-A parallel 6V6 witha larger hammond PT and a allen amps power house SE OT and the hammond even though good and large got so hot I could not keep my hand on it for more than a minute so i added a small fan . It used a 5Y3 sovtek before they changed them and even with a 6L6 it still ran hot on the PT and the hammond PT was a higher rated PT than what I have now because I was told I neede it , it started out as a simple version of a 5F2-A and I used the small filter caps used in a stock 5F2-A

[jeff]

I also at the same time switched the NOS 5y3 for a Sovtek.

Sorry to get off subject for a sec, but I've had problems with Sovtek 5Y3s
Did you notice a rise in your B+ with the Sovtek. My little amp has 360V with a NOS 5Y3 but 420V with a Sovtek 5Y3.

[John]

I also at the same time switched the NOS 5y3 for a Sovtek.

Sorry to get off subject for a sec, but I've had problems with Sovtek 5Y3s
Did you notice a rise in your B+ with the Sovtek. My little amp has 360V with a NOS 5Y3 but 420V with a Sovtek 5Y3.

Yes, but that's actually WHY I switched them. With the NOS I had barely 300 at the plates, and I really was trying to get as close to Geezer's voltages as I could. With a SS, I was at 395, way too high. So popped in the Sovtek and that brought the plates to ~345. Then all I had to do was up the first dropping resistor from 10k to 20k, and the preamp voltages are within 10 volts of where his are too.

Now all I have to do is figure out the right combination of preamp coupling cap values. My bass and mids sound great, but the higher notes I play sound almost as if they're attenuated somehow, so next time in I'll start lowering cap values between tubes (if I understand what I read correctly ) And even with that, I still have a hard time putting the guitar down!

[SoundmasterG]

Last question: will the 20% capacitance increase affect the tone of the amp? positive /negative way - I read something about bass response (my current design is kind of trebly at high volume) 

Thanks in advance
 

Electrolytic caps have always had wide tolerances like that. That is just typical of electrolytics in general and I wouldn't let it worry you. You can adjust the "tone" of the stages supplied in the preamp and phase inverter by going to larger (increases bass) or smaller (reduces bass) caps, but in the B+ and screen supply area, it affects the feel more so than the tone per se. Larger caps in the power supply make the amp quicker to respond to demands of large bass tones....so essentially it makes the bass notes tighter. Larger caps in the screen supply will make the amp hum less usually.

Greg