Where Can I Find New Multisection Caps For My Ampeg V4

[methodofcontrol]

it needs to be recapped...i'd prefer to mount the new caps where the old ones are instead of seperately inside. anyone know where i can get them? also...after installation, do i need to bring the voltage up slowly to form the caps? or can i just turn the amp on w/out sending a signal through for a few hours?

[bob p]

i don't know which caps the V4 uses, but have you looked at the AES site? tubesandmore.com

[methodofcontrol]

yeah i checked them out. the multisection caps are:
40/40/40 @ 475v and two 70/40/40 @ 450v.

i sent an email to ted weber and i checked mouser. fliptops.net sells a re-cap kit, but it doesn't add up from what i can tell. if anyone here has recapped their V4, please share the details w/ me.

[stokes]

When recapping vintage amps,especially Ampegs,most times it is tough to come up with exact replacements,so getting close suffices.The fliptop kit will work,it just takes a little fudging.If you look at the first filter on the schem the total uf value is around 55uf but the voltage value needs to be over 500 so they use them totem poled and paralleled to give you 55uf/900v's.On the totem poled screen and PI cap I would suggest putting 2 220k 2watt resistors across the caps just like the first cap has the 100k's.The rest are pretty straight forward.I have always used Spragues to recap Ampegs and usually shoot for 80-100uf on the first cap-a little extra filtering here aint a bad thing it really helps tighten things up especially when you crank it up.

[methodofcontrol]

i see what you are saying...the 70uf@ 450v in parallel w/ the 40uf@ 450v is 110uf@ 450v? and that's stacked in series w/ the other 70/40 @ 450v to give you 55uf @ 900v? (i think i did my math right, please correct me if i'm wrong)
so how do you apply the 100x100@500 or a 50x50@500 fliptops supplies to this position?
also...on my schem, where c19 connects to point B, you have 2x 40uf@450v in series....why can't we just use one 20uf@900v? w/out the caps in hand, i'm having a hard time seeing how the fliptops kit adds up. thanks for the help, stokes.

[stokes]

Let me just correct something from the earlier response.The PI is not connected to the screen tap,should have my coffeee before looking at a schem.Anyway,here is what you do.You stack the single 100uf/450 on top of one of the 100uf/500v's in the double can,this gives you 50uf/950v for your first or main tap.then you parallel the 2x50uf's and stack them on top of the empty 100uf/500 and use this for your screen tap.You will need to use 4-220k/2watt resistors across the stacked pairs.The 40x40x40/450 is then used for the remaining preamp caps.You will notice that instead of 20uf on the screens you now have 50uf,this is a good thing as it will help the screens get a better supply.Be sure to use 220k/2w resistors in your totem poled main and screen.The originals had 100k's because of the paralleled status of that first cap arrangement.Thats it.You could also just buy individual caps,but caps that have over 500v ratings are very large and hard to come by.I cant comment on the quality of the caps that fliptop uses,but I only use Sprague or F&T brands,to me any other brand is inferior.

[methodofcontrol]

i think i get it, i'll check it out w/ the schem in front of me later on. but let me ask you...where did you get your spragues from when you recapped a V4?

[stokes]

I order my parts from Newsensor,they are a bit pricier than other suppliers,but I have access to an account with them.There are many suppliers who carry these parts.You wont get the multisection caps from Sprague,so it will take some squeezing to get them to fit.And it will leave a hole where the can cap used to be,on a couple of Gemini's I did I used that hole to install a tube rectifier.

[Richard]

Stokes, how do you install a tube rectifier on an amp that came without one?

[stokes]

The two Gemini's had a 5volt winding taped up and unused,put a socket where the old can cap was and wire it up.If the amp you want to do it to doesnt have a 5v winding you need to add an auxilliary 5v tranny.

[methodofcontrol]

hey stokes....you've implied that although the fliptops.net cap-kit will work, there is a better way.
i'm wondering what values you would use in this situation and why?
also...in regards to the fliptops kit, you suggested one section of the 100/100@500v to be used in series w/ the 50/50@500v. you said the 50/50 should be wired in parallel which would give you 100uf@500v, and then wired in series w/ the second half of the 100/100@500v. anyway...i'm wondering why a 50/50@500v would be used at all if it's just going to in parallel w/ itself, wouldn't it make more sense to use an additional 100@450v in that position? or maybe a multisection cap was selected just to fill in the hole that's already in the amp?

[stokes]

I am not saying it is necessarilly better,just a different aproach.I have always used Sprague caps,never used can caps,so you have to do some fudging to get them to fit for one thing.I merely pick the values to try to get close or higher than what the schem calls for,and in the case of the 20uf screen tap,I always shoot to get at least twice that,to me 20uf just aint enough,its just a preference,I like to keep the screens as stiff as the plates,just the way I was taught.As far as the hook-up I described,I was basing it on what the supplier was supplying,you could certainly replace that 50/50uf with 1x100uf cap.I suspect the supplier is giving these values and configurations so he can sell one kit to fit a few different amps.In this case I would likely choose 2x220/350v F&T caps for the main or plate supply,2x100uf/450v for the screen and then 30 or 40uf/450v for the remaining 3 preamp caps.Of course the main and screen caps are totem poled with the 220k/2w resistors across them.It would most likely be better for you to use the kit,if you are not used to squeezing components,you may even have to put a couple on the outside of the chassis like the Fenders have.