changing filter cap values

[misterwhizzy]

Re: changing filter cap values

Maybe pulling two power tubes and running at 50 watts would be a better option. You have to adjust the output impedance too, but I'm not sure if you double it or halve it.

 

[Darg1911]

Re: changing filter cap values

I think they are solder in. My tech said something about having to solder them in when I get them. I was thinking going 550v 47uf's I know they still make those.

"Snap in" caps still need soldering. They are radial caps with short, strong pin type leads that are designed to hold them on the PC board without falling out prior to soldering. They are designed for a specific hole spacing (5mm, 7.5mm, 10mm etc.) so you have to choose the appropriate cap. Since they are radial caps that stand upright, you also have to have enough clearance to use them. But basically, I was wondering if that's what already was in the amp. If it is, then you could probably find replacements in the voltage rating you need.

First site that came up. I didn't check for values but this is what they look like. http://www.bgmicro.com/capsradialsnapon.aspx

 

[GoldenVulture]

Re: changing filter cap values

 

[Little Pigbacon]

Re: changing filter cap values

What product is that?

 

[GoldenVulture]

Re: changing filter cap values

A peavy Windsor.

Hi this question is for all the amp techs out there reading this post.How can I re-design the power supply in my amp(100 watt Windsor)to give it more "SAG" I have a good tech that can do my work for me I just don't know what I have to do to achieve this?Can you please help me and just let me know how you do this and I can relay to him what I need parts wise?Does it need a slightly under-powered power trans? I do believe "sag" is created when your B+ voltage drops while playing is this correct?Any help at all will help thanks.

Hey I have 3 filter caps in my amp and I am looking to lessen the stiffness of the power supply by reducing filter cap values. Right now the caps are 550v and 100uf a piece. Would 550v 50uf value be ok to install instead. Or is it ok to just remove one of the caps to have 100uf instead of 200uf.The amp is a Peavey Windsor 100 watt head. The caps are c-10/c-11 on scehmatic and c-12 is the screen cap at 100uf as well.

 

[Darg1911]

Re: changing filter cap values

Yep, those are "snap in" caps. Got to be careful removing, especially on a thin pcb. A solder sucker and solder wick will work.

One other thing. Looks like there is ample room to connect caps in series (axial caps). That would allow use of 2 lower voltage caps if you cant find single 550 volt caps. As long as the two caps are the same uF value, they will "share" the voltage, or split the voltage. So, you'd need two caps rated for at least 275 volts each. Of course, the capacitance is halved as well, so two 100uF caps in series = 50uF.
I'm no electrical/electronics genius and not trying to act like one. I don't know how much the OP knows so I'm just sharing what I think may be of help. Sorry if this is basic stuff that you already know.

 

[LLL]

Re: changing filter cap values

It needs to be said that if you're gonna fiddle with those caps, they *must* be drained first, or you'll be in for a rude awakening. Seriously.

 

[tman]

Re: changing filter cap values

What kind and what are your volts and uf's on that Windsor?

 

[Chickenwings]

Re: changing filter cap values

Have you tried changing the nfb resistor. It is a much simpler, safer and rich sounding way to dramatically change the way you amp sounds and feels.

 

[tman]

Re: changing filter cap values

Not sure what that is???Negative feedback resistor no not sure where its at on the Windsor. I have already added a 25 watt 100ohm resistor after the bridge rectifier and before first filter cap to give it a sag feel and it does work and feel better just wanted a little more sag and vintage feel.Thats why i was thinking changing cap values down a bit from 100ohmx3. I was thinking 550v 47uf's if I can find them.

 

[tman]

Re: changing filter cap values

And what size in mm are those caps so I know what will fit?

 

[GoldenVulture]

Re: changing filter cap values

What kind and what are your volts and uf's on that Windsor?

If you mean this pic,it is DranoMax's. I posted it to show the caps.

I presume they're 100ufd/550 volt.[ as in the schematic ]
- http://bestnetworx.com/uploader/files/52/Peavey Windsor SCHEMATIC.pdf -

And what size in mm are those caps so I know what will fit?

DranoMax modded one recently, I'll ask him if he can fill in those details.

Also: The NFB is linked to the Presence and Resonance controls according to the circuit.

 

[Drano Max]

Re: changing filter cap values

The modded Windsor above is mine. It's pretty much a 2204 now. Well, it is.

What you are trying to get is one of the things I was looking for in my mod.

You need to install a choke. I stayed at 20H, but the higher you go, the more of that "sag" you will get. Just google Marshall JCM 800 choke. They aren't very expensive, and do the trick the right way.

Also keep in mind, that Windsor in stock form is NOT a JCM. The circuit really isn't even close in a lot of ways. Big difference in tone if you mod the right way, like 2204.

You can run the amp with the 2 outer tubes pulled, as mentioned before. Just drop your impedance switch down a notch, your laod halves when you do. It may give you a little more of that loose feel. Mine does.

If you need some help just ask. That amp does not auto drain. You MUST drain those caps before installing a choke, or you are in for a bad day. There is about 450V at around 2A in that thing. It'll bite the piss out of you if you aren't carefull.

On a side note. You can convert that amp to a 2204 for less than $100. Choke included. You can cut the price in half if you don't use the most expensive components you can find, like I did. It's just a lot of work.

Golden Vulture helped me figure my mod out, and trouble shoot. Listen too him if he tells you something. He knows whats up.

 

[tman]

Re: changing filter cap values

I already did OT and a choke and a 25 watt 100ohm resistor after bridge rec and before first filter cap.What are the size of the caps so I know in mm so I can order 3 new ones with less value than the 100ohm ones. I want to get some more sag this way as well. I only used a 3H in mine. And I am getting more of the feel I want I figured changing cap values will get me to where I need to be so if you have info on the size then I will know what caps to get.Im thinking of going with 550v 47uf's And what will chaging the NFB to do and what do I change it to? thanks

 

[GoldenVulture]

Re: changing filter cap values

I stayed at 20H, but the higher you go, the more of that "sag" you will get.

I only used a 3H in mine. And I am getting more of the feel I want

This might be more effective than changing the caps.

Alternately , pull out one of the pair of 100ufs. The caps are also a resevoir of power that deliver power to match the draw, the pair are keeping that fairly constant. That's where the sag comes in: if they aren't delivering enough constant power.
You could also measure the cap pin spacings if you removed one and use it for reference if you change the caps.

 

[zzmoore]

Re: changing filter cap values

You guys added a choke to this amp...where did you install it.?
A "choke" is part of a Stiff Power Supply. If you want "sag" the last thing you would want is to add a choke.
You changed the OT as well.?

 

[GoldenVulture]

Re: changing filter cap values

[ I don't have any direct experience with a Windsor ]
Here they are talking about power supply , pre-amp plate voltages and NFB and other mods.
- http://www.ax84.com/bbs/dm.php?thread=377358 -

 

[GoldenVulture]

Re: changing filter cap values

You guys added a choke to this amp...where did you install it.?
A "choke" is part of a Stiff Power Supply. If you want "sag" the last thing you would want is to add a choke.
You changed the OT as well.?

DranoMax's [ Choke to the right ]

 

[Drano Max]

Re: changing filter cap values

You guys added a choke to this amp...where did you install it.?
A "choke" is part of a Stiff Power Supply. If you want "sag" the last thing you would want is to add a choke.
You changed the OT as well.?

If you can't figure out where the choke could be mounted on that massive, wide open, chassis, how do you know the choke won't help?

Does your vast experience in not personally modding these amps give you an insight that escapes us, that have?

Do you have a degree in electronics? I do.

If you don't truly understand what is going in amp, you shouldn't be offering false information. I don't do this, but I'm going to now. You are 200% wrong.

And just to show how easy it is to make a mistake, and own it, as it happens to everyone. My choke is 15H, not 20.

To the OP, with those 3 caps all in parallel, you could try removing C10 from the circuit. I have it in my notes as an option. If I can free up a few minutes sometime today, I'll try it myself and see if it makes much of a difference.

 

[Darg1911]

Re: changing filter cap values

First, I am not a tech. But, aren't the benefits of a choke the reduced voltage drop and better filtering (less AC ripple) relative to a resistor? The reduced voltage drop would tend to mean less "sag", yes? That's my laymens understanding anyway.