Metropoulos Forum

Here is a mod for the Peavey Windsor head. It works great. I got the idea after browsing all the mods located in the Van Halen section of this forum most notably the Mod 5 topics.

I noticed the screen cap change affects the sound of the amp in a very positive way. Replacing the screen cap with a 16uf value brings out the "wood" in the brownsound. This confirms it for me. Van Halen's original main plexi has a 16uf value in the screen caps (i.e. 32ufs in series) as well as Slash's JCM800 that he used to record UYI.

This mod will bring out your intestinal fortitude. The hardest part is drilling a couple of holes in the PCB board by the master volume pot to drop in and solder a 220K resistor.

Amp modding is dangerous work. Get your local guitar tech to apply this mod.

http://i1057.photobucket.com/albums/t39 ... ndsor1.jpg" onclick="window.open(this.href);return false;
http://i1057.photobucket.com/albums/t39 ... ndsor2.jpg" onclick="window.open(this.href);return false;

No one should be gouged big bucks for wanting awesome tone out of their amp.

This might be usefull to some of you...

I came up with a way to turn the cathodine phase inverter and its driver stage into a long tailed pair that doesn't require the use of a terminal strip.



I've put the required values of the components and erased the ones that need to be removed.

Don't forget to lift B++ ground Jumper!!

While you are at it you might want to replace the grid stopers (R32,33,34,35) with 1k5 or 5k6 and the screen grid resistors (R41,41,43,44) with 1k or 1k5 (3W).

So how did this work out? Any improvement on the tone? 100% safe? I'm getting ready to tear into my Windsor head.

Well, I think the Windsor is probably the worst JCM800 wanna be that ever existed. The circuit is just ugly and wrong in so many ways that is hard for me to understand how some one would even think such a circuit was a "good idea".

Having said that, it's a modder's dream. The PCB's have plenty of space and are quite easy to "read" even if you don't have an schematic. It's very sturdy and even though the tube socket's are PCB mounted it just feels reliable. More than both my Triaxis and 20/20 poweramp. I shit my pants every time I have to swap tubes on those filmsy pieces of expensive crap.

What I've done to my Windsor is basically convert it to a JCM800 and used one of the relays to switch in and out the second gain stage. I turned the cathodine phase inverter into a proper long tailed pair as shown on my previous post. It now has a Larmar MV and a 5k presence pot instead of the stock 10k. I also added the bias resistors so I can bias that thing correctly.

loud and dirty wrote:100% safe?

If you drain the caps there's nothing to worry about. The actual mods are not dangerous to the amp if that's what you're asking.

loud and dirty wrote:Any improvement on the tone?

It depends on what you are after. I wanted an 800 and I got it in spades.
What do you want to get from it?

loud and dirty wrote:I'm getting ready to tear into my Windsor head.

If you decide to mod yours feel free to ask as many questions as you want, I'll be glad to help.

inkomodo.dragon

I just want it to be more Plexi, JMP, or even 800ish. Clean up when i turn down the guitar's volume and not so so trashy with the gain up. No extreme gain or anything like that. I just want to use it when i am jamming early 80's metal like Saxon, Wolf, Thor, etc. I have other amps for high gain.

btw...i am going to see Winger on the 20th.

loud and dirty wrote:I just want to use it when i am jamming early 80's metal like Saxon, Wolf, Thor, etc. I have other amps for high gain.

If you are after that type of sound you have basically two options, you can go for an 800 type of circuit or more of a Super Lead one. Each one have its pros and cons.
The 800 sounds right when using the standard master volume but the SL just doesn't cut it. For a good SL tone you have to crank the amp or use a LarMar in order to get some phase inverter distortion.
Sounds to me like you would love the mod I did to mine. If you give me a couple of days I can upload some files to help you go through it.

loud and dirty wrote:btw...i am going to see Winger on the 20th.

I'm filled with nothing but envy because I know for a fact the I'll never get to see 'em live. Enjoy it for me dude

Not to hijack the thread but to go in a completely different direction with these amps I offer the following pictorial of a Windsor I picked up on Ebay for around $100.
http://smg.photobucket.com/albums/v623/ ... 20circuit/" onclick="window.open(this.href);return false;

My thought process was: where can you get a totally ready to go donor amp with a full set of power tubes and preamp tubes, a huge chassis and perfectly adequate power and output transformers for this price? Don't like the tone? I just gutted the entire thing and built a modified AFD #39 style circuit complete with footswitchable extra gain mode for way less than I could do this for from scratch or a kit. Of course, I am all about saving money but getting good tones. To me this was the ultimate high power donor amp to start from.

That same thought crossed my mind when I bought it but it is so close to the JCM800 that it seemed a lot of work and no so much benefit. I still think that for 12 Series and 800 style circuits the stock PCBs are perfect.

You on the other hand, changed the circuit a bit more so doing it with the stock PCB boards would have been a bit more hard work.

I recently bought a Windsor head off a friend for $100. The thing looks like it's in perfect condition and I bought it because I read that it's a modders dream. I've been looking for a way to switch in/out a gain stage for a while now, but I cannot find a definitive answer anywhere. inkomodo.dragon, I read that you have done this using a relay. Would you be so kind as to share your design with us, and if not, would you help point the rest of us "novice" tweakers in the right direction?

The Windsor has two relays that you can use for this application. The one used to bypass the FX loop and the one that engages the boost. I've never liked the sound of the stock boost so I removed that relay (the one closer to the boost button on the front panel) and used it to bypass a gain stage.

It's important to take into consideration that the shared EQ makes it really hard to have two different "channels" because each mode will need different equalization. If you still like the idea or you simply want to have two different circuits inside one box you should give it a go.

What are you trying to do?

Thank you for the information. I'm not exactly sure what I'm trying to do yet. I like a nice clean sound with just a touch of dirt with a distortion pedal, but at the same time I LOVE the sound of a nice crunchy overdriven tube amp. The lack of tone controls for each channel makes me hesitate trying to make this a 2 channel amp. But the fact that I can't help but tinker with every last piece of equipment I own makes me want to jump in head first. Maybe I can find a way to add in some pots for a clean channel EQ inside the head to kind of "set and forget".

If you want a clean channel and the "inner" tone stack idea is good enough for you I suggest you add another tube just for the clean channel and wire the triodes Fender style with the TS in between. One side of the relay will have to route the input signal to either the new "clean channel" tube or the standard "overdriven" circuit. The other side will select between channel outputs.
You could also remove the boost button from the front panel and use the hole for a pot.

A couple of things about the sound...
Don't expect it to sound 100% Fenderish, it just won't. Fender amps have a fixed amount of full signal feedback and the speakers they use are the complete opposite of standard Celestions. Your clean channel will sound good but more Hiwattish which is not a bad thing but is always good to know what to expect before making such a drastic mod.

What's the deal with that bright green jumper line?

inkomodo.dragon wrote: ↑

Fri Jun 15, 2012 9:38 am

This might be usefull to some of you...

I came up with a way to turn the cathodine phase inverter and its driver stage into a long tailed pair that doesn't require the use of a terminal strip.



I've put the required values of the components and erased the ones that need to be removed.

Don't forget to lift B++ ground Jumper!!

While you are at it you might want to replace the grid stopers (R32,33,34,35) with 1k5 or 5k6 and the screen grid resistors (R41,41,43,44) with 1k or 1k5 (3W).

So, where is the b++ jumper and is it necessary to pull it if you converted the phase inverter to a long tailed pair on a terminal strip? I've noticed that when I did the long tailed pair p/I mod I lost a lot of volume. Would this remedy that volune Loss? Thanks for any help.

Okay, so I've been modding amps for a while as a hobby. I've even built my own amp from scratch. However I recently picked up a peavey windsor as a platform for modding and have run into a snag. Long before I heard about any "marshall" mods I had come across a schematic for the windsor and thought, this could be very similar to a jcm800. So, when I got one to fool with that's what I set out to do. Now what has thrown me for a loop is that after I modded the preamp, no issues. Sounded better than stock but I felt that I needed to go ahead and mod the power amp and change the phase inverter to a long tailed pair. It wasn't that hard to do honestly but after the mod I noticed a HUGE loss of output volume. I have gone over my work at least a dozen times even with a continuity meter and can"t find issues with miss wiring or wrong parts. Has anyone else here experienced this after modding the phase inverter in this amp? I'm kinda at a loss. Any help would be awesome.