ShortScale.org

Mike wrote:Is that as a result of the tweaks you've done to it? I think they're super overgained stock.

Not really, It's pretty much stock, but i can switch between the different resistor in the inputn and it drops the gain down quite a bit. I'm thinking about putting a pot there and experimenting with that. At lower volumes, this amp does seem a little skanky, but when you turn it up to a realistic playing volume, it's great. I'm still planning on finding a switchable clean mode too, it would really make the amp more practical for most people.

AWW SHIT Y'ALL.

Disregard my previous "mod" it didn't really achieve what I wanted, but I think I got it last night. I'm bypassing the first gain stage completely for cleans and have a separate volume control for that "channel" as well.... more later...

That sounds more like it, similar to "teh 800z"

Yeah pretty much, I was looking at a Soldano SLO schematic and it's a lot different, but still the same basic idea and has switchable stuff.
I cleaned it up a bit more by using the DPDT switch to switch the first gain stage (v1a) out and also change the Cathode Resistor on the second gain stage (v1b - which would be the first gain stage in clean mode), this really cleaned it up and got rid of that lingering distortion characteristic. It still breaks up a little with the clean volume up, but it's way better now.

Now I've got the problem of having to add a Master volume for the new clean channel so that the channels can be balanced out....

Once I get these things done, I don't think it would be *too much* of a hassle to have it footswitchable.

Sounds awesome, you're doing everything I would do.

Mike wrote:Sounds awesome, you're doing everything I would do.

I FEEL AN PRIDE.

Lastly, the word "electrocution" is used in many high voltage device writings. That's bad, because it was only intended for the "electric chair", short for electro + execution.

hnmmmm.

ROLF

Hi guys, new here!
I have found this great site and this particular thread while I was searching the Internet for Windsor Studio mods.
I have had this puppy for one week and I am pretty sure it is a great platform for tweaks and mods.
This amp does not seem to get very good reviews.
It's been late over one year and its out of the box tone is not that great, except for heavily overdriven sounds.
It sounds tiny and it is almost impossible to get cleans out of it.
I was a bit disappointed first.
Then I hooked it up to the 2x12 speakers of my crappy H&K Attax 200 combo turned into a not so bad cabinet.
The tone was instantly much better with stronger basses and some kind of Marshallesque "hump" to the tone.
Much better then, but still no cleans and too much drive.

I have been tampering with sound and tubes for ages and I am able to somehow "hear" what is going wrong, if that makes sense.
What I can say:
- the gain of the input stages is way too high for rendering any clean tone
- there is definitely something wrong in the tone stack
- the boost switch just adds confusion to the sound
- implementation and switching circuitry of the effect loop has some issues making it almost unusable (tried with external preamp and various effects)
- the power amp part looks good but may be biased a little on the hot side. I hate auto-bias.
- the power amp may need some slight negative feedback to avoid too early breaking
- reverb is mostly OK but need to try a real Accutronics large tank (got one to try and see how it goes)
- power sponge is great and works well
- I am not sure about the BM speaker

The first change I have made is to swap the first 12AX7 and put a Groove Tubes 5751M in.
Instant beautiful and warm cleans with humbuckers (Gibson 490T bridge and 500T neck) on the low gain input up to 4-5 dialed in, with the edges getting nicely dirt beyond 5 or on string attack!
The hi-gain input goes from crunchy to heavy overdrive with an overall nice tone.
The amp is quieter too. There is still too much gain for real cleans.

This is the first mod.
I you can get hold of a 5751 tube, it is really worth trying the swap. It is a quieter and sturdier 12AX7 with some 30% less gain.

Next potential mods could be about:
- connecting the low gain input straight to the second triode, but I have still to do some reverse engineering to figure out the circuitry
- looking into the tone stack and attempt to improve the frequency response
- recycle the boost switch into a fake second channel switch
- add an adjustable negative feedback loop in the power amp
- add an adjustable bias pot in the cathode of the power tube
- swap the EL34 for a 6550 or some big KT

It would be really helpful to have the schematics to work from.

Lol, way too long blurb for a first post

I am very interested in your ideas and own mods.
Sloan is doing an awesome job at exploring those amazing Peaveys

Great first post dude!

- connecting the low gain input straight to the second triode, but I have still to do some reverse engineering to figure out the circuitry

This is basically what I did with my high gain input (i removed the low gain jack for the time being).

You will want to go from the 68k resistor that is connected to the jack's TIP and jump directly to PIN 7 (grid) of the first 12ax7. Put a potentiometer in before PIN 7 and that will be your clean preamp gain. I've got a 500k pot that works ok for testing, but would like to try a 1meg pot.

[ input > 68k resistor > potentiometer > pin 7 on first 12ax7 ]

This change will completely bypass the first triode gain stage and it's voltage divider. Also, you will want to replace the second triode's cathode resistor and cathode resister bypass capacitor with just a higher value resistor. I'm using a 10k resistor just like a JCM800. I've incorporated a toggle switch for now so I can switch between "channels", but a lack of a separate master volume for the clean channel defeats the usability since the high gain is so much louder.

- the boost switch just adds confusion to the sound

As far as I can tell so far, the BOOST function just bypasses the tone stack like some older Mesa Boogies used to do.

- I am not sure about the BM speaker

The Classic series come stock with the Blue Marvel speakers as well and they've always sounded good to me, but I would definitely try something else. I'm running my Windsor Head through a 2x12 with Warehouse Guitar Speakers VETERAN 30'S (Celestion Vintage 30 clones), and it sounds great. My 4x12 has two of those and two Celestion G12-t75's, it's sounds great through that cab too.

The first change I have made is to swap the first 12AX7 and put a Groove Tubes 5751M in.
Instant beautiful and warm cleans with humbuckers (Gibson 490T bridge and 500T neck) on the low gain input up to 4-5 dialed in, with the edges getting nicely dirt beyond 5 or on string attack!

If you want switchable clean, I think it would be better just to keep higher gain tubes for switching to "lead mode". Also, the 490T and 500T pickups seem to be relatively high-output pickups as far as I know.




If you don't mind, could you PM me some gut shots of your Windsor Studio?
I could compare it with my Head and see how similar the circuits are.... Both sides of the main PCB would be mega helpful!

Damn, if I just had a 3pdt switch, I could definitely hook up a separate master volume easily. A few years ago, RadioShack would have every fucking component you would need, but now they've got nothing useful. Shit is WEAK.

I put all my stuff on one of those RadioShack PC Boards, makes it way easier to work with!

lol at XTREME modifications.

I love Sloan's posts.

Sloan wrote:Great first post dude!

Thanks man for the welcome and additional tips

I am going to rip her apart and take shots of all of her upskirts lol
Will do this over the week-end.

You're right, bypassing the first stage for cleans is the way to go for sure and then work further down the circuitry.
I am still impressed by the improvement following the tube swap with these hot pick-ups.
But... after some more testing, strangely, the amp seems to no longer like my Fender's single-coil original alnicos.
There is something wrong with the tone, like it is bleeding awful mids, not Fenderish and twangish at all - damn tone stack?

Welcome to the boards, Zorglub. Awesome first post.

haha @ Sloan. I love you mate, you're a legend.

Mike wrote:Welcome to the boards, Zorglub. Awesome first post.
Thanks man!

haha @ Sloan. I love you mate, you're a legend.

Yes, kinda crazy experimenter with some style. That's good!

Quick update:
- I have had an in-depth look at the Windsor head's schematics and I believe I mostly get it now
- I assume Windsor head and Studio schematics are similar, at least for the first 3 stages (will see that after ripping her apart)
- Rockmaster preamp's floor board works with the Windsor studio. I can switch the ugly boost thing in and out no problemo

I have drafted a modded schematics that does the following:
- Recycle the boost switch to a clean low-gain to dirty high-gain toggle, and this is key: without losing the functionality of the floor board in parallel!
- New wiring to link the inputs either to first pre-amp stage or right to the pre-gain pot, front-panel or floor-board switchable!

Kinda fake two-channel mod.

Normal: clean or crunch depending on input ot pup's outpout and pre-gain
Boost: crunch or overdrive depending on input ot pup's outpout and pre-gain

This the first mod on my roadmap.

Cathode resistors and caps are next on my list, just like Sloan has spotted and already made progress
Tone stack needs some work to bring bottoms up a little bit.

My English may be weird somehow, sorry for that, it's not my first language

Hi all!
Here are some pics of the ripped apart Windsor Studio.
These show a mod-work in progress.
The goal is to achieve a channel switch (clean-->dirty) via the Peavey remote-switch floorboard.
Had to cut some pcb tracks and add a relay to toggle-switch input between clean an full gain.
I am working in parallel on the power amp stage to optimize.
I have to say that build-quality is sub-standard.
The pcb is dirty and I had to refresh several solder joints that were more or less dry (see bright solder spots I had to rework).
Metallization of holes between both sides is very bad and will go away when trying to un-solder some connexions.
In a word, POS quality and components, not modder-friendly at all.
I am not the type to give up, so stay tuned for the ultimate Windsor Studio mod! Yeeeeaaaaaahhhh!

Note for the attention of Sloan: the schematics of the pre-amp is the same as its bigger cousin (same component values and numbering).















Edit: just click the pics to see full-size images

Mad. Skills.

Awesome work. Do you have the facility to make demos?

Mike wrote:Mad. Skills.

Awesome work. Do you have the facility to make demos?

Thanks, man!
I believe we are going to achieve something
I have done a dry test, hard-wired run on the "new" clean channel.
It sounds interesting, clean/warm with sparkles on the edges.
The DI circuit is awesome.
I will upload a clip tomorrow if I find some spare time. Some very simple arpeggios and sweeps to concentrate on the tone only.

Perfect, this is my ethos completely. Simple playing and chording is a far more transparent way to demonstrate the sound.