My Marshall Conversion From PCB To PTP

[shredaholic]

Re: My Marshall Conversion From PCB To PTP

I agree you're right John to use your ears with CC's. I've got quite a lot of them in my Marshall just out of convenience (I got a lot of them cheaply), the only time I've ever been shocked at how they improved my sound was when I put a 1/4w 1k CC as V2's cathode resistor. Whether the rest of them have contributed to the amp's great sound, I have no idea as I haven't really listened/compared as I was putting them in. Apparently the smaller the CC the more 2nd order harmonics it has, which I guess could be the reason I liked the one on V2.

 

[STRATDELUXER97]

Re: My Marshall Conversion From PCB To PTP

I agree you're right John to use your ears with CC's. I've got quite a lot of them in my Marshall just out of convenience (I got a lot of them cheaply), the only time I've ever been shocked at how they improved my sound was when I put a 1/4w 1k CC as V2's cathode resistor. Whether the rest of them have contributed to the amp's great sound, I have no idea as I haven't really listened/compared as I was putting them in. Apparently the smaller the CC the more 2nd order harmonics it has, which I guess could be the reason I liked the one on V2.

That's cool.....I had basically all of the original resistors on my original PCB,but I didn't re-use them simply because they wouldn't fit on my PTP board,but the amp sounded great before the switch to PTP...I did see some changes in my B+ voltages on the PTP board upon completion that I had to tweak a bit to get those voltages where I wanted them...

The amp is tighter and brighter,but I think it has alot to do with the new caps and I think the amp will warm up and lossen over time...It's loud and really strong though...Some other tubes would be a great place for me to really dial it in even better.....I have an early Mullard in V1 and a 12AX7A Chinese tube in V2....Not sure about V3,but it's a Groove Tube? The output tubes are Svetlana EL34s from the original early run.....I'm looking for maybe a bit less highs and a slightly looser tone feel....I could screw with the B+ voltages again and get what I want also,by slightly lowering it....

 

[STRATDELUXER97]

Re: My Marshall Conversion From PCB To PTP

Bump

 

[wixedmords]

Re: My Marshall Conversion From PCB To PTP

Stratdeluxe, you did a great job my forum bro.

Congrats. You should feel very good about yourself.

How about starting a business making masses of modern Marshall's ptp?

 

[kmcguitars]

Re: My Marshall Conversion From PCB To PTP

The amp is tighter and brighter,but I think it has alot to do with the new caps and I think the amp will warm up and lossen over time...It's loud and really strong though...Some other tubes would be a great place for me to really dial it in even better.....I have an early Mullard in V1 and a 12AX7A Chinese tube in V2....Not sure about V3,but it's a Groove Tube? The output tubes are Svetlana EL34s from the original early run.....I'm looking for maybe a bit less highs and a slightly looser tone feel....I could screw with the B+ voltages again and get what I want also,by slightly lowering it....

John, How do you screw with your B+? ( I imagine by changing some resistance?) In a attempt to get a looser feel, I lowered the filtering in my pre-amp to a 32x32uF cap. I'm still using 2 Weber 50x50uF's for my mains.
I'll post some pics when I get all proper components and wiring squared away.
Right now it looks like a slop fest compared to yours. :disappoin Seriously, You have one of the cleanest layouts I've ever saw.:bowdown:

 

[seafoamer]

Re: My Marshall Conversion From PCB To PTP

super secksie, dood!

 

[STRATDELUXER97]

Re: My Marshall Conversion From PCB To PTP

John, How do you screw with your B+? ( I imagine by changing some resistance?) In a attempt to get a looser feel, I lowered the filtering in my pre-amp to a 32x32uF cap. I'm still using 2 Weber 50x50uF's for my mains.
I'll post some pics when I get all proper components and wiring squared away.
Right now it looks like a slop fest compared to yours. :disappoin Seriously, You have one of the cleanest layouts I've ever saw.:bowdown:

How do you like the 32 mfd values instead of the 50/50? That might do it? PM me for furthers on voltages etc...

 

[shredaholic]

Re: My Marshall Conversion From PCB To PTP

I'd definately recommend lowering the filtering to "warm up and loosen" the tone of the amp.

My preamp filtering is dual 16uF, and I used the dual 50uF's on the screens as single's (saves buying different cap values) to lower the screens filtering to 25uF; I'd say both these changes make the amp looser and warmer, the screens change is probably a more uncolouring change as it just makes the distortion smoother and you seem to have more control over making the lower notes tighter or looser.

The preamp filtering is more of a tonal change, it shifts the attitude of the amp quite a bit. I presume 32uF would be quite a bit more subtle there than 16uF though, it's worth trying changing both preamp and screens filtering and seeing what you like best.

 

[STRATDELUXER97]

Re: My Marshall Conversion From PCB To PTP

bump

 

[kmcguitars]

Re: My Marshall Conversion From PCB To PTP

How do you like the 32 mfd values instead of the 50/50? That might do it? PM me for furthers on voltages etc...

It definitely works IMO (Thanks to Kevlar3000 for the heads up on that) The amp has a more open feel to it,And is very Dynamic/Touch sensitive. The only downside I've noticed,It seems to take a Lil' of the zing out of your solo's. Not your Blues licks (Does that very well ) but more aggressive stuff like a Michael Schenker like tone. (I got a SFX-03 coming my way,That should solve that problem:18: ) I should be getting my 5.6k swamp resistors today. With that and shielding my case should kill my oscillation problem? As far as my voltage's? There still a Lil' screwy? But I think I need to buy a better DMM. This thing is a cheap POS and I think it's F**KING with me!!:33:

 

[STRATDELUXER97]

Re: My Marshall Conversion From PCB To PTP

It definitely works IMO (Thanks to Kevlar3000 for the heads up on that) The amp has a more open feel to it,And is very Dynamic/Touch sensitive. The only downside I've noticed,It seems to take a Lil' of the zing out of your solo's. Not your Blues licks (Does that very well ) but more aggressive stuff like a Michael Schenker like tone. (I got a SFX-03 coming my way,That should solve that problem:18: ) I should be getting my 5.6k swamp resistors today. With that and shielding my case should kill my oscillation problem? As far as my voltage's? There still a Lil' screwy? But I think I need to buy a better DMM. This thing is a cheap POS and I think it's F**KING with me!!:33:

Alot of guys like making the screen caps lower but leaving the other 2 at 50/50 on the 50 watters? I still have all 50/50 caps,but I Might mess wit it?The amp sounds pretty amazing right now though....Reminds me of Angus Young's tone with my SG....I've been looking at the Marshall schematics on the 16 and 32 mfd caps and how they were used...Guess they felt the amps needed more filtering?

 

[kevlar3000]

Re: My Marshall Conversion From PCB To PTP

I love lowered filtering in Marshalls, my Plexi RI had 32s all the way around. Made a beautiful difference. I also had the negative feedback wire on the 16 ohm tap with no volume cap. It really made that amp open up.... It was a great sounding amp by the time I got done messing with it...

On some of my heads, I like having higher filtering, I have 50s in a couple amps, 16s in a couple, 32s in a couple...lol. I love the variety.... Always changing something to see what it does.

 

[Zerberus]

Re: My Marshall Conversion From PCB To PTP

Nice work, John... I´m not personally a fan of modding vintage Marshalls, but still very nice work

 

[STRATDELUXER97]

Re: My Marshall Conversion From PCB To PTP

Nice work, John... I´m not personally a fan of modding vintage Marshalls, but still very nice work

Trace owned the amp before I did and had already installed some stuff at the back of the amp etc....Holes and all were already drilled...I'm keeping the amp cause it's great and the added mods really makes the amp alot more versatile...No stupid high gain preamp tube add ons,but just some very reliable,practicle mods were added and placed on the back panel...I'm keeping the original PCB but PTP is way better and alot easier to mod or work on....Looks alot cooler also!

 

[STRATDELUXER97]

Re: My Marshall Conversion From PCB To PTP

I love lowered filtering in Marshalls, my Plexi RI had 32s all the way around. Made a beautiful difference. I also had the negative feedback wire on the 16 ohm tap with no volume cap. It really made that amp open up.... It was a great sounding amp by the time I got done messing with it...

On some of my heads, I like having higher filtering, I have 50s in a couple amps, 16s in a couple, 32s in a couple...lol. I love the variety.... Always changing something to see what it does.

The negative feedback hookup to your 4,8,16 ohm taps is on the opposite side of the feedback resistor,why no Presence cap?

Also....You probably already knew this...You get a bit more gain and a darker,"slightly" looser tone by going with a 100k resistor hooked to the 4 ohm tap....

The only other Presence pot mods is switching from .1 to .68 but I've not heard of removing the cap totally?

I Have a resonance control between the 4 ohm tap and the feedback circuit that loosens or tightens up the overall amp...

 

[kevlar3000]

Re: My Marshall Conversion From PCB To PTP

The negative feedback hookup to your 4,8,16 ohm taps is on the opposite side of the feedback resistor,why no Presence cap?

Also....You probably already knew this...You get a bit more gain and a darker,"slightly" looser tone by going with a 100k resistor hooked to the 4 ohm tap....

The only other Presence pot mods is switching from .1 to .68 but I've not heard of removing the cap totally?

I Have a resonance control between the 4 ohm tap and the feedback circuit that loosens or tightens up the overall amp...

Talking about the volume cap, sorry for the confusion. I personally dislike the 4 ohm tap, too clunky for me. The lowered gain on the 16 just gave beautiful chime to chords and took out some of the muck on the bass while still giving a real nice jump on the note. Coupled with the lowered filtering, it was a perfect match as I got the loose vibe ( lowered filtering, shared cathode ) w/o the flub.. This was with .1 coupling caps. After I had switched the amp to a shared cathode, it seemed to be a perfect fit with the way I ran the amp, after trying the 4 and 8 ohm taps. I had emailed Dave Bray, way back when and he told me to try the lowered filtering, shared cathode, 16 ohm tap set up. It really did the trick for me, I never recorded the Plexi after all the tweaks were done. I think my CD would have sounded a good deal richer vs the stock set up, the amp had, when I was tracking.

I have .68s on a few of my amps presence caps, some still like the .1 best.

 

[STRATDELUXER97]

Re: My Marshall Conversion From PCB To PTP

Talking about the volume cap, sorry for the confusion. I personally dislike the 4 ohm tap, too clunky for me. The lowered gain on the 16 just gave beautiful chime to chords and took out some of the muck on the bass while still giving a real nice jump on the note. Coupled with the lowered filtering, it was a perfect match as I got the loose vibe ( lowered filtering, shared cathode ) w/o the flub.. This was with .1 coupling caps. After I had switched the amp to a shared cathode, it seemed to be a perfect fit with the way I ran the amp, after trying the 4 and 8 ohm taps. I had emailed Dave Bray, way back when and he told me to try the lowered filtering, shared cathode, 16 ohm tap set up. It really did the trick for me, I never recorded the Plexi after all the tweaks were done. I think my CD would have sounded a good deal richer vs the stock set up, the amp had, when I was tracking.

I have .68s on a few of my amps presence caps, some still like the .1 best.

Cool info Kevlar! I like staying with the .022 values before the output tubes....A cool mod also,is to be able to switch the feedback resistor back and forth between 47k and 100k on whatever tap you prefer....I always have mine tapped to the 4 ohm tap with a 100k,but these days I Might even like the 8 ohm tap better? My amp is very tight and that's why the 32 mfd filter caps on either the preamp or the screens or both,might be something worth trying....The lower cap values I guess darkens and loosens the tone and feel up a bit.....I'd like slight looseness and maybe I should just try changing the 50/50 can at the screens first to 32/32?

I've kept the bright channel cathodes at 2.7k/.68 and I also like the 470 pf mica cap across my 470k mixer resistor....I did away with the "ultra too bright" .005 across the volume pot and went with just a 56 pf there...This keeps the tone bright enough at setting below about 1/4 and once I get to about 1/2,the cap is completely out of there....

On the Normal side I have an 820/1 Mfd with another 470 pf across the 470k and a 120 pf cap across the volume pot....

I Like the Sozo caps and I feel they make the amp a bit sweeter and more alive? Not sure yet,but it seems so?

 

[kevlar3000]

Re: My Marshall Conversion From PCB To PTP

Dave told me to lower the screens first, if I like it go with it. I love a little squish to the note, where you can feel the digging in a bit.

I started messing with some tweener values. I have .047s on one of my Traynors, the other two still have .1 OC caps. All of my Gibsons have .068s in place of the .022. Those amps really needed the help on the bass and lower mide side. I have different filtering on the 3 of em.... Different vibe from all of them.

 

[STRATDELUXER97]

Re: My Marshall Conversion From PCB To PTP

Dave told me to lower the screens first, if I like it go with it. I love a little squish to the note, where you can feel the digging in a bit.

I started messing with some tweener values. I have .047s on one of my Traynors, the other two still have .1 OC caps. All of my Gibsons have .068s in place of the .022. Those amps really needed the help on the bass and lower mide side. I have different filtering on the 3 of em.... Different vibe from all of them.

Agreed....I Own several different amps also,so I don't get sick of one tone...:wave: