Some Mods for Marshall Class 5

[blamo]

weird.....thanks for the info. maybe I will install my other one and see if it works...

[Lyle Caldwell]

The ohmage doesn't really matter. It's the inductance and current capability that matters.

The 120pf cap shown in the schematic is NOT C13. Sorry for the confusion. C13 is jumpered and a 120pf-250pf cap is added across lugs 1 and 2 of the volume pot. The schematic is done from the first gen Class 5s where this was most easily done with LK18 and LK19. On the later gen boards you should do it at the volume pot on the bottom of the board.

[Jimmy3711]

I took out R6 completely and just ran the wires directly to the holes. I twisted the wires in a braid like twist from the choke to the board. I have not repositioned the transformers. I mounted the choke perpendicular between the transformers aligning the choke mounting holes with the bolts on the transformers closest to the front panel. Then drilled a hole just in front of the board mounting screw that comes through the chassis between the transformers.

[Jimmy3711]

So it sounds like I have some redundancy in having bath C13 and the cap on the volume pot. Since I have the jumper on C13, I should just be able to remove the cap from that position and be good?

[blamo]

Originally Posted by Lyle Caldwell

The ohmage doesn't really matter. It's the inductance and current capability that matters.

can you think of any reason a couple of us get the ghosting and some of us do not?

Originally Posted by Lyle Caldwell

On the later gen boards you should do it at the volume pot on the bottom of the board.

on the later models, could you not run it(bright cap) across C13 and C9 on the volume pot side?

Originally Posted by Jimmy3711

I took out R6 completely and just ran the wires directly to the holes. I twisted the wires in a braid like twist from the choke to the board. I have not repositioned the transformers. I mounted the choke perpendicular between the transformers aligning the choke mounting holes with the bolts on the transformers closest to the front panel. Then drilled a hole just in front of the board mounting screw that comes through the chassis between the transformers.

I did the same....

[Lyle Caldwell]

Originally Posted by blamo

can you think of any reason a couple of us get the ghosting and some of us do not?

I cannot verify people's soldering jobs or that the ground screw is tight, etc. This has worked for me every time, and others have not had problems. I don't want to be a dick about it, but how things are done matters.

Originally Posted by blamo

on the later models, could you not run it(bright cap) across C13 and C9 on the volume pot side?

You could but you'd have to do it from the bottom of the board either way.

[Lyle Caldwell]

Originally Posted by Jimmy3711

So it sounds like I have some redundancy in having bath C13 and the cap on the volume pot. Since I have the jumper on C13, I should just be able to remove the cap from that position and be good?

As C13 is jumpered it doesn't matter if the cap is there or not.

[blamo]

Originally Posted by Lyle Caldwell

I cannot verify people's soldering jobs or that the ground screw is tight, etc. This has worked for me every time, and others have not had problems. I don't want to be a dick about it, but how things are done matters.

You could but you'd have to do it from the bottom of the board either way.

I do agree with you there, so i wouldn't say you were being a dick about it.

I have to tear into the amp to fix my VVR. I will double check my connections then, I suppose.

thanks for the help.

[Jimmy3711]

With the exception of C13, does my list look complete?

[blamo]

well, i tried one last time.... rewired my VVR and put in the hammond. its better this time but still oscillates....

and same problem with the VVR as before.

i give up.

Lyle, sent you a PM, going to send my amp off to you to do the mods.

[Tyler_351]

Ok so my brother just recently got a c5 and likes the way that it sounds at low volumes but for what he uses it for,would like for it to be cleaner at a little higher volume. Is this possible?

[Lyle Caldwell]

Originally Posted by Tyler_351

Ok so my brother just recently got a c5 and likes the way that it sounds at low volumes but for what he uses it for,would like for it to be cleaner at a little higher volume. Is this possible?

Yes, though it's tricky. You want to decrease the gain earlier in the circuit and increase it later.

Add in the 470K from the V1 side of R7 to ground I mentioned a few posts back. Then change R23 to a 220K. Then jumper R24.

[meballar]

Originally Posted by Lyle Caldwell

I cannot verify people's soldering jobs or that the ground screw is tight, etc. This has worked for me every time, and others have not had problems. I don't want to be a dick about it, but how things are done matters.

Lyle,
Thanks again for all your help. I just want to be clear about the choke--is it the 195 ohm or the 262? Is it correct that you have not had any ghosting problems using the 195 ohm versions?
Thanks.
Mike

[Lyle Caldwell]

I have not used a Hammond choke in a C5, but again, the resistance does not matter. It is the inductance (you want 9-10H) and the current capacity that matter.

[blues8]

Lyle,

I am interested in having you do the mods on my Class 5. If you are able to do this, please let me know the info need to get the ball rolling.

Thanks,
Dave

blues8@cox.net

[tengnagel]

Originally Posted by Tyler_351

Ok so my brother just recently got a c5 and likes the way that it sounds at low volumes but for what he uses it for,would like for it to be cleaner at a little higher volume. Is this possible?

Couldn't you change the tubes to different models that gives you more headroom? eg. V1 til ECC81

[Guitarguru_1960]

I just did the R20 mod and put some other tubes in it (JJ EL84 and some GT and chinese preamp stuff), and found out that I have less volume

[Stan Malinowski]

Attention abilly73, I live in Southington and have a Class 5 I'd like to mod. also a friend in Waterbury is also interested. I'd like to compare notes with someone local. Can you email me... Malinowski.sm@gmail.com

[blamo]

wow... whts with all the newbies up in the last buncha posts...

[Stan Malinowski]

Actually, I was member back in the around 2005, couldn't seem to find my account/password so I had to re register.

I own a 2009 R9, 2007 R8 & a 2009 Custom Shop LP DC Special.

Been tracking this thread since I bought a C5 last October. Hopefully I can get some local help/feedback from abilly73 on modding my C5. Pretty unusable in its original state & trying to decide whether to mod or sell it. Just bought a Dr Z Maz 8 which does an incredible mix of Fender & Marshall tones.

[b3john]

Originally Posted by blamo

wow... whts with all the newbies up in the last buncha posts...

They are probably finding this thread by searching the intarwebs for "Marshall Class 5 mods".

[Jimmy3711]

So, what is this Weber Solver Bell speaker people are speaking of? I looked on their site and didn't find any one "Silver Bell" model. Anyone have the specifics on this?

[blamo]

you must not be looking very hard.

12"
https://taweber.powweb.com/weber/silver12a.htm

10"
https://taweber.powweb.com/weber/silver10a.htm

[Jimmy3711]

I guess I should have been a little more specific...

I was looking to see what to was the suggested one between the Alnico and the Ceramic. Both have the "Silver" series.

[blamo]

Originally Posted by Lyle Caldwell

Matt,

My choice for a Class 5 would be a Weber Silver Bell in the 15W paper cone version with light doping.

While there are other great speakers that also do versions of a "Marshall sound" with a 5W amp you really don't want a 25W or 30W or higher wattage speaker - a higher power speaker won't really come alive with the low wattage amp.

But the 15W Silver Bell with the options above will be perfect - think Clapton's Bluesbreaker era tone - that amp had two early '60s silver alnico Celestions, which the Silver Bell recreates.

here you go....Lyle's suggestion on a 12". reading between the lines says Alnico, not ceramic.

[shaun]

Originally Posted by blamo

on the later models, could you not run it(bright cap) across C13 and C9 on the volume pot side?

Can i just connect aligator clip leads to the vol pot side of C13 and C9 (from the top side of the board), and try different cap values?
My C5 head has version 4 PCB, and is a 240volt model. Does the type of construction material of the cap matter (polyester, ceramic etc) and also the voltage rating of the cap?
Thanks

[blamo]

shaun, you can alligator clip leads. I did this when I was testing it out.

you'll have toruble running those clips under the PCB when its installed though.

i ran mine from the 2 cap leads on the top of the board since C13 is jumped and C9 had a lead that was easy to access.

[shaun]

Originally Posted by blamo

shaun, you can alligator clip leads. I did this when I was testing it out.



i ran mine from the 2 cap leads on the top of the board since C13 is jumped and C9 had a lead that was easy to access.

thanks Blamo, this is just what i was thinking of doing. What size cap did you find works best (in the 120 - 250 pf range, i think).
Also, how, or why did you jumper C13?

[blamo]

I removed C13 and just put a wire across it. 20awg seems to be a good fit.

You can also just solder a wire across the joints on the bottom and not remove the cap.

I ended up with 120 in the switch and 120 on the board as per Lyles schematic. I tried it with a 68pf and it wasn't bright enough. Anything more than 120 in the switch was too bright for me.

I run the switch off whe I use my tele and the switch on with my les Paul's. It works well for me.

[JCM900MkIII]

Originally Posted by Tyler_351

Ok so my brother just recently got a c5 and likes the way that it sounds at low volumes but for what he uses it for,would like for it to be cleaner at a little higher volume. Is this possible?

Cheapest "non-mod" way of achieving this is by trying the Sovtek EL84M.
This should give ~20% more headroom/more clean volume.