here are some marshall mod schematics!!

  • Thread starter Thread starter bmf5150
  • Start date Start date
FortinAmps":2gfim4k3 said:
bmf5150":2gfim4k3 said:
please guys add what schematics you guys have for marshall mods!

here is the kurt mitchel langer mod!
langermod.jpg





here is the spln mod
splawnmarshallnosoloboost.jpg
Click to expand...


The first 3 cathode bypass caps are the wrong value. If you build it the way that schematic is, it will be a woofy mess.
Click to expand...
I was wondering abou that; 4.7uf seems a bit high; I was thinking something b/w 1-2.2uf and 1.5-2k might be better. What values would you recommend? I think I'd like to try this on mod some time.
 
here is a schematic for a very trans parent attenuator i built.its a copy of an expensive very popular attenuator.

16-OhmReactiveAttenuatorRevCLight.jpg

here are some notes of parts i used
The LPads you can get from Parts Express on amazon

The transformer is a torroidal type power trany with a 240v:30v or 120v:15v ratio. 160VA rating.

The resistors are just Welwyn 50W aluminum housed wirewounds. Like Arcols. I used arcols. Same thing.

(R means ohm on the schematic)

L-Pad 100W Mono 3/8" Shaft 8 Ohm
http://www.parts-express.com/pe/showdet ... er=260-262


power tranny im using
newark model number 38k4910
specs
TRANSFORMER, 160VA, 2 X 15V; Voltages, primary:0-115, 0-115; Voltages,
secondary:0-15, 0-15; Power, per secondary winding:80VA; Approval Bodies:EN60950,
EN60742, UL Recognised; Current rating:5.33A; Diameter, bolt hole:6mm;
Diameter,

link
http://www.newark.com/multicomp/mcta160 ... dp/38K4910

resistors 330ohm and 15ohm
mouser part number
284-HS50-15F
50W 15 OHM1%

284-HS50-330F
50W 330 OHM1%

a case
Something about 3" high x 10" long x 8" deep
the lpad is 2.5 inches tall.

http://www.hammondmfg.com/dwg10.htm
vented version
you may want to add a fan to this desing,the biggest problem is that it get hot...
 
Thanks for the attenuater schematic, seems from talk some are trying to make money off of simular drawings...........
 
I'm wondering how the standard 10k and .68uf/820 values at V1a and V1b would sound with something like 1u/2.2k for the extra tube's cathode C/R on the Langer mod? If you needed to bump the bass up you could always go up in cap value at V2. With the added compression from an additional gain stage feeding a cascaded circuit, I think .1uf output couplers might be in order to give back a little head room. Has anyone tinkered with this mod? I'd love some input. :yes:

EDIT: Ok, clearly the wrong crowd for tech talk. :aww:
 
(i have obg ) ;) ...The Langner scem posted above--will absolutely NOT work.

WAYYY too much gain--to the point of the amp going into oscillation/ motorboating/ cutoff , if you turn the gain above 6 or 7 ..

There IS a way to make that work with a couple changes.
 
The DCP-1 Langner preamp I have will actually go into oscillation if you have a less than able tube in the V1 position, it was just past 2' o clock on the gain setting. I had to go through quite a few to find the right one for the job. I dont think that schem is the same at all as the DCP1 (not from what I see) but I was just throwing that out there ;)
The range of gain in that pre is amazing, but still tight and with clarity and lots of detail. The midrange control will rip your head clean off :D :D
 
496dart":372ynn6a said:
(i have obg ) ;) ...The Langner scem posted above--will absolutely NOT work.

WAYYY too much gain--to the point of the amp going into oscillation/ motorboating/ cutoff , if you turn the gain above 6 or 7 ..

There IS a way to make that work with a couple changes.
Click to expand...
It seems like it would be gain overkill to me too; the cathode cap values at the first two gain stages are definitely too high. There's no way that much bass could sound good.

I'm certainly open to suggestions. :D
 
OBGYNkanobi":36c7w776 said:
496dart":36c7w776 said:
(i have obg ) ;) ...The Langner scem posted above--will absolutely NOT work.

WAYYY too much gain--to the point of the amp going into oscillation/ motorboating/ cutoff , if you turn the gain above 6 or 7 ..

There IS a way to make that work with a couple changes.
Click to expand...
It seems like it would be gain overkill to me too; the cathode cap values at the first two gain stages are definitely too high. There's no way that much bass could sound good.

I'm certainly open to suggestions. :D
Click to expand...

raise the 3rd cath resistor up to something like 22k-47k

lower some of the cath caps down to 1 or 2uf :thumbsup:
 
Can anyone post the schematic of the splawn deal above? I cant see the values of anything---zooming in it gets blurry
 
496dart":fzti3w5a said:
OBGYNkanobi":fzti3w5a said:
496dart":fzti3w5a said:
(i have obg ) ;) ...The Langner scem posted above--will absolutely NOT work.

WAYYY too much gain--to the point of the amp going into oscillation/ motorboating/ cutoff , if you turn the gain above 6 or 7 ..

There IS a way to make that work with a couple changes.
Click to expand...
It seems like it would be gain overkill to me too; the cathode cap values at the first two gain stages are definitely too high. There's no way that much bass could sound good.

I'm certainly open to suggestions. :D
Click to expand...

raise the 3rd cath resistor up to something like 22k-47k

lower some of the cath caps down to 1 or 2uf :thumbsup:
Click to expand...
Cool, thanks for the help.
 
496dart":36zulmla said:
Can anyone post the schematic of the splawn deal above? I cant see the values of anything---zooming in it gets blurry
Click to expand...


bump :)
 
That Langner mod is close but your missing some key components on that first stage ;)
 
also cathode bypass cap's need to be .47's....not 4.7's that's way too much! .47 will keep it nice and tight
 
Damn first time I have reade Ben's posts since his passing.

RIP shipmate.
 
I see you guys got a hold of an old concept layout of one of my mods.

It's been updated to version 4. P.M. for a copy.
 
Oh. A thread worth perusing in the near future. Marked. Thanks for all the info for those that contributed.
 
Updated the Version 3 layout with a pre-tonestack master volume. This version works better with the grind switch diode clipping. Has better saturation and sustain when the zener diodes are switched in.
 
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