1959 cascade mod (Randy Rhodes head) HOW TO

[rgalpin]

I see. That's similar to the way I had it with the 680/1uf combo, but I had the .022uf coupling cap. If Larry spec'd that value I'm sure it's a good one.

I would think that 1.5/.68uf would have less gain though. I have that first stage volume dimed. Correct me if I'm wrong because if it had more gain I would swap it in there tonight. I like it as is, but more gain in the first stage would give me some tweaking room. I had thought about adding a 1.5/1uf combo in there which would have a cutoff of 106Hz, but didn't want to lose any gain.

interesting thought about the gain... i always think about the tone shaping to the exclusion of gain considerations. but that's a good thought. for me, the circuit has more gain than i even find to be useful. if i take either vol over 5 it mushes out and compresses too much.

http://soundclick.com/share?songid=6750528

that's with v1a up at about 7 i think and v1b down around 3-ish. it actually sounds great that way when yer in the room - but it doesn't record well because you can hear the walls just fall down when a full volume chord slams in there.

Woowww, your clip sound fantastic. I like your sound. You are a locky guy, I'jalous.

Could you please share with us the setup you have?
Like, is your preamp is mod exactly like the schematic from Larry? or you did more mod?
Also, which type of pickup and speakers do you have?
Effect....or extra overdrive pedals...???

I will mod my Plexi 1959SLP reissue like the RR or Larry's mod, but would like to know what is your setup first

Big Thanks
Stephane

thanks - the schematic is attached. larry drew it up for me. i can barely read it!

[Grosh_Guitars]

Can someone draw up a layout of the RR amp?

[neikeel]

Here is switchable RR on a 1959

http://home.comcast.net/%7Ejbjdav26/1959RR1wireswitch.jpg

I tried it and works well if you change the V1a bypass cap to < 10uF and 3.3k resistor. Best gain is with 2k7 and 0.68 like other half or with a 10k like a 2203/4 but then you lose a distinguishable normal channel if you want to use the amp with y cord or jumpered in typical NMV plexi mode.

Having tried all the 1 wire and 2 in 1 versions my fave is a 2 in 1 but use a dedicated 1meg gain pot in normal channel high input position with push-pull on it.

[Stephand]

Hi all

Very good info here. Thanks to all. I like Randy Rhoad

FYI, I did compare the schem of the 1959SLP and 1959RR.
I won't talk here about the wire mod, the expert did it already

Here are the parts change I found

Fr Marshall 1959SLP to Marshall 1959RR
Power amp section
R48 none 56K
R49 none 56K
R37 1K5 5K6
R36 1K5 5K6
R35 1K5 5K6
R34 1K5 5K6
R51 none 1R
R50 none 1R
R26 1W 2W
R26 1W 2W
R21 47K 100K (from presence to Transfo imp selector) ???

Preamp section
R18 none 4k7 (fit to VR6 PRESENCE)
R15 1W 2W
C4 3n3 22n (Pin6 of V1)
R1 820R 2K7 (Pin8 of V1)
C7 680n Remove (Pin 8 of V2)


Question, do we really eed to the change the power section to get the RR sound?

Question 2, what about R21... this is connect on 16 ohm on SLP but 4 ohm on the RR. Do we really need to change this?

Question 3, on the RR, the third pin of the 1M pot (BASS) is connect with the middle pin. This last one is connect to the Treble Pot. This Third pin is not connect on SLP. Is this make sense?

Thanks for sharing you expertise with us

Stephan

[Stephand]

Here is switchable RR on a 1959

http://home.comcast.net/%7Ejbjdav26/1959RR1wireswitch.jpg

I tried it and works well if you change the V1a bypass cap to < 10uF and 3.3k resistor. Best gain is with 2k7 and 0.68 like other half or with a 10k like a 2203/4 but then you lose a distinguishable normal channel if you want to use the amp with y cord or jumpered in typical NMV plexi mode.

Having tried all the 1 wire and 2 in 1 versions my fave is a 2 in 1 but use a dedicated 1meg gain pot in normal channel high input position with push-pull on it.

Hi all

Very good info here. Thanks to all. I like Randy Rhoad

FYI, I did compare the schem of the 1959SLP and 1959RR.
I won't talk here about the wire mod, the expert did it already

Here are the parts change I found

Fr Marshall 1959SLP to Marshall 1959RR
Power amp section
R48 none 56K
R49 none 56K
R37 1K5 5K6
R36 1K5 5K6
R35 1K5 5K6
R34 1K5 5K6
R51 none 1R
R50 none 1R
R26 1W 2W
R26 1W 2W
R21 47K 100K (from presence to Transfo imp selector) ???

Preamp section
R18 none 4k7 (fit to VR6 PRESENCE)
R15 1W 2W
C4 3n3 22n (Pin6 of V1)
R1 820R 2K7 (Pin8 of V1)
C7 680n Remove (Pin 8 of V2)


Question, do we really eed to the change the power section to get the RR sound?

Question 2, what about R21... this is connect on 16 ohm on SLP but 4 ohm on the RR. Do we really need to change this?

Question 3, on the RR, the third pin of the 1M pot (BASS) is connect with the middle pin. This last one is connect to the Treble Pot. This Third pin is not connect on SLP. Is this make sense?

Thanks for sharing you expertise with us

Stephan

[IloveMyMarshall]

what do you all think of this version of oen wire mod:
http://www.marshallforum.com/workbench/ ... e-mod.html

and this:
http://music-electronics-forum.com/show ... php?t=2205 you need to scroll down where a person is writing in red.

I did the first one works fine, is there any tonal difference between the one I did and the others?

[rip]

would this be easier? 1959RR with a switch.

And I was wondering for those who have done this type of mod using the parallel/series input jack cascade mod. Without the switch shown in the picture but the "normal" 1959RR way. Can you still jumper channels? Seems like you would get some weird feedback loop going.

Rip

[Grosh_Guitars]

would this be easier? 1959RR with a switch.

And I was wondering for those who have done this type of mod using the parallel/series input jack cascade mod. Without the switch shown in the picture but the "normal" 1959RR way. Can you still jumper channels? Seems like you would get some weird feedback loop going.

Rip

As far as I know you can't jump channels anymore.

[Stephand]

I see. That's similar to the way I had it with the 680/1uf combo, but I had the .022uf coupling cap. If Larry spec'd that value I'm sure it's a good one.

I would think that 1.5/.68uf would have less gain though. I have that first stage volume dimed. Correct me if I'm wrong because if it had more gain I would swap it in there tonight. I like it as is, but more gain in the first stage would give me some tweaking room. I had thought about adding a 1.5/1uf combo in there which would have a cutoff of 106Hz, but didn't want to lose any gain.

interesting thought about the gain... i always think about the tone shaping to the exclusion of gain considerations. but that's a good thought. for me, the circuit has more gain than i even find to be useful. if i take either vol over 5 it mushes out and compresses too much.

http://soundclick.com/share?songid=6750528

that's with v1a up at about 7 i think and v1b down around 3-ish. it actually sounds great that way when yer in the room - but it doesn't record well because you can hear the walls just fall down when a full volume chord slams in there.

Thanks

Do you use an attenator or MV on your 1959?
Also , which type of OT do you have?, Stock Marshall?

Thanks to share your Idea

[Stephand]

Here is switchable RR on a 1959

http://home.comcast.net/%7Ejbjdav26/1959RR1wireswitch.jpg

I tried it and works well if you change the V1a bypass cap to < 10uF and 3.3k resistor. Best gain is with 2k7 and 0.68 like other half or with a 10k like a 2203/4 but then you lose a distinguishable normal channel if you want to use the amp with y cord or jumpered in typical NMV plexi mode.

Having tried all the 1 wire and 2 in 1 versions my fave is a 2 in 1 but use a dedicated 1meg gain pot in normal channel high input position with push-pull on it.

Very interesting mod. I like the Idea of having both option, stock 1959 plus RR.
Question, What will happen if somebody will jump the imput channel 1 and 2 (old way) and at the same time have the switch on cascade position?

Is it dangerous?

Thanks

[OnTheFritz]

Bringing up an old topic.
Anybody have any more experiences or *tweaks* in regards to SDM's RR layout?
I have an amp a player wants to buy with a higher gain option, and this seems perfect. Noticed in the layout that there's no V2A cathode cap. The amp I want to try this on is a '68 era 50 watt build layed out/spec'd like the Metro kit.
Any input would be appreciated.