Fender choke in Marshall JTM45 style amp

5F6-A

Senior Member
Joined
Aug 16, 2007
Messages
10,148
Reaction score
2,529
My main big amp is a JTM45 style amp with KT66 valves. I have noticed that it uses a custom made PT, a RS Spares style OT and a ClassicTone (relabelled RUBY) Choke. This choke was made for big Fender amps (specs: 90 mA , 4 Henry and 105 Ohm DCR).

http://www.classictone.net/40-18003.pdf
I'm not planning on changing it as it sounds great but I can't help but to wonder what is the impact that this Fender spec unit has on tone.
Thanks!


choke.PNG
 
Last edited:

el84ster

Senior Member
Joined
Jan 25, 2014
Messages
326
Reaction score
367
Very little if any, assuming it specs close to original Marshall. parts in the power supply tend to effect the feel of an amp much more than the sound. So if this choke is a lot larger than original spec, it may make the amp slightly stiffer feeling, and possibly quieter
 

5F6-A

Senior Member
Joined
Aug 16, 2007
Messages
10,148
Reaction score
2,529
Very little if any, assuming it specs close to original Marshall. parts in the power supply tend to effect the feel of an amp much more than the sound. So if this choke is a lot larger than original spec, it may make the amp slightly stiffer feeling, and possibly quieter
I think the originals were 100ma, 3h and 110 ohms DCR. This one is 90ma, 4h and 105 ohms DCR.
 

bblooz

Senior Member
Joined
Oct 8, 2014
Messages
3,575
Reaction score
2,144
JTM45 was Jim Marshall's attempt at copying the Fender Bassman 5F6-A , so not surprising that "Fender" spec parts would be working in this environment.
 

el84ster

Senior Member
Joined
Jan 25, 2014
Messages
326
Reaction score
367
Specs pretty close. Probably not much difference there if at al.
 

ivan H

Senior Member
Joined
Apr 19, 2014
Messages
129
Reaction score
168
The filter choke in a JTM45 was a Radio Spares unit, 20 Henry, 690 ohm DC resistance & rated at 70mA, so the Fender unit you have is way off spec.
The 3 Henry, 110 ohm, 100mA choke was in the JTM50/100 & later JMP amps, though the Radio Spares choke can also be found in the JTM's. Cheers
Edit:
Of course, it won't hurt anything having the Fender unit in there, just won't feel the same. Cheers
 
Last edited:


Latest Threads



Top