NAD: Ceriatone JTM45 (2xKT66, 50-watter)...

[Lake Placid Blues]

Re: NAD: Ceriatone JTM45 (2xKT66, 50-watter)...

Would like to try EL34s in there... but it sounds like a bit of a process to do the switch.

Probably not. I don't know exactly how Ceria Tone wires up their JTM45s but with most Marshalls and Marshall clones you can go back a forth between 6L6 and EL34 tube families with nothing more than bias adjustments. (thats not the case with Fender amps however.)

Look on the tube sockets. Are pins 1 and 8 connected together in some way? If so you are probably good to go with EL34s.

 

[Lake Placid Blues]

Re: NAD: Ceriatone JTM45 (2xKT66, 50-watter)...

If you have a JTM-45, then the old school trick is to just jump your channels.

Treble channel set higher than the normal channel.

It's much more effective with the split cathode instead of the shared cathode set up. With my JTM45 I just plug into the upper left input only. The normal channel is turned down.

The bass knob is rarely set higher than 2 at gig volume. Otherwise the bass response is overwhelming.

 

[Red_Label]

Re: NAD: Ceriatone JTM45 (2xKT66, 50-watter)...

Probably not. I don't know exactly how Ceria Tone wires up their JTM45s but with most Marshalls and Marshall clones you can go back a forth between 6L6 and EL34 tube families with nothing more than bias adjustments. (thats not the case with Fender amps however.)

Look on the tube sockets. Are pins 1 and 8 connected together in some way? If so you are probably good to go with EL34s.

Interesting! I'll have to look into that. The amp came with KT66s. From what I understand, that's a pretty common configuration for the JTM. And I read enough to know that the 6L6s and KT66s are close enough to interchange at-will with only a bias adjustment. But I'm pretty sure that I've read in several places that the jump from either of those two tubes types to EL34s requires a few component swaps to handle the different plate voltages. I'll have to look closer. I wish I had the close-up gut shot of this beauty. I guess that I'll have to remove the chassis tonight after I'm done playing and get some good shots of it (or maybe tomorrow when the sun is shining and I can get a better natural light shot and not have to use flash).

 

[zzmoore]

Re: NAD: Ceriatone JTM45 (2xKT66, 50-watter)...

http://ceriatone.com/images/layoutPic/marshallLayout/JTM45ceriatone.jpg
Looks like they tied the suppressor to the cat... Pin1 to Pin 8 for the external bias. So you should be good from that perspective.
I don't know...not sure I would even want to run EL34 in a JTM...but what the Hell. you can always change back.
Sometimes 34 can have wimpy screens, you may want to 2x or 3x those 470 Ohm resistors, they will still work with 66 L6 or whatever it is you are using.
Just something to think about.
good luck

 

[Lake Placid Blues]

Re: NAD: Ceriatone JTM45 (2xKT66, 50-watter)...

If I recall correctly, I installed 1000 ohm grid resistors from the get go (Metroamps JTM45).

I have run KT-66, 6L6GC, EL34, E34L, and 6CA7 in mine with just re-biasing. I really like it with 6CA7s. EL34s get more distortion sooner, but you notice the tube rectifier sag more as well.

But I'm pretty sure that I've read in several places that the jump from either of those two tubes types to EL34s requires a few component swaps to handle the different plate voltages.

On my Jubilee I must run EL34s because the bias adjustment range is too narrow to run those other tubes. Even 6CA7 run too hot in the Jubilee with its bias adjustment limits. I could mod it for a wider range of adjustment but I'm fine with EL34s in that amp. It runs a much higher plate voltage than the JTM-45. The Jubilee reads around 460v with a hot bias setting (its slightly lower plate voltage with a hot bias setting because more current flows) and the JTM around 400 volts.

 

[scorch]

Re: NAD: Ceriatone JTM45 (2xKT66, 50-watter)...

I didn't know that was a RP36 in the photo. But it makes sense since it looks just like mine. Mine is very modified though. I put paralleled 12X7's in both 1st stage pre-amp spots. Plus, I had trouble with red-plating EL84's and was having to drop about 80 volts off the rails to get them calmed down.

So.....I switched them out to fixed bias 6V6's. Sum***** is stinkin' loud now! Quieter and cleaner.

I've also got a Germino Classic 45 coming so I will be running a similar rig to yours!

 

[Red_Label]

Re: NAD: Ceriatone JTM45 (2xKT66, 50-watter)...

*** UPDATE ***

Was able to experience my full rig in all of its stereo glory last night and was reminded just how much BIGGER a stereo rig sounds when the amps and/or cabs are different and compliment each other.

Where the RP has a mid-range roar and lives in the mids, the JTM has a bigger bottom and a bright edge. A/B'd back and forth I preferred the RP for OD and the JTM for cleans (no surprise there), but together... YUMMAY! So big, full, and crunchy. Dang... I may hold-off for a while on any mods to the JTM. I think that I dig this setup just like it is!

 

[xxxplorer]

Re: NAD: Ceriatone JTM45 (2xKT66, 50-watter)...

^I have been doing the same with a stock Marshall 800 and a souped up HW 800. The sound is amazing. Nice rig!