Crate Stealth GT50H Mods

[David Ray]

I was looking at some of the suggestions on an earlier thread about the voicing of the Crate Stealth GT50. It is a one trick pony as far the lead and crunch channels are concerned. I was wondering if I added a choke to replace R89. The schematic was on the earlier thread, but it's the first 5 Watt 470ohm resistor after section A in the power supply. I believe this is the normal placement for a choke. I was wondering if it would smooth out the raspiness and give a little more vibe to the amp. Most 40 watt and above amps have chokes and I wonder why these amps don't. Any suggestions?

[rockon1]

Originally Posted by David Ray

I was looking at some of the suggestions on an earlier thread about the voicing of the Crate Stealth GT50. It is a one trick pony as far the lead and crunch channels are concerned. I was wondering if I added a choke to replace R89. The schematic was on the earlier thread, but it's the first 5 Watt 470ohm resistor after section A in the power supply. I believe this is the normal placement for a choke. I was wondering if it would smooth out the raspiness and give a little more vibe to the amp. Most 40 watt and above amps have chokes and I wonder why these amps don't. Any suggestions?

I doubt it. As Jerry mentioned in my other thread(to much SS in there) and he's probably right. I tried a few suggested voicing mods and basically went back to stock with it. It changed it but always had its inherent distortion intact but weaker sounding. Ive had more success with the right speaker and a bit of tweaking. Its a pain to pull the board out,do the mos and come out with an enimic sound! lol!

Heres a clip of the Stones "Brown Sugar" rhythm I did with mine stock save for a speaker change and old glass. Still sounds like the Stealth but closer to classic rock. Bob

SoundClick artist: The Bob R Band - Rock,blues,and alternative mixed into one

[David Ray]

What kind of 6v6's do you prefer? I've currently got JJ's in there

[rockon1]

Originally Posted by David Ray

What kind of 6v6's do you prefer? I've currently got JJ's in there

I got confused before in your other thread-I had two Stealths. The combo I modded the bias circuit in had EH's not JJ's. I had the JJ's in my GT50H. At the moment Ive got a pair of Sovtek "5881's" in it-I think I prefer the EH's to the "5881's"-too stiff in an already stiff amp.......

While I have an affinity to the JJ's since they are so robust a 6V6 thats more like a 6V6 might help the tone when you crank up the amp. With that in mind I might get another set of EH's for it or maybe some "Tung Sol's". Bob

[David Ray]

I want to try the EH's. But I've got to get my bias supply under control first. I'm reading the negative voltage at the resistors per tube just like in the video I bought from Lee J., but I can't get the #'s down under around 28. According to your great example, I'm way above the acceptable level. Maybe the bias supply resistors have drifted up or something.

[rockon1]

Originally Posted by David Ray

I want to try the EH's. But I've got to get my bias supply under control first. I'm reading the negative voltage at the resistors per tube just like in the video I bought from Lee J., but I can't get the #'s down under around 28. According to your great example, I'm way above the acceptable level. Maybe the bias supply resistors have drifted up or something.

Sooo... if your reading the neg voltage then your biased colder than hot-more negative voltage means cooler or less ma draw. Get a probe and know exactly where you are at. Its just the simplkest way to measure current draw on an amp like this. Then you can swap out resistors if you find its actually running too cool for your tastes as I suspect it is.

FWIW- As I stated earlier I tried some mods with little success. The best thing Ive found to make the amp sound more classic rock is a speaker swap. To that end there are a few good choices but so far the one Ive found that does this the best is the Celestion Heritage G12-65. Really smoothes it out and de-metals the amp a lot. Also this amp sounds much better at higher volumes. It sounds downright SS at bedroom volumes. Bob