I had one of these years ago and traded it on the 5153 mini head. Wished I would have kept it, gets nice floor chunk at lower levels. Given the size of venues we usually play, I kinda missed it. Found a good used one today! Only issue is static for the first 20 secs after releasing standby. Once it warms up it's fine. Changed some pre tubes. Haven't tried power tubes yet. As long as it sounds good and works fine I don't really care. Killer gain.
No I realize it has high gain hiss. This is static. No source, volume zero. Seemed to be worse when tapping amp top thus the micro tube thought. But it's not that. I might try a conditioned power supply. Or power tubes. Oddly when I removed the chassis, it did not do anything amiss when I rapped on the top edge of chassis. But it did once mounted again. I think it's once it warms up it's fine.
You are getting oscillation in the gain stage.it is the same thing as microphone feed back.you have some much gain it is leaking in to the grids and getting amped up.a lot of times something needs to be grounded
20 seconds hiss then no more is some kinda tube issue imho Don't blame it on the high gain circuit, that's not how it works OP: you keeping it stock or speaker swapping?
No I have NO guitar plugged in. Volume at Zero. Gain at zero. Noise starts as soon as standby switched off. It is static sort of like a dirty pot. It is not. I cleaned them just in case. It is not a microphonic tube as far as I can tell. I will look at whether it is coming from pre or power amp.
Yep. It's the stock Sheffield. Sounds ok so far. I'll play when I get a chance. Try a V30 to brighten it up some. Or what have you. T75. It's a heavy large bugger for a 1x12. Nice addition to the fleet though. Something different.
Cool. Was wondering if it was a Sheffield. Id rock it stock and see too. yeah man they are not grab and go combos by any means. Love the tones though.
Congratulations JR nice amp I was also going to say try power tubes, I have had a bad one on 2 occasions with the same thing you described, cool you got it figured out. Rock on with it bro! Mitch
Have not played one myself, but one of the guys in Cherry Monroe used one when I saw them around 2006. It sounded killer! Congrats!
Sorry to drag open an older thread.... but I’m considering getting a nice used 6505 combo in the next few days. Just curious how you like it? Any issues using the loop (delay)?
Loop works great with a multi unit for reverb and delay. I initially found it to be a bit too compressed, that is, whe you have the gain down at like 4 on channel 1 with crunch on, that "blatty" sort of midrange Marshall punch was missing. The low end thump was there. I wound up almost pinning the Presence control. This really opened it up and made it closer to a very high gain Marshall at least in that way. I used it witn the stock speaker in Nov. live. I may switch out to a V30 to really emphasize the mids but may not have to with careful EQ. More gain tha anyone needs. Closed back punchy, floor shaking amp!
