Thanks mate.. Yeah, the tech at the studio where I work is gonna do something like that! He's got scopes and stuff, so he's gonna monitor the measurements over a period of time and get back to me. Missin ma amp though!
Thanks guys..! Def not my ears as its the same when I play it quiet at home...! So output tubes could be the culprit? Is there a way of checking the tubes before I buy new ones? Cheers
Hey guys my 1978 2203 is sounding great since I modded it last year but after about 10 mins of being on it sounds as if the gain has been turned down a little and is a tad duller! Im sure the tubes are fine and wondered if it may be the caps which are the originals? Cheers
Good question. I know that when I had the output transformer replaced with a no name brand in my 78 2203 in the nineties, some mojo was definately lost. :(
Im def gonna replace it shortly.
Thanks Joey. I tried it a little colder, in fact I dropped it down 1ma at a time, plugged back in had a blast, down 1ma had a blast ect, all the way down to 30ma. But 37.5 seemed to hit the spot, with my batterd ears anyway :eek:
Thanks Jon. I thought as much! :cool:
Kiddin!
Cheers...
Thanks Jon. When I checked the plate voltage about a week ago it showed 480, so I set the bias to 36ma. Today I replaced the screen resistors and out of curiosity checked the plate voltage again, which this time read 466, so I tweaked the bias up to 37ma. I presumed it was the new screen...
This is a more of a curiosity than anything else so..
Replaced the screen resistors in my 2203 today all good no worries.. Then I checked the plate voltage and it was 466, so I re-biased. Funny thing is, I checked the plate voltage a few days ago and it was 480! Presumably this is a side...
The bias filter caps in my 78 2203 are 10uf 100v but in the schematics Ive looked at they are 10uf 160v?? :confused:
Gonna be buying some replacements so should I go for the 100v or 160v?
Cheers
Cheers Bieling3. I'm wondering if its worth just replacing v1 or all 3? Ive noticed a lot of people using 3 different preamp tubes which sounds interesting! Did you ever try this?
Thanks again.
Update:
I checked the bias and re-set it to 36ma as it was set pretty cold, the plate voltage was 480. As soon as I hit a chord it sounded SOOOO.. much better! So out of curiosity I put the 68k resistor back onto the wiper and hit a chord... fuckin wicked! Fat and sooth.. Now I can turn up...
Mmm.. interesting. As you mention, could be country specific then?
Thanks bud. I notice you use a Flying V with 'the beast'...aint it a wicked combination. :thumb:
Hey cheers bro.. yeah, that's odd concerning the turrets.. wonder why mine doesn't have them?
I noticed the heat damage to the screen grid resistors when I first decided to try the mod but did'nt have anything to compare them with to know if this was normal or not on amps this old, so cheers...
Ive put the 10k cathode resistor back and the amp sounds great again! Then I took the 68k resistor off the wiper and back on to the input side of the pot and it sounds even better, so many thanks for the suggestions MajorNut1967 :)
Ill leave the treble peaking circuit and the bright cap off...