Tube Amp Archive

Hi there, I was in a similar situation with my express. I’ve carted around the express head and various 1x12 and 2x12 cabs for years. My favourite 1x12 is the CAA dual front ported 1x12 that’s very similar the the Bogner cube, It just happens that the internal width on the CAA is a cm or so wider th...

Two of the best low to moderate volume speakers I've heard are Celestions recent offerings, the A Type and even more so the G12-35XC.

I actually had the same issue as mentioned with PEC pots. I installed a set in my Express build, as I was trying to resolve noisy pot issues. The problem was conductive board, once I changed out the boards I still had an issue with the Pec pots. They were noisy when turned after a couple of months u...

Yet another fine amp that will end up on the shelf of discarded chassis's.....i give you a month Azatplayer I'll say it again, your a Rocket guy, and ive heard you play every fine amp you've built!

Azatplayer your son needs to break in all my speakers ;) The gold in that 1 x 12 Z Cab sounds fantastic! After trying alot speakers in my 1 x 12 and 2 x 12 open back Ulbrick cabs, What suit my express the best are a G12-65 in the 1 x 12 (a single pre rola g12m sounds amazing in my smaller 1 x 12 cab...

Thanks Mark, seems you were spot on, the boards are the holed brown fiberglass variety i purchased, and if i measure dc in the hole next to the turret to ground, nearly a volt! Strange thing is the amp is incredibly quiet, stable and sounds amazing, the dc on the pots have been the only issue. No ea...

Hi there, This has been a problem on my Express for some time now, scratchy sounding pots are the result, and it would be great if i could get this issue fixed. I have replaced the silver mica 500pf with various caps (polystyrene and pio) this seems to help some times for a very short time, turn it ...

I assumed only 1 cap was leaking , so i only lifted one cap at a time and then measured the dc on the treble pot. The problem Was c2 and c4 were both leaking dc so while c2 was lifted , c4 was still leaking and vice versa. As the readings didn't change with either lifted I thought both caps were fin...

Well it seems both the C2 and C4 were leaking dc, that's why lifting one at a time showed no improvement. Replaced both and we're down to under 2 mv on the pots, all scratchy noises have disappeared as a result. Glad to get that fixed, now where's that wine
Cheers Lee

Sorry, Seems I had mA on the brain( must have been a combination of wine, and 2 hrs of myspace programing :/ And replying on a tiny I phone screen) so the voltages I'm measuring at the treble pot are in the 150- 300 mv range, on measuring all the pots the treble pot is where the highest Voltages are...

I should add it's Monday night where I am
Cheers Lee

My apologies I meant mA ( 2nd bottle of wine in after 2 hrs of dealing with myspace code

Thanks for your repies, I actually just lifted the treble mica cap off at the tail end and measured at the same tag on the treble pot and the dc reading was roughly the same, which was around 360 Ma, as for the bass and mid .022 caps, I disconnected the tail and temporarily soldered in another .022 ...

Thanks for the reply, all the pots are scratchy(some more so than others) and considering the considerable dc showing on them I'd tend to think it is a bad cap leaking dc through, I was actually quite careful not to heat the pots up too much when soldering the ground buss to them, I'm just not sure ...

Hi there, my express has scratchy pots and I'm putting this down to the dc I'm measuring in the tone stack. I get readings varying from 120 Ma to 380 Ma on the treble pot leg which connects to C2. I've tried replacing C2, C3 and C4 but it only has marginally changed the dc readings. The highest read...