Moderators: pompeiisneaks, Colossal
Don't think I'm going to find a 6J5 to 6SC7 adaptermartin manning wrote:I can see how rewiring that would be a bit of a pain. Nice looking point-to-point, BTW. Now, if you had an adapter socket thingy, all you'd have to do is change the Rk...
The 6SC7s like to be left as alone as possible. They are a seriously troublesome tube. If I cursed loud enough at V1 bet I'd hear it come out the speakers! Have no idea how these worked out in combos.Why does the amp not like being close to the cab?
rp wrote:I was (jocularly) suggesting that you could make one :^)martin manning wrote:Don't think I'm going to find a 6J5 to 6SC7 adapter
No bottom plate/shield?martin manning wrote:Why does the amp not like being close to the cab?
For about 5 seconds I actually entertained it. I could do it quick and it'd be really hairy, or well and it'd be as laborious as rewiring the socket. But, I have been sitting on one of these nice Amphenol thingies for 20 years, and am bored and unemployed... it would allow me to A/B the two versions... now I've entertained it for 5 minutes, thanks for planting the idea...martin manning wrote:I was (jocularly) suggesting that you could make one :^)
Sure, it has a nice thick bottom plate with a piece of bitumen-type sound damper stuff I put on it. And, V1 & V2 are shock mounted early Tweed style w/ rubber grommets - which does nothing or not much IMO but I haven't tried it w/o. 6SC7s like to squeal and dink and bing I've discovered. I got my best 2 in V1 and V2. V1 the grid leak side is even more sensitive. I first thought it might be an oscillation problem but moving the cab ended it, the farther the better. It's just the nature of metal 6SC7s I'm pretty sure. I'll find out in time rolling more tubes and when I get it somewhere where I can play it flat out.Phil_S wrote:No bottom plate/shield?
I do want to save mine in case one on my DIY bias box every breaks. Martin, I've never been able to hear any difference after 5mf on preamp cathode bypass caps, so I was thinking it wouldn't matter, but I also have absolutely no idea what actually happens frequency/gain-wise when you do something weird like bypass only one of 2 series resistors. Any idea? I have 25 across the 1500 now (I'll likely make it 220 just for the sake of historical accuracy when I order some up). If I don't add an other cap will I simply see 12.5mf across 2500? If so I'm all set with a 220, I know I, or anyone else, won't hear any difference between 110 and 220!martin manning wrote:The cathode R and C are a bit of a problem. Just adding a series R will get the bias correct, but you will only be partially bypassing the Rk. To get closer to a true A-B comparison I think it would be ok to add a bypass cap across the additional 1k... It's low voltage so the cap can be physically small.
