7868

[9pins]

went through an old ampeg gemnini, replaced power side with the new production EH 7868, everything is fine. My only beef is that the pin wire is significantly bigger than the nos, it could be a real issue on fragile sockets and or flaky pin retainers in the socket, other than that its nice to have the drop in.

[camerongrieve]

I have an old Hammond organ amp that uses 2 7868's. It's one of those "one day" projects.

I wasn't aware you could get new production 7868 valves (in fact I hadn't even looked into it), so thanks for that


Cameron

[gldtp99]

EH 7868: http://tubedepot.com/eh-7868.html

I've used several pairs of these and they hold up well------ yes, the tube pins are thicker than NOS 7868's so be careful when installing them for the first time. The EH seem to resist screen grid over dissipation better than the NOS--- in some amps the NOS have exibited excess screen grid flash corrosponding to signal.
I think Sylvania 7868's sound better---i've got one Bogen CHB35A converted to a modded Plexi preamp running Sylvania 7868's and it's a very good sounding lo buck amp......................gldtp99

[9pins]

I tend to favor NOS too, screen grid flash resistance might mean a tighter mfg tolerance, especially if it came to screen grid alignment inside the tube structure, I guess the EH product comes from a variety of eastern European and former Soviet and Russian sources, just simply being made to a metric tolerance could be the difference.

I had a fuel filter issue in a Nissan once, the dealer used a MFG part made in Asia with a metric screen gauge, never had so much trouble, the issue vanished when I replaced it with a third rate American made filter. And there was nothing truly wrong with the Asian made filter.

slight differences in tolerances can mean a world of difference either way, like with the tube pins, I've gotten some new production tube where the pins where a mix of wire thicknesses, trouble shoot the whole amp only find that it was the tubes, that were really just fine other wise, cept the pin wire... I've also read that sovtek has and is working with its suppliers to improve its product, nice to hear of positive results.