Valve Matching For Fisher X-100 A

[DG Nelson]

There is a missing 7189 valve as part of the output stage for the Fisher. I'm looking to order one online (tung-sol from Russia) where they say you can order a matched pair. Is it important to get a matched pair?

Thanks
Dan

 

[Tim D]

Without bias adjustment on the Fisher X-100-A, yes you should get a matched pair. Better yet. A matched quad. I'd suggest an IBAM or IBBA for some flexibility.

BTW, are you talking about EL84M tubes? Or have you found a source for new manufacture 7189 tubes?

 

[DG Nelson]

Thanks Dave. I've found a new 7189 made in Russia.
https://www.thevalvestore.com.au/home/196-tung-sol-7189.html?search_query=7189&results=2

 

[larryderouin]

DG Nelson; Factory matching is for mutual conductance not Cathode Load. You want the cathode draw (load) to be within a couple of ma. Factory testing doesn't account for that. Try Jim McShane, he has them for $64.50 a quad MATCHED at operating voltages and Cathode draw. Something that you won't get from the Valvestore. If you're down under, shipping may be a NO-GO.

Tim; EL84M are Sovtek's. Tungsol el-84 ReIssues are relatively new. There are 7189 clones that don't make the cut for Vox AC-30 type amps. Apparently this is the most reliable of the very few that do make the cut. Haven't tried them yet, but eventually I will.