Schu Posted October 4, 2016 Share Posted October 4, 2016 I am looking for a source to find some more Tubes... I am more interested in the harder to find items in good + condition by reputable sellers. Brent jesse is good, but maybe I can find a source that can save me a few bucks on the high priced items. right now, mainly looking for different 12au7's... maybe Amperex 7316's, Telefunken 802's... things like that Quote Link to comment Share on other sites More sharing options...
jimjimbo Posted October 4, 2016 Share Posted October 4, 2016 Sent you a PM Quote Link to comment Share on other sites More sharing options...
NOSValves Posted October 5, 2016 Share Posted October 5, 2016 Schu, I have a nice pair of HP Amperex made in Holland "O" getters 7316 I'd consider selling for $175. Shoot me an email if interested. Quote Link to comment Share on other sites More sharing options...
Schu Posted October 6, 2016 Author Share Posted October 6, 2016 Thanks craig... let me contemplate that. I am looking for a 7316 d getter.... and only one tube. Quote Link to comment Share on other sites More sharing options...
thebes Posted October 6, 2016 Share Posted October 6, 2016 I've got a crapload of 12AU7's , most used, some NOS. What are you looking for? Quote Link to comment Share on other sites More sharing options...
Schu Posted October 7, 2016 Author Share Posted October 7, 2016 Mullard 10m, Amperex 7316 d-getter long plate, Telefunken 802, to begin with if I can find reasonable pricing. Quote Link to comment Share on other sites More sharing options...
paul79 Posted October 12, 2016 Share Posted October 12, 2016 What you putting the tube in? Quote Link to comment Share on other sites More sharing options...
Schu Posted October 12, 2016 Author Share Posted October 12, 2016 A very simple Pre amp.... 6x4 rectifier, 12au7 follower, and a 12au7 output. Quote Link to comment Share on other sites More sharing options...
paul79 Posted October 12, 2016 Share Posted October 12, 2016 Let me see what I can find.... Most my tubes are in pairs though, and would hate to split anything up, but I am sure I have some singles for you to play with. For preamp though, try the RCA COMMAND 5814, Sylvania 6189 with triple mica grey plates, or if you get really lucky, and you want to be done, the Long Plate Valvo ECC82's are about the best 12AU7 there is IMO. Another great tube is the RadioTechnique Short Wing Plate 12AU7 as well as the CBS 7318. I have heard a couple preamps with a very similar layout as the one you are using, and a combination of tubes will likely be your best result, as in there will be a clear choice for the output tube, and a clear choice for the input tube, once you find them I would try the RT Wing Plate or the CBS 7318 at the output, and any of the other above mentioned for the input tube. I can help you out with these, but I can't split up pairs.... What model preamp? Quote Link to comment Share on other sites More sharing options...
Schu Posted October 12, 2016 Author Share Posted October 12, 2016 Eastern electric minimax... no phone set up, no tone controls, no nothing except a selector switch and a stepped volume Quote Link to comment Share on other sites More sharing options...
audiowize Posted October 12, 2016 Share Posted October 12, 2016 You'll get better results from that EE-MMX by replacing the electrolytic coupling capacitors with something else. Parts Express Dayton metalized film caps are a good start, try 3.3uF. Try clipping out the 220uF cathode bypass caps on the first stage. This will reduce the gain, but you don't need a preamp with 24dB of gain. Current sources in place of the plate loads on the first stage and cathode loads on the second stage will do wonders for the performance of the circuit, and there are some kits available for this. You actually do not need matched pairs of tubes for this preamp. One tube is the voltage amplifier for both channels and one tube is the current amplifier for both channels. I have 1000-2000 12AU7's sitting around. PM me if you're looking for anything specific. Quote Link to comment Share on other sites More sharing options...
Schu Posted October 13, 2016 Author Share Posted October 13, 2016 I realize its a single ended design.... I already asked craig O to take a look at the unit and see if there are any advantage to replacing caps or doing anything to the unit.. he said it wasnt worth it and that space is extremely limited in the chassis so he wasnt interested. Quote Link to comment Share on other sites More sharing options...
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