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Post by mossback on Mar 27, 2008 13:49:16 GMT 7
Got the New Sensor catalog today and noticed the Genalex reissue Gold Lion KT77 is listed as “Coming Sprig 2008”. The bad news is price, $50.20 each. They sent an email stating the catalog prices do not reflect the devaluation of the dollar so the actual prices will be higher.
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Post by splendor on Jun 29, 2008 3:11:51 GMT 7
Saw it in www.audioasylum.com. A report or thread discussing the merits of this tube. Among the discussants was tube guru Jim Mcshane.
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Post by mossback on Jun 30, 2008 16:15:27 GMT 7
In March Jim said he would email me once he finished evaluating the new Golden Lion KT77. I will email him tonight asking what his thoughts are. I trust Jim to give his honest thoughts on tubes.
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Post by mossback on Jul 1, 2008 13:34:34 GMT 7
Quote from Jim June 30.... "I'm running them now. I can only get 10 tubes at a time, so it'll be a while before I have a large enough sample to draw many conclusions.
The build quality is super on the ones I have. They also bias slightly different than an EL34. At a given bias point the KT77s seem to have lower cathode currents.
More info ASAP!"
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Post by splendor on Jul 2, 2008 4:00:45 GMT 7
Hi Dan! Good to know Jim is trying them.
It would be interesting to hear his sound thoughts on them.
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Post by splendor on Jul 2, 2008 7:01:31 GMT 7
By the way Dan, I'm now using the Mark IVs on my LS. When was the last time you biased the IVs if you can recall? Could it be that the el34s RFTs are Siemens? I noticed angela selling a Quad under the Siemens brand, and describe it as having a "dimple" on top. So does my Svets! West and East Germany in collusion? It could well be Russsian too in Germany! I'm happy with the sound, "rich harmonics and got crunch" as Angela puts it.
It's been quite around here. Where are all the LS folks? On vacation? Hope not for long!
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Post by mossback on Jul 2, 2008 15:23:28 GMT 7
I set the bias just before bringing the amps to Cebu. The Bias resistors are new as are the whole power supply and some other stuff that I have now forgoten. I sugest you check the bias now. The caps in the PS will have settled in and there could be a small change in the bias values. Those amps should be good for many years. Yes I too have high hopes for the new Golden Lion KT77 tubes. It would be nice if they out perform the JJ KT77 and all those EL34's now made. The fact is we are lucky that there are so many nice new tubes made today. I have no idea who made those tubes. The man who sold them to me said they were "old" whatever than means. Could be East German even though the tubes are marked West Germany.
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odaey
Junior Member
Posts: 62
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Post by odaey on Jul 2, 2008 18:08:02 GMT 7
Hi guys!, Quite interesting how jim mcshane will think about the genalex gold lion kt77reissue. About 2months ago one of the jj el34's on my dyna mark 2's turned white. Could be a sign that i should consider getting a set of the genalex reissue. Though i really like the sound of jj kt77, i've been quite uneasy about the reliability issues that go with it. So far they been holding their bias on my pilot 260 and i still have a spare quartet.
lets hope the genalex re-issue turns out to be a good alternative and hope they last forever just like the originals.
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Post by mossback on Jul 2, 2008 18:33:15 GMT 7
Yes, those JJ KT77's sound darn nice but still have some quality issues. I think they are worthwhile if from a respected seller. Sorry to hear your tube lost vacuum.
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Post by splendor on Jul 2, 2008 21:52:06 GMT 7
Thanks Dan. I checked the bias and they were just a wee bit off. Higher. But they're now trimmed back to 1.56.
I read these tubes were either called Siemens or RFT and were surely German made.
Howdy Rodney! It's been quite a while. No post here, so good to know you're also considering the Genalex KT77.
I hope Dan's friend will not have us wait too long.
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odaey
Junior Member
Posts: 62
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Post by odaey on Jul 3, 2008 14:48:31 GMT 7
Hi james,
Was out of the country for a while, Did some post grad studies in sydney and melbourne and could'nt log in since the internet rates in the hotel were like $20/hr. ( i'll save the money instead to buy tubes ;D)
I kinda like the refinement of the siemens over the mullards that i have, at the moment i've pulled them out and saving them till i have the urge to hear them again.
Mossback, about the kt-77's, do you have any idea what the bias figures should be for the dynacos?
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Post by splendor on Jul 3, 2008 17:14:43 GMT 7
Re garding your question of bias, I too am wondering. I heard someone complaining about the amps being too darn humanly "hot" for comfort. Got the same question now after I read it from the HKtube club. Our dynacos should keep the 1.56v I think?
Rodney nice to hear you've got those Siemens tubes. Angela instruments sell them on ebay. I suspect the tubes I got from Dan are of the same maker, RFT whatever that means, ITT in collaboration with another German manu from East Germany in the 70s and 80s may have supplied Siemens, Gold Aero, and RFT and God knows what other labels or brand they were supplying guitar amps makers mostly.
Nicely made. Tall and slender and nicely done innards that's typical of German quality . Angela has a lot since they bought the whole supply from the factory in Germany I believe also supplying the U.S. military. 220 U.S. for a quad and they're anticipating prices to go up. I've seen the lab report comparison of this tube with all russian el34s in the market and they rate higher, so I think you're right on the "refinement" of this tube compared to mullards at half the price of a quad that closed on ebay at 400 plus U.S. a few days ago.
The Gold Lion KT 77 sells at 200 at least for a quad. Angela sells those NOS siemens at 219 U.S. I believe. Check it out before they raise the fuel on them!
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Post by mossback on Jul 4, 2008 20:59:29 GMT 7
James, your amps have a new high quality power supply section. It’s a modern design with better parts. The bias resistors (15.6 ohm) are new, look stock and are matched. I checked this carefully. The stock cathode bias is 1.56VDC with no signal this provides ~50mA. If you want longer life adjust the DC voltage down to 1.3VDC. See how it sounds. I used the JJ KT77 tubes at ~60mA. To figure currant use Ohms law… Voltage = currant X resistance R= Resistance E= Voltage I= currant You know the resistance is 15.6 you can adjust the voltage to whatever you want. Dynaco says 50mA or 1.56VDC. To give your tubes longer life set it to ~40mA. To do that is. I=E/R and is... 1.3V=.083A (two tubes) = ~40mA The JJ’s like it HOT! I ran them at 2VDC and had no issues! This was done in the MK IV's and a pair of HF 60's. Use your ears for best sound. Don’t get too low or too hot and you will be fine.
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odaey
Junior Member
Posts: 62
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Post by odaey on Jul 4, 2008 22:02:47 GMT 7
Thanks for the info Dan.
The dynaco mark 2 can take 6550 biased at 1.92vdc though I still prefer the sound with the el34's. Interesting that the kt77 is biased at 2vdc. Will try that one of these days.
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Post by splendor on Jul 5, 2008 3:30:58 GMT 7
Interesting that there should be a "sound" difference between 1.56 and 1.3? Grant mentioned that to me too and told me to "listen" for any difference. Here's my take.
I hear the Mark IVs more relaxed and "comfortable" at 1.56. A little agitated at 2 plus vdc, and a wee bit "distant" or lighter at 1.44 or lower with the same RFT tubes.
Thanks Dan for walking me through this bias settings. Those RFTs are a little forced in at higher bias since they can only take something like 380v at the plates, am I right? The KT77s are described (like) to work on higher plates which makes these babies real HOT!
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