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Post by chetz on Oct 27, 2010 16:55:44 GMT -7
Or did the Dr. put these 7189s in because they were the best of the EL84/7129/6BQ5 type?
It would sure open up some options in the voltages were at 300V and you could run a good EL84. No to worry, I'm not going to jack with amp but I am curious.
Thanks, Jeff
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Post by stratovarius on Oct 27, 2010 17:17:51 GMT -7
I was under the impression that he chose those because he managed to find a big cache of them. If you are going to use NOS tubes, then you don't want to wind up sawing off the branch you are sitting on!
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Post by Scott on Oct 30, 2010 1:55:31 GMT -7
I would like to know the answer to this question too. Will the Z-Wreck run on EL84's too, or only 7129's?Thanks!!
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Post by markT on Oct 30, 2010 4:05:41 GMT -7
Will the Z-Wreck run on EL84's too, or only 7129's?Thanks!! Yes...the tube complement label inside my Z Wreck only says EL84...also on the website: "Output Tubes 4 -7189 (EL84) Cathode Biased " The 7189 is a military grade EL84. Just a sturdier tube with higher manufacturing tolerances.
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Post by Scott on Oct 30, 2010 4:11:27 GMT -7
Sweet. That tells me that the amp was actually designed to be an EL84 amp. Amps designed to be for 7189's, would have 100 volts or more going to the Power Tubes that an EL84 couldn't deal with. This is the smarter move, as 7189's wont be around forever... I now believe these are the rules on the 7189.The difference with pinouts between the 7189A and the 7189 are all the same except that the 7189A has:Pin 1 is connected internally to Pin 2 (grid) Pin 6 is connected internally to Pin 9 (screen)In the Maz Jr's case, YES, a 7189 will work fine as a replacement for an EL84.A 7189A would usually work in an EL84 amp too, but a 7189 might not work in an amp designed for 7189A. There is one way a 7189A wouldn't work in an EL84 amp. If somebody was using pins 1 or 6 as a solder point for a resistor. Some amps will use pins 1 or 6 to get more point to point going. (Fender comes to mind). Will a 7189A work in my EL84 Amp? Unknown for sure, but probably... The Tube Socket would have to be examined to verify that pins 1 and 6 were not in use. Also, you can't use an EL84 in place of a 7189, in an amp designed for 7189's. 7189's have 400V on the screen and plate, and the 7189A has even more at 440. The EL84/6BQ5 can only handle 300 volts, so they couldn't happily exist in an amp looking to send them an extra 100 volts or more.It's putting EL84's into an amp designed for 7189's that you may get into difficulty because of the higher voltages. A 7189 will run down to the same voltages as an EL84, but an EL84 won't run up to the same voltages possible as when using a 7189. I would think NOS 7189's running in an EL84 Amp, would last a long time as far as Power Tubes normally go... They are running way below their max voltage, and they are high quality tubes.
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Post by chetz on Oct 30, 2010 9:23:49 GMT -7
Will the Z-Wreck run on EL84's too, or only 7129's?Thanks!! Yes...the tube complement label inside my Z Wreck only says EL84...also on the website: "Output Tubes 4 -7189 (EL84) Cathode Biased " The 7189 is a military grade EL84. Just a sturdier tube with higher manufacturing tolerances. Not so fast MarkT, the biggest difference is the 7189s handle 400V, the EL84s do 300V. Put some EL84s in something that was designed for 7189s and you fry some tubes quickly. Interesting the labeling, I wish the Dr. would clear this up......Pretty Please!
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Post by benttop (Steve) on Oct 30, 2010 9:47:27 GMT -7
Just because the maximum plate voltage is stated as 400 volts doesn't mean you have to design the circuit that way. The Doc's web site says 7189(EL84) which means you can use either, which means the plate voltage is safe for either tube.
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Post by chetz on Oct 30, 2010 10:32:04 GMT -7
Thanks Steve! I just wanted to make sure, I understand the circuit design but not necessarily having to be at 400V even if 7189s are used. The parenthesis caused me to balk......it would be much easier and less confusing to say 7189 or EL84. Or use 7189/EL 84.
Thanks again!
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Post by basementhack on Oct 30, 2010 10:32:23 GMT -7
Yes...the tube complement label inside my Z Wreck only says EL84...also on the website: "Output Tubes 4 -7189 (EL84) Cathode Biased " The 7189 is a military grade EL84. Just a sturdier tube with higher manufacturing tolerances. Not so fast MarkT, the biggest difference is the 7189s handle 400V, the EL84s do 300V. Put some EL84s in something that was designed for 7189s and you fry some tubes quickly. Interesting the labeling, I wish the Dr. would clear this up......Pretty Please! The 'Wreck is likely not a 7189 circuit. Actually, the NOS tubes Doc mentions are actualy NOS Russion 6P14P-EV tubes. I bought some of these relabelled tubes on Friday from the Tube Store. This 7189 tube is rated for higher power and plate voltage plus longer life making it a premium upgrade for amps with tough operating conditions. The solid construction and heavy glass also minimize microphonics. For the hifi crowd, this tube is the perfect choice for Scott, Eico and Fisher amps.
Our Preferred Series 7189 starts life as a NOS (New Old Stock) Russian 6P14P-EV as translated from Cyrillic. It is a military build that meets or exceeds the 7189 specifications.
6P14P = 6BQ5, EL84 and 7189 tubes. E = Extended or long life (>5,000 hours) V = Mechanically ruggedized for low microphonics and reliabilitySo, even though this tube will handle higher plate voltages, there is also the benefit of extended life and great build (lower microphonics). I think this is why they are in the 'Wreck. As well, it's what the Z site allude to... Dr Z has acquired a massive amount of NOS Russian 6P14P-EV 7189 (EL84) tubes to use in the Z Wreck. These output tubes were chosen because of their superior sonic qualities and excellent life span.I would think that if the tubes were used becuase they handled the excessive plate voltages in the amp, that would have been one of the points mentioned in the blurb on the Z Wreck page. But I could be wrong It would be good to make sure Keith
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Post by Scott on Oct 30, 2010 12:53:45 GMT -7
I agree...
I think the proper way to think about the Z-Wreck is: It is an EL84 based amp, with some high end NOS tubes installed for your first usage.
After the initial power tubes ware out, I would expect to see numerous EL84 tubes installed by users.
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