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Post by Paul (TRANE) on Jun 5, 2006 11:23:00 GMT -7
I am looking at going with some NOS EL-34 tubes for my 6545 head. Some of the NOS tubes should not be used in amps with plate voltages over 450V. Now I know that the 6545 is designed to go from 440V to 480V (depending on rectifier choice). My question is with the GZ34/5AR4 tube rectifier in use will I have any issue using these tubes? Most of the plate voltages I have seen on 6545s have not been as high as 440V. Any thoughts and advice would be greatly appreciated.
Thanks,
Paul
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Post by johnnyl on Jun 5, 2006 14:45:27 GMT -7
I had very good luck with the Winged C Svets (SED) when I had my SRZ65 and it was running at about 470 volts. I never had any trouble with them. As far as NOS, you're taking more of a gamble I would think. I was looking at several different kinds (Siemens, Tesla, a few others) and I was warned about their reliablilty at that high of a plate voltage. Maybe Myles or Mike can chime in with some ideas as well. I really did like the sound of the SED's though. They won't break the bank either.
johnny
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Post by Paul (TRANE) on Jun 5, 2006 15:22:45 GMT -7
Johnnyl,
Thanks for the comments. I have heard really good things on the SED EL34s. Actually, I just got off email with the Dr and he said I should have no issues as long as I have a 5AR4 rectifier in the amp. At 34mA I should be right around 450V. So looks like I should be good to go.
Thaks again. So did you selll your SRZ?
Paul
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Post by prowler on Jun 5, 2006 18:33:17 GMT -7
I would stick with NOS for everything BUT your power tubes. Most of us don't play an amp like the 6545 loud enough for you to really notice the difference nor warrant the expense. You get more bang for your buck with NOS preamp tubes & rectifiers. I played my SRZ with the gain full up & the volume at 3 O'clock once. The only reason it was up that loud was because I wanted to hear what it sounded like The SRZ sounded amazing but man was it LOUD... too loud.
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Post by Paul (TRANE) on Jun 5, 2006 18:52:52 GMT -7
Prowler,
Very true. However, I actually run the amp pretty hot volume wise. The lowest I have the volume on Either the KT-45 or SRZ-65 is 1 O'clock. I really like having the volume up. Seems like that is where the tone really starts to bloom. At 1 O'clock I can get that good edge of breakup sound and clean it up with the guitar volume and changes in attack. I will let you know what kind of diffrence I hear. My usual settings are Volume 1 O'Clock and Gain at 12 Noon.
Thanks for the inputs,
Paul
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Post by prowler on Jun 5, 2006 20:36:17 GMT -7
Let us know how you like it.
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Post by cementman on Jun 6, 2006 6:50:15 GMT -7
hey maybe myles will read this, or someone more experienced than i. i bought a quad of GE mullard el34s from a fellow on the weber board who went deaf,, sad deal, and i also have a pair of mullard xf2's i picked up a few years ago along the way. i geuss i am saving them for some rainy day ,,, i have the groove tube e34ls (same as jj's but matched differently i think) in the 6545 matched at 33 ma, along with a sag 12ax7. the amp sounds sublime. what would i bias these NOS tubes if were to put them in,,, 33 ma? ...i did put the xf2's in a kt45 i had a few years ago without biasing and they sounded so quiet and perfect it was scary,, i put them back in the box... but i never have used them in the 6545... gerald weber has some dvds all about tube amps, very pricey, anyone have any other sources of studying this stuff out?
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Post by prowler on Jun 6, 2006 8:00:10 GMT -7
what would i bias these NOS tubes if were to put them in,,, 33 ma? I use the following formulas to figure out my bias. Lets assume for both of these formulas that your EL34 tubes are 25 watt tubes & that your plate voltage is 435 volts. 60% Max Plate Dissipation: (tube wattage * 600) / Plate Voltage = Bias current in mA 25*600 = 15000 / 435 = 34.48 mA 65% Max Plate Dissipation: (tube wattage * 650) / Plate Voltage = Bias current in mA 25*650 = 16250 / 435 = 37.35 mA So if your amp has a plate voltage of 435 volts & you are using 25 watt EL34's you should set your bias between 34-37 mA. The key is knowing what the plate voltage of your amp is.
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Post by myles on Jun 6, 2006 8:19:38 GMT -7
For one of the folks here ....
I replied back to your direct email on your two picks.
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Post by Paul (TRANE) on Jun 6, 2006 9:03:23 GMT -7
Wow!! Thanks for all the advice and tips. I am looking forward to trying out the tubes. I chose the NOS Siemens EL-34s from KCA. Mike and Myles have been truly great with all my questions and such. It is really great to have folks like this in the forum, especially folks with as much knowledge as Mike and Myles have. Plus, compared to a lot of other forums the folks here actually seem to care about helping others. Thanks again and I will let you know how it all goes.
Paul
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Post by myles on Jun 7, 2006 9:56:36 GMT -7
Wow!! Thanks for all the advice and tips. I am looking forward to trying out the tubes. I chose the NOS Siemens EL-34s from KCA. Mike and Myles have been truly great with all my questions and such. It is really great to have folks like this in the forum, especially folks with as much knowledge as Mike and Myles have. Plus, compared to a lot of other forums the folks here actually seem to care about helping others. Thanks again and I will let you know how it all goes. Paul Paul, Happy playing
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