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Tube Rolling 12au7, 12ax7 (Read 1515 times)
P K
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Re: Tube Rolling 12au7, 12ax7
Reply #15 - 06/22/14 at 17:26:50
 
Mark,

I made a mistake in my post.

My ZP3 is using a pair of NOS ribbed plates "12AX7" tubes with good results.

The 12AU7 tube is a RCA NOS (a $20.00 tube), again with good results.

My preamp is an Aesthetix Calypso Signature, I am using the GE 5751 blackplate triple mica tubes in the 12AX7 slot and Amperex SQ 6922 tubes.

My tweeter amp is a Mini Torii using a pair Amperex 7316 Holland Ct1-delta 9C in the 12AU7 slot and new production Valve Art 350B in the 6V6GT slot.
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« Last Edit: 06/22/14 at 17:27:51 by P K »  
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mark58
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Re: Tube Rolling 12au7, 12ax7
Reply #16 - 06/22/14 at 18:06:39
 
Peter, your gear is very different than mine so what you are hearing may be quite different but I think generalizations should still apply.  I like Black Plate 12AU7 and 12AX7 tubes...to me they seem warmer and richer in character... smooth and detailed.  I tallied up what I've spent on the 5157's I've bought recently...I was a little shocked...hehe.  Except for another pair of the Sylvania 5751s at a great price, I think I'm done buying tubes to roll in the ZP3.  I do plan on trying a mid fifties RCA 5U4G in place of the RCA 5Y3G in there currently.  Also I'll try a 1960 Tung Sol OA3 instead of a 50's RCA OA3 currently in place.

In regards to the Telfunken ribbed plate 12AX7...this is what Joe had to say...again his descriptions of the teles has discouraged me from trying them.

"Telefunken 12AX7 ribbed plates - a typical soft, unfocused 12AX7 sound with big, soft, images allied with a bright bass shy character. I was shocked when I heard these guys first hand, but the more I talked to people who knew these tubes the better I understood them. I generally associate NOS tubes with a warmer, more harmonically complex & rich sound than current production, but light and airy is the order of the day here - to the pint of brightness. The secret is that these guys are a favorite for use in a lot of old classic gear from the '50s & '60s where the transformers, wire and caps used were thick, dull sounding sonic sludge. The bright balance of this tube is great complement for this kind of gear, but drop it into current broad bandwidth tube gear (like the Thor) and you might just get sonic hell - all for just $50 to $65 a tube!"

Your original post last night has me reading through the ZP3 thread.  has anyone else reading this used 5751's in the ZP3?  If so I'd like your impressions.  Next I'll concentrate a little on input tubes...so far I've tried the stock Russian tubes, Amperex 7308's and Amperex Bugle Boy 6DJ8's...all sound different but good. PK any favorite 6922 tube types?  Keep on Rolling fellas,  Mark.
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« Last Edit: 06/22/14 at 18:09:04 by mark58 »  
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mark58
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Re: Tube Rolling 12au7, 12ax7
Reply #17 - 06/22/14 at 22:37:09
 
Peter, you don't have to try a GE Blk Pl Triple Mica 5814A...I just bought two for $35 including S&H.  I suspect they'll be similar to the RCAs, which would be good because they are much cheaper.  I'll let you know how they sound.  Mark.
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P K
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Re: Tube Rolling 12au7, 12ax7
Reply #18 - 06/28/14 at 17:15:22
 
I learned the following from Steve Deckart of Decware about the tubes for the ZP3,

The first tube slot at the front in the most important tube, it is the input tube running in stereo from one tube (I am using either a GE Triple Mica Blackplate 5751 or a Tele 12ax7 ribbed plate).

The second slot for the 12ax7 tube is the output tube.  This tube does NOT need to match the input tube, it may be an entirely different brand (this will drive me a little crazy, because I like to tube roll, and I have a bunch of single 12ax7 tubes sitting around).

I have found that each old stock mystery 12ax7 tube from my tube stash has a different sound.  I am in the process of picking the one with the lowest distortion while providing great sound.

The third slot for a 12au7 is a tube buffer and must be a 12au7 or equivalent like a 5814a . I am using a RCA Triple Mica Blackplate 5814a and a NOS Mullard Blackburn Factory branded Valvo in this slot.

     
 
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« Last Edit: 06/28/14 at 17:17:42 by P K »  
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P K
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Re: Tube Rolling 12au7, 12ax7
Reply #19 - 06/28/14 at 18:15:19
 
It looks like at the end of my testing it is NOS 12ax7 Teles at both the first 12az7 slot and the second 12ax7 slot.
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P K
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Re: Tube Rolling 12au7, 12ax7
Reply #20 - 09/01/14 at 12:37:49
 
I found a better 12au7.

Thanks to Brent Jessee.

It is a 12au7 Mazda greyplate, 1960s, made in France

From Brent Jessee:

New old stock, original and white Box. Grey plates, very similar to the very rare Mazda silver plate tubes. These are also hard to find in the USA. Excellent, 1960s vintage long lived 12AU7 types with the distinct European vintage flavor that a modern tube just cannot capture! These have the sweetness and dynamic punch typical of Mazda


Try tube rolling the 12au7, it makes a big difference in the sound.

My result:

Higher resolution and detail

Bass punch (a big difference)

Livelier
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P K
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Posts: 138
Re: Tube Rolling 12au7, 12ax7
Reply #21 - 09/07/14 at 18:09:51
 
My Current Favorites (after a lot of tube rolling):

12ax7 (first slot from front, input tube): NOS Baldwin shiny blackplate made by Ratheyon (organ tube) from Brent Jessee for $50.00.

New Old Stock in whiteboxes. These are the genuine 1950s vintage Raytheon shiny blackplates. For a short time we have a very limited special LOW PRICE on these rare tubes made for organs, some OEM repair stock with no labels. Nothing like these are likely to ever be made again, and these have the added advantage of being factory screened for use in organ audio circuits. These beauties rival the vintage European 12AX7s, and are the best bang for the buck going in a vintage USA made.



12ax7 (middle tube or second from front, for RIAA curve): NOS Telefunken from my stash



12au7 (third from front, tube buffer): NOS Mazda (French) Grey Plate (1960's) from Brent Jessee for $80.00

New old stock, original and white Box. Grey plates, very similar to the very rare Mazda silver plate tubes. These are also hard to find in the USA. Excellent, 1960s vintage long lived 12AU7 types with the distinct European vintage flavor that a modern tube just cannot capture! These have the sweetness and dynamic punch typical of Mazda
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