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Tube Rolling 12au7, 12ax7 (Read 2295 times)
P K
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Tube Rolling 12au7, 12ax7
06/07/14 at 14:23:34
 
I have found that a new old stock RCA 12au7 ($20.00) works best.

I also found a new production Tung Sol 12ax7 works best.

I even tried a Mullard 10M 12ax7 but thought the Tung Sol was about as good.

I also tried an Amperex (7316 Selected Grade early Amperex/Philips, large halo getter, original Holland made) and Mullard Blackburn 12au7, but the NOS RCA still was the best sounding.

The Amperex have replaced the Mullards in my Mini Torri (12au7), but both sound great in my Mini Torri.

Oh by the way the ZP3 is a great sounding pre-amp.
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mark58
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Re: Tube Rolling 12au7, 12ax7
Reply #1 - 06/07/14 at 15:14:41
 
PK, if you like the sound of the RCA Black plate 12AU7...I do too...you should try a RCA Triple Mica 5814A...that's my favorite so far.  In the 12AX7 spot, so far I've liked the GE Triple mica 5751s best...I've tried a pair of 1957 RCA Black plate 12AX7s and a pair of Raytheon 12AX7s there.  I have one RCA Triple mica 5751 on the way and I'm looking for another one for about $50 to try in the ZP3.  In the 12AU7 spot, I've tried more than a dozen tubes...I've lost count. Ain't this fun?  Mark.
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« Last Edit: 06/07/14 at 15:20:43 by mark58 »  
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P K
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Re: Tube Rolling 12au7, 12ax7
Reply #2 - 06/07/14 at 16:11:40
 
I just ordered a RCA triple mica for the 12au7 slot

Let me know your results on the 12ax7 slot

Peter
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mark58
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Re: Tube Rolling 12au7, 12ax7
Reply #3 - 06/07/14 at 16:30:44
 
Peter, I definitely will...I'm hoping the RCA triple mica 5751s will beat out the GEs. I'm going to send an email to a favorite seller in the past to see if she has any. What are you running for a rectifier in your ZP3...I'm using a NOS RCA 5y3g and then a NOS RCA OA3 tops it off.

Let me know what you think of the  RCA triple Mica 5814.  Copy the link of what you bought, so I can have a look. Mark.
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P K
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Re: Tube Rolling 12au7, 12ax7
Reply #4 - 06/07/14 at 16:34:55
 
My ZP3 came with a new Chinese 5u4g st.

I tried a 5y3, but it did not work, are both tubes supposed to work?

I have tried a NOS 0D3 and a 0C3, but I want back to the stock 0A3,

I  will look for a NOS 0A3
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mark58
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Re: Tube Rolling 12au7, 12ax7
Reply #5 - 06/07/14 at 17:05:35
 
Peter, the NOS OA3's are dirt cheap, buy several for back up and other Amps in the future...I use them in my newly acquired  SE84ZSM Monoblocks and my Torii MK IV. I've never tried others in this position.

Get rid of that Chinese tube...yes, the RCA 5Y3G works there and seems to be the preferred tube for that position in the opinion of many here.  It's the only one I've used besides the stock one briefly. But if you prefer, you can use a NOS RCA 5U4G...I use these in the Monos...they're nice.

I just went and looked at the owners manual...link below.  And the picture has a 5Y3GT in that spot and on page 4 they talk about the tubes.  It would appear that the ZP3 was originally voiced with the 5Y3 type rectifier but I know the 5U4 types work too.  Mark.

http://www.decware.com/newsite/ZP3%20ownersmanual.pdf
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Lon
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Re: Tube Rolling 12au7, 12ax7
Reply #6 - 06/07/14 at 17:27:53
 
PK, if you see a good deal on a NOS OB3, those are worth a listen. I used to prefer the OA3 but have been running OB3 for some time now. These seem to work differently with different rectifiers and input tubes and offer usefulness as fine-tuning tubes.
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« Last Edit: 06/07/14 at 19:22:00 by Lon »  

Decware:ERR,HR-1,ZP3,CSP2+,Torii Mk III,PS Audio PWT+DS,PowerBases,PPP,AC-12 pcs, Denon DVD-A1UDCI, Rega RP3 +TTPSU,white belt+Exact2, VooDoo Cable:Stradivarius, Ultra Linear+Evo ICs, Iso-Pods,Mapleshade:Double Heiix Plus,Samsonv2+v3 +4" platforms,Herbie's Iso-Cup
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P K
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Re: Tube Rolling 12au7, 12ax7
Reply #7 - 06/21/14 at 17:43:14
 
Current tube rolling Favorites:

12AU7 Slot:  NOS RCA 5814A BLACK  P 3 MICA S-RODS

12AX7 Slot:  NOS Telefunken 12AX7



Other 12AX7 tubes that I tried, I was surprised the Mullard 10M tubes were not the best fit:

GE 5-Star TRIPLE-MECA 5751 BLACKPLATES (second place to the Teles)

Mullard 10M Master Series Gold Pin 12AX7

New Stock Tung-Sol 12AX7


I am also trying a NOS RCA Branded Philco 5U4G
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« Last Edit: 06/22/14 at 05:22:26 by P K »  
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mark58
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Re: Tube Rolling 12au7, 12ax7
Reply #8 - 06/21/14 at 17:58:23
 
PK, that RCA Triple Mica Blk Pl 5814A is my favorite too after rolling about a dozen different tubes in the 12AU7 spot of the ZP3.

In the 12AX7 spot I've tried...

Raytheon Black Plate 12AX7s
RCA Black Plate 12AX7s
RCA Triple Mica Blk Pl 5751's
GE triple Mica Blk Pl 5751's
Sylvania Triple Mica Blk Pl 5751's

Until recently the GEs were my favorite...the RCA 5751s were then a little better, maybe a bit warmer but I put in the Sylvanias yesterday and they are by far my favorites now.  I'll have to think for a couple days before I can put the sound into words...I'm not too good with the "Audio Lingo".  All I know is I love them.  These are the ones with Blk Plates and steel pins that were made for the military or sold under the Gold Brand....NOT the Grey plate with gold pins, Gold Brand 5751 version that also is very popular and expensive.  Reading the descriptions, I thought I'd like the cheaper Black Plate/steel pin version....appears I was right. I paid about $110 plus shipping for my pair and another in the mail.  I plan on picking up another set if I see a good testing pair for less than $100. Try them...you'll like them!  Mark.

PS...I should say all of the tubes I tried sounded good in the ZP3.  You can't go wrong with any of the 12AX7 types I've used.  The RCA or Raytheon Black plate 12AX7 and the RCA Black plate 12AU7 would be an affordable and great sounding option for those on a budget.
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« Last Edit: 06/22/14 at 03:56:51 by mark58 »  
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P K
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Re: Tube Rolling 12au7, 12ax7
Reply #9 - 06/22/14 at 05:23:27
 
My RCA 5814A has just failed (after a couple of days), back to my RCA Blackplate 12au7.

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« Last Edit: 06/22/14 at 05:24:12 by P K »  
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mark58
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Re: Tube Rolling 12au7, 12ax7
Reply #10 - 06/22/14 at 13:46:08
 
That's not good.  Luckily there are a lot of good testing ones on ebay. Why don't you try a GE triple Mica Black Plate 5814A and let me know how they sound.  I've been tempted to try one, they're a bit cheaper but should be great...or buy both a GE and a RCA.  Mark.
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P K
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Re: Tube Rolling 12au7, 12ax7
Reply #11 - 06/22/14 at 14:50:37
 
Did you ever try a NOS Telefunken 12au7?

It is very good (the Mullard 10M did not sound right in the phono preamp}

It seems tubes in the RIAA portion of the ZP3 have a dramatic impact on the sound (more than any other tube rolling that I have been involved in).

I might try the Sylvania 5751, but in my system the lower output of the 5751 tube does not sound as good as the 12ax7 (the 5751 allows for more background noise, the 12ax7 approach dead silence).

I have experienced a problem with some tubes that create hum at around 1000 hz and below, I wonder if this characteristic  is considered a noisy tube or just a tube that creates hum.  

The next tubes I will try will be Platinum Grade.
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« Last Edit: 06/22/14 at 14:52:09 by P K »  
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mark58
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Re: Tube Rolling 12au7, 12ax7
Reply #12 - 06/22/14 at 15:33:51
 
Yes Peter,  I have found the 12AU7 spot to have a sometimes dramatic effect on the sound of the ZP3.  Plus, since you only need one tube, it was easy and relatively inexpensive to try a lot of them...Mullard, Amperex, RCA, Mazda, GE...are manufactures I've tried with multiple variants. Only recently have I started experimenting with the 12AX7 spot.  These tubes are more expensive.

I always thought the 5751 were quieter with less microphony because of the reduced gain factor of 70 and thick triple mica construction with added support rods.  I just read the below...

"The gain factor of a tube simply measures how much it amplifies the input signal.  For example, the common 12AX7 tube has a gain factor of 100, while a 5751 tube (which is often used in place of a 12AX7) has a gain factor of 70. This means that if you plug a 5751 into a socket that expects a 12AX7, the pre-amp will have about 30% less gain. Not only will this make the amp quieter, but it can also alter the sound by making the power section work harder when you turn it up. Many guitar amp users (particularly harmonica players) like to reduce the gain to get a different sound or calm the amp down to prevent feedback."

What Amp are you using and do you use a preamp? Also you need to use a shielded cable between the Amp/Preamp and ZP3...in every other position I use the Decware DSR 1 meter interconnects. In my Torii I once used 5Y3GT rectifiers when I had trouble with intermittent distortion.  Once I changed to a 5U4 type, almost all distortion was gone.  With my revealing system, I've found I now hear the faults of the original recordings more often.

I've never tried Telfunkens anywhere.  When I've read the descriptions, I've been led to believe they would be Brighter/Hotter than the Black Plates I like.  Anyway,  let us know what you do.  Mark.
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« Last Edit: 06/22/14 at 15:37:44 by mark58 »  
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mark58
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Re: Tube Rolling 12au7, 12ax7
Reply #13 - 06/22/14 at 16:07:34
 
Peter,  Have you read "Joe's Tube Lore".  I'll give the link below.  As you read, remember that he was probably using a different pre amp and gear than you.  Also his tastes may be different than your's. So don't exclude a tube solely because he didn't like or list it. With those caveats, I've found his post from the late 90's to be very helpful.  Unfortunately,  I also think his views have been partly responsible for many of his favored tubes dramatically increasing in cost since he revealed his lists.

I went back and read what he said about Telfunken and Mullard 12AU7 type tubes...I copied it below.  This is why I haven't tried one.  I have tried a Mullard CV 4003 from Upscale Audio...I liked it, just not better than my favorite Black Plate types made by RCA. It's worth reading his lengthy thread.  Mark.

"Now shifting back to the present, the only other comments I might add relate to the obvious "what about the Mullard rib plates & legendary Telefunkens?" question. Well frankly there wasn't much to say. IMHO these are two of the most overrated brands in the NOS universe. generally speaking all the Telefunken 12A family tubes I've heard ('X7s, 'T7s, 'U7s) are a bit bright, thin and airy sounding. I've talked to Charlie Kittleson at Vacuum Tube Valley about this and he basically agreed, observing that these guys more or less built their reputation on their use by the old gear crowd. Why? Well his comment was that the caps, resistors & transformers in old gear were dark sounding sludge and the Teles offered a useful brightening of the sound to a more natural balance. The issue, of course, is that when you put them in a contemporary design with much wider bandwidth and a more neutral '90s kind of balance things can go over the top.

Now before any Tele lovers who find them ideal in their new gear freak out and tell me how wonderful they sound - I believe it. There is a system out there somewhere that's the ideal match for any tube. This is just a comment on a general tendency. Now Mullards are another matter. I have found a few that sound quite nice and they generally are warmer than Teles, but in my rig they never quite make it to the top of the heap."

http://www.audioasylum.com/scripts/d.pl?audio/faq/joes-tubes.html
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« Last Edit: 06/22/14 at 16:09:24 by mark58 »  
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mark58
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Re: Tube Rolling 12au7, 12ax7
Reply #14 - 06/22/14 at 16:41:17
 
Peter,  more on the 5751 tube...

From Audiotubes.com

"5751: This version was usually the one made for the US military. These have a lower gain than the 12AX7, but are otherwise totally compatible. Great hi-fi tubes, as the lower gain reduces noise and microphonics. These are all ruggedized and most can withstand a drop on the floor. The internal triode elements are matched as well. The early versions are more sought after as they usually have extra support rods and an extra mica spacer on top of the plate structure ("Triple Mica"), as well as blackplates, all said to contribute to low microphonics. Don't overlook the greyplate versions, they are also excellent tubes, and many of these have the triple mica as well. The GE non-military version is usually the "five star" series, intended for broadcast use. The RCA broadcast type is the "Command" series. Both the RCA and GE broadcast types are scarce, as are any of the triple mica types."

"...the Sylvania 5751 variants are very balanced and pleasant to listen to for hours. The GE blackplate 5751 triple mica is also in great demand as a very musical vintage tube. The RCA 5751 is more like the Mullard, with a rich warmth and wide bandwidth. Currently, the USA made tubes are a nice surprise with their low prices as compared to the European types."
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