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Old 25th December 2010, 03:49 PM   #731
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[QUOTE=Vinylsavor;2410278]

It's a matter of personal preference and where you are willing to put the compromise. I have built it and in this case the sacrifice of ultimate treble bandwidth is where I would choose to compromise. A 26 linestage with all it's associated issues (microphonics) has nothing to do with 'HiFi specs' anyways

Agreed!
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Old 25th December 2010, 03:53 PM   #732
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Hi Pieter,

when I wrote that it has nothing to do with HiFi specs, I actually meant this in a postive way. The 26 makes a nice linestage. Even the UX201A with it's even higher rp still sounds very good in this application. My preference is the 801A

Thomas
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Old 25th December 2010, 03:56 PM   #733
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Thank you again Thomas. For the time I will use a normal volume control - I have in my stash an Alps black and a stepped attenuator - but in a later time I will try your suggestion regarding transformer volume control.
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Old 25th December 2010, 04:03 PM   #734
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Hi Thomas,

My agreement was on the "personal preference and where you are willing to put the compromise".
I like to work with good specs in mind, mostly it correlates with what sounds good to me; others are merely interested in "the sound".
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Old 2nd January 2011, 03:24 PM   #735
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Any comments or experience on how a preamp would be with, instead of the 26 tube, the 01-A (different filament, etc);
- sound quality
- availability of tubes
etc
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Old 2nd January 2011, 05:06 PM   #736
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I've listed many times to 01A compared with 26 and others. The 01A is a little more dynamic - involving but not quite as smooth overall as the 26. They are close but if pushed I'd take the 26. Nevertheless we are talking two of the best tubes at any price here, so this is still way ahead of most other tubes except for 10Y and a small number of others.

As for availability, I bought loads of both when they were cheaper. The 01A has gone up in value more than the 26, so again I'd go with the 26. What the 01A does have is a thoriated filament like the 10Y so it's pretty, plus filament requirements are easier.

Andy
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Old 2nd January 2011, 05:19 PM   #737
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Hi!

Quote:
Originally Posted by otto88 View Post
Any comments or experience on how a preamp would be with, instead of the 26 tube, the 01-A (different filament, etc);
I have built a universal linestage which can be configured to use 26, 10Y, 801A, UX112 and UX201A. This linestage was publicly demoed at last years 'Vienna Vibes' festival. A brief report can be found under this link. The part about the linestage is around the middle of the page.

http://theaudioeagle.com/columns/vienna_vibes_2010.html

My personal favorite is the 801A for it's neutral and extremely transparent sound. The 26 is a bit creamy in comparison which sounds quite pleasant, it has a bit less resolution. The UX201A is very special. It is extremely euphonic but in a positive way. It is less transparent and shaves off some rough edges in a pleasant way. Some people call it the ideal tube for blues music. It could be very beneficial with digital sources which sound a bit harsh.

Here some more pics of that linestage:

ImageShack® - Online Photo and Video Hosting
ImageShack® - Online Photo and Video Hosting
ImageShack® - Online Photo and Video Hosting
ImageShack® - Online Photo and Video Hosting
ImageShack® - Online Photo and Video Hosting
ImageShack® - Online Photo and Video Hosting

Best regards

Thomas
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Old 2nd January 2011, 06:04 PM   #738
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Andy & Thomas

Thank you both.

I have some 801A's; but Rod's supply has the option of 01A with jumper to allow a #26

But i love old blues - which sounds great via the UX-201A . .

Can you show the circuit of the universal linestage? I'd be VERY happy with the ability to swap creamy 26/ transparent 801A / bluesy UX201A

to switch tubes, how many parts need replacing ?

Last edited by otto88; 2nd January 2011 at 06:22 PM.
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Old 2nd January 2011, 06:49 PM   #739
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Thomas has got it exactly right with "euphonic" for the 01A. I'm not sure if I'd call the 26 creamy - though it does have a very lovely midrange. I'd say it was neutral, though with a little warmth, so I can see what THomas means.

One trick you could use is glow tubes. When I was discovering DHT small tubes I used to switch tubes by using a bench supply for the filaments. To change the operating point I had two sockets for glow tubes. By using a selection of two glow tubes I could get the following values for the HT in a couple of seconds.

75
85
90
105
150
180
195
210
225
240
255
255
300

Andy
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Old 2nd January 2011, 08:58 PM   #740
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Hi Andy,

Quote:
Originally Posted by andyjevans View Post
Thomas has got it exactly right with "euphonic" for the 01A. I'm not sure if I'd call the 26 creamy - though it does have a very lovely midrange. I'd say it was neutral, though with a little warmth, so I can see what THomas means.
I think we pretty much mean the same, maybe creamy was not the right word. The 26 is warmer in comparison to the 801A in the same circuit environment. A bit less transparent but very good nonetheless.

The universal linestage I built was a bit complicated to enable the usage of allt hose different tubes. I'm currently working on another DHT line which is switchable just between 26 and 801A with minimal circuit overhead.

The UX201A is quite worthwhile to try. Very special, so maybe not so well suited for general use. But it could be the right ticket in certain set ups to get a good overall balance.

Best regards

Thomas
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