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Old 2nd January 2011, 09:28 PM   #741
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Hi guys,

You are discussing differences in sound between 01A, 26, 801 a.s.o.
But as these are all used in SE mode we know how important the influence of the power supply is.
Are the differences between these tubes so clear that no matter of which type of power supply is used the typical character of these tubes always comes out? And then we are not talking about the impact of all passive components apart from power supply capacitors for instance.
In other words, by choosing particular types of resistors, capacitors, chokes, transformers a.s.o. could not you tune for instance the sound of a 801A more in the direction of a 26?
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Old 2nd January 2011, 09:50 PM   #742
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Hmmm - there are always variables when switching between things. In my preamp breadboard I just switched the glow tubes for the HT and used the same bench supply at different voltage settings, so the PSU was basically the same.

I think originally I tried resistor loading on the plate and cathode - can't remember if the values changed. In that setup I really liked the 26 against the 01A and 10Y. I tried and discarded active plate loads and LED bias for the cathode. I tried an anode choke for the 26 and 01A and that was very good, so listened to the 26 like that for a while. Thanks to Thomas I converted to filament bias and that was a big step forward in sound.

I then got a Hammond 126C SE transformer, 10K:10K. Inductance wasn't enough for the 26 at 106H, and this is where the 10Y just streaked ahead. It sounded wonderful and I still have this front end. I then went over to a choke input filament supply and it sounded even better. I just got Rod's boards and want to try those after the choke - should be excellent.

So that was the journey. I have Lundahl LL1660/5mA which are perfect for the 26 so that might make a recovery and challenge the 10Y at some point, but the 10Y into the Hammond 126C is a tough act to beat - they just sound lovely together.

Andy
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Old 2nd January 2011, 11:54 PM   #743
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Hi Thomas

When you are ready, would you publish the switchable 26 and 801A circuit?
I see at the Audio Eagle reference to a kit for the 801A power amp; might there be one for the 26/ 801A pre-amp?

Thank you
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Old 3rd January 2011, 12:10 AM   #744
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Andy,

That' s what I meant, so many variables, and it seems that most of us pay so much attention to the tube because that's what we see and like. Tubes with their soft or bright glow, not to speak of the blue or purple glowing VR tubes....
The same seems to be the case with loudspeakers; we see the speaker, not the room acoustics..
Well this was more of a philosophical expression, but what I think is important is to keep an eye and ear on the whole thing, and not to focus on one particular subject while taking other things for granted.
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Old 3rd January 2011, 12:13 AM   #745
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Hi!

Quote:
Originally Posted by otto88 View Post
When you are ready, would you publish the switchable 26 and 801A circuit?
I see at the Audio Eagle reference to a kit for the 801A power amp; might there be one for the 26/ 801A pre-amp?

All my designs are availble either assembled or as kits. I plan to publish the circuit. I just created a new blog site. I will use this to share my circuits. Nothing there yet, but stay tuned:

VinylSavor

Best regards

Thomas
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Old 3rd January 2011, 12:28 AM   #746
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Thanks Thomas I’ll keep up with your blog via Google connect.

I guess there will be a lot of iron in the 26 and 801A circuit? . . What approx cost might we expect?
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Old 3rd January 2011, 09:41 AM   #747
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Hi!

Quote:
Originally Posted by otto88 View Post
I guess there will be a lot of iron in the 26 and 801A circuit? . . What approx cost might we expect?
Yes, as in most of my designs there is a lot of iron
But People can also get a partial kit, for example if they want to use their own filament supply instead of my LCL approach with two chokes per tube.

As for cost we can exchange that per email.

Best regards

Thomas
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Old 3rd January 2011, 01:26 PM   #748
Magz is offline Magz  United States
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Quote:
Originally Posted by andyjevans View Post
Hmmm - there are always variables when switching between things. In my preamp breadboard I just switched the glow tubes for the HT and used the same bench supply at different voltage settings, so the PSU was basically the same.

I think originally I tried resistor loading on the plate and cathode - can't remember if the values changed. In that setup I really liked the 26 against the 01A and 10Y. I tried and discarded active plate loads and LED bias for the cathode. I tried an anode choke for the 26 and 01A and that was very good, so listened to the 26 like that for a while. Thanks to Thomas I converted to filament bias and that was a big step forward in sound.

I then got a Hammond 126C SE transformer, 10K:10K. Inductance wasn't enough for the 26 at 106H, and this is where the 10Y just streaked ahead. It sounded wonderful and I still have this front end. I then went over to a choke input filament supply and it sounded even better. I just got Rod's boards and want to try those after the choke - should be excellent.

So that was the journey. I have Lundahl LL1660/5mA which are perfect for the 26 so that might make a recovery and challenge the 10Y at some point, but the 10Y into the Hammond 126C is a tough act to beat - they just sound lovely together.

Andy
Hi Andy,

May I ask why you discarded active plate loads and LED bias? I have gone that route with my 2C22 preamp and the improvement over resistors is HUGE. I find the background to be much quieter, the bass to be stronger and the treble and mids to be clearer - the treble just floats in the room, in fact. I use a cascoded IXYS 10M45s CCS at 175V and 14.6mA on the plate and SiC Shottky diodes (3.4V bias) on the cathode for bias.

Did you get a different effect with your system?
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Old 3rd January 2011, 01:53 PM   #749
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Folks,
For those of you using the 26 and 01A interchangeably in this preamp, is there a common op point point shared by both of these tubes?
Happy new year,
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Old 3rd January 2011, 02:34 PM   #750
E.T. is offline E.T.  United States
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Quote:
Originally Posted by andyjevans View Post
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.

Andy
Since we're talking tube types, has anyone compared the sound of #26 with 3a5. AIUI, #26 is a rather finicky little thoroubred that's not easy to design around. But the 3a5 is said to have a 'liquid sound,' and whatever that is, I think I want it! I also haven't been able to find the 26 online. Are they scarce?

***The difference between theory and practice is that in theory there is no difference between theory and practice, whereas in practice there is.***
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