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Old 2nd August 2008, 01:57 PM   #391
Tea-Bag is offline Tea-Bag  United States
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Default Salas Pre

It may sounds better, but will be hard to make it look as cool.
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Old 2nd August 2008, 02:27 PM   #392
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Default Re: Salas Pre

Quote:
Originally posted by mithomas
It may sounds better.............

hardly ..........
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Old 2nd August 2008, 02:39 PM   #393
Salas is offline Salas  Greece
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Its a bit difficult to sound better than a single stage SE open loop 5W idling, common cathode triode with valve rectified and FET regulated B+. The JFets are solid state low voltage pentode imitators and a follower means 100% local feedback. Plus I have done JFet circuits before and they are better than op amps but play second fiddle to good tube circuits in general.
My intention is a general use wee box with excellent value. I like making little clever things. Having a good reference I can evaluate its merits more correctly. That is one of the reasons I want it sans caps.

Does anybody know if 2N5459 gives a sonic penalty VS 2SK170 at 3VP-P CD level and no gain? It is a very available, cheap JFET that bunches very well for Idss by 10 pieces sample.
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Old 2nd August 2008, 02:57 PM   #394
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Quote:
Originally posted by salas
.......
Does anybody know if 2N5459 gives a sonic penalty VS 2SK170 at 3VP-P CD level and no gain? It is a very available, cheap JFET that bunches very well for Idss by 10 pieces sample.

I think that you'll probably will not hear difference , once when you find sweet spot for 5459
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Old 2nd August 2008, 03:27 PM   #395
Salas is offline Salas  Greece
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OK I will try it.
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Old 3rd August 2008, 09:25 PM   #396
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Quote:
Originally posted by salas
OK I will try it.
Have you tried it?
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Old 3rd August 2008, 09:29 PM   #397
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I will very soon. If it succeeds, you will see squarewaves, offset info, sonic evaluation, schematic, perfboard pic, and comparison to tube sound.
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Old 4th August 2008, 03:30 AM   #398
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I'm putting together my parts list for the B1. Re: the Diode D2... There is no number so I guess this would be any LED any color rated at 2 to 2.5 volts and plugged into the pc board? Mouser shows "Fairchild J109" as a cross refrence match for 2sk370. This number is in stock and a dozen cost $3.24. will the Fairchild J109 work for the B1 application?
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Old 4th August 2008, 06:59 PM   #399
ElFishi is offline ElFishi  Europe
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Hello, another n00b here

The B1 looks simple enough that I would consider building it as an input buffer for my TA2024 based amp.

Questions are now:

1) I run the amp from a single-rail 16.5V SMPS. Will this be enough to also drive the B1?

2) The TA2024 has 2.2 uF MKT input coupling caps, a 20k input resistor and a DC null circuit as depicted in the schematic on p.11 of the datasheet

http://pdf1.alldatasheet.com/datashe...H/TA2024C.html
(see also attachment)

I guess it doesn't make an awful lot of sense to have this input in series with the 10uF output caps of the B1.
How can I best adapt the output of the B1 for this intended use?


Thanks for any advice
Attached Images
File Type: jpg dc null.jpg (19.9 KB, 2007 views)
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Old 4th August 2008, 08:28 PM   #400
Salas is offline Salas  Greece
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Quote:
Originally posted by Tolu


Have you tried it?
Your vote please!

I managed to discover another 9 pieces 2SK170BL. I have a couple of good matches now. What do you prefer me to make and test? The 2N5459 symmetric supply B1 spin off, or a 2SK170BL one?
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