[Jazz59]

Thank you for the update Justin. I hope there will be no problem and the time will not longer. 
 
Jazz59 

 

 

[preproman]

Looks like your in for record breaking times.  This current batch really did get ready fast.  Comparing it to the first shipment of the GS-X mk2s.

 

[magiccabbage]

I'm excited for you guys!

 

[justin w.]

Matching day 1

 

[cwtim01]

Are these 2SK170s BL grade or V grade?

 

[justin w.]

BL 2SK170 and 2SJ74

 

[BeyerMonster]

  maybe all the $ signs in the email triggered the spam filter

This probably makes you guys want to laugh and cry at the same time.

 

[Cante Ista]

  also emailed your gmail account

Got it! It was in my spam folder. Thank you!

 

[Cante Ista]

Are these 2SK170s BL grade or V grade?

What's the difference?

 

[justin w.]

nothing in this application. BL grade parts have an IDss of 6-12mA, V grade from 10-20mA
 
The parts in this amplifier are run at 1mA so IDss isn't an important spec. Matching of V grade parts could be more difficult due to the wider possible range of IDss, but i havent tested to know.
 
I paid about 40 cents each for these parts nearly a decade ago, and today they can command up to $5 each. Inferior new replacements are going for $8 each limit 5 per person. If i had more, I'd be in the obsolete parts selling business instead of the amplifier building business.

 

[David1961]

While IMO the GS-Xmk2 is a remarkable amp, I've recently sold the one I had because I was hardly using it, my BHSE is to blame for that.

 

[GloryUprising]

nothing in this application. BL grade parts have an IDss of 6-12mA, V grade from 10-20mA

The parts in this amplifier are run at 1mA so IDss isn't an important spec. Matching of V grade parts could be more difficult due to the wider possible range of IDss, but i havent tested to know.

I paid about 40 cents each for these parts nearly a decade ago, and today they can command up to $5 each. Inferior new replacements are going for $8 each limit 5 per person. If i had more, I'd be in the obsolete parts selling business instead of the amplifier building business.

A decade ago?!?!

Damn Justin I didn't know you've been in business so long!

 

[cwtim01]

What's the difference?

 
Justin already explained it, I recently purchased a matched quad of BL 2SK170/SJ74 and it cost me USD35. V grades are practically "unobtainium" in the market and only people who acquired them years ago will have them, V grade's higher Idss and transconductance will give an advantage in SQ for certain applications.
 
These JFETs are often found in the Nelson Pass (founder of Pass Labs and First Watt) designs and used as frontend input device, and are very popular in the DIY community.

 

[Crashem]

   
Justin already explained it, I recently purchased a matched quad of BL 2SK170/SJ74 and it cost me USD35. V grades are practically "unobtainium" in the market and only people who acquired them years ago will have them, V grade's higher Idss and transconductance will give an advantage in SQ for certain applications.
 
These JFETs are often found in the Nelson Pass (founder of Pass Labs and First Watt) designs and used as frontend input device, and are very popular in the DIY community.

 
Aren't V grade only used in high current applications of which GS-X does not need?
 
Btw, Nelson Pass is like a DIYer on steroids.  Love what he is doing with his First Watt company as he is still doing essentially DIY on the side even though he is the founder of Pass Labs.  Shows his love of the field.

 

[preproman]

I'm looking at the Pass Labs INT-30 for my next HE-6 and to replace my First Watt F1J.