i'm on a roll... the kgsshv

[justin]

Amb only sell to builders of their amp. I had to do the matching myself and was pretty lucky. Followed : http://www.diamondst...ching_jfet.html

guess it depends on the circuit but in gilmore's amps I match for Vgs at the current used in the circuit, rather than Idss. i found this makes more sense.

Edited October 11, 2012 by justin

[RudeWolf]

Bah, I'll just buy some from you guys at inflated prices sometime next year when I'll be ready to tackle a stat amp.

[jgazal]

I'm in for 50 2sa1486

[cobra_kai]

I'd take 50 2sa1486

It really sucks how so many of these transistors get discontinued.

I just went in for 50 pairs of matched sk170/sj74 as well. Didn't realize they were getting so rare. Hopefully I can get some decently matched quads in there

Edited October 11, 2012 by cobra_kai

[JoaMat]

^/

Edited November 12, 2015 by JoaMat

[vvs_75]

Also in for 50 x 2sa1486. thanks

[jantze]

I'm in for 50 2SA1486's as well.

[PICaudio]

I'm in for 100 2sa1486 if it's possible

-- o --

Rodrigo

[nattonrice]

I'm in on this bus, I'll take 100 of 2SA1486 if available.

[johnwmclean]

I now have my HV running 8.88 mA.

[jwzhan]

I now have my HV running 8.88 mA.

Congrats! What exactly did you change? Did you have to get a beefier transformer? IIRC your PSU was confirgured for 450V right?

[johnwmclean]

Thanks!

The transformer is a beefier 150VA model, it uses a screen and the 420 V windings are now capable of continuous current @ 250mA.

The psu is standard 450V, for the amp boards I changed R8 and 9 from 180ohm to 113ohm, simply by parallelling 300ohm over the existing 180ohm resistors which saved lifting the amp boards of the heat sinks. I was going to dabble with the third stage, but chose to leave it, I was concerned about not being able to get the boards to balance. As it is I can get both boards under 1 V, but cannot get down to the ~ 0 V where I was before, not that is matters, just worth mentioning. As for heat, there’s not much difference, runs slightly warmer overall.

Listening I found higher frequencies have opened up, sounded really good to my ears and definitely worth the effort.

[eggil]

Justin, I'd like to change my request to 100 pieces of 2sa1486 if possible. Thanks.

John: that sounds pretty interesting. Would love to compare it with the standard resistors.

[Victor Chew]

Congrats John. Any pictures of your mod to show us?

[johnwmclean]

Thanks Victor,

There’s not really much to see, however here is what I did. Either side of the LED in R8 and R9 positions the default 180ohm resistor is still in place I simply paralleled a 300ohm resistor over the top. This changes the value to 112.5ohm.

The calculation mA is derived;

1.7v - vbe junction (.7) /112.5 ohms == 8.8mA

(see Kevin’s post #1893 for detail)

Thanks Kevin and Birgir for all your help with this.

Edited October 13, 2012 by johnwmclean

[ujamerstand]

That's smart. Ganna steal that trick for later.

[Victor Chew]

Nice and clean work. What transformer did you change it to? SumR as well?

Edited October 13, 2012 by Victor Chew

[johnwmclean]

Nice and clean work. What transformer did you change it to? SumR as well?

Yes SumR.

[eggil]

Better highs wold be good for the 007 and Sigmas; would it make the 009 brighter though?

Edited October 14, 2012 by eggil

[justin]

Justin, I'd like to change my request to 100 pieces of 2sa1486 if possible. Thanks.

John: that sounds pretty interesting. Would love to compare it with the standard resistors.

i'm going to order them but the lead time is 12-14 weeks

[spritzer]

If you'd like to reach some price break then just let me know...

[guzziguy]

Justin, please put me down for 100. I may never use them, but they'll probably be a good investment in that case.

[justin]

If you'd like to reach some price break then just let me know...

they're only dropping it by 1 or 2 cents a piece, and ive already had up to 4000pcs quoted

[JoaMat]

For latest version of kgsshv PSU, what value is the current limit set to?

[wokstarr26]

Justin please count me in for 50 2sa1486.

Thanks