[Jupiter]

I'm having some trouble measuring the IDSS of the JFETs for my META42 following tangent's instructions at http://www.tangentsoft.net/audio/meta42/tweaks.html
I don't understand the part about "apply a voltage through a milliammeter". Could I use my digital multimeter for this? And how should this breadboard be set up?

 

[tangent]

I just rewrote that section of the site for clarity. Let me know if it's clear enough now; thanks.

 

[Jupiter]

Your new section is much clearer and should be detailed enough for newbies such as myself. I tried it and I got values in the correct range. Thanks tangent!

 

[zbuddah]

It is Definitely clearer, so I should be looking for one with a low IDSS value and pairing that one up with a slightly higher IDSS values, I should go back and test mine

. The larger the IDSS difference between Q1/Q2 the less current it will draw right?
By the way that extra resistor on R8 or R9 really makes the amp dead silent at full volume with no source. Darn I wish I had a mini-mini cable, then I could listen to some music rather than dead silence. Gonna go buy one in the morning.

 

[tangent]

I don't know about Q2 being "slightly" higher -- it just needs to be higher. It probably shouldn't be too close to Q1's Idss value. I'd put 1 mA or more of difference between them, given a choice.

On R8/R9, I haven't needed it myself to get silence at full volume. But then, I favor high-Z phones.

 

[zbuddah]

Quote:

Originally posted by tangent On R8/R9, I haven't needed it myself to get silence at full volume. But then, I favor high-Z phones.

Heh yeah I can't really hear the hiss with my HD-600's but you know... I tried the amp with my crappy low ohm (16ohm?) ear buds first just in case it were to blow up on me

. Heard some hiss with the crappy earbuds and I just decided to put it in. Dead silence afterwards with the crappy earbuds.

Gonna go out to get me mini-mini cable now!