F5 power amplifier

Ex-Moderator R.I.P.
Joined 2005
ok, lets do it

title suggestion

Your F5 parts

reason, I would like it to be based on what kind of parts are being used
would be nice with pictures too

then I think questions comes natural
but the foundation should be members showing what kind of components are being used
even simple resistors
 
Member
Joined 2009
Paid Member
I await your listening comments. You'll love it!

Russellc

You're not wrong Russell. I've been listening for a week now and I really like this amp. I was expecting a big difference after using an Aleph 5 for the last few years what with the lower gain but its only a couple of clicks on the volume control and the lower power still goes plenty loud enough to elicit a " turn it down" response from my wife.
 
Member
Joined 2003
Paid Member
You're not wrong Russell. I've been listening for a week now and I really like this amp. I was expecting a big difference after using an Aleph 5 for the last few years what with the lower gain but its only a couple of clicks on the volume control and the lower power still goes plenty loud enough to elicit a " turn it down" response from my wife.

I would love to do an Aleph, very nice. Yes, a couple more clicks usually does it. Something bothered me at first about the limited absolute volume (with B-1 anyway) but if "absolute" volume is louder than you need (which it is) whats the trouble? Plus, it sounds great. Glad you like it, I've yet to see an unenthusiastic response on the F-5.

Russellc
 
Hey folks, sad news: I just had for the first time a faked 2SJ74BL in my hand.

Sad to see that now also these are faked, although there must be plenty of genuine stock available.

The parts I got all had the batch code 7C, had matte faces that looked like the original marking on its face was removed with acid. All parts had an IDSS far above the usual values for BLs, about 20mA.

I didn't have time so far to test for transconductance, but I would expect a low transconductance part anyway.

Beware, I got mine from a usually very trustfull supplier from Europe, not from some doubtfull source from far away.

So take care, Hannes
 
> there must be plenty of genuine stock available.

Then you know something that I don't.

ZhouFang couldn't get any at an affordable price. My German suppliers ran out. My Japanese supplier is rationing them 10 pieces max per person. If you can still find a few thousands of them for less than 1USD, I am the first one who wants to know.

Of course we can all wait for Linear Systems for their LSK74s, like we did for the last 4 years or so ?


Patrick
 
Ooops!

I would never have imagined that the distributor pipelines would run dry so quickly, this part was in full production until a few years ago. The decline has gone even faster than for the silicon tubes 2SK389/2SJ109, crazy.

Hannes

Maybe a lot of people of hoarding them. I can't imagine that many have been used in products and diy projects. I also don't understand why Toshiba discontinued them when there's a demand for them. You'd think they'd have a replacement that's even better.
 
Hey folks, sad news: I just had for the first time a faked 2SJ74BL in my hand.

Sad to see that now also these are faked, although there must be plenty of genuine stock available.

The parts I got all had the batch code 7C, had matte faces that looked like the original marking on its face was removed with acid. All parts had an IDSS far above the usual values for BLs, about 20mA.

I didn't have time so far to test for transconductance, but I would expect a low transconductance part anyway.

Beware, I got mine from a usually very trustfull supplier from Europe, not from some doubtfull source from far away.

So take care, Hannes
Could you post some pics, so we would be "trained" to identify them?

Thanks in advance, regards
 
How many million jFETs can be produced if the production line is moved to jFETs for one day?
What special procedures need to be on line for that run? How often will that run need to be repeated?
Can we adjust our production methods so that we can cheaply do a 2hr run for the jFET that is coming out?

**** this, we can make more money producing switching mosFETs