Well.....My F4 is under way.
Santa brought me matched triplets of 240/9240's all the way from Israel.
He also brought me some 74V/170V's from Hong Kong I hope they are genuine.
My question is on the trimmer pots; how do you know they are oriented properly for clockwise gain in Ω?
Also I ordered TO-92 heatsinks just for kicks; should I thermally couple the 74 & 170?
Santa brought me matched triplets of 240/9240's all the way from Israel.
He also brought me some 74V/170V's from Hong Kong I hope they are genuine.
My question is on the trimmer pots; how do you know they are oriented properly for clockwise gain in Ω?
Also I ordered TO-92 heatsinks just for kicks; should I thermally couple the 74 & 170?
Attachments
I was just thinking...
...I wonder if Einric is gonna start a build-thread for his new F4 ?
Mmmm...?
Oh well...need not wonder, any longer !
Hi Einric !
I hope you didn't get your 2SJ74's from where I did !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Cheers.
Si.
If you didn't; tell me where you did...
...I could do with some genuine-product !
...I wonder if Einric is gonna start a build-thread for his new F4 ?
Mmmm...?
Oh well...need not wonder, any longer !
Hi Einric !
I hope you didn't get your 2SJ74's from where I did !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Cheers.
Si.
If you didn't; tell me where you did...
...I could do with some genuine-product !
I have no nine volts but I do have a AA 8-pack holder with leads.
I figured I could run the circuit off of that with the LM371 to lower the voltage.
I have a second AA 8-pack holder that I could use also.
I heard it was best to try matching transistors while at their working voltage.
So.....I was just throwing that out there.
I figured I could run the circuit off of that with the LM371 to lower the voltage.
I have a second AA 8-pack holder that I could use also.
I heard it was best to try matching transistors while at their working voltage.
So.....I was just throwing that out there.
Last edited:
Hi Einric
Thanks for the tip on where you got the 74's from.
I dunno if you have a camera that can do this, but...
...is it possible to see a close-up of the 74's.
Mine were undoubtedly fakes !!! ( different supplier ).
25% were 'out of spec.' ( for what they were pretending to be ).
On inspection with an eye-glass...
...the front-flat-face, had been finely-sanded...
...& remarked with a laser !
Not a bad job; compared to some I've seen on the sites 'fake transistor hall-of-fame page'.
But OBVIOUS, never the less.
Have a look at yours Einric...
...if the front-face, is 'plastic-shinny' & printed, NOT pitted ( laser )...
...you prob. got good 'uns !
Cheers.
Si.
Happy New Year dude !
Thanks for the tip on where you got the 74's from.
I dunno if you have a camera that can do this, but...
...is it possible to see a close-up of the 74's.
Mine were undoubtedly fakes !!! ( different supplier ).
25% were 'out of spec.' ( for what they were pretending to be ).
On inspection with an eye-glass...
...the front-flat-face, had been finely-sanded...
...& remarked with a laser !
Not a bad job; compared to some I've seen on the sites 'fake transistor hall-of-fame page'.
But OBVIOUS, never the less.
Have a look at yours Einric...
...if the front-face, is 'plastic-shinny' & printed, NOT pitted ( laser )...
...you prob. got good 'uns !
Cheers.
Si.
Happy New Year dude !
So I guess the next step may be testing these to the rated voltage of the 74&170.
I'm kinda IRKED right now.
At this point I think I'm just going to get my de-soldering stuff out and remove these JFET's.
I don't even want to risk firing this thing up with my known genuine output FET's.
I'm kinda IRKED right now.
At this point I think I'm just going to get my de-soldering stuff out and remove these JFET's.
I don't even want to risk firing this thing up with my known genuine output FET's.
Last edited:
I wouldn't try to check the "rated voltage" of your jfets. Just check the Idss with a 9V battery, or your 12V AA pack, whatever. The main thing is just to see what you've got. If you need genuine jfets, try Spencer or seller "alweit" on ebay.
oh, just remembered Mouser has more 2SK170's in stock right now (BL's): http://www.mouser.com/ProductDetail...=sGAEpiMZZMsCAa3STv8uCYUtR2s0T0G1CCKMDb1ds9w=
so grab those while you can
oh, just remembered Mouser has more 2SK170's in stock right now (BL's): http://www.mouser.com/ProductDetail...=sGAEpiMZZMsCAa3STv8uCYUtR2s0T0G1CCKMDb1ds9w=
so grab those while you can
Last edited:
Alweit is where I got my matched output FET's from.
He was an absolute pleasure to work with.
It appears that he only has GR parts, is it possible to cascode input FET's with some jumpers on the F4?
Maybe we should start a Sticky Thread on reputable suppliers for obsolete parts.
He was an absolute pleasure to work with.
It appears that he only has GR parts, is it possible to cascode input FET's with some jumpers on the F4?
Maybe we should start a Sticky Thread on reputable suppliers for obsolete parts.
Last edited:
Just checked my jfets from Spencer and they are printed. I have dealt with him before and he supplies well matched devices just ask for what idss you need and he will let you know what he has before you order.
Store | FET Audio
Store | FET Audio
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.