Hello Brendon
Not to much progress, weekend weather fantastic. Spend it riding my bike all over the city. 17 degrees, unheard of in late november.
I think my HS worries are over for the moment. My next concern is matching mosfets. I believe at one time Nelson Pass sold matched pairs, no longer the case. Anyone out there aware of a source for matched pairs.
Gustavo
Not to much progress, weekend weather fantastic. Spend it riding my bike all over the city. 17 degrees, unheard of in late november.
I think my HS worries are over for the moment. My next concern is matching mosfets. I believe at one time Nelson Pass sold matched pairs, no longer the case. Anyone out there aware of a source for matched pairs.
Gustavo
Just buy more than you need....and match them....
although I WILL (within a day or two) have some spare matched IRF9610's and IRFP240's left over from my own matching exercises....
If you really want pre-matched ones I can probably work out a deal there.
although I WILL (within a day or two) have some spare matched IRF9610's and IRFP240's left over from my own matching exercises....
If you really want pre-matched ones I can probably work out a deal there.
Matching FETs
Gustavo,
Matching mosfets is very time consuming (more time than matching 1% resistors). When I ordered the FETs for my BLS pre-amp I also ordered a batch of IRFP-240 (for another SoZ project at my other home in Canada and of course.. for back-up).
For the 4 channel pre-amp, I ordered 30 IRF610 and most of them matched - even found quad set matches.
You have my e-mail so let me know if you need any.
re: jduncan
IRF9610 are P-Chan devices. I assume they're not for the BLS pre-amp project? Only 1 IRF9610 mosfet is required in the pre-amp which goes in the power supply board.
Gustavo,
Matching mosfets is very time consuming (more time than matching 1% resistors). When I ordered the FETs for my BLS pre-amp I also ordered a batch of IRFP-240 (for another SoZ project at my other home in Canada and of course.. for back-up).
For the 4 channel pre-amp, I ordered 30 IRF610 and most of them matched - even found quad set matches.
You have my e-mail so let me know if you need any.
re: jduncan
IRF9610 are P-Chan devices. I assume they're not for the BLS pre-amp project? Only 1 IRF9610 mosfet is required in the pre-amp which goes in the power supply board.
super_bq:
No, I'm using the IRF9610's as the input differential pair in my Aleph 4.
But again, if anyone wants to buy pre-matched sets of these I've got a few of both IRF9610's and IRFP240's sitting around.
No, I'm using the IRF9610's as the input differential pair in my Aleph 4.
But again, if anyone wants to buy pre-matched sets of these I've got a few of both IRF9610's and IRFP240's sitting around.
matched mosfets
Guys, if you have extra matched mosfets, I'm more than wiling to take them off your hands. Save me a bit of grief and money trying to do it myself.
Guys, if you have extra matched mosfets, I'm more than wiling to take them off your hands. Save me a bit of grief and money trying to do it myself.
OK, after taking out the mosfets I want myself, I now have these additional IRFP240's available...of course I'd prefer it if someone wants to take most/all of them but just contact me anyway.
Vgs
4.29
4.27
4.38
4.33
4.42
4.30
4.38
4.32
4.30
4.27
4.34
4.32
4.36
4.29
4.18
4.28
4.40
4.29
4.14
4.27
4.28
4.16
4.14
4.39
4.41
4.37
From an initial purchase of 50, I took the 24 which were between 4.20 and 4.26.
Cheers,
Joseph
Vgs
4.29
4.27
4.38
4.33
4.42
4.30
4.38
4.32
4.30
4.27
4.34
4.32
4.36
4.29
4.18
4.28
4.40
4.29
4.14
4.27
4.28
4.16
4.14
4.39
4.41
4.37
From an initial purchase of 50, I took the 24 which were between 4.20 and 4.26.
Cheers,
Joseph
need them matched pairs
I need to buy some irf 240 or 244 matched pairs
Minimum of 2 pr. but 4 would give me some back-ups
I'm making a SOZ
Anyone still have some from their Pass projects? I guess I'm too lazy or overwhelmed to want to match 'em.
Actually I'm just in a big hurry to hear these amps!
Thanks,
Mark
I need to buy some irf 240 or 244 matched pairs
Minimum of 2 pr. but 4 would give me some back-ups
I'm making a SOZ
Anyone still have some from their Pass projects? I guess I'm too lazy or overwhelmed to want to match 'em.
Actually I'm just in a big hurry to hear these amps!
Thanks,
Mark
Mark, it might be fun testing out the arrangement as seen on Fig.16 of the Zen Lightenment article. saves you the trouble of having to find the ( elusive? ) matched pair.
Borbely Audio
www.borbelyaudio.com sells mosfets and he will match them. I don't think he sells IRF but he has toshiba and I think Hitachi. He also sells some nice kits😀
www.borbelyaudio.com sells mosfets and he will match them. I don't think he sells IRF but he has toshiba and I think Hitachi. He also sells some nice kits😀
Easy and not time consuming
Matching FET's as per NP's instructions is easy, not time consuming. I did my 200 devices (4 types) in about 2 hours including setup.
Number the devices (with a small sticky label or a marker).
Put the results into Excel or other spreadsheet
Sort by Vgs (at appropriate current).
Make a cell with difference between Vgs lines.
Use the odd ones as current sources?
This is unlikely to cost you much more than buying pre-matched ino the exact quantity that you need.
Petter
Matching FET's as per NP's instructions is easy, not time consuming. I did my 200 devices (4 types) in about 2 hours including setup.
Number the devices (with a small sticky label or a marker).
Put the results into Excel or other spreadsheet
Sort by Vgs (at appropriate current).
Make a cell with difference between Vgs lines.
Use the odd ones as current sources?
This is unlikely to cost you much more than buying pre-matched ino the exact quantity that you need.
Petter
Two variations on Petter's suggestions:
1) I use Whiteout to paint one surface (usually the side or top) of the transistor, then write on it with a pen. If you want to remove the label later, just scratch it off with your fingernail.
2) Out of spec transistors can go into delay/mute relay circuits.
Grey
1) I use Whiteout to paint one surface (usually the side or top) of the transistor, then write on it with a pen. If you want to remove the label later, just scratch it off with your fingernail.
2) Out of spec transistors can go into delay/mute relay circuits.
Grey
matching
Dudes, I just mark a sheet of paper with the numbers, set the fets in piles on the matching sheet, then bag them in numbered antistatic bags in groups. You may need a little more space, but it's fast.
Dudes, I just mark a sheet of paper with the numbers, set the fets in piles on the matching sheet, then bag them in numbered antistatic bags in groups. You may need a little more space, but it's fast.
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