Because the J27 P-channel went off stage silently, due to lack of interest.
NEC eventually sold the SIT technology, after which it dramatically changed hands a couple of times.
The NEC 2SK77 N-channel is manufactured again as 2SK77B in a Humvee SOT227 dress code.
Half a year ago, Musen to Jikken magazine featured an article on a 2nd serial manufacture K77B SIT power amp, for the moment one needs to Rap some Jap to buy these and they're not cheapo, old stock NEC K77's are more affordable.
Making the SIT power part freely available cuts the cost of the part manufacture for the SIT part owner, and may boost the popularity of SITs, similar to what Philips did with various of their junk.
As a downside, that makes it less likely that Digital do-MaiN will also chunk out a 2SJ27B P-hoenix (imo).
Some forum members paid $50USD ea. for the first batch of SemiSouth SiC parts
They are available through ZhouFang's sales thread now for somewhat less. Not PapaFETs but probably some of the best availble devices
$50 a pop sound good
If I was a bit more experienced I would realy get a few.
F5 with those sound just perfect.
So if somebody could give us a sketch I am willing to try and do the grunt work.
PS
Papa said a batch of Papa fets cost $300 K suposing a batch is 10K units
I am good for aniting up to 40.
If a batch was 1000 but do not think so I still be good for 4
GB anybody?
If I was a bit more experienced I would realy get a few.
F5 with those sound just perfect.
So if somebody could give us a sketch I am willing to try and do the grunt work.
PS
Papa said a batch of Papa fets cost $300 K suposing a batch is 10K units
I am good for aniting up to 40.
If a batch was 1000 but do not think so I still be good for 4
GB anybody?
You could simply ask instead of guessing.
My 10-week Irish lush, trained at current to smell dirty underwear.
(Harry the Cat RIP, the funny dame turned rare leukemia before her 2nd birthday)
Attachments
I'm talking about a pair like these for an F5.
VFET Sony's Rare 2SK82 and 2SJ28 (KE-33) VFET (1 Pair) | eBay
VFET Sony's Rare 2SK82 and 2SJ28 (KE-33) VFET (1 Pair) | eBay
Same Vgs class pairs look great, even cheap at $48 a matching complementary pair, imo.
Bit hefty on both Ciss and Crss number, compared to FQA and IRFP.
Real downside is that they'll require a really chunky heatsink for F5 use, if operated at regular long term die temperature. (only 95W, and not Id champs either)
Bit hefty on both Ciss and Crss number, compared to FQA and IRFP.
Real downside is that they'll require a really chunky heatsink for F5 use, if operated at regular long term die temperature. (only 95W, and not Id champs either)
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vdi_, Do you need/want some of those? Rare dose not make them good, even for F5. I have some, 4 pair I think. I just don't have a good application, I don't think.. Lets see what they go for ehh? Looks like $48/pair and there is no bids??? I did not buy the ones I have to sell, but, I could be tempted
I don't know about agreeing with you that they would make a good F5? I'm not sure we could do that without serious changes to the circuit???
I commented on the N Only SemiSouth devices because they are that good. Most realize no one makes any quality audio output devices anymore especially compliments, due to the reasons previously stated.
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flg and All,
Sorry, I left too much for interpretation. What I should have said all along is-
I think the F5 wth jfet front end and jfet outputs would be a interesting amp.
I never did look at the spec on those Vfets; just know that they are complimentary.
Let's get back to talkin' about the PASS-SIT-1. Sorry for the interruption.
V~
Sorry, I left too much for interpretation. What I should have said all along is-
I think the F5 wth jfet front end and jfet outputs would be a interesting amp.
I never did look at the spec on those Vfets; just know that they are complimentary.
Let's get back to talkin' about the PASS-SIT-1. Sorry for the interruption.
V~
Sony 2SK82 and 2SJ28
Just an information from someone, who probably knows the Sony 2SK82 and 2SJ28 V-FETs a little better than people who called them wrongly "power J-FETs" still some time ago :
These are dual die devices, which were designed for switching (Class D) operation in the Sony TA-N88B.
These actually have two 63W dies from the "linear" 2SK60 and 2SJ18 inside, but these two dies are not matched regarding Vgs off, gm and mu to each other, so in non saturated operation (linear range) most likely only one die is actually working (amplifying, dissipating), but the parasitics of the second die are always there ...
Since the maximum chip temperature is also very low (125°C), I would not give these transistors higher sustained dissipation of more than 20W even on the biggest heatsinks.
The lower Vgs ranks also beg for a high operating voltage in order to achieve significant currents, but higher voltages produce high dissipation, especially in single ended Class A, which is easily a killer.
So:
Class D: Perfect !
Complementary Class AB: OK (if you know, what you are doing)
SE-Class A: No Go !
Just an information from someone, who probably knows the Sony 2SK82 and 2SJ28 V-FETs a little better than people who called them wrongly "power J-FETs" still some time ago :
These are dual die devices, which were designed for switching (Class D) operation in the Sony TA-N88B.
These actually have two 63W dies from the "linear" 2SK60 and 2SJ18 inside, but these two dies are not matched regarding Vgs off, gm and mu to each other, so in non saturated operation (linear range) most likely only one die is actually working (amplifying, dissipating), but the parasitics of the second die are always there ...
Since the maximum chip temperature is also very low (125°C), I would not give these transistors higher sustained dissipation of more than 20W even on the biggest heatsinks.
The lower Vgs ranks also beg for a high operating voltage in order to achieve significant currents, but higher voltages produce high dissipation, especially in single ended Class A, which is easily a killer.
So:
Class D: Perfect !
Complementary Class AB: OK (if you know, what you are doing)
SE-Class A: No Go !
Our own Mike Rothacher has built some nice amplifiers SE Class A with the
2SK82. They work great, but the gain is a little low.
I have done that, and also used them with 2SJ28 in followers, where they
give quite low distortion, but they are a pain to bias.
You can build F5's with these, but the same bias issues apply, and it will
have less gain, as with the SE Class A case.
I have heard about these being multi-chip, but given the low dissipation
rating, I tend to discount it. Also, the data sheet I have calls them out as
4mm chips, which fits the 65 watt dissipation.
I have the 2SK77B's, and they work well. In a 10 watt SE Class A they give
a little less gain and about the same distortion as SIT-1's, but the input
capacitance is higher, so they are not as suitable for single-stage amplifiers.
They would be better in multi-stage, and because of their higher dissipation
figures, could be taken to higher power. I haven't gotten around to
exploring that.
By the way, they are SITs which are a particular breed of power Jfet.
2SK82. They work great, but the gain is a little low.
I have done that, and also used them with 2SJ28 in followers, where they
give quite low distortion, but they are a pain to bias.
You can build F5's with these, but the same bias issues apply, and it will
have less gain, as with the SE Class A case.
I have heard about these being multi-chip, but given the low dissipation
rating, I tend to discount it. Also, the data sheet I have calls them out as
4mm chips, which fits the 65 watt dissipation.
I have the 2SK77B's, and they work well. In a 10 watt SE Class A they give
a little less gain and about the same distortion as SIT-1's, but the input
capacitance is higher, so they are not as suitable for single-stage amplifiers.
They would be better in multi-stage, and because of their higher dissipation
figures, could be taken to higher power. I haven't gotten around to
exploring that.
By the way, they are SITs which are a particular breed of power Jfet.
Nelson,
I have to relativate my comment on Single ended Class A, I should say, they are not really feasible for OTL SE-Class A. Transformer coupled they are certainly very nice, but in this case the desired transformation ratio eats up all gain. In this case you need a separate gain device in front of them. The achievable output power is lowish anyhow ...
The Hiraga V-FET complementary Class A (originaly using NEC devices) would also be a rather feasible topology, if the bias current is not adjusted too high, or a blend out of Hiraga Class A and Hiraga "Le Monstre".
Please find enclosed a picture, which shows the two dies of an opened 2SK82.
Please also find enclosed some other small signal "Triode treasues". The 2SK79 (And 2SK63 brother) are brilliant small signal devices, which provide more gain than the power devices. Also watch the Yamaha 2SK75 mu !! The comparison to Nuvistors or E88CC is probably not so far off ...
I also appended a list with V-FET data I collected in the past. Please don't see the data to be definitive or up to date.
In my data collection the 2SK82 has a Pd of 95W, which somehow would represent a wrongly matched pair of dies or combined thermal resistances. But your 65 W are certainly also feasible. In this case the 2SK82 would be rated like one 2SK60 (which is definitely rated 63W).
Very interesting stuff are also the Hitachi V-FETs, the late (80ies) low-voltage Yamaha V-FETs and the N-SIT monsters from Tokin.
To my recent knowledge even Russian manufacturers made Si-SITs in the past.
So the SITs were here on earth all the time (beginning from perhaps late 1969 at Sony R&D), only the Audio/Hifi world forgot them in the mid 80ies ...
If you ask me: right so, this gave me the chance to build up a V-FET amp collection without too much hype related costs ...
greetings,
Mirko
I have to relativate my comment on Single ended Class A, I should say, they are not really feasible for OTL SE-Class A. Transformer coupled they are certainly very nice, but in this case the desired transformation ratio eats up all gain. In this case you need a separate gain device in front of them. The achievable output power is lowish anyhow ...
The Hiraga V-FET complementary Class A (originaly using NEC devices) would also be a rather feasible topology, if the bias current is not adjusted too high, or a blend out of Hiraga Class A and Hiraga "Le Monstre".
Please find enclosed a picture, which shows the two dies of an opened 2SK82.
Please also find enclosed some other small signal "Triode treasues". The 2SK79 (And 2SK63 brother) are brilliant small signal devices, which provide more gain than the power devices. Also watch the Yamaha 2SK75 mu !! The comparison to Nuvistors or E88CC is probably not so far off ...
I also appended a list with V-FET data I collected in the past. Please don't see the data to be definitive or up to date.
In my data collection the 2SK82 has a Pd of 95W, which somehow would represent a wrongly matched pair of dies or combined thermal resistances. But your 65 W are certainly also feasible. In this case the 2SK82 would be rated like one 2SK60 (which is definitely rated 63W).
Very interesting stuff are also the Hitachi V-FETs, the late (80ies) low-voltage Yamaha V-FETs and the N-SIT monsters from Tokin.
To my recent knowledge even Russian manufacturers made Si-SITs in the past.
So the SITs were here on earth all the time (beginning from perhaps late 1969 at Sony R&D), only the Audio/Hifi world forgot them in the mid 80ies ...
If you ask me: right so, this gave me the chance to build up a V-FET amp collection without too much hype related costs ...
greetings,
Mirko
Attachments
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