J109
Transistor, RF, JFET, N-channel, Sym, 25V, 40mA, 15pF, SOT54,
Can the above specs 'J109' manufactured by NXP be use instead? Please see link(I do not know how to insert image).http://malaysia.rs-online.com/web/search/searchBrowseAction.html?method=searchProducts&searchTerm=626-3140&x=27&y=14#header
Alternative, can the Toshiba 2sk170 fet be used? I am able to get hold of some 2sk170.
Transistor, RF, JFET, N-channel, Sym, 25V, 40mA, 15pF, SOT54,
Can the above specs 'J109' manufactured by NXP be use instead? Please see link(I do not know how to insert image).http://malaysia.rs-online.com/web/search/searchBrowseAction.html?method=searchProducts&searchTerm=626-3140&x=27&y=14#header
Alternative, can the Toshiba 2sk170 fet be used? I am able to get hold of some 2sk170.
getting SJ109
may be this link can help to get 2sj109 BL
http://www.donberg.de/descript/2/2sj_109bl.htm
may be this link can help to get 2sj109 BL
http://www.donberg.de/descript/2/2sj_109bl.htm
An XJ with +/-24V rails and 1.8A bias per section and stereo would require about 450VA continuous so a 625VA would not be advisable. 1KVA would be the minimum I would use.
Best, Bill
Bill,
Wouldn't that actually be about 90va idling per section? I was thinking about a Plitron 300va for each monoblock JX or a single stereo J.
J109
I can't read German.🙁
Looks like NXP J109 is different and so can't be used😕..
No luck with the 2sj74 either.
I see N.Pass subs the SK170 with SK370.
I can't read German.🙁
Looks like NXP J109 is different and so can't be used😕..
No luck with the 2sj74 either.
I see N.Pass subs the SK170 with SK370.
Someone already post a source in ebay for the 2J109,
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=220474634430&ssPageName=STRK:MEWNX:IT
Or, take a look at Swap Meets and look for Spencer who has an ad for 2SK170, but he also has a limited amount of 2SJ74 matched quad for $6 a quad. 2 x 2SJ74 = 1 x 2SJ109.
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=220474634430&ssPageName=STRK:MEWNX:IT
Or, take a look at Swap Meets and look for Spencer who has an ad for 2SK170, but he also has a limited amount of 2SJ74 matched quad for $6 a quad. 2 x 2SJ74 = 1 x 2SJ109.
Et al,
I am real new to this so do not slap me to hard. Could not the entire frontend be mirrored to run off the negative rail and then use dual jfets like 389 from Linear Systems.
I might learn something here if it was explained to me why this can not be done.
Tad
I am real new to this so do not slap me to hard. Could not the entire frontend be mirrored to run off the negative rail and then use dual jfets like 389 from Linear Systems.
I might learn something here if it was explained to me why this can not be done.
Tad
Et al,
I am real new to this so do not slap me to hard. Could not the entire frontend be mirrored to run off the negative rail and then use dual jfets like 389 from Linear Systems.
I might learn something here if it was explained to me why this can not be done.
Tad
I am real new to this so do not slap me to hard. Could not the entire frontend be mirrored to run off the negative rail and then use dual jfets like 389 from Linear Systems.
I might learn something here if it was explained to me why this can not be done.
Tad
Maybe this could be usefull.
This BOM is for AJ standard version.
I've selected Vishay Dale CMF55 as 1/4W resistors.
All Mouser's parts are shown as exemple.
Let me know for mistakes. 😉
This BOM is for AJ standard version.
I've selected Vishay Dale CMF55 as 1/4W resistors.
All Mouser's parts are shown as exemple.
Let me know for mistakes. 😉
I was told by Peter Daniel that the CMF55 would only fit on the PCB if installed vertically, the CMF50 however, will fit without any issues.
I think Q1 alternative is 2sj74 and not 2sk170.
Also C1 should be a film foil capacitor, not metal film.
Thank you for the feedback, modifications done :
a) 2 x 2SJ74-BL matched = 1 x 2SJ109-BL
b) CMF55 refs shown int the BOM will fit Verticaly (1/4w)
c) CMF50 will fit horizontaly on the PCB (1/8w)
d) C1 capacitor type changes to Film Foil
a) 2 x 2SJ74-BL matched = 1 x 2SJ109-BL
b) CMF55 refs shown int the BOM will fit Verticaly (1/4w)
c) CMF50 will fit horizontaly on the PCB (1/8w)
d) C1 capacitor type changes to Film Foil
That is true but there are large current peaks in the PS that greatly exceed the average rating of the amp. If you want the PS cool and quiet 400VA would probably be the absolute minimum.
I agree with Bill. The time and effort involved in successfully building an amp is not a trivial matter. The last thing you want to do is skimp on the transformer VA rating. If the VA rating is not adequate or only marginally adequate it won't matter how much money you spend on boutique components the amp will not sound at it's best.
just curious how many of you are building the JX version over the standard version and why. Is it you need more power?
thx
thx
I am just trying to build the standard version. 8 output devices per channel seems like a lot. I don't have that kind of heatsink unless I build them as monoblocks.
But I am curious to what the advantage of the X version if you already have very efficient speakers. (I have Druids).
But I am curious to what the advantage of the X version if you already have very efficient speakers. (I have Druids).
The X amps are push-pull amps that incorporate distortion cancelling, the J is a single ended amp. Different animals that sound quite different to my ears, but YMMV.
You could always build a Mini-JX with 4 output fets instead of 8, still plenty of power.