Anyone contemplating using J201s for xc phaser?

Paradox916

Well-known member
Them 2N5952 And equivalents are hard to get a hold of these days anyone give SMD subs a go like the the J201? Just curious.
 

benny_profane

Well-known member
So, they need to be matched for the effect to work properly. Unless you have a stash, it’ll be quite a gamble to buy four and expect them to work. SMD devices usually have a closer distribution, but that doesn’t help if you can’t find them. I’d suggest getting a matched set from small bear or lectric fx.


 

Paradox916

Well-known member
Damn near ever equivalent I have seen mentioned is out of stock or you are looking at around $20 bones for them I thought I would just get a bunch and learn a new skill them have extra stock.. but it’s slim pickings out there.
 

PedalPCB

Administrator
Staff member
I used four random unmatched MMBF5457's (from Tayda) for testing the XC Phase prototype. (Which explains me not catching the reversed pinout on the silkscreen)

It worked perfectly fine, in fact, surprisingly well considering I didn't bother with matching them in any way.

The phasing might be more "lush" with a matched set, I certainly won't dispute that, and maybe I got lucky, but it was good enough for rock 'n roll. 🤘:D:ROFLMAO:
 

benny_profane

Well-known member
It’s difficult to name specific part numbers because JFET manufacturing tolerances vary widely. The published Vgs(off) parameter for the 2n5457, for example, is -0.5V to 6.0V, whereas the 2n5952 is -1.3V to -3.5.

Without changing the zener diode, you’ll want devices with tightly matched Vgs values within the range of -1V or 1.5V to -3.0V.

Again you’re far more likely to get consistent batches of SMD devices than TO-92 packages.

So, take a look at the data sheets of what is available and consider that along with available stock, price, and how comfortable you are with taking the measurements. Or get a matched set and call it a day. (Or be a madman and solder whatever you’ve got in blind!)
 

Barry

Well-known member
Damn near ever equivalent I have seen mentioned is out of stock or you are looking at around $20 bones for them I thought I would just get a bunch and learn a new skill them have extra stock.. but it’s slim pickings out there.
Where you located? I may have something
 

finebyfine

Well-known member
I used four random unmatched MMBF5457's (from Tayda) for testing the XC Phase prototype. (Which explains me not catching the reversed pinout on the silkscreen)

It worked perfectly fine, in fact, surprisingly well considering I didn't bother with matching them in any way.
Last time I measured mmbf5457's with my peak I was pretty floored at how close they were, to the point that until this thread I thought I must have been misunderstanding how to match JFETs.

Without changing the zener diode, you’ll want devices with tightly matched Vgs values within the range of -1V or 1.5V to -3.0V.
Thank you so much for the info (only quoting a hair to not clog up the thread - anyone else should read the reply in full!)

Quest Components (USA based) - who I've never heard of before so I can't personally vouch one way or the other - has mmbf5457s in stock w/ a MOQ of 24 that comes out to $5, which is great deal given what the prices are listed at for places out of stock. That's about what I've paid for them before the recent price increases.
 

Barry

Well-known member
Last time I measured mmbf5457's with my peak I was pretty floored at how close they were, to the point that until this thread I thought I must have been misunderstanding how to match JFETs.


Thank you so much for the info (only quoting a hair to not clog up the thread - anyone else should read the reply in full!)

Quest Components (USA based) - who I've never heard of before so I can't personally vouch one way or the other - has mmbf5457s in stock w/ a MOQ of 24 that comes out to $5, which is great deal given what the prices are listed at for places out of stock. That's about what I've paid for them before the recent price increases.
$25 minimum order

Edit: Well it only took me 5 minutes to spend $70
 
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