XC Phase - where to get matched quad 2N5952 JFETs?

[mkstewartesq]

Title really says it all. Seems like everyone is out of stock (apart from buying them individually from Tayda but I really have no way (either in knowledge or equipment) of testing a batch to try to find four that are close in value. I’ve tried various of the usual suspects sites like Stompboxparts and Smallbear. Any ideas or suggestions?

Thank you.
Mike

 

[jimilee]

Title really says it all. Seems like everyone is out of stock (apart from buying them individually from Tayda but I really have no way (either in knowledge or equipment) of testing a batch to try to find four that are close in value. I’ve tried various of the usual suspects sites like Stompboxparts and Smallbear. Any ideas or suggestions?

Thank you.
Mike

Did you try guitarpcb.com?

 

[mkstewartesq]

I did. They are out as well (also, it looks like they were significantly more expensive than, say, Smallbear, for a matched set – but if that’s the only game in town, that’s the only game in town. But none available anyhow).

 

[Guardians of the analog]

Matched smd sets can be bought from lectric-fx and aion

 

[mkstewartesq]

Matched smd sets can be bought from lectric-fx and aion

Aion doesn’t have the 2n5952 - their only quad matched sets are the 2SK208-GR. I’ll have to look at lectric-FX, I’ve not heard of them before. Thanks

EDIT - no bueno at lectrric-fx. Only 2N5457.

 

[Guardians of the analog]

Aion doesn’t have the 2n5952 - their only quad matched sets are the 2SK208-GR. I’ll have to look at lectric-FX, I’ve not heard of them before. Thanks

2n5952 are obsolete and haven't been made in years. 2n5457 is the equivalent of 5952 with a reverse pinout. Lectric-fx sells matched quads of 5457.

 

[Locrian99]

2n5952 are obsolete and haven't been made in years. 2n5457 is the equivalent of 5952 with a reverse pinout. Lectric-fx sells matched quads of 5457.

I used 57’s in mine and worked great.

 

[Harry Klippton]

Matched smd sets can be bought from lectric-fx and aion

I wish you told me about this this morning

 

[Betty Wont]

I can’t say how your results would be with the XC phase but I’ve had nothing but good success using 4 smd 5457 (or whatever) taken off the strip in order, for any fet phasers. They have pretty tight tolerances these days. Most through-hole fet sorting these days is re-sorting something that was likely sorted, but not cataloged, once before.

 

[Deperduci]

aye, last 2 fet based phasers, I just got few dozen smd on adapter boards from Aion and used the simple matcher circuit on most diy forums, likely not the 'right' results but anything within 5% was made a group and IF, and I did find, some were within 1 point(752,753.. etc) it's what I used and they work fine. Just turn them around/about until the pins match.

 

[mkstewartesq]

Thank you all. Still evaluating my options- whether to go with the 5457s from Lectri-Fox or wiait for the others to come back into stock at GPCB. Luckily for me, this build is several pedals down the road, so I have some time.

 

[owlexifry]

here ya go:

2N5952 matched transistors :: Transistors (matched, selected) :: Semiconductors :: Electronic Parts :: Banzai Music GmbH

i bought these and they're great

 

[mkstewartesq]

here ya go:

2N5952 matched transistors :: Transistors (matched, selected) :: Semiconductors :: Electronic Parts :: Banzai Music GmbH

i bought these and they're great

Thank you, I just ordered these.

 

[darwin999]

Just updating this for people that arrive at this old post through search.

Obviously, one popular use of matched 2N5952's is for a phaser. I stumbled upon the following useful information in Aion FX's build docs for their Apex (MXR Phase 45) and Zenith (MXR Phase 90) phasers, so I thought I'd share some selected excerpts here.

• Most TO-92 through-hole JFETs have been discontinued, and of the few that are still active, none are very well-suited to the Phase 45 / Phase 90 circuits. There are still plenty of SMD types available, though. The Toshiba 2SK208-GR and Fairchild/ONSemi MMBF5485 (2N5485) are great choices, though matching can be difficult due to the SMD's small size.
• For the MXR Phase 90 phaser, the JFETs in the four phase stages must be matched for the phasing effect to occur. The JFETs are used as variable resistors controlled by the gate voltage. When used as soft switches, the gate voltage changes make the source-drain channel resistance switch between very low ("on"), in the hundreds of ohms, and very high ("off"), in the megaohms. However, for soft switches, the exact “on” and “off” resistance is not important. But for the case of phasers, we need a set of JFETs that have nearly the same channel resistance when the same gate voltage is applied. This way, all four of the phase-shift stages will respond the same way to the LFO voltage.
• This means that for phasers, the JFETs must be measured and sorted. Historically, most manufacturers graded JFETs according to their VGS(off) parameter, the voltage at which the channel resistance is highest, also called pinch-off voltage. However, some luminaries in the DIY scene suggest that it’s better to match phaser JFETs to their VGS(10k) parameter, the voltage at which the channel resistance is 10k - which is within the normal operating range of a phaser. This leads to better matching, since the correlation between VGS(off) and VGS(10k) isn’t always exact.
• The most straightforward way of measuring JFETs is to use an electronic component tester such as the Peak Atlas DCA75. This will give you all of the standard datasheet parameters of a particular JFET, including VGS(off). These testers won’t give you the VGS(10k) value, but it’s very simple to breadboard a circuit that can test either the OFF value or the 10k value.
• How well matched do they have to be? Aion measured the stock FETs on an MXR Phase 90 and found VGS(10k) to be matched to within 0.09V, although Aion recommends matching to within 0.05V for better results.

Note that for those that can't or don't want to do their own matching, Aion sells highly-matched 2SK208-GR FETs - which are "typically matched to within ~0.01V of each other" [for VGS(10k)], which is impressive. They look to be a good value, especially compared to matched NOS 2N5952's at today's prices.

• https://aionfx.com/component/2sk208-gr-matched-set/

Here's the links to read more, as Kevin go through the issues in additional detail.

• https://aionfx.com/app/files/docs/zenith_documentation.pdf
• https://aionfx.com/app/files/docs/apex_documentation.pdf