Wampler jfet sorter

[MAO]

Hope this helps save some time for those of you frustrated with properly biasing Wampler clones and working with smds...

After reading this post from Induction, and this one on DIY regarding Wampler designs, I've ditched the trimmers and have gone back to using the original drain resistor values.

And based on this suggestion by lars-musik, I built a stripped down version to sort through my smd J201s.



I used a 2P4T rotary to select drain resistor values 5.6k ('65), 15k (plexi), 16k ('57) and 22k ('57 & Pinnacle). Of course the rotary switch isn't necessary, just a convenience.  

Probably should have socketed at least 1 of the resistors and the source resistor to easily accommodate other designs, such as the Sovereign (27k drain and 2k2 source)

I used a row of 5 SIP IC sockets with 24 gauge wire to make standoffs to mount the smd converter board and a post for an alligator clip for the black multimeter probe.  I cut the gate and source posts short and left the drain post long to accommodate an alligator clip for the red meter probe. (one of the SIP sockets isn't used, just there to keep the entire row sturdy)

The smd converter board and the SIP sockets make a nice little platform to test the smds. I used the side of my needle nose pliers to temporarily hold the little buggers in place. Took a few times to get the hang off it.

It took about 2 hours to sort through 100+ SMDs looking for drain voltages between 4.5 and 5v with the various drain resistors. Found multiple candidates for all but the 5k6. (black '65 - ordered another 100 smds from Newark to see if I get any hits with the 5k6)

I randomly picked 3 of the sorted "15k" J201s, soldered them to their own adapter boards and popped them into my latest plexi drive. All 3 read between 4.5v and 5.0v in the pedal. Whew!

Now I'm set for a few more Wampler builds.

Parts
2P4T mini rotary (I can spare a couple of these if anyone is interested as I have 14 of them)
smd adapter board
SIP Sockets
and the little buggers

posts for allgator clips

hook up clips and meter

place smd in position

hold smd in place while taking reading and adjusting switch









   

[MAO]

So I received another 100 smd J201s from Newark Electronics, they all read fairly consistant between 4.5v and 6.4v with a 22k drain resistor.

I ended up with another dozen or so biased in between 4.5v and 5.0v with the 22k drain resistor, none biased in with anything smaller.

Good news is it took about an hour to check another 120 SMDs.

Looks like I'm set for the '57 and Pinnacle, but not the '65 or Plexi.

[strassercaster]

cool layout. I have several questions.

1 for the pinnacle did you match all 6 jfets the first 4 or last 2?

2 once you found the proper biasing jfets did you test them using the rg jfet matcher to see what the working jfets measured in those terms?

3 the links for the smd adapter socket converter and are  dead links now could you repost please

4 would you be interested in selling or trading any sets for the pinnacle or plexi? I thought you were looking for the vtl5c3/2 vactrols i have about a 8 i would be willing to part with for a couple sets.Or cash your call

5 did you ever get lucky with the 65? this is on the wish list for me as well,

Jfets are a pain have been a few disappointing builds for me. my pinnacle isnt that good i think i ended up at 15k and 12 k so its way off and squeals with gain past 2 oclock and at 12 with boost engaged. i have similar issue with the mercury box. ihave bought hundred of jfets 20 at a time from everywhere small bear mammoth tayda ebay aliexpress to name a few almost all are between .18 and .50 on the vgs . very low spec what a disappointing waste of time and money

[MAO]

Hey Strass, nice to hear from you. Hope all is well.

1. just those that had drain resisters. I think it's the last 2.  

2. sorry, I did not, but will be glad to do so next time.

3. hmm, not sure why. I'll check it out.

4. trade sounds great! Let me know how many you'd like. And would you like them mounted on smd adapters? I think I need 3 of the vtl5c3/2 though. But I'll send you some anyway.  

5. I only had one set of 4 that biased properly! I may have a single one left over, waiting on 3 more...

Let me know if you want me to measure the vgs on any or all sets before sending.

[MAO]

For the SMD boards, try this main oshpark link and search for J201.

There are a bunch of them listed.

https://oshpark.com/shared_projects

[strassercaster]

Cool well. im afraid all my jfets are rubbish from hell. I have spent over 100 bucks and not a single jfet shows over .40 vgs on my tester and using the rg method up to .60 where they should read much higher.

my new  email is [e-mail] email me your home address and ill send out the vactrols By Thursday . How many do you want? I think I have 8 total. I dont pay that much for them locally but they go for about 18 each on ebay so if you want more than 3 I have no problem and you can keep or sell them for you time and helping me. :-)

I would like anything you can spare for a pinnacle and plexi . if you could send a couple converter boards to get me going that would be cool. I am making your  tester layout this weekend. I am going to order some mmbfj201 from aliexpress they take a month to arrive  . its 10 bucks for 50 with shipping. I figure ill spread my Biz around as well maybe ill score some that work for the pinnacle or the 65 . dif batches may be the key since they seem to be similar with in the runs . maybe we can help each other out ha ha.

If you have the 2 that work for the pinnacle with sockets i can check the RG measurements i am dying to find out what it actually is or even if thes rg method  can be counted on as a way of measuring for the Wampler stuff  . it would be nice to be able to buy sets of these like for a phase 90 but the sets i bought for the phase 90 weren't all that accurately matched when i tested them with the RG method and hence the 2 phase 90's i made aren't as good as my real mxrs .However I did just get some seemingly decent 2n5952 from small bear but they were all below 2.39 which is in the so so on the chart 2.5-2.6 is optimal . I am wondering if small bear cherry picked for the prematched sets they sell and sell off remainders  SIGH ha ha

[strassercaster]

well correction I just bought 90 for 9.27 on aliexpress with shipping .

[MAO]

Buying from multiple reputable sources and at different times is a good idea.

My experience has been most readings fall within a 1.5v-2.0v window within every batch I have purchased.

The range itself has varied between sources and timing.

The last batch of 100 I purchased from Mouser read between 6.0v and 7.5v with a 15k resistor, none were withing range for a proper Plexi build.  

But this last batch of 100 I purchased from Newark, most read between 3.7v and 5.5v with a 15k drain resistor. 10 of those were between 4.6v and 5.1v with a 9.25v source, and should work well in the Plexi. A few more were just outside the optimal range, but may still work well.

Crazy Brian has taken the time to sort these J201s and find good use for multiple pedals. Maybe at one point early on he figured what am I going to do with all these that are outside the targeted range, and then developed the Plexi, '57, '65. Sovereign and Pinnacle to make use of the wide tolerances...

Wonder if he has the "power" to request J201s within his specifications?  

[Muadzin]

strassercaster wrote

well correction I just bought 90 for 9.27 on aliexpress with shipping .

Do I read this correctly? Are you buying actual through hole J201 transistors? From places like aliexpress?

While I think there might still be some genuine J201's out there, by en large you're far more likely to get fakes. Especially when you buy from anyone in China. My rule of thumb with uobtainium parts is, if the deal sounds too good to be true, it almost always is. Going SMD J201's is the only really reliable method left out there.

[strassercaster]

The only fakes I have ever got were off ebay and I got a full refund all three times. The aliexpress jfets were in the ballpark with  other jfets batches  I have purchased from other sources for 3-6  times the money so yes I loaded up. If I get fakes its very easy to get a full refund on aliexpress. The only issue I have ever had with aliexpress is 3 out of 288 orders never arrived and one of those orders eventually showed up at 6 months I was already refunded and contacted the seller to send him money. He gave a discount off original price because of the extended time and I paid him in full. Ill let you know how it turns out.

 I have  60 jefets that I already tested from 3 aliexpress seller 3 orders of 20pcs. they had about the same percentage as MAO test results with the sot23 mmbfj201 jfets . In fact half of the good 57 jfets were from one batch of 20 thats a fantastic  ratio .Ill keep you posted in about 24 days when they arrive how it works out for me.  So far not a single issue . I have had good luck with lots of stuff on aliexpress and they have great pricing better than anyone on a lot of things. I get  all my op amps there now tl072 opamps are 68 cents for 10 free shipping. They test exactly the same on my mk168 as the tayda small bear and mammoth op amps.they have awesome deals on just about any opamp we builders use. The enclosed jacks exactly like tayda kind they sell for 48 cents I got 250 for 75 bucks.

The stuff is so cheap its worth the risk and its not even a risk imo I havent got jipped yet off aliexpress. If you look at the stores most have a huge inventory and are well diversified not like an average joe or wang  on ebay.  

I was skeptical at first too but it so cheap for everything I had to try and it works for me . I have had better much better success there than ebay. My jip rate on ebay has been about 4 percent across the board. ali its been one bad order out of 288. I have bought op amps tc4053,cd4013,cd4049,op2134,ad712,jrc455b,lm13600,lm13700, and several dozen other chips at hald the cost of Tayda even. resistors are 59 cents for 100 with shipping , sockets are 2 cents each with shipping,Caps are half price compared to tayda when you buy 100pcs. Anyway Ill let you know if I got jipped I am sure eventually I will and Ill get a refund anyway .

[strassercaster]

ok well i was checking out the 57 build . How many of the 22k transistors will i need ?it looks like q2 3 4 5 6 need to bias with the 22k and only q 1 for the 16K?. Man thats a bummer if so I cant make a good one I guess . I was thinking i had several sets for the 57 now i have about another 15 jfets that are useless ha ha. well i have about 200 on the way hopefully I can load up and make a 57 and another pinnacle . After watching the 65 and 57 videos i want to make a 57

I also made a mercury box that has never been all that great . i biased what i had but i feel its lacking. it also has a 22k bias resistor . this could get very expensive and time consuming ha ha. it feels good to finally get the pinnacle sounding great. I put mine in a 125b and the footswitches are to close for me so ill probably make it again with a 1590bbm and try not shielding every wire since i think the squealling was from the jfets

[MAO]

edit: The '57 needs 4 jfets for the two 22k drain resisters and 1 jfet for the 16k. The last jfet's drain is tied to the source voltage.  

I seem to recall there is an incorrect resistor value in the '57 layout on the main site, the 1k resistor at the gain pot lug 3 should be 10k. Might want to socket that one.  

[MAO]

Corrected my last reply: Referring to the original layout on the main site, Q6 is not biased with a drain resistor, that drain is connected directly to the filtered source voltage.

So you need Q2,Q3,Q4 and Q5 biased with the two 22k resistors. Q2 & Q3 are in parallel and share a single 22k drain resistor. And Q4 & Q5 share their own drain resistor.

Q1 is biased with a 16k resistor.

I'm not sure what effect having the jfets in parallel has regarding the drain resistors, meaning will a single jfet properly biased with a 22k also bias correctly when used in parallel with another (22k biased) jfet?

Haven't checked that out yet, let me know if you do.      

[strassercaster]

Thanks Mike I appreciate it. I started the artwork and box for the Plexi Drive last night. I figure I should make a couple of these since I got the Jfets for it. I bought another 120 j201 to-92 jfets last night and I bought 60 bbmfj201's so I have a total of over 380 to-92 jfets coming for just under 50 bucks and 90 smd j201 for 9.27 with shipping   . I really need to get a batch thats loaded for the 22k resistors . Ill keep you posted at this point the 65 isnt on my list I like it though but prefer the 57 if I get some that work for the 65 Your in.

[Tesla]

Really amazing idea!  I only have 2P6T rotary switches right now but the second I get some 2P4T this willl save me a lot of time🙂. I’ll customize the resistor values for the BE100 and 5150 lll Pedals I’m doing but it’s perfect

[MAO]

The switch isn't really necessary, just a convenience when sorting through a hundred or so.

The last time I sorted a bunch, i added a 25k pot between a 5k1 resistor and the 9v supply and used the pot to dial in the resistance to get me 4.5vs. I used a switch to kill the supply and place the meter leads across the pot and 5k1 to get the total resistance. Then sorted the jfets by the nearest resistor value. So if I ended up with 16,7k, that one went into the 17k pile.

This way I wasn't limited to the "wampler" drain resister values when sorting.

Hope that makes sense.

[Tesla]

I’m on that right now lol. Thank you very much for the tips🙂