Waaah. Phase 45 not phasing

PCS · June 08, 2005, 01:51:56 PM

I verified the JFET pinout with my DMM and tried all possible combinations. The 2N5458's from SmallBear are in standard pinout TO-92 cases.

Fret Wire · June 08, 2005, 01:59:32 PM

If you tried them in all postions, then that eliminates the pinout question. Most all jfets use a TO-92 case, that means nothing in regards to identifying pinouts. There is no standard pinout when it comes to jfets. Even the same manufacturer will switch around the drain, source, and gate on the same part #.

After you try some jfets known to be in the right range, it will narrow your problem down.

PCS · June 08, 2005, 02:06:55 PM

Okay. What I meant was that with the flat side facing me, the left to right was DSG as I have typically seen.

Paul Marossy · June 08, 2005, 02:29:55 PM

Some JFETs have the gate in the middle - DGS...

PCS · June 08, 2005, 02:39:23 PM

If I understood RG correctly, the Gate would be the pin which is resistive in one direction and not in the other, while the Drain and Source are resistive both ways. Using that method, mine are DSG. But, I tried other ways.

Paul Marossy · June 08, 2005, 02:49:59 PM

The surest way to confirm the pinouts is to look at the data sheet for your actual JFETs. Although, if you did as RG directed, then that's another story...

PCS · June 08, 2005, 02:53:49 PM

I haven't the foggiest as to how to get a datasheet. The trannies are from SmallBear, and they came in a little baggie. :?

Paul Marossy · June 08, 2005, 02:56:47 PM

Do a search on Google.com for your FETs. For example, if you had 2N5457s, you would type in "2N5457 data sheet". You'll most likely get a manufacturer's data sheet on the first page of the results. If it's an old, obsolete type, it may not show up.

fikri · June 08, 2005, 03:21:08 PM

Hi guys, I have been planning to make my own phaser too, what do you think about the layout of phase 90 from tonepad ? is it fully working ? and i see that matching JFET is a kind of headache too ! what is the best way to match them ?

Fret Wire · June 08, 2005, 03:29:41 PM

Quote from: PCSI haven't the foggiest as to how to get a datasheet. The trannies are from SmallBear, and they came in a little baggie. :?

Do they have any writing on them denoting the manufacturer? They should. You'd probably have to use a magnifying glass to read some of them.

PCS · June 08, 2005, 03:32:52 PM

They have a stylized F on them, as well as B411. I'm assuming they are Fairchild Semiconductor products, and their datasheet confirms the DSG pinout.

Fret Wire · June 08, 2005, 04:01:12 PM

The stylized "F" is Fairchild, correct on the pinout. You've eliminated pinout as a problem.

Have you inspected the solder side of the board with a magnifying glass to make sure you haven't bridged any of the solder strips together. Even a sliver strand of copper or solder will cause a problem. Especially around the IC's, which are easy to bridge the traces together. Maybe I'd also double check the trace cuts. There is something like 28 spots where you have to cut the strip trace.

Paul Marossy · June 08, 2005, 04:20:34 PM

Quotewhat do you think about the layout of phase 90 from tonepad ? is it fully working ? and i see that matching JFET is a kind of headache too ! what is the best way to match them ?

I've built the tonepad version, and it works great. For matching JFETS, check out www.geofex.com

PCS · June 20, 2005, 12:43:30 PM

Well, I got tungngruv's FET's, and it still doesn't phase. :evil: :evil: But many thanks to tungngruv. I'm at a loss as to what to do now. :x

Paul Marossy · June 20, 2005, 01:23:24 PM

My suggestion is to take a break and build it again at a later date (few weeks maybe). I have had a few possessed circuits that worked the second time around, after some period of time went by without even thinking about it. My hunch is that I just kept glossing over the same mistake over and over, so after I took a break, mistakes became a lot more apparent... :oops:

PCS · June 20, 2005, 01:34:07 PM

Well, I'm going to rebuild it now. I've already waited almost a month! I have one more piece of stripboard. I'll check each component prior to soldering. Any way to test capacitors (w/out a cap meter) other than testing for for resistance indicating a dielectric breach?

PCS · June 20, 2005, 07:59:21 PM

Okay. Rebuild. Exact Same Thing. All components check to the best of my skills. All wiring is triple checked.

Every portion of the circuit works except the phaser. The mix has the light/dark effect, the speed changes the speed of the LED/LFO, the bias changes the voltage on the FETs. I guess the answer is to order a million fets from Mouser?

Paul Marossy · June 21, 2005, 10:05:08 AM

So your'e positive that the veroboard layout that you have has no errors? It shouldn't be that hard to get the Phase 45 working with JFETs that are reasonably close to eachother. Have you tried some J201s in it? I used some in my build, and it works great (even though they're not supposed to).

PCS · June 21, 2005, 10:07:14 AM

It's Torchy's famous layout. A bunch of people here have built it. I'm going to PCB's after this.

Paul Marossy · June 21, 2005, 10:14:08 AM

QuoteIt's Torchy's famous layout. A bunch of people here have built it. I'm going to PCB's after this.

I was wondering if maybe you were working off of an early version that may have had a small error or something, that's all. I know other people have built it from that layout. Reminds me of my ill-fated Boss Slow Gear clone that I built - it doesn't work with any JFET that I have tried. :cry:

Anyhow, I built the tonepad Phase 45, and it worked great on the first try. Viva PCB! Uh, did I say that out loud?! :lol:

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Waaah. Phase 45 not phasing