I built this using the updated LND150N3 in Q2 per Dead End. Something still isn't right and I cant seem to find it. I traced your layout and dead ends schematic and everything seems to be correct.
All of my voltages are correct except im getting only 2v at pin 6 of the IC.
All I get is sputtering distortion when hitting the strings hard. Really nothing else.
Thanks for the headsup about the updated build doc.
I've been over the schem once again and I can't spot any errors iether. have you checked the pinout of the J FET? The layout has DGS pinout while J201 or 2N5457 has DSG. Also did you bought the OTA chip from a trustworthy vendor like Smallbear? Appearantly there are fakes circulating on Ebay and similar sites.
I got mine working with a caveat or two, so maybe tag it verified? Oddly enough, I had to borrow a working CA3080 from my Ross comp build to test this one out haha. I tried one of my ebay 3080's for kicks, and no dice. The drive and tone controls are backward to standard layouts, so you may want to flip-flop the 1 & 3 lugs on those pots. I think it sounds pretty good! The only differences that I've noticed compared to videos of the original is that it doesn't seem to get very far above unity/bypassed volume, and the tone control seems a little different. The tone control is almost like a Muff tone stack and gets fairly scooped/ perceived volume drop in the middle of the sweep. Now I have to make an adapter for a LM13700 so I can put the 3080 back in my compressor. I used a J201 with the legs twisted for the J-fet (2n5457 sounded flubby) and a 2n3906. I'm going to have to wait on my next parts order to try the LND150-N3. Anyone know a drop-in N-Channel Jfet with the DGS pinout??
Nice! You might need the LND150-N3 to get it properly working with higher output and eventually a better working tonestack? It is basically a recovery stage. Looking forward to hear your findings when your MOSFETs arrives. I used DGS pinout simply because it flowed much better in the layout and I have tons of good J FETs like 2SK30, 2SK117 and 2SK170 which has that oinout.
Yup, it definitely needs the LND150-N3. It fixed the volume and tone control issues I was having. I'd tag it verified. I'd still swap the 1&3 lugs on the tone and gain pots for a "traditional" direction of control.
Yes! I'll tag it. Will keep the tonestack as is since thats how the original is wired but will add notes about your idea to swapping the pins....it is definitely something I will do since reversed tonestacks tottally wrecks my piece of mind....:-)
I never built any layout with ferrite, I never bought it, too. Is this ok for everything? https://www.taydaelectronics.com/axial-ferrite-bead-76-ohm.html
I built this using the updated LND150N3 in Q2 per Dead End. Something still isn't right and I cant seem to find it. I traced your layout and dead ends schematic and everything seems to be correct.
ReplyDeleteAll of my voltages are correct except im getting only 2v at pin 6 of the IC.
All I get is sputtering distortion when hitting the strings hard. Really nothing else.
Thanks for the headsup about the updated build doc.
DeleteI've been over the schem once again and I can't spot any errors iether. have you checked the pinout of the J FET? The layout has DGS pinout while J201 or 2N5457 has DSG.
Also did you bought the OTA chip from a trustworthy vendor like Smallbear? Appearantly there are fakes circulating on Ebay and similar sites.
At first - the JFET totally threw me off. I did have the wrong pinout since I was using a J201.
DeleteBut you may be onto something. I totally bought my CA3080's from ebay. I bought 5 though and all might be bad?
Damn....
I have a ROSS Comp that uses this I built a long time ago. Ill try that chip in this since I know that one is working.
Thanks for the reply!
I got mine working with a caveat or two, so maybe tag it verified? Oddly enough, I had to borrow a working CA3080 from my Ross comp build to test this one out haha. I tried one of my ebay 3080's for kicks, and no dice. The drive and tone controls are backward to standard layouts, so you may want to flip-flop the 1 & 3 lugs on those pots. I think it sounds pretty good! The only differences that I've noticed compared to videos of the original is that it doesn't seem to get very far above unity/bypassed volume, and the tone control seems a little different. The tone control is almost like a Muff tone stack and gets fairly scooped/ perceived volume drop in the middle of the sweep. Now I have to make an adapter for a LM13700 so I can put the 3080 back in my compressor. I used a J201 with the legs twisted for the J-fet (2n5457 sounded flubby) and a 2n3906. I'm going to have to wait on my next parts order to try the LND150-N3. Anyone know a drop-in N-Channel Jfet with the DGS pinout??
DeleteFYI, I used the older layout suggesting the 2n3906 for Q2. I didn't have any success using a 2n7000 as a temporary substitute for the LND150-N3.
DeleteNice! You might need the LND150-N3 to get it properly working with higher output and eventually a better working tonestack? It is basically a recovery stage. Looking forward to hear your findings when your MOSFETs arrives.
DeleteI used DGS pinout simply because it flowed much better in the layout and I have tons of good J FETs like 2SK30, 2SK117 and 2SK170 which has that oinout.
Yup, it definitely needs the LND150-N3. It fixed the volume and tone control issues I was having. I'd tag it verified. I'd still swap the 1&3 lugs on the tone and gain pots for a "traditional" direction of control.
DeleteYes! I'll tag it. Will keep the tonestack as is since thats how the original is wired but will add notes about your idea to swapping the pins....it is definitely something I will do since reversed tonestacks tottally wrecks my piece of mind....:-)
DeleteI never built any layout with ferrite, I never bought it, too.
ReplyDeleteIs this ok for everything?
https://www.taydaelectronics.com/axial-ferrite-bead-76-ohm.html
Yes, those will work just fine. I'm using the ones from Murata.
Delete