tag:blogger.com,1999:blog-6847048658257278783.post5135113287239216525..comments2024-03-29T01:36:12.851+00:00Comments on Guitar FX Layouts: Tone Bender MkII - PNP with negative groundIvIarkhttp://www.blogger.com/profile/08416945174853142251noreply@blogger.comBlogger83125tag:blogger.com,1999:blog-6847048658257278783.post-11255854768758103832022-09-13T21:37:03.850+01:002022-09-13T21:37:03.850+01:00"Never use a Russian transistor"....uhhh..."Never use a Russian transistor"....uhhhh....not necessarily. I built an NPN version with a Russian transistor for Q1 and it was fine. It depends all sort of depends. Q1 requires some leakage to self bias but there's no written rule. In the old days, when these were first made, tolerances and values were kinda all over the place really. They didnt have the time to be so meticulous, they just cranked out one pedal after another on the production line. I've used an MP38A around 72 hFE with 80ua of leakage and it really sounded just fine.Shanehttps://www.blogger.com/profile/00193755448608016742noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-22895030095865642772021-03-04T22:58:53.943+00:002021-03-04T22:58:53.943+00:00Hi, thought I'd post an update in case someone...Hi, thought I'd post an update in case someone reads this. I got it working by re-heating all solder joints another time, then going through the vero, cutting the tracks with a razor/sharp knife. There must have been bad connections somewhere that I didn't see. The polarity reversing IC part works fine, now I get -9 V on pin 5 as intended so that was just due to the other vero issues.<br /><br />Great sound, I'm using AC128. Now off to install a trimpot and do some biasing... <br /><br />Thanks for the layout!Robhttps://www.blogger.com/profile/06887872060119554951noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-40733460258574270102021-03-01T11:36:08.780+00:002021-03-01T11:36:08.780+00:00Hi, sorry for posting in such an old thread but I ...Hi, sorry for posting in such an old thread but I was wondering how to troubleshoot this one... In bypass I get a clean signal, but when I engage the pedal, I get a whining noise only. I measured the board for solder bridges before mounting anything, and checked all my connections etc. but couldn't find anything wrong. <br /><br />Then I measured the voltages on the IC and got -0.2 from pin 5, so that seems wrong. I use a ICL7660 SCPA and even tried to swap that to another as I have a couple of them, but no change. I'm using battery only at this point, no power supply. Any hints on how to proceed with troubleshooting or to isolate the problem? <br />Robhttps://www.blogger.com/profile/06887872060119554951noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-15272446206518678692018-09-01T19:34:03.731+01:002018-09-01T19:34:03.731+01:00Nope. Its right, may have to twist the pins.Nope. Its right, may have to twist the pins.Mulekickerhttps://www.blogger.com/profile/02560136987462145600noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-63079661203968273602018-03-11T18:23:23.696+00:002018-03-11T18:23:23.696+00:00Just a quick question about Q3. Is the collector ...Just a quick question about Q3. Is the collector supposed to be in the middle instead of the base? Or is that a mistake?Anonymoushttps://www.blogger.com/profile/06138722868265095266noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-11808153863177598862017-10-23T13:51:00.654+01:002017-10-23T13:51:00.654+01:00Hello,
Little problem:
The pedal Sounds fuzzfacy b...Hello,<br />Little problem:<br />The pedal Sounds fuzzfacy but with a quite high noise floor.<br />If I touch the box or any Ground pin on the circuit or outboard the noise disapears and It Sounds very good actually.<br />I changed the IC but the noise is the same. It isnt daisy chained. The power adaptar is visual Sounds 1 spot. Its good with other pedals.<br />I attached a batery snap and solved... <br />Could you help me to fix it yo work without so much noise with the power adaptar? (Please discard to touch the box with my bare foot so my body does the ground hahaha)Jokin Glaukomahttps://www.blogger.com/profile/01490913732909874668noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-79286189960339656442017-09-07T00:09:32.314+01:002017-09-07T00:09:32.314+01:00Hrum. I changed the 10n again, the audio probe isn...Hrum. I changed the 10n again, the audio probe isn't getting input though that capacitor. It seems to mysteriously stop at the opposite leg regardless of how many times I change the capacitor. Anonymoushttps://www.blogger.com/profile/04727962058206645054noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-48070384428457076042017-09-06T01:22:01.608+01:002017-09-06T01:22:01.608+01:00currently debugging one of these, when I use my au...currently debugging one of these, when I use my audio probe the signal stops at the 10n, and I've replaced it twice now. What would be the obvious explanation for this? I have blown an Ic once already. <br /><br />Also when i measure the voltage coming out of the ic, none of the pins read negative. What does this mean?Anonymoushttps://www.blogger.com/profile/04727962058206645054noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-47526114635803483732016-06-26T22:32:35.631+01:002016-06-26T22:32:35.631+01:00Thanks, Travis. I was using the 7660SCPAZ from Ta...Thanks, Travis. I was using the 7660SCPAZ from Tayda, but I switched is for a TC7660SCPA and the squeal is gone. I dont know what the deal is there, but it's working. The attack pot is also working now. Thanks for your help though!Anonymoushttps://www.blogger.com/profile/02291346792987429823noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-77054793531012242192016-06-21T05:30:06.924+01:002016-06-21T05:30:06.924+01:00What charge pump are you using? If you use a 7660 ...What charge pump are you using? If you use a 7660 instead of a 7660S it will squeal.<br /><br />If the attack pot isn't working properly, you may need to try some different transistors, or you may have made a mistake in your build.Travishttps://www.blogger.com/profile/00836791717229314419noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-85443344624194724702016-06-20T19:33:33.801+01:002016-06-20T19:33:33.801+01:00Hello, hoping someone can help here. I built this...Hello, hoping someone can help here. I built this and it's squealing on my test board. Also, the attack pot doesn't seem to be adjusting the gain as it should be.<br /><br />Any suggestions? I see a few others have had similar issues.<br /><br />Thanks in advance!Tim Crowehttps://www.blogger.com/profile/00583620401288512094noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-45676993221652283702016-02-15T06:08:26.159+00:002016-02-15T06:08:26.159+00:00So built this the other day and it goes but I can&...So built this the other day and it goes but I can't get it to clean up on the guitar volume. Also it has huge fuzz but crackles out if you let the note ring out (kind of fuzz factory gated sounds). Anyway I might get this to 'tone down'. Tried AC128's, AC132's, 2SB54's. Mostly the same outcome.bassybeatshttps://www.blogger.com/profile/17776850237022032646noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-63667476832835718522015-08-12T07:31:09.731+01:002015-08-12T07:31:09.731+01:00exactly, and solder them in where the transistors ...exactly, and solder them in where the transistors would go. it's always suggested to socket your transistors and IC's (get IC sockets)<br /><br />these will work for 8 pin IC's like the charge pump here<br />http://www.taydaelectronics.com/8-pin-dip-ic-socket-adaptor-solder-type.html<br /><br />this way you can easily swap out IC's if you get a bad one, and it allows you to experiment with other IC's of the same type to see how it affects the circuit.<br /><br />and no problem buddy. glad to help. Zachhttps://www.blogger.com/profile/00044917566185720896noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-38872678958337625802015-08-11T22:27:25.339+01:002015-08-11T22:27:25.339+01:00Okay! Thanks!
Do I just break off 3 little things...Okay! Thanks!<br /><br />Do I just break off 3 little things from the 40?<br /><br /><br />Thanks in advance, Zach!Anonymoushttps://www.blogger.com/profile/09202919004686383793noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-41851323625239970152015-08-11T06:19:12.406+01:002015-08-11T06:19:12.406+01:00awesome, and welcome. if you take a look at the la...awesome, and welcome. if you take a look at the layout you'll see on the transistors the letters C, B, E which stand for the legs of the transistor. C is for the collector, B for base, and E for emitter. i haven't ordered a set from smallbear, so i'm not sure if the legs will be marked so you'll know what leg is what. short answer is yes, it does matter what transistor goes in each position, and they should be marked which transistor is Q1, Q2, and Q3. if when you get them the legs aren't labeled, i believe the leg by the dot should be the collector, middle will be base, and the last will be the emitter. you can always post up later if you're unsure or need more help when you get them.<br /><br />my suggestion is to get some sockets so that you can easily install and remove the transistor, and not have to worry about burning them up when soldering.<br /><br />http://www.taydaelectronics.com/30-pin-dip-sip-ic-sockets-adaptor-solder-type.html<br /><br />good luck buddy, and again welcome to the site.Zachhttps://www.blogger.com/profile/00044917566185720896noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-37213690428442894752015-08-11T05:18:25.059+01:002015-08-11T05:18:25.059+01:00Hey! I'm excited to build this pedal. I have o...Hey! I'm excited to build this pedal. I have ordered all the parts, and am 100% ready to go! It'll be my first build.<br /><br />I have a few questions first, regarding transistors. I ordered a matched OC77 set from Small Bear. I want to know how to put the transistors in, so that it's right. What pin where. Does it matter where I put which transistor, say Q1 in the Q3 spot, or does it not matter where, as long as they're matched? I don't want to blow anything up! <br /><br />Thanks for any help you may have! Anonymoushttps://www.blogger.com/profile/09202919004686383793noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-15931947364605025202015-02-04T01:01:08.440+00:002015-02-04T01:01:08.440+00:00Just for a little update:
I still don't have...Just for a little update: <br /><br />I still don't have this boxed, so I got my Test Box and started playing with it once again. Took some measurements and Q3 voltage was exactly @ 7V lol I'm not sure if it's because we're in Summer here in the southern hemisphere or if I made some resistor change and can't remember (I have an 18K resistor going to Q3 C now). <br /><br />Anyway, this thing is animalesque as hell - loads of volume and thick fuzz. Actually, I can't tell much difference in fuzz with the gain control past noon or so (I'm one of those using a 2KB gain pot and a 1K resistor instead of 470R). Even with gain on "0" it's pretty fuzzy. Volume is plenty loud by the same 11-12:00 mark also (louder than both my Si and Ge fuzz faces). Still cleans well on those higher gain settings, especially considering the amount of fuzz this circuit puts out - possibly better than my Si fuzz face. <br /><br />I think my transistors were in the 70's - 90's - 120's range. Iagohttps://www.blogger.com/profile/13478141026000247956noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-14327331933978514822015-02-04T00:57:48.623+00:002015-02-04T00:57:48.623+00:00This comment has been removed by the author.Iagohttps://www.blogger.com/profile/13478141026000247956noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-89910158879226059332014-08-19T18:25:53.090+01:002014-08-19T18:25:53.090+01:00Just built this. Very nice. I'll post some pic...Just built this. Very nice. I'll post some pics when I get it boxed. All MP20A. <br /><br />I probably can't trust my HFE measurements on my crappy multimeter, but I ended up choosing ones that read the standard recommended HFE. Biased a bit past 8v.Kinskihttps://www.blogger.com/profile/05289368766380894271noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-61958026075204869732014-08-16T05:12:18.958+01:002014-08-16T05:12:18.958+01:00Built this one today! My second Tone Bender MKII (...Built this one today! My second Tone Bender MKII (used a different layout for the first one though, which I didn't like so much ;)). Used a TC1044S CPA from Tayda and it works wonders here. I got the first IC fried though - when I plugged in this old power supply there was this little spark coming out of the DC jack - I still don't know if the problem was the supply or the IC... <br /><br />I biased mine by hear, using a pot soldered to the board, while playing with the gain and volume control. Checked the voltage later and it was ~6V.<br /><br />Oh yeah, one more circuit that needs to get boxed!<br />Thanks, Mark!Iagohttps://www.blogger.com/profile/13478141026000247956noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-9864395967704759072014-08-06T03:08:39.344+01:002014-08-06T03:08:39.344+01:00I cleaned every line real good it's working pe...I cleaned every line real good it's working perfect, I didn't notice much difference adding the 10 k trimpot for biasing Q3 <br />Thanks guysAnonymoushttps://www.blogger.com/profile/02601068030084288323noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-27757070955188100732014-08-05T17:47:59.136+01:002014-08-05T17:47:59.136+01:00I just built it on the proto board and it works pe...I just built it on the proto board and it works perfectly, there's something wrong with my board I'm thinking a solder bridge, but it sounds great on the proto I think I'm gonna ad the bias trimpot to the Q3<br />Thanks!! Anonymoushttps://www.blogger.com/profile/02601068030084288323noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-33561989388436603052014-08-05T06:01:32.964+01:002014-08-05T06:01:32.964+01:00Oh wait.. That's 1 and 8.
What kind of power ...Oh wait.. That's 1 and 8.<br /><br />What kind of power supply are you using Leon? In my experience, sometimes a MKII just needs to be powered by a battery. I don't understand why, but I've had a lot of problems with MKIIs and wall warts<br /><br />Try powering your build with a battery and see if that worksTravishttps://www.blogger.com/profile/00836791717229314419noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-51048294185872317832014-08-05T01:24:36.722+01:002014-08-05T01:24:36.722+01:00Is the difference in voltage between pin 1 and 5 o...Is the difference in voltage between pin 1 and 5 of the 7660 a possible indicator that they are not directly coupled (and therefore not engaging the boost function)?Travishttps://www.blogger.com/profile/00836791717229314419noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-34008479611414740542014-08-04T17:45:59.051+01:002014-08-04T17:45:59.051+01:00I tried another set of pnp silicon and got the sam...I tried another set of pnp silicon and got the same result, this is really weirdAnonymoushttps://www.blogger.com/profile/02601068030084288323noreply@blogger.com