tag:blogger.com,1999:blog-6847048658257278783.post5263768848633823647..comments2024-03-27T15:26:01.893+00:00Comments on Guitar FX Layouts: Germanium Transistor TesterIvIarkhttp://www.blogger.com/profile/08416945174853142251noreply@blogger.comBlogger92125tag:blogger.com,1999:blog-6847048658257278783.post-16068439904997159432021-11-06T04:04:53.057+00:002021-11-06T04:04:53.057+00:00Actually one I downloaded ages ago is correct. Actually one I downloaded ages ago is correct. Jimijamhttps://www.blogger.com/profile/04425566931407259771noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-20523861411025594822021-05-03T06:04:58.005+01:002021-05-03T06:04:58.005+01:00This spreadsheet is wrong.
Don't use it.
You&#...This spreadsheet is wrong.<br />Don't use it.<br />You're supposed to multiply, not divide. And your units are wrong too. <br />"Let's say the device really leaks 93uA, and has a gain of 110 - a prime specimen. What happens when we test? We chuck the thing in the socket, and read (93uA)*(2472) = .229V. Then we press the switch, and read 1.330V. To get the real gain, we subtract 0.229V from 1.330V and get 1.101V. The true gain is just 100 times the reading."<br />From the GEOFX page. Anonymoushttps://www.blogger.com/profile/04561126157453306390noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-30130340083929940242020-05-12T10:20:48.820+01:002020-05-12T10:20:48.820+01:00Thanks for this. I've combined this into my T...Thanks for this. I've combined this into my Test Box 2.0 build too. Just bought my first batch of Ge Transistors from e-Bay and used this to see how lucky I got (bought 20 MP20's; only 1 Hfe >80 and 3 > 60), bit better with my GS109's but still a bit shy of optimum Fuzz values. ThanksBishb2https://www.blogger.com/profile/03539401217646204417noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-30191421674661632102018-08-05T09:16:55.113+01:002018-08-05T09:16:55.113+01:00Im having trouble testing npn’s with this. Ive rec...Im having trouble testing npn’s with this. Ive recersed my power leads, and the multimeter connections, but get no change in reading when i insert the 2.2m resistor. Ive tested dozens of germanium pnp’s on my breadboard with this circuit and had much success. And I get clear readings from my “mega328” transistor tester, which also confirms the leads for me, so i know my pinouts are correct. Any idea what my problem could be? Gumby85https://www.blogger.com/profile/01528809019751761365noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-73350000965078933332017-07-15T14:13:08.303+01:002017-07-15T14:13:08.303+01:00Swap your power leads to make it NPN.Swap your power leads to make it NPN.Anonymoushttps://www.blogger.com/profile/04861884393776718214noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-22834896801223110382017-07-15T00:49:54.122+01:002017-07-15T00:49:54.122+01:00This comment has been removed by the author.Anonymoushttps://www.blogger.com/profile/04861884393776718214noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-91525715110903185262017-03-01T13:39:41.902+00:002017-03-01T13:39:41.902+00:00Hi ,i need to test some AF127 and the pinout is C ...Hi ,i need to test some AF127 and the pinout is C E B the rather than twist the legs just need a little jumper on the board for it<br />https://servimg.com/view/15990981/2317<br /><br />Anonymoushttps://www.blogger.com/profile/03347170975665689357noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-54077414581535367082017-02-09T15:50:30.765+00:002017-02-09T15:50:30.765+00:00work for pnp but no for npn :-(work for pnp but no for npn :-(Anonymoushttps://www.blogger.com/profile/18382526275341725852noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-66057795262548266052016-10-07T00:31:00.219+01:002016-10-07T00:31:00.219+01:00Lol I know this thread is old but I recently order...Lol I know this thread is old but I recently ordered some MP38s and had some better luck. <br /><br />They were supposed to be rated 35-75 hfe, but nearly all of them (out of a batch of 40) were in the 90-100 range with about 3 sitting in the 70-80 range. Only two of them read below 70 (35 and 68). Three came in fried (oh well), and I ended up finding one that read 120 but the leakage was awful. Rest of them had very low leakage.<br /><br />I popped a few into my fuzz face (77 and 101 hfe) and they sound fantastic.Anonymoushttps://www.blogger.com/profile/03551370005336623785noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-6461415491936711162016-02-26T08:48:27.112+00:002016-02-26T08:48:27.112+00:00Great site, thanks for your work, Mark! Here's...Great site, thanks for your work, Mark! Here's my 2 cents. I recommend using ZIF IC socket for transistors. With ZIF socket you can easily insert transistors with tweezers thus they won't be heated with your fingers. You should measure hundreds of transistors with the speed of light ;) Also a good idea is adding a couple of jumpers so you can easily plug transistors with EBC (most of russian MPxx transistors), ECB (russian GT40x, GTx08 etc.) or even wierd BEC (such as russian GT309) pinout without twisting their rather fragile legs (I broke some really ancient soviet P11 and P13 transistors while twisting their legs though this might be due to the fact that their legs were already heavily bent). So here is a link to my modified PNP version vero of Ge transistor tester if someone is interested:<br /><br />https://drive.google.com/file/d/0B8tGpeW4CJgzSG5OZXNtc3VzTWM/view?usp=sharing<br /><br />The vero is not verified but it should be OK. I'm going to build this as soon as possible.<br />Cheers from Russia and sorry for my English.Glenn Dalehttps://www.blogger.com/profile/10660032467066787725noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-12579498839641265512016-01-21T05:37:27.362+00:002016-01-21T05:37:27.362+00:00I was wondering how to determine the leakage of tr...I was wondering how to determine the leakage of transistors using this test circuit. The ones I have are AC128 with hfe ranging from 58 to 69. I'm trying to build a Tone Bender and need to know the leakages. fuzzbenderhttps://www.blogger.com/profile/06349384857864318828noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-4118523914724003562015-10-06T10:07:10.671+01:002015-10-06T10:07:10.671+01:00measured something like 100 transistors with the g...measured something like 100 transistors with the germanium transistor tester (which thanks to Ivlark I built myself). except for the few 2sa12s which were mostly very low leakage with hfe around 30,nearly all of them were of hfe's around 150 to 250. it seems that the usable ones must have moderate leakage with hfe's around 50 to 150. am I right? do you think there is something wrong with my measurement. by the way the trannies were Gc301, 2sb75, 2sb54, 2sb175, 2sb176,2n270 and 2sa12<br />thanks a lot.ashkanhttps://www.blogger.com/profile/14949196158453629658noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-86167507113965468322015-08-21T16:50:24.967+01:002015-08-21T16:50:24.967+01:00Make sure to give it time for the temperature to s...Make sure to give it time for the temperature to stabilise. Anonymoushttps://www.blogger.com/profile/06201678011261105677noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-45665360885029417872015-08-21T07:51:22.541+01:002015-08-21T07:51:22.541+01:00Basically, yes. Make sure the transistors orientat...Basically, yes. Make sure the transistors orientation is correct when changing from type to type - that could be one reason you're getting weird readings.Iagohttps://www.blogger.com/profile/13478141026000247956noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-53605676411705771142015-08-21T04:11:06.750+01:002015-08-21T04:11:06.750+01:00So for NPN silicons would I have +9V where ground ...So for NPN silicons would I have +9V where ground is on the layout, and ground where 9v is on the layout? I would just swap them right? Same thing for the MM leads? I'm just gettings some really funky readings. I don't know what I'm doing wrongJighead81https://www.blogger.com/profile/16701474259642270852noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-17670062123544148042015-06-22T22:52:08.379+01:002015-06-22T22:52:08.379+01:00At my list :) BTW if connected in parallel 15k, 8...At my list :) BTW if connected in parallel 15k, 8k and 4,7k we have exactly 2,472kAnonymoushttps://www.blogger.com/profile/12675408339771878245noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-89764703886254317442015-04-16T20:25:37.449+01:002015-04-16T20:25:37.449+01:00What type of switch should be used, spdt?What type of switch should be used, spdt?Garfohttps://www.blogger.com/profile/08902368854605872798noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-24912234329785740202015-02-06T18:55:36.609+00:002015-02-06T18:55:36.609+00:00This comment has been removed by the author.Jay guitaristhttps://www.blogger.com/profile/16225767375560795315noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-30823803944961913822014-09-18T20:37:39.646+01:002014-09-18T20:37:39.646+01:00The gain and leakage of germanium transistors incr...The gain and leakage of germanium transistors increases with even a small amount of heat, so the warmth from your fingers is enough to get the value higher and then start to drop when you're measuring. Best bet is to avoid touching the body altogether and just touch the leads, but if you do touch the body and transfer heat the most accurate reading is as it will be when boxed in a pedal, so you're going to have to leave it until the numbers stop changing, or at least until they slow to a trickle which should get you close enough. <br /><br />Remember that probably the most important thing about measuring isn't to get an absolutely bang on accurate number, because the best gain for any given pedal is completely subjective, but more to give you a point of comparison between the transistors you own, so you know which ones will give you lower and higher gain compared to the one you're auditioning.IvIarkhttps://www.blogger.com/profile/08416945174853142251noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-48530013970928122322014-09-18T18:06:53.890+01:002014-09-18T18:06:53.890+01:00what setting do i use on my dmm mA or uA?what setting do i use on my dmm mA or uA?glasspak73https://www.blogger.com/profile/11792030395861982394noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-36956783324016793772014-09-18T17:33:26.139+01:002014-09-18T17:33:26.139+01:00on step 1 how long should it take once i turn powe...on step 1 how long should it take once i turn power on to transistor for the meter to stop dropping and level out? Is this normal for the numbers to start high then drop way down and then stop?like when i tried to read them with my dmm on hfe setting?glasspak73https://www.blogger.com/profile/11792030395861982394noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-82092977325037496602014-08-20T00:56:28.369+01:002014-08-20T00:56:28.369+01:00Thanks. I gave up after getting through two transi...Thanks. I gave up after getting through two transistors, and ordered a DCA55. Found a great price, ships from Japan. $60.90 USD, free shipping! <br /><br /><br /><br /><br />Kinskihttps://www.blogger.com/profile/05289368766380894271noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-11064527130651457412014-08-19T22:54:40.723+01:002014-08-19T22:54:40.723+01:00That makes sense. The gain of these transistors g...That makes sense. The gain of these transistors goes up with the heat from your fingers and then drops as it cools, and so that's exactly what I would expect.IvIarkhttps://www.blogger.com/profile/08416945174853142251noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-54150324621172785382014-08-19T22:39:07.775+01:002014-08-19T22:39:07.775+01:00Okay, so I built this, and set my multimeter to DC...Okay, so I built this, and set my multimeter to DCV. Something like 0.6XX shows up, then slowly over the next 10 min, the voltage slowly drops. Is this just my terrible multimeter being terrible? Or am I doing something wrong? Kinskihttps://www.blogger.com/profile/05289368766380894271noreply@blogger.comtag:blogger.com,1999:blog-6847048658257278783.post-5309078078719353432014-08-19T12:04:00.891+01:002014-08-19T12:04:00.891+01:00Hi everyone, Cansomebody tell me what the function...Hi everyone, Cansomebody tell me what the function to use for this test?<br /><br />here are the multimetter : http://p.lui.li/img-40819_dmm_j-r-full.jpg<br /><br />thanks a lot for that who can help.Anonymoushttps://www.blogger.com/profile/02026752509657065618noreply@blogger.com