Members Zozobra Posted December 8, 2010 Author Members Share Posted December 8, 2010 On the clean channel I'm getting a very feint (and distorted) output with everything dimed. Nothing from the lead other then hum.Just gone over the cathode and plate voltages and written then down and they're all looking sensible. Link to comment Share on other sites More sharing options...
Members Zozobra Posted December 8, 2010 Author Members Share Posted December 8, 2010 Heres the voltages, drawn in paint as I have nowt else and the font tool in paint blows hard. http://dl.dropbox.com/u/8802910/voltages.PNG Link to comment Share on other sites More sharing options...
Members Zozobra Posted December 8, 2010 Author Members Share Posted December 8, 2010 Tonight I will try this: Gonna bypass the relay switching (the pins are on sockets) and I'm going to jump from the back of the 1st stage after the coupling cap somewhere to the input of the output stage so I'm bypassing as much as possible. If I get nothing then there is a problem with the input/output and I dont have to worry about pots or switching cocking things up. I need to replace the LM7806 with a 7805, bought the wrong part was never going to get enough volts from a rectified heater winding for a 6v regulator. Link to comment Share on other sites More sharing options...
Members Zozobra Posted December 8, 2010 Author Members Share Posted December 8, 2010 Found error one: input socket wired the wrong way :faceplam:The clean is passing signal but the lead isnt. The treble and volume control work as expected but im not sure about the mid and bass as with both on zero they cut all signal. The MV is wired backwards too. I got places to be tonight so this is a job for tomorrow but I at least know it isnt totally cocked. Link to comment Share on other sites More sharing options...
Members Casey4s Posted December 8, 2010 Members Share Posted December 8, 2010 kool... at least you have a good starting place now. I think you'll have it up and running pretty soon. Link to comment Share on other sites More sharing options...
Members Zozobra Posted December 9, 2010 Author Members Share Posted December 9, 2010 It's going to be something dumb like a pot wired wrong or something is shorted/grounded.Tomorrow I'll go with my original plan of jumping the input stage straight to the output stage to see if that makes a sensible sound. I'll then move through each stage until things get screwy. I missed out on a decent o-scope on ebay today. went for Link to comment Share on other sites More sharing options...
Members Zozobra Posted December 9, 2010 Author Members Share Posted December 9, 2010 A ha! I have took off the relay switching and manually jumped to the output. The clean channel works and the pots work as you'd expect. Its very clean and glassy - could do with more bass. apparently this is an issue with split input stage amps but the large bypass cap should have taken care of that. needs tweaking The MV is very sensitive. The signal off the clean may be too hot. The lead is very quiet and doesnt overdrive. This may be because of the 470k resistor going into the gain pot and the wiper then having a probably superfluouss 68k grid resistor. I'll remove those to see what happens. Could just be that my switching circuit is a bag of dicks. Probing with a sine wave shows the signal pre v2b tp be much weaker than what goes into the TS of the clean. Link to comment Share on other sites More sharing options...
Members Zozobra Posted December 10, 2010 Author Members Share Posted December 10, 2010 Turned out it was a bad join to the input of the gain pot! It lives! It lives! I need to play with the interstage attenuation levels on the lead channel as it isnt gainy enough. Currently getting a moderate crunch with the lead controls dimed so it needs to be hotter. I may bring the 3rd stage cathode resisitor down to 10k too. Overall its bright and it needs taming a litte and the bass content needs to go up on both channels. Link to comment Share on other sites More sharing options...
Members Zozobra Posted December 10, 2010 Author Members Share Posted December 10, 2010 The switching works now with a 5V regulator and the LEDS are hella bright and dont dim when more than one is on. Tonally it needs work though. Its shrill and has no/little bass for some reason. Link to comment Share on other sites More sharing options...
Members Zozobra Posted December 10, 2010 Author Members Share Posted December 10, 2010 Okay so I jumped the clean channel to the output manually with a crocodile clip and it sounds great. Must be gremlins lurking in the switching circuit. The lead needs some work as it isnt really clipping all that much although with three stages perhaps I'm expecting too much Link to comment Share on other sites More sharing options...
Members Zozobra Posted December 11, 2010 Author Members Share Posted December 11, 2010 It all works now Made a few tweaks to the lead: Changed R17 from 100K to 220K for more output swing, also removed C13. Changed R22 from 39K to 10K so I get more gain but still coldish clipping. Tonally its 95% of what I was gunning for. There will be a few tweaks to come but not just yet. Link to comment Share on other sites More sharing options...
Members Casey4s Posted December 11, 2010 Members Share Posted December 11, 2010 I can't wait to hear a demo clip. Link to comment Share on other sites More sharing options...
Members Zozobra Posted December 11, 2010 Author Members Share Posted December 11, 2010 I'm not feeling overly guitary right now but clips will come Link to comment Share on other sites More sharing options...
Members Zozobra Posted December 12, 2010 Author Members Share Posted December 12, 2010 I'm tracking something with my new toy this afternoon Link to comment Share on other sites More sharing options...
Members Zozobra Posted December 12, 2010 Author Members Share Posted December 12, 2010 I havent managed to get a distorted tone im happy with using my strat and mic placement and all my other guitars are tuned to dick so errr... here it is with the end missing until I can get another guitar to do properly. I've never managed to get a good distorted tone in this room http://dl.dropbox.com/u/8802910/shelter.mp3 Link to comment Share on other sites More sharing options...
Members Zozobra Posted December 15, 2010 Author Members Share Posted December 15, 2010 So I have been tweaking this: Output coupling cap (c19) 47n > 220n Removed c10 and c11. changed c13 treble cut anode bypass to 500p but I want to try a few different values increased r17 to 220k Changed R22 to 10k next i'm going to change c1 to 10 or 47u to fully cathode bypass the input stage as I'm still struggling for low end. may increasd c9 to 47n too. The amp is pretty quiet so I'm happy there although there is a lot of noise from engaging the boost and I cant put my finger on where its coming from. It works pretty well after the lead TS too which I was surprised by to be truthful. I may go with a bit of a more cold clipping feel to the boost, say 10k or more, this will bring the gain down a bit which will make it a bit more manageable too hopefully. I'm going to try a DI recording with some impulses. I've never really tried these so wish me luck Link to comment Share on other sites More sharing options...
Members Zozobra Posted December 15, 2010 Author Members Share Posted December 15, 2010 Hmm, i'm not going to the the gain reduction if I bypass it. Link to comment Share on other sites More sharing options...
Members Zozobra Posted December 21, 2010 Author Members Share Posted December 21, 2010 I'm converging on something that I'm happy with now. I still have some noise in the boost stage though so I'm going to try and work out where that is coming from. Updated schematic: big print edition Its quite a bit different in a few places now. The lead tone stack is a little wacky perhaps but it sounds good. Dont know if it'll cut in a mix though Also there is a 500p anode bypass cap on R13 too. The MV is sufficient for my interface and the fx return of my A15 but it doesnt have enough juice to power my speed twin to full output for some reason. the speed twin does have an SS loop and it might be more suited to rack gear perhaps? I'll work something out when I've got the rest of it right. Link to comment Share on other sites More sharing options...
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