Tweet
Some of you may remember my ongoing troubles with my Bogen K15 conversion and a harsh, nasty distortion "on top" of notes which I'm quite sure was blocking distortion.
Anyway, I got sick of messing around with the paraphase so I built a LTP in its place. Actually I tried to clone the output stage of the Trainwreck Express but used cathode bias. So here's the schematic I drew up for it.
http://i120.photobucket.com/albums/o...MN/CBWreck.jpg
Anyway, the distortion is still there as bad as ever. I don't get it. Anyone see anything wrong with the schematic? Anything I could check out inside the amp ad far as layout? I'm not thrilled with how I had to set it up but given the space I had to work with I think it turned out alright. As far as I can tell nothing is touching or anything like that if it isn't supposed to. I thought the problem might be the 6BW4 rectifier couldn't handle the current draw so I tried a 6CA4 but it does the exact same thing.
Sometimes when I turn it on I get kind of a strane pulsating and the volume will fade in and out but it stabilizes after a minute or so.
Also, kind of unrelated but I'm using Tung-Sol 6V6s that only have a few hours on them. One of them randomly redplates though, and when it does it I see a positive voltage on the control grid for some reason. At first I thought the coupling cap was bad (a Hovland Musicap, it better not be!) but I swapped positions and the tube did it in the other spot too. When I play through it it actually goes "normal" for a while but as soon as I stop it lights up like a christmas tree. Is this for sure just a bad tube from the factory or is there something else I should be checking out?
As always, thanks in advance for any ideas. At this point I'd be willing to paypal a few bucks to anyone who can guess correctly what this thing's malfunction is. I'm sick of dealing with it.
-Darren
Anyway, I got sick of messing around with the paraphase so I built a LTP in its place. Actually I tried to clone the output stage of the Trainwreck Express but used cathode bias. So here's the schematic I drew up for it.
http://i120.photobucket.com/albums/o...MN/CBWreck.jpg
Anyway, the distortion is still there as bad as ever. I don't get it. Anyone see anything wrong with the schematic? Anything I could check out inside the amp ad far as layout? I'm not thrilled with how I had to set it up but given the space I had to work with I think it turned out alright. As far as I can tell nothing is touching or anything like that if it isn't supposed to. I thought the problem might be the 6BW4 rectifier couldn't handle the current draw so I tried a 6CA4 but it does the exact same thing.
Sometimes when I turn it on I get kind of a strane pulsating and the volume will fade in and out but it stabilizes after a minute or so.
Also, kind of unrelated but I'm using Tung-Sol 6V6s that only have a few hours on them. One of them randomly redplates though, and when it does it I see a positive voltage on the control grid for some reason. At first I thought the coupling cap was bad (a Hovland Musicap, it better not be!) but I swapped positions and the tube did it in the other spot too. When I play through it it actually goes "normal" for a while but as soon as I stop it lights up like a christmas tree. Is this for sure just a bad tube from the factory or is there something else I should be checking out?
As always, thanks in advance for any ideas. At this point I'd be willing to paypal a few bucks to anyone who can guess correctly what this thing's malfunction is. I'm sick of dealing with it.
-Darren
Thanks Bruce.
Comment