adam87 Posted January 20, 2014 Share Posted January 20, 2014 Hello, My Trace elliot I have owned for a number of years now has never worked on the valve side, only on the solid state. After going back to look at the problem a good 8 years later I can see that the input blend between solid state and valve has a snapped board on one side. 6 pins in total, two rows of 3. I assume one set is for the solid state side and the other valve side? Is this more than likely the cause of my problems? The valve was changed and it glows when the amp is on so that bit works. It's the PCB board that has broken on the pot just above the where one set of pins go into the main board. I'd rather get some confirmation that this indeed the problem before I set about taking it to pieces to remove and replace! Thanks Adam Quote Link to comment Share on other sites More sharing options...
flyfisher Posted January 20, 2014 Share Posted January 20, 2014 Well, it's certainly A problem but whether it's the ONLY problem will be difficult to determine until it has been repaired. Your description does make sense though so fingers crossed that it will be the only problem. Quote Link to comment Share on other sites More sharing options...
icastle Posted January 20, 2014 Share Posted January 20, 2014 The blend pot works in such a way that, as you turn the control, that valve side increases as the solid state side decreases (and vice versa of course). If the pot contact is busted then one side of the blend isn't going to work. Take a careful look around the broken area and make sure nothing else (including the PCB) is broken, get that pot replaced and you've got a pretty fair chance of success. Quote Link to comment Share on other sites More sharing options...
adam87 Posted January 21, 2014 Author Share Posted January 21, 2014 Cheers guys. I thought that might be the problem but it is always good to hear others opinions. Now my question is where can I get a direct replacement? Lots on ebay but I am unsure what one I need to get. The pot says this... B50KΩ2P. I've seen mono, stereo, linear and log pots. What sort is right for my trace? Here is a picture of the broken pot and one of the whole unit for you tech lovers. Quote Link to comment Share on other sites More sharing options...
Ghost_Bass Posted January 21, 2014 Share Posted January 21, 2014 Yep, just the pot needs replacing. For an original TE part these guys are your best bet (http://www.britishaudioservice.com/) but they're from US, maybe another BC'er could point you to a UK dealer. That's an easy fix if you're comfortable with a soldering iron but if you haven't done anything like this in the past then take it to a good tech instead. Quote Link to comment Share on other sites More sharing options...
flyfisher Posted January 21, 2014 Share Posted January 21, 2014 [quote name='adam87' timestamp='1390298077' post='2343609'] The pot says this... B50KΩ2P. I've seen mono, stereo, linear and log pots. What sort is right for my trace? [/quote] Probably a 'log' pot but with dual pots they can be 'log/antilog' so it's hard to be completely sure. You won't do any harm by fitting an incorrect type (make sure it's 50k though) but if the 'sense' is wrong then the blend won't work as intended. I'd take ghost-bass's suggestion and go for an original TE replacement part if possible, just to be sure. Quote Link to comment Share on other sites More sharing options...
Ghost_Bass Posted January 21, 2014 Share Posted January 21, 2014 [quote name='flyfisher' timestamp='1390317281' post='2343963'] Probably a 'log' pot but with dual pots they can be 'log/antilog' so it's hard to be completely sure. You won't do any harm by fitting an incorrect type (make sure it's 50k though) but if the 'sense' is wrong then the blend won't work as intended. I'd take ghost-bass's suggestion and go for an original TE replacement part if possible, just to be sure. [/quote] I would bet that that "B" on the pot's description means linear. In balance knobs is usual to use linear pots because they offer a constant efect as you rotate them, not like tone knobs where you're looking for a percieved sound change that acts close to the way we hear things. Not sure about what i wrote though, allways better to check everything first. Quote Link to comment Share on other sites More sharing options...
flyfisher Posted January 21, 2014 Share Posted January 21, 2014 Agreed. A balance pot might well be linear, but they are not usually a double pot. This application is more to go with increasing the gain on one channel while reducing the gain on a separate one, hence the dual pots. Could easily do this with two linear pots but could also use log pots for matching the gain change to the way we hear sound (as you rightly point out), although the use of log pots would really require one to be log and the ganged one to be antilog, hence 'log/antilog' pots. So I don't really know either I'd still go with your suggestion of getting an original replacement part! Quote Link to comment Share on other sites More sharing options...
adam87 Posted January 22, 2014 Author Share Posted January 22, 2014 Thanks again! When I get round to fixing it I'll post some pictures of it working, and maybe a little video going from solid state to valve. If it works! Quote Link to comment Share on other sites More sharing options...
icastle Posted January 25, 2014 Share Posted January 25, 2014 http://www.ebay.com/itm/2-x-50K-OHM-Linear-Dual-Taper-Rotary-Potentiometers-B50K-50KB-POT-ALPHA-/250956199544 To translate B50KΩ2P: B = Linear 50KΩ = the value (50KΩ) 2P = two pots Quote Link to comment Share on other sites More sharing options...
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