longtimefred Posted December 4, 2012 Share Posted December 4, 2012 Dudes, could do with some of your help and guidance on this one if you could. The other week, one of my tung sol 6550's in my V4 decided to light up like the sun and blew the amp out as well as the mains fuse, all valve fuses still in working order. The right hand side output transformer seemed hot enough to cook on! i tried swapping out a few valves with some spares i have and it kept popping the fuse. I then decided to send it away to my local amp dude (Barry something or other in Crewe). Got it back 2 weeks later saying the only thing it needed was 2 tubes replacing and didnt get much of an in depth story on what was wrong. I dont mind, as long as it works!! I picked it up today from the shop and took it for rehearsal tonight and found that yes it did work but it farted like an arse and just had no guts, meat or volume to it even when maxed out, which i have never ever done. it seemed like its running at half power or something. I had to have a pair of second hand valves installed instead of a full re valve as i cant afford it this close to christmas, they are also a different brand its all biased correctly but something is still not right. all the EQ and compressor works fine but its just running on empty. again the right hand side output transformer felt rather hot compared to the cool left one even when only played for 10 minutes. I then decided to use the back up Peavey firebass thing that had loads more headroom and is only a 450w SS amp. Any clues dudes? I will be sending it back but could do with some help in diagnosing myself. Nice one!! Will Quote Link to comment Share on other sites More sharing options...
MarkBassChat Posted December 4, 2012 Share Posted December 4, 2012 Clearly something failed in the amp and it was not fixed and tested by "Barry something". You can only check whether external preamp (e.g. from 450W SS amp) works (or not) with the power amp from V4. Most probably it won't work. This would indicate that the power amp in V4 still needs to be fixed. If you have some electronic skills, you can check bias of the output valves. Here is how to do it: [url="http://www.dustyend.com/finnbass/oxblood_stuff/V-Type_V4_instructions.pdf"]http://www.dustyend.com/finnbass/oxblood_stuff/V-Type_V4_instructions.pdf[/url] Mark Quote Link to comment Share on other sites More sharing options...
longtimefred Posted December 4, 2012 Author Share Posted December 4, 2012 Cheers dude i will have a go! Quote Link to comment Share on other sites More sharing options...
Chimike Posted December 7, 2012 Share Posted December 7, 2012 Hi Will, Got a feeling that the right hand transformer is the mains transformer, will check my V4 on monday, to confirm. Likely it will run warm , after some use, but if it gets really hot, it's pulling too much current. I'm not qualified to advise further, but if it were mine, I would pull the output tubes, and see if the tranny still gets too hot. Hows the power on half power setting ? BTW , setting the V4 bias is easy, but read the manual carefully. Don't go poking around inside, t'aint safe ! Mike Quote Link to comment Share on other sites More sharing options...
longtimefred Posted December 8, 2012 Author Share Posted December 8, 2012 cheers Mike, i will try it again at rehearsal on monday to give it another try and after that its back to the repair shop, the guy who 'repaired' it first time just changed the valves and set the bias. obviously missed another problem somewhere. Yeah it got warmer than usual on just a few minutes playing which aint normal. I didnt try the half power setting but will give it a go. Thanks for your help mate. Quote Link to comment Share on other sites More sharing options...
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