Graham's Cat Posted July 31, 2016 Share Posted July 31, 2016 My recently acquired YBA1 has lively and microphonic EL34 Philips tubes. I've read these should be replaced or have dampeners fitted. I don't want to replace these unless really necessary. However given my lack of tube knowledge, I once again ask you lovely people. Also read Svetlana Winged-C are a good replacement tube, but there are quite a few to chose from. Opinions and advice welcomed! G Quote Link to comment Share on other sites More sharing options...
naxos10 Posted July 31, 2016 Share Posted July 31, 2016 I have used valves in hi-fi applications and tube dampers are a good bet if you like the sound of the valves you are using. Try searching the internet or companies like Watford Valves. Quote Link to comment Share on other sites More sharing options...
Skybone Posted July 31, 2016 Share Posted July 31, 2016 IIRC, if your power valves are going microphonic, then it's certainly time to get your amp checked out by a good amp tech. The best EL34 valves I've used are JJ's, though "Winged C" Svetlana's get good reviews. Try looking at HotRox in Nottingham for valves as they used to be a bit cheaper than Watford Valves ([url]www.hotroxuk.com[/url]). The downside to some valve amps is that they need to be maintained regularly, or the quality of sound and volume will drop over time (unless you find something with either fixed or cathode biased, or if it has bias points on the rear panel). Quote Link to comment Share on other sites More sharing options...
Graham's Cat Posted August 1, 2016 Author Share Posted August 1, 2016 How much impact do the power valves have on the tone? Is this more defined by the preamp 12ax7 tubes? Quote Link to comment Share on other sites More sharing options...
Graham's Cat Posted August 1, 2016 Author Share Posted August 1, 2016 Hoiked a couple of 12ax7's out, didn't help much though I did find the noisy culprit in my Cornford in the process. Thinking now maybe the power valves are alright. The amp is generally noisy and doesn't like any pedals other than a battery powered Compulator in circuit. I've found that even PSU's for my guitar induce elements of noise in the amp. Going to have to find a decent Valve repairist! If anyone knows someone in SE Kent let me know! Quote Link to comment Share on other sites More sharing options...
Twincam Posted August 2, 2016 Share Posted August 2, 2016 The yba1 is a pretty old amp. I assume its a 70s one. Great amps and Pete Traynor in my view was a legend. Has it been serviced recently. I have had two traynor amps a bassmate which I loved and a yba1 that I had very briefly. They were not particularly noisey amp and both could take pedals Quote Link to comment Share on other sites More sharing options...
Reissueplayer Posted August 2, 2016 Share Posted August 2, 2016 I have rarely seen microphonic power valves, but some amps have had slightly microphonic preamp valves (12ax7) and that has actually been on purpose. In use, this has given some shimmer and an almost reverb-like feel to the amp. The amp was a guitar amp built by an expert in the field. I don't know if I'd make the same choice for a bass amp, but I wouldn't automatically assume it is bad. Quote Link to comment Share on other sites More sharing options...
Sparky Mark Posted August 2, 2016 Share Posted August 2, 2016 (edited) One of the worst places to position a valve amplifier is on top of a bass cabinet that is going to vibrate the relatively fragile elements within the valves. Once you are confident that you have isolated and replaced any faulty valves it would be a good idea to place some shock absorbant material beneath the amp or even better place the amp somewhere other than on top of the cabinet. Edited August 2, 2016 by Sparky Mark Quote Link to comment Share on other sites More sharing options...
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