Good to see you back Stuart.. That was an interesting diagnosis as the valves weren't giving the game away with the chopstick challenge The sound I was hearing on my set-up here sounded like the voice coil was rubbing, but I knew it couldn't have been that as they usually perform to all the other strings 😅.. Hope you have a healthy, productive and prosperous 2024.
My experience has been that voice coil rub is specific to certain low frequencies. I have a 30 year old Celestion Vintage 30 12 inch speaker that buzzes only on the first 4 or 5 low notes on the low E string, at least at low to moderate volume. This is probably an issue I created by over-tightening the speaker into a cabinet, deforming the speaker frame, before I knew any better.
Excellent video and fault finding process I thought a dry joint after you first ruled out a valve problem. The use of the tappy lappy stick as we used to call it to me back to my days of working on repair of electrical test instruments, and the time I used a pencil instead of the usual peg wood (loss of concentration) the ensuing belt certainly re-focused my concentration. Keep up the good work really enjoy your videos.
A belated Happy New Year, Stuart! I am pleased that 2024 has you performing business as usual. This repair was quite a poser. The journey in your process of elimination always keeps things interesting. Please stay safe, and out of reach from winter's icy grip. Well done. Cheers!
Stuart, It's always exciting to see new video from you on the feed. I'm always intrigued by your process of elimination. It really teaches how to think about these amps. I've never seen one one of these before, and it's good to get a look inside one. I would have never thought of a speaker vibration as the cause of this issue. Thanks again for the education. Cheers, Mike
Hello Stuart. I had that same fault on one of my own amps after I dropped it at a gig. I didn't notice when I used it at the gig as I use two amps together. But once I plugged it in at home it was very noticeable. Another good video. Take care Stuart.
Fascinating video, I had a similar problem on a 5e3 that I made last year. It was ok until it was mounted in the cabinet with the Celestion Blue. Luckily I managed to tame the resonance using a valve damper ring and avoided the extra cost (for now). Thanks for the great videos. It’s good to know there is someone local to Reading to call on if the need arises.
@@stuartukguitarampguy5830 I suspect that eventually I’ll need to change the valves. Unfortunately the large Alnico Blue is a few mm from the valve. Every “G” I played made the little tweed cabinet resonate along with one of the 6V6’s. The ring fixed it straight away which was lucky as I thought it probably had a 5% chance of working. I am spending my Sunday morning planning a Dumble build. So many Dumble variants to choose from lol. Plus looking into the best way to add in switchable power output as it is getting increasingly hard to turn up our lovely valve amps. Looking forward to seeing your next video
That's why I try to avoid using combo tube amps. If tubes aren't microphonic already in the first place, they soon will be after the high dB acoustic vibration attack offered by the speaker at very close range.
I suspected that it was a power valve from the start; I have experienced similar problems (the audio on RU-vid sounded like a wind-up alarm clock ringing in the background which sounded like filament rattle).
A few seconds in at the start of the video my first thought was lose elements within one or more of the valves, I have built a JTM 45 and in valve line up are 3, ECC83's + 2 EL34'S the first in line pre amp ECC83 is microphonic made by Mazda UK, tried USA Raython still the same problem but only when set at full gain with both valves. These ECC83 have a very high gain and I think they suspectable to microphonics. I did buy 2 EL34 made by Sovteck and straight away when pluged in they where very bad with microphonics, sent them back to the UK supplier got a refund including postage.
Hi Stuart, I have a blues deluxe reissue and if I plug anything into the effects loop the amp loses treble. I usually just use my loop pedal through the effects loop and no other pedals. I tried other pedals and even just a cable plugged into the effects loop to test it, but it loses high end if anything is plugged into it. Any idea why it’s doing that?
