Beer of the Bass

I'd agree about the microphonic aspect - these are vibration sensing pickups, after all. But I did manage to break my J-Tone! It worked fine for several years, and then started giving a crackly, distorted sound when I played more firmly. After ruling out every other posible cause, I got curious and dissected the J-Tone, and found that it uses a thick ceramic disc type piezo element inside, which had cracked on mine.

I noticed there's a new model of Beyma driver, the 612 CM, a cheaper cast-frame speaker. Has anyone modelled it? At a cursory glance it looks potentially useful, but I'm not on my laptop with WinISD on. https://www.bluearan.co.uk/index.php?id=BMA612CVM28

Yep, I find my KNA to have a fair bit of high end, though it's quite easy to EQ as it doesn't seem peaky. I'm getting better string to string balance and evenness across the bass range than I've had with other wing pickups so far (I've had a Rev Solo II and a J-Tone), though perhaps that has something to do with the G- side placement. Nice and easy to fit too.

I've just played through it for a while, with the old Telefunken in the phase inverter spot. I must say, for all of the niggles (which I seem to have just got unlucky with), it is a very nice sounding amp. It does this great articulate but grunty sound that I reckon will be fun to explore in a band context.

Tapping the valves through the cage using a cocktail stick revealed that it's the phase inverter 12au7/ecc82 that's microphonic. I popped in a very old Telefunken ECC82 I had in my parts box, and it's much less microphonic, but still very slightly so. So I reckon that with a fresh new valve I should be good to go. It's a pain in the bum, but then so is going through another returns process...

Seems I'm not having good luck with this one. It arrived back today, and Polar have replaced the power valves on the original amp rather than sending a replacement amp as the shop thought they would. The bias indicator is no longer going red when it's been on for a while, at least. But now something is microphonic - I can hear it ringing through the speaker if I gently tap the chassis. I'll have a think about what to do, if I can track it down to one valve I might be inclined to sort it myself rather than going back through the returns hassle again.

I did phone them yesterday, the response was that they'd chase it up and get back to me before the end of the day (which they didn't manage to do). I've just had an email back saying a replacement has been dispatched that should be with me by Thursday at the latest, but I wish they'd kept up communication rather than promising an advance replacement then going silent. I think if this one has any minor valve-related issues I'll just sort it myself!

I've just emailed Kenny's again as I've still had no response to let me know what's going on. This is getting silly...

I've tended to have my GK MB200 around when gigging a valve amp, though I haven't needed it yet. I've had one failure of a valve guitar amp on a gig, but it had been dropped on the way from the last gig.

I hope you have better luck than me! I'm just hoping I have mine by the weekend, when I wanted to gig it...

Well, that's Kenny's opening hours finished for the day, and they didn't call back. And that's after not dispatching a replacement last week as they said they would, and not answering my email enquiring about that earlier today. Not sure why the seem to have dropped the ball for me when they've been OK for others. I'm not too worried about the reliability of valve amps in general, or even particularly about this model, as these things happen with all sorts of gear. But it'd be fair to say I'm not impressed with the shop right now.

Yep, when I emailed on Thursday they gave the impression they'd send the replacement in advance so that I wasn't waiting, but when I called them today they seemed much less certain about whether it would be repaired or replaced or what the wait would be. They're apparently calling me back by the end of today, though I think there's only half an hour of their business hours left. Beginning to wish I'd just kept quiet and bought some new power valves...

Hmm, I'm hoping they come through OK for me. I contacted them on Thursday, my amp was collected on Friday, but I haven't had any notification about the replacement being dispatched yet. Was hoping to try it out at a rehearsal tomorrow too...

It looks like an Underwood. Shadow also make one that looks similar, though I'm not sure how to tell them apart.

Hmm, I may have spoken too soon - after the first couple of hours playing at home, the bias indicator lights are showing a fault and it can't be adjusted to the correct condition. Reading through the manual, it's almost certainly a power valve issue, though I don't have any 6L6GT valves around to verify this. Fortunately, Kenny's have been helpful to deal with, and are arranging an exchange. I did suggest that I'd be happy with just replacement valves, but apparently Polar don't stock them, they just exchange whole units. Still, it does sound good, and failures in the first few hours can happen with any valves, so I'm not too worried as long as it gets sorted...

Another quick observation; the published dimensions are wrong. This thing is 15" or 381mm wide, not 353mm as quoted. Worth noting if you're searching for a case or if you use a small cab and are bothered about overhang.

It has arrived intact, and first impressions after some low volume noodling are good. It's a nice width to sit on top of my homebuilt 1x12 cabs too. Like most Ampegs I've played, I have to roll the bass back a little, but it does a very nice subtle transition into grit as the gain is advanced, which is a big part of what I'm after.

I've been well pleased with my MB200, and not just as a backup - it's a good sounding little amp and has enough oomph for most settings I've played in. They're cheap as chips secondhand, and they use a speakon connector so you wouldn't have to carry different cables to use one as backup.

They're scooped if you turn the bass and treble up all the way, which seems to be a surprisingly popular way to use them!

In the kind of setting I'd tend to play in, guitarists are rarely using more than a 1x12 combo, drummers usually have some subtlety and there are often multiple vocals or acoustic instruments that necessitate keeping the stage volume reasonable. In that environment I've found that a 100 watt valve amp through a reasonably efficient 2x12" cab was always more than ample. So I'd expect to push a 50 watt amp a little more, but that should be a fun sound anyway. With that in mind (and experience with several valve amps from 40 up to 100 watts), I'm pretty confident that the Pf-50t will work for me. If your guitarists and drummer have more rockish tendencies, then you'd probably want a little more.

Well, I went for it! I guess I'll report back when it shows up...

Aargh, I notice Kenny's is showing the PF50t as still available, and I might be close to caving in! I have a new band lined up who are retro-minded and not crazy loud, so I'm kind of tempted. My old Dynacord would do the job, but this is lighter and has useful stuff like midrange EQ and DI outs that would make it more useful for gigging...

That would make sense, since since the Series 2 is the one that Francis published the schematic for! Myself, I'm going to pick up a Schalltechnik Vong Filterung kit (snappy name!) when they're back in stock. They have a fixed and a variable HPF in a similar configuration to the Series 3, plus a switchable lowpass filter and boost and a DI output.