Quickie tube issues / suggestions for a Quickie 2

[Jeff]

I've been using my Quickie for a few months now, and there are some issues I wanted to relate FWIW. I was a little disappointed with the extreme microphonics of my kit, but I liked the overall sound. Most of the issues, as I can tell, would be really easy to address in a second version of the kit (if that ever happens).

I notice that many builders mount the battery holders on the bottom of the plate, which to me doesn't seem to beautify things that much because of the dozens of exposed nuts. A separate subchassis plate for the batteries (and top plate with only four mounting holes) would solve this, though it would add to the cost. It's just a thought; I realize this thing was designed to a price point.

One annoying problem for me is the layout-- having the power switch next to the tubes means that every time I go anywhere near it I excite odd noises from the tubes. It would make more sense to move all switches away from the tubes further to avoid these problems with the excitable tubes, with the trade off being potential noise issues with the input selector, if it were moved.

But the worst issue is the availability of decent tubes. Yes, 3S4 tubes may be really plentiful and accessible for the "insiders" but here is my experience. The Tung Sols that shipped with the kit were decent, but occasionally noisy and quite microphonic. So I ordered some expensive Mullards from a forum member here, and bought a pair of cheapies on ebay. One of the cheapies was DOA, and the Mullards never arrived. I had to file a claim to get my money back after no contact in five weeks. I ordered another set of Sylvanias from ebay; one had a bent pin that snapped off when I straightened it. My original tubes are now so noisy as to be unlistenable, and I have a missmatched pair of "cheap" tubes that cost around $40 with shipping. Not to mention lending a forum member $40 for a month for the promise of something better.

That is nearly equal to the price of the kit. I have ordered Pass B1 boards, and I have an Aikido LV on deck to build but I would at least like to get a little more use out of my Quickie.

Does anyone have any suggestions for reliable sources of 3S4 tubes? I know there is a thread on that, but it's getting long in the tooth and has caused me much consternation trying to avoid saying ugly things about the source recommended by the staff/long time posters.

Jeff Ward

[Doc B.]

Give Eileen a call at 206-451-4275 or email her at queen at bottlehead dot com and she will send you another pair of tubes.

[matthewmckay]

Check out Tubeworld.com .  I got a pair of 50's RCA($25/pr) and some 60's amperex($30/pr).  The RCA's have more presence, and a bit more noise, (not microphonic at all).  The amperex are far more laid back and have a much darker background.  I Havn't decided which is my favorite. Both are very good, just different.  I also definately recommend finding some auricaps as well.

[Jeff]

Check out Tubeworld.com .  I got a pair of 50's RCA($25/pr) and some 60's amperex($30/pr).  The RCA's have more presence, and a bit more noise, (not microphonic at all).  The amperex are far more laid back and have a much darker background.  I Havn't decided which is my favorite. Both are very good, just different.  I also definately recommend finding some auricaps as well.

Awesome. That was exactly what I was looking for. I have been completely willing to pay for tubes, and wasn't really looking for a handout-- though I appreciate the offer, Doc.

Jeff Ward

[Doc B.]

Sorry, I didn't mean it to sound like a handout. We are more than happy to send out replacement tubes if someone gets a bad one. Though one must bear in mind that a directly heated tube used like this is always going to have a tendency for microphonics. It's the nature of the beast.

[Jeff]

Sorry, I didn't mean it to sound like a handout. We are more than happy to send out replacement tubes if someone gets a bad one. Though one must bear in mind that a directly heated tube used like this is always going to have a tendency for microphonics. It's the nature of the beast.

I didn't get a bad one. I've been listening to the Quickie 8 hrs a day for these last two months, and the tubes were fine. I wouldn't expect you to warranty NOS tubes, and I'm satisfied with how well they performed. The noise issue is a recent development. I was looking for sources of other tubes for variety's sake as much as anything else.

The fact that microphonics are a part of the design was also assumed, which is why I couched my thread title the way I did. I think that the microphonics are exaggerated by the layout, and some shifts in the switching arrangement would make operating the preamp less jarring.

I notice that a few of the experimenters have moved the switches off the top plate (and relocated the signal jacks), which would help. I know that this is impractical in a basic kit with the standard bottlehead base arrangement, but it seems to me that locating the power switch further away from the sensitive tubes (and some mass between the switch and the tubes, say on the other side of the battery area) would help quiet things down.

[Paul Joppa]

There are some interesting ideas here. When the Quickie came out, we were hoping that the collective brainpower on this forum would be experimenting with ways to deal with the microphonics. In the early days, we did some experimenting with tube damping (not very effective) but we never thought about placing switches etc. for less handling noise - it's a great idea!

The discovery (by forum denizens here!) that there are some 3S4s that are significantly less microphonic was great, but it seems to have taken the steam out of other mechanical solutions. Hopefully this post will inspire some more experiments.

A bit of history - we dithered for a couple years about making it a kit at all. The original prototype was on a large 0.040" aluminum Hammond box and was very microphonic indeed. We also tried two or three tubes, but never ran across any low-microphonic ones. We decided to give it up, but kept coming back to it for the quiet power supply and the DHT filament sonics. It was PB who suggested the smaller plastic chassis, which reduced the microphonics quite a bit - and was also just enough cheaper to get below the $100 price point. (The original Foreplay was $99 when it first came out, which would be around $135 in today's dollars.) We moved the batteries to the top for more convenient changing at the same time.

My own idea would be to put the tube socket and batteries on some kind of isolation mounted subchassis - using the battery mass along with the subchassis mounting compliance to provide maximum isolation.

Incidentally, excess system gain (power amp and speaker sensitivity) will make the problem worse. On the Community page of the Bottlehead site is my white paper on signals and noise which addresses this issue. It might help some systems.

[Moko]

I managed to solve the microphonics on my Quickie by wrapping the tubes in Bubble Wrap and putting them inside an old pair of tin tube dampers.

(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fi787.photobucket.com%2Falbums%2Fyy154%2FMokoMilk%2FHiFi%2FQuickie%2FIMG00161-20101024-2029-1.jpg&hash=5f301408d599d9af460119a37c35efd793f9ae6d)

That's not to say you can't hear a noise when you operate the switches but in general operation I can't hear any unwanted noise.