I'm guessing you split one of the long pieces . . .

Close. It's hard to describe briefly.  I'll look through my photos and make up a small webpage with the procedure on it, if you're really interested.

I'm sure you can get one together scratch.  It's not an elaborate circuit; and in all honesty, the divided chassis is a cosmetic feature; it's the physical separation of the PS and audio circuit that keep the noise down.  I'll help you as much as I can.

The chassis is Jarrah on this one, an Ozzie hardwood that's much used for floors and decks.  She's a gum tree, mate.  I sometimes use Koa, but not for pieces going out of Hawai'i; it's getting too rare.  I sometimes also use Padauk, Zebrano, Wenge.

Yah, each tube type will have both a basing type, and a bulb type.  These define its physical characteristics, which have to be dealt with by the implementation guy.

Aloha,

Poinz

Yes, I'd love to see additional frame construction and wiring details.
There's certainly no hurry. Since I travel during the week and am only home on weekends, my projects are often stretched out longer than what I would like.

Oh, Jarrah wood. Nice! I've heard some of these tropical woods can be difficult to glue because of the oil content. Are you using any special glue, or regular "carpenter's glue" (alphaic resin)?

I'm afraid I'd be stuck using walnut, cherry, or possibly maple. Those are the common ones here, along with oak, but generally I don't favor the grain pattern of oak. I often just stain it black.

I was poking around on eBay for 6AQ5's and noticed some Russian ones that were 9 pin, not 7 pin miniatures. Interesting. So, that basing type is important to mind. I had no idea. I just thought a 6AQ5 was the same, with the same pin-outs, etc. no matter what.

I'm curious as to why you selected this particular tube since it appears no manufacturer is making them new. Sonics, I assume?

Regards,
Mark

Mark

The 6P1P is not a 6AQ5, any more than the 6AQ5 is a 6V6.  It'a a mystery to me why these two devices have been touted as equivalent on the auction sites; since they do not even have the same basing or envelope.  I sympathize; I have been corresponding with a gentleman in G. Britain about his Svet (real, St. Pete) 6AQ5's for a week now, and they are actually not, they're 6P1P's and will not fit my gear.  Strange.

I did not select this tube, it selected me.  I was looking for a line amp tube with lower (about ten) mu, and lower (about 2K) rp, and saw it in the tube manual.  Beam tube, but I've been using beam tubes and pentodes in triode since day one, so hey.  Looking on the vendor sites, I saw that it shifts typically for $2-5, so how could I lose?  First guess, whooda thunk it would be so fab?  I got quad of brand-matched quads from Alltronics, and they made de Poinz look so-o smart.  Don't tell, now.

Poinz

In addition to my little "TV repair guy" stash of 6AQ5's (don't know how many, if any, of those really work), I won an e-Bay auction yesterday for about dozen of mixed brand 6AQ5's yesterday. Cheap, cheap...only $8.50 plus the shipping.

So, I'm all set!

Now I just have to get you to reveal any additional construction / wiring secrets, then start ordering stuff.

I will check out Alltronics. Have not heard of them.

I figured that those Russian tubes were not really 6AQ5's since they were 9 pin miniatures, not 7 pin miniatures.

Appreciate your continuing help and advise!
Regards,
Mark

I do sell these as a (very small) business, and so you may rely upon Wayne (who has demo'd this very piece at The Show) to scold me in public if I huckster the commercial offering in the guise of DIY advice.

It's a simple circuit with a simple power supply, as you have seen. It performs in my (not-unbiased) view, remarkably. Monster soundstage, high and natural color of timbre, intergalactic black background, bandwidth (+0, -0.5dB) 16Hz - 150KHz.

Don't forget to let me know (preferably through this channel) how you get on.

Aloha,

Poinz

These defects are more difficult to detect when stereo transducers are used, because cancellation from out-of-phase signals is incomplete (or in the case of headphones, nonexistent). Nevertheless, this issue points out how poorly source material is being produced and processed these days, and how important it is to select programming carefully when evaluating a system.

Sorry, I know this doesn't have much to do with the preamp under discussion, it just caught my attention.

The thing is, in these huge mixing boards, the signal may go through ten or twenty op-amps, which can invert or not, and I don't know if there's any standard for this in the construction of the boards, so the engineer is sort of stuck; how's he to know?  It might only be the little purist recordist who uses practically no electronics (and those made by him) between the mike and the tape who can control this.

I think it makes a difference, which is why I mention it.  It seems to show up most in transients, like drum whacks, which sound more natural if they're in correct absolute polarity.

Poinz