Conn Dynalevel

[Enzo]

One of these came into the shop recently for general repairs. I've never seen one, though I hear Lenny Kravitz uses one for level monitoring.

Essentially a visual VU meter in a light tree. The light tree or tube is about 18" long, with 11 segments inside the frosty glass. In each is a colored bulb like from old Xmas lights.

The chassis drives the bulbs with 11 2D21 tubes, which act more or less like triacs. Only plpace I ever saw 2D21s was in jukeboxes, where they controlled relays and solenoids.

Otherwise simple circuits. Whole thing built into a handy case with handle.

Pretty cool.

http://www.petersontuners.com/oldweb/images/bank/Dynalevel1.jpg

[Sweetfinger]

THAT'S the COOLEST fry-toy I've seen in a while! Looks like you can 'customize' the colors in your display with bulb selection. The perfect thing for the occasion where a 'magic eye' tube just isn't quite magic enough!

[Enzo]

Yes, move the colors all you want. Only about four of the bulbs lit, and I found the others had just worked loose. Screw all the bulbs in tight and they all worked. A blown fuse and loose bulbs was all it had wrong.

[Enzo]

Followup: The customer was happy as a clam when he got this back working, and I for a big "You da man, Enzo." Now apparently the guy has been talking about this online with his buds, one of whom asks "So you got a guy who fixes those?" He tells him yeah.

So the online buddy mails another one of these to my customer to bring to me.

So I now have another one of these things here in my shop. I went from never having even heard of these machines to being the national expert. Or something.

[Paleo Pete]

Cool toy.

I think 2D21 is also the tube used in Seth Thomas metronomes years ago. I had one, not too long ago it got left in a studio/music store and I never got it back, just realized it a few days ago. It and my wind up were there, we were planning to use them to record. The guy flaked out big time and closed up, I never got some of my stuff back.

[Enzo]

It really is great to watch it work.

[bob p]

wow, that is a pretty cool old toy.

enzo, you know that being the national expert means that people are going to start looking to you for a schematic... :D

actually, i'm kinda surprised that people have so much trouble getting them serviced. why don't they just send them to peterson?

[Enzo]

I don't know that Peterson works on those, maybe. I drew out a schematic, the circuit is simple. REmember it is just a level meter, not a tuner.

I probably should redraw the thing neater and on one page.

Audio in, a couple triode stages of amplification, then a triode driving a small transformer ala reverb driver. The secondary output is then rectified and fed to a long string of resistors. Each bulb has its own 2D21 tube to turn it on, and each step of the resistor ladder feeds one grid. As the signal level rises, more and more of the 2D21 grids reach the point of turn on, and the bulbs light.

[ccglenn]

I have a Conn Dynalevel T-80 manufactured in 1969. I would be glad to share the manual and schematic with others that need a copy. It has been sitting in the closet for the last 35 years so I need to read the manual to see if the unit is still working. More later. cc glenn

[Enzo]

I would love to have the oficial schematic. If the file is under 1MB, attach it to your post.

I have shown the units to various guests in my shop, and they never fail to ooh and aah.