Question for Zvex

[mlabbee]

i built the nano head on one. including the high-voltage switcher. 8^) i also built my stereo hi-fi prototype on one. of course, completed, it looks and works much better in an enclosure

In the hopes of turning a silly thread into a useful one . . .  Zachary, you mentioned that you breadboarded the nanohead and another tube amp on a radioshack breadboard.

I've been wanting to play with those 6021 tubes (I'm going to try a "Real McTube" with them to see if I can make a really small high voltage pre-amp) and have been trying to figure out how rig up some kind of alternative to my pre-fab breadboard because I was under the impression the pre-fab ones couldn't handle the high voltage.  I'm planning on running voltages from 100-200 volts in my experiments - is this in the range of voltages you've used?  I take it you had no problems (other than some increased noise, presumably)?  It would make life a lot easier than trying to nail up a turret board, but I'd also rather not burn down my house or give myself a perm . . . any advice you can offer would be appreciated.

[zachary vex]

i experimented with tons of different voltages... i went to 200% of maximum rated voltage on the plates (but i watched the dissipation carefully so i wouldn't melt them down).  the sound quality is highly related to plate voltage but it is also strongly related to the surrounding circuitry... i used whatever voltages sounded the best for the particular application.  for example, the plate voltage on the class-a nano is 230 VDC and, remarkably, the best sound i got for my class ab hi-fi amp was with a completely different voltage from that.  so you just have to wing it, really.   a nice adjustable high-voltage supply is the best way to go.

[Brian Marshall]

wow, id be kind of scared with that much voltage on a breadboard...  When i work on breadboard im usually pretty messy... id probably burn the house down, or get shocked a a lot.

[petemoore]

Urethane Glovies your so fine !!!
 I want to make glove all the time.
 [I used to re-design a glove factory machines to make glove]
 and sing
 'For your gloves' [?Yardbirds?]
 I feel like makin' glove [B.C.]
 Glove is a many splendored thing [?]
 Dirty Glove [Zappa knock off]
 'Somebody to Glove' [J. Airplane]
 "Glove me 2 Times"   [Doors]
 "I Glove the Flower Girl' [?]
 "Dr. Glove" [Kiss]
 "Dr. Strangeglove"   lol :lol:
 Then when the machine was wasting material and causeing huge downtimes...songs like:
 "Had enough bad Gloves" [EC]
 "You Give Gloves a bad name" [B.J.] :twisted:

[mlabbee]

Zachary - thanks for your thoughts. That raises another question - can anyone recommend a variable power supply that gets up to tube voltages? I've found tons of bench supplies that go up to 30V, but none much higher.

[zachary vex]

i found and old Hewlitt-Packard 6209B at a surplus electronics store in Minneapolis called ABC electronics, where i used to buy all of my knobs and a lot of odd parts.

there's one on ebay right now.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=58286&item=3855233377&rd=1&ssPageName=WDVW

[petemoore]

Long story short, you can find old stuff that has high DC Voltage PS built in it.
 Be Very careful with Potentially Lethal Voltage, be certain that you're able to identify it, and protect yourself from it.

[mlabbee]

Awesome - thanks guys!

[zachary vex]

the advantage to a professional power supply, of course, is built-in precision current limiting, noise-free regulated power, and any output voltage you want.  you can control a high-voltage power supply salvaged from some old tube piece using a variac, but you won't have current control, if that matters to you.  at least, you should put a series resistor in line with the output of the supply to limit the current to some reasonable value... until you're sure your circuit is wired up safely and operating.

[ErikMiller]

I bought a Heathkit IP-17 at a ham swap and it has everything the tube tech/experimenter needs.

B+ voltage 0-400, C- of 0-100 (for bias), and both 12.6 and 6.3VAC for filaments. All available simultaneously.

When I picked it up for $30, all I noticed was the 0-400V, and then when I got it home, flipped out about the other stuff.

It also had a pair of "Mullard" 6L6's in it. Notice I use the past tense....

I want to build a tube characterizer (mu and transconductance) I can power with it. Still looking for the best schematic.