Anybody looking for 2K Tempcos?

Tim Servo · Posted: Sat Dec 10, 2011 9:38 pm Post subject: Anybody looking for 2K Tempcos?

Hi All,

After much searching, I finally have some 2K Tempco resistors in stock!! These are 1/8W 3300PPM units, BTW. Prices are one for $1.80, 2 to 5 for $1.50 each, 6 to 10 for $1.20 each, 11 or more for $1.00 each (+ shipping). Smile

I also have in stock what is probably the last run of TH-301 "Cucamonga" VCLFO boards (from the AS21C book). And finally, I have 566, 2206 and 8038 chips, although I would prefer to sell them with the TH-101, 102 and 301 boards.

Give us a shout at magsmoke@gmail.com if you want more info. Thanks!

Tim (temperature compensating) Servo

diablojoy · Posted: Sat Dec 10, 2011 11:55 pm Post subject:

just bought some SN voice boards and planning some other boards
so yes about 20 or so
email sent

rosch · Joined: Oct 03, 2009 Posts: 165 Location: germany

hey that's really great news!
email sent Very Happy

arsonus · Joined: Apr 17, 2011 Posts: 14 Location: Slovakia

e-mail sent for 24.
Very Happy

MadScientist · Joined: Nov 28, 2011 Posts: 63 Location: Denmark

Suspect Mr. Servo has been overwhelmed by the response to his post. Mail sent, yesterday. Very Happy

frijitz · Posted: Mon Dec 12, 2011 1:34 pm Post subject:

Soooo ... What happened to our deal?

Very Happy

Ian

toppobrillo · Posted: Mon Dec 12, 2011 3:44 pm Post subject:

great price!! I have some 1K TCs fs over at muffs, http://www.muffwiggler.com/forum/topic-48377.html
maybe we could swap a batch?

Tim Servo · Posted: Mon Dec 12, 2011 5:54 pm Post subject: Anybody looking for 2K Tempcos?

Yep, several people have been waiting for these. Took me almost a year to find a source! I'll get messages out to everyone over the next few days.

Ian, I'll get some to you to check out. Smile

I hope they have a reasonable response curve, as I've got about 600 of the little buggers!

Toppo - I don't think I really need any 1k parts, but let me look at what you've got later on (I'm not at home right now).

Thanks to everyone who has been patiently waiting for these, and also to those who have ordered already. Smile

Tim (Mister Resistor) Servo

Leshrac · Joined: Dec 13, 2011 Posts: 6 Location: Germany

tried to get in contact with magsmoke but there comes no reply .. HELP Shocked

Tim Servo · Posted: Tue Dec 13, 2011 12:32 pm Post subject: Anybody looking for 2K Tempcos?

Hi Leshrac,

Whoops! Here's the problem:

"i am not sure how i can contact magsmoge@gmail.com because i wrote 3 times and no answer is coming back."

Just to make sure everyone knows, you can contact me here or at
magsmoke@gmail.com
Smile

I'm a small operation (just me shipping stuff and John M. running the web site), so hang tight if I can't get back to you right away. Rest assured, I'll get back to you as soon as I can!

Tim (could really use a couple of clones this time of year) Servo

defog · Joined: Aug 24, 2011 Posts: 113 Location: Philadelphia

For anyone looking for inexpensive smaller sized tempcos you can epoxy right onto an IC/transistor, I've been using SMT 1ks in series and they've worked wonderfully.

http://search.digikey.com/us/en/products/ERA-S33J102V/P1.0KCDCT-ND/526980

frijitz · Posted: Fri Dec 23, 2011 11:40 am Post subject:

defog · Joined: Aug 24, 2011 Posts: 113 Location: Philadelphia

defog · Joined: Aug 24, 2011 Posts: 113 Location: Philadelphia

So I just ran a test that lasted for an hour. I allowed both the through-hole tempco Soundlab Ultimate and the SMD Sound Lab Mini to warm up for 30 minutes, then tuned two oscillators on each to Note C3. These were both built with 1% metal film resistors. My ultimate has SSM transistor ICs and my Mini uses extremely carefully circuit tested hand matched 3904 transistors with proper Hfe values. They both have pretty much identical oscillator circuits, so it is a good comparison for drift.

I measured in 5 minute intervals and checked Hz on both.

Sound Lab Mini - 5 Minute : +-03.0 Cents, 0.0 cents
Sound Lab Ultimate - 5 Minute : +03.0 cents, +06.1 cents

Sound Lab Mini - 10 : +04.0, -01.2
Sound Lab Ultimate - 10 : +08.5, +13.3

Sound Lab Mini - 15 : +04.7, -02.4
Sound Lab Ultimate - 15 : +11, +18

Sound Lab Mini - 20 : +1.8, -05.3
Sound Lab Ultimate - 20 : +13.3, +21.3

Sound Lab Mini - 25 : +03.0, -04.3
Sound Lab Ultimate - 25 : +15, +23

Sound Lab Mini - 30 : +03.0, -3.5
Sound Lab Ultimate - 30 : +17, +26

At least for the soundlab builds I've done, it is pretty obvious that the SMD tempcos are superior to the thru-hole version in a 30 minute run. I can't say that will be the same in all builds, but at least in the two of mine that is the truth.

frijitz · Posted: Sat Dec 24, 2011 9:47 am Post subject:

defog · Joined: Aug 24, 2011 Posts: 113 Location: Philadelphia

defog · Joined: Aug 24, 2011 Posts: 113 Location: Philadelphia

Sorry for bumping an old thread, but I just wanted to double confirm anyone's suspicions with using these SMT parts. They work, and they work beautifully.

The bass player in my band has a set of organ pedals that he uses going into a midi to CV converter into a soundlab mini, and the pitch hardy drifts at all using these parts. He does not have to re-tune at all throughout a 45 minute set (with a warm-up period). It is much more stable than the other synths I have built when used live with through-hole equivalents, I'd say 3 to 4 times more stable. The only drawback is that soldering them together and sticking leads on them is VERY tricky.

Even if you were to make 2 or 3 of these, I'd recommend getting a minimum of 10 or more, as you'll most likely destroy a few in the process. In my experience, soldering the leads to each resistor first is crucial, as it works better to dissipate heat when joining the two 1k resistors together. Low heat setting on your iron is a must. After that is done, a quick epoxy coat over them ensures they won't budge and another coat on top of it right onto the transistors/IC ensures good thermal contact. I am considering going back into my other gear and replacing the through-hole tempcos with these now.