Yahoo Groups archive

MOTM

Index last updated: 2026-04-28 23:35 UTC

Thread

Time Machine problems

Time Machine problems

2002-04-05 by Kevin Boudreau

Warning:� long rambling explanation of my Time Machine problems.� Please skip it if you're not interested.
Those of you that have this module, maybe you can help me:� I just finished building my MOTMized Blacet Time Machine, and I'm not sure if it's working properly.� It may well be that I just don't know how to use it, but I've been fooling with it for several days now, and I just can't seem to get a long delay/echo type sound out of it.� It does make some sort of trill-like reverby/warble noises that are really cool, but something does not seem right.� Here's how I have it set up:� standard VCO-VCF-VCA-2EGs patch with the output of the VCA into IN of TM and TM out to mixer/monitors.� I'm assuming that I don't need any sort of LFO into any of the other TM inputs to get the standard long and short delays, right?� Anyway, assuming that, I have been attempting to calibrate it with the Blacet instructions that say to set the Delay pot to 3, the Regen to 0 (center detent), the Mix to wet, and all other pots CCW.� Ok.� Then, when adjusting the trim pot (I think it's RT4, I don't have it in front of me right now) until the processed signal can be heard when the Mix pot is fully wet, I hear sound, but no delay.� As I turn the delay pot, the sound changes, it makes a sort of warble sound as I move the pot back and forth, but no delay sound.� Only when I turn the Regen knob to either the far right or far left to do I start to get any sort of "delay", but this is sort of a trill-like reverb sound that quickly gets distorted.� I realize that analog delays are supposed to do something like this, but that is the only�effect I can get from this thing.� Now, I followed the directions very carefully, checking the voltages on the board before installing the ICs, and calibrating that one trimpot for 10.0V.� Then I installed the ICs, and at first only got a really distorted sound that didn't sound right at all.� The next morning, when I looked at it again, I noticed that I had installed one of the ICs improperly--one whole side of the chip had the pins hanging over the edge of the socket, not connected.� D'oh!� So I fixed that, and also loosened the board to re-inspect all my solder joints, and fixed a few that looked less than perfect, checkd the pot wires to make sure they go where they're supposed to etc.� After all that, I put it back together and pluged it back in, and it's pretty much as I described above:� no delay except when Regen is fully CW or CCW.� Just FYI for anyone who�is kind enough�to help me with this, I did both of Larry Hendry's mods--the bypass switch, and the negative voltage protection (the one with the teepee resistors and 2 diodes, as the one with the "piggyback diode" was double protection and not needed, right?).� Also, I built the board before Larry's fine, fine instructions were put up on his site, and when changing some of the resistors required for his mods, a bit of the trace started to come loose from the board.� But when I soldered the resistor in place, it seemed to stick down fine, and never broke free or anything.� I am relatively new at building MOTM and electronics in general, and thus not very good at diagnosing a problem�using the schematics, especially on one as dense and the TM, �otherwise I would try to figure this out myself.� Could I have damaged the IC that was not seated properly while powering up the module, or could it be one of those traces�*is* broken, or...maybe since I don't have a frequency counter, the 2 trim pots that require one to set them are way out of whack?� I just don't know.� I tried to give as much info as possible in this post so any potential helpers could help me diagnose this problem.� Someone help, please!� Thanks, in advance,
Kevin

Send and receive Hotmail on your mobile device: Click Here

Re: [motm] Time Machine problems

2002-04-06 by John Blacet

There could be damage to the IC that was powered up with pins out of the
socket.

With the MIX full wet, delay may not be apparent because there is no
reference. You need to add some dry signal and make some changes in the
input signal frequency to hear the effect.

If you use a short delay and add in some LFO, you should hear some
flanging type sounds.

Regards,
___________________
John Blacet
Blacet Research
http://www.blacet.com

Re: [motm] Time Machine problems

2002-04-06 by Kevin Boudreau

>
>"Could I have damaged the IC that was not seated properly while powering
>up the module...?"
>
>Of course! Which IC?
>
It was U14.

_________________________________________________________________
Chat with friends online, try MSN Messenger: http://messenger.msn.com

Move to quarantaine

This moves the raw source file on disk only. The archive index is not changed automatically, so you still need to run a manual refresh afterward.