An URGENT, but also quick and easy Total Recall question!

[morkmango]

Hi everyone,

I built my total recall a few months ago and I had some issues following the biasing/calibration section of the build doc as others have mentioned. I ended up calibrating it by ear and have been really happy with the pedal.

I had never played a DMM before, but I knew that I was about 90% there with my build, but not 100%... So, today I rented an actual DMM for a day or so to compare as I calibrate my TR (Hence the URGENCY... I want to get it all done when I am off tomorrow!)

Anyways...

Do I NEED to take out all of the MN3008s before recalibrating, or can I just leave them in their place?

The reason I ask is that I have had chips lose their legs when I removed them in the past and this is a major pain. I would hate to ruin a MN3008 and I would much rather be able to leave them be.

BTW... After comparing the real DMM and the TR, I am convinced that I can get the TR extremely close with a bit of tweaking. They already sound extremely close, but my TR is clearly not calibrated 100% correctly.

Thanks for the help!
Mark

[m-Kresol]

Removing them is the way to go according to the build doc, but I guess if you are using an audio probe anyways to check a certain point you can also leave them in. I recently got an IC-remover tool from banzai which is totally worth the 1.5€.

[morkmango]

Thank you for the reply.

I do have an audio probe, so you think I'll be alright to jus leave them in ?

Thanks again.

[m-Kresol]

The instruction says to add one after the other. But I guess as you probe one BBD output at a time, it should work with all of them in anyways. BUT it also says that adjusting Gain1 and bias 2 is interactive, so I guess having Gain1 set to a good starting point before inserting the second BBD will be advantageous.
You can have a go at it with all of them in and if that doesn't work, pull the ICs. You won't loose more time than you already have discussing about it

[morkmango]

The instruction says to add one after the other. But I guess as you probe one BBD output at a time, it should work with all of them in anyways. BUT it also says that adjusting Gain1 and bias 2 is interactive, so I guess having Gain1 set to a good starting point before inserting the second BBD will be advantageous.
You can have a go at it with all of them in and if that doesn't work, pull the ICs. You won't loose more time than you already have discussing about it

It was night time (Australia) and the wife wasn't having any of me calibrating analog delays. But now, game on!

I'll let you all know how it goes.

[lincolnic]

Make sure that you note the build doc is wrong when it tells you how to calibrate the Gain 2 trimmer. The actual way to do that is to set it so the volume is equal at pin 7 and pin 14/15 (either one) of the NE570.

[morkmango]

Update:

So, and it always seems with building pedals, there was some ups and downs, but in the end I'm pretty happy.

I ended up having to take out all my chips a few times... I swapped them around and (at least in my mind) ended up with a better one for ic6... I'm able to bias it lower on the trimmer... Not sure if this really matters or not, but I feel it has made the whole thing better

In the end, when compared to the real dmm, you can totally tell they are the same pedal, the only issue I have with the TR is that when I turn my modulation up high, it's quite a bit noisier than the dmm. I can hear the throbbing of the modulation, whereas the dmm is quite quiet. Both have nice modulation though.

Overall, mine goes into self oscillation quicker than the real deal, but also has a longer delay time.

Thanks Lincolnic, you saved me a few headaches.

[lincolnic]

Glad to help (and you can thank Scruffie for providing the correct method)! Brian said he was going to update the build docs a month or two ago, but it hasn't happened yet.