Quad Sound Skulptor Tape Simulator

I finally finished my quad version of Sound Skulptors Tape Simulator:




I had some problems when powering up because I switched the BC139 and BC140 transistors. Aside from that, no problems.
It’s nice to, now and then, build a kit and not having to search for all the parts.
Everything works as it should but there's one weird thing:
When turning the ground level way up there’s a 50Hz hum. I guess this is normal but what’s weird is that this hum is perfectly out of phase on channel 2 and 4.
Thus when panning 2 channels (1 and 2 or 3 and 4) center the hum is cancelled out.
Anyone any thoughts on this?

About the sound: like some have mentioned before the effect is somewhat subtle, especially with the input before 5, but then again so is a going trough a good taperecorder.
When pushing the input further you get a nice fat sound. A subtle combination of saturation, compression and EQ.
I don’t have a lot of experience with tape but this machine seems to do what others say tape does. It reminds me a bit of the tape control on the Crane Song Hedd.
A friend of mine has the Neve Portico, I’ll try to compare the two some day.

I know some of you want some soundclips. I’ll post some files one of these days.


Pieter

Very nice! Congrats 

Looking forward to the sound clips.

Is that transformer "shield" aluminum, by the way? If it is, it won't actually do anything of value. Just a dead weight in the case. Aluminum has pretty non-existant ferromagnetic property, and as such will not block any of the 50hz magnetic hum you are probably trying to combat. It does block radio frequencies, but toroids won't radiate them anyway.

Great build and the FP looks stellar!

For your hum issue, look into grounding. I'm not sure how the PCB is connected to ground, I just see the small green to the chassis.

Really nice looking unit, Pieter, and great front panel!
The hum very probably comes from a transformer proximity to the saturation coils.
Have you placed the unit in your rack close to another transformer powered device ?
Or maybe is it your transformer that radiates to the coils which are very sensitive.
You should make a test moving your STS far from any other device and if not enough, moving the PSU transformer away.

On the issue of shielding toroidal transformer low frequency magnetic hum, this guy is selling sheets that actually do help: http://www.groupdiy.com/index.php?topic=38026.0

I have used them successfully in nearly all of my projects.

OK, so aluminium doesn't block magnetic radiation. Didn't know that. I thought as long as it conducts electricity...
Anyway, it also connects the bottomplate to the back and so helps to support the toroidals weight.

Moving the case or the toroidal doens't make any difference, nor does adding extra grounding, but like I said I only hear it when I turn the output and my speakers way up. (the input doesn't make a difference) It's still a lot more then my SSL tough.
Maybe capacitors with a higher rating in the PSU?
I still think it's weird that the phase of the hum is reversed on channel 2 and 4.

The front panel is made by Frank from NRG recordings by the way.

OK, so aluminium doesn't block magnetic radiation. Didn't know that. I thought as long as it conducts electricity...

Click to expand...

What is good at blocking magnetic radiation is called "Mumetal", but it's not cheap, and the best cheap solution is the one Kingston pointed out, but if you get Mumetal, than a thin layer over a steel frame would work also

The next thing would be to check if you have handled ground-to-chassis point correctly. Are all those eight XLR pin1's touching PCB ground plane? That might be your problem.

Remove all those connections and take a single wire from your chassis star ground to each PCB. Make sure nothing else touches the PCB's from chassis.

Looks great!

Anyone seeing these used in mastering studios?

Looking forward to the sound clips.

Click to expand...

;D

need clips!!!!!!!!

Is it at all possible for someone to compare this next to a Anamod unit?

If its even close I would buy one. 

Looks great.  Love the Knobs

Is it at all possible for someone to compare this next to a Anamod unit?

Click to expand...

Seem to be different beasts....

Anybody has some webspace I can use to post some clips?

i do,pm me

Very nice build!

So has anyone tried this piece at the input and feedback loop of a digital delay?

I did make a loop test some time ago.
It can be found here: www.soundskulptor.com/audio/loop.mp3
But be warned, it is very boring!

Thus the need of other samples! ;D
I already have listened to yours, JPK. ;-)

Great build, congrats.

I made some clips. Dan will put them online.
For those of you who can't wait, here's a link to the yousendit page:
https://www.yousendit.com/download/UFVxSkhRUzgxUUJFQlE9PQ

Pieter

thanks for the effort - sounds nice!