Motown Direct Amplifier-inspired Preamp?

[s wave]

I just figured I would interject here. I had the pleasure to talk to Bob O. (hey there) a few times on other site. If no one previously mentioned it; James Jamerson's bass was plugged into an DI/amp that used a UTC A-10. (someone had a probable Motown one with a UTC-11) The old gray ones. https://reverb.com/item/55686219-utc-a-10-transformer. James would listen back to a direct signal through the studio monitor and the ["amp" consisted of a mixer, a McIntosh amp and an Altec monitor speaker.] Interestingly Babbit used a UTC-11 in Philly? Sigma commented on how 2 great bassists/studios ended up using a similar tranny. Prolly cuz the low end bliss. The ol wolfie box schematics is trackable I think. https://en.m.wikipedia.org/wiki/Wolfbox Big Bob Olhsson fan here https://en.m.wikipedia.org/wiki/Wolfbox

 

[abbey road d enfer]

I just figured I would interject here. I had the pleasure to talk to Bob O. a few times on other site. If no one previously mentioned it; James Jamerson's bass was plugged into an DI/amp that used a UTC A-10.

As anyone that's followed the thread from head to toe, this in full contradiction with other testimonies, e.g. Jim Joe Messina who affirms James Jamerson's bass was plugged in the same box the three guitarists were. Now, i'm not saying Bob O. or Jim Messina is wrong but maybe someone is mistaken, OR it could be that different set-ups were used in different sessions, due to a legitimate desire to experiment, so they would both be right.

 

[CJ]

Joe Messina,




On most Motown songs you can barely hear the guitars, they are way down in the mix, so the amp might not he a big as factor as say the instruments and the players. Most of it sounds like a click track tied to the snare to either push the beat forward, keep it the same or drag it back a bit.
It us really hard to hear the guitars on the tracks with a lot of horns, strings, vibes, etc. The best way to hear the subtle effect of the guitars is to listen to the track with and without the guitars.

But I still want to know what was in that box!

 

[abbey road d enfer]

Joe Messina,

You're absolutely correct. I know very well the difference, but fingers did not follow brains.

 

[CJ]

Not you fingers, AI spell check,

 

[olhsson]

Last year I spent a week at the studio with John Windt who had actually assembled the box. It turned out I was wrong about the reverse UTC A-10. It had a high impedance tube input. It may have had a UTC output transformer for each input because it was balanced in the patch bay. Joe's memories match mine. Mike's information in the first post is correct. He designed it and John assembled it.

 

[CJ]

Looks like an LA2a circuit without the side chain would be a good starting point. 1/4' input jack. UTC HA size output,

 

[MidnightArrakis]

But I still want to know what was in that box!

[But I still want to know what was in that box!] -- Is there an actual complete and working schematic of this box somewhere in this thread? I would go ahead and build this thing, even including the VU-meters, if doing so didn't require piecing together 7 different partial schematics from 11 different people!!! Anybody know of an entire schematic of this box or maybe a link to someplace that has one posted or something?

/



/

 

[CJ]

Any schematic would be speculation at this point.

Plus there is somebody selling this as a product.

Does not mean we can't build something similar,

Sweetwater has the tube compliment listed,

I have a hunch that Triad made the OPT,

 

[abbey road d enfer]

I would go ahead and build this thing, even including the VU-meters,

What for?
This was a product built at a specific time for a specific use in a specific environment. In order to make sense, you would need to build a studio around it, with tape machines and not many channels, making records with all the musicians in the studio.
It doesn't exist anymore.

 

[CJ]

Triad HS-50 is a 5:1 with sec taps , it was mentioned that the engineers might need 300 ohms if trying to drive multiple inputs, so the HS 50 could be strapped for that.

The HS 50 I tested only could handle about 14 volts on the primary at 10 hz before saturation, so the 26 db rating is a bit puffed up, it might do that at 40 hz but not 20.

So what we have so far is 2 ea. 12AT7's and a 6BX7 White cathode follower feeding a Triad HS 50 strapped for 233 ohms.

And a vol control.

Now all you have to do is figure out how they are all connected and with what parts.

Unfortunately there is no original sample to compare it with so how will you know if you got it right?

Still fun to try.

I see that the Motown EQ reissue is now available.