this might be a dumb question - Motown D.I. Build

[ReRibbon]

I'm building a passive DI and the schematic calls for 3 toggle switches all together. each one is a two position switch (like a light switch - on/off).
The switches have 3 lugs which are unlabeled. My question; is there a way to identify which lug is commonly labeled 1,2,and 3 respectively?  Its a switch from Radio shack, part number 275-0603.

Thanks in advance.

 

[Andy Peters]

I'm building a passive DI and the schematic calls for 3 toggle switches all together. each one is a two position switch (like a light switch - on/off).
The switches have 3 lugs which are unlabeled. My question; is there a way to identify which lug is commonly labeled 1,2,and 3 respectively?  Its a switch from Radio shack, part number 275-0603.

Thanks in advance.

Generally, the toggle points away from the lugs which are connected.

The easiest way to sort this out is to use your DMM in its continuity mode and just buzz it out.

 

[PRR]

The center goes to one side OR the other.

Get the center correct. Put it in. If it works "backward", unmount it and put it in the other way.

(This is foiled if the switch has a slotted bushing and you have the punch with the key-tab, so the switch can only go one way. But only large shops have those specialized punches.)

As Andy says, on *toggles* *usually* the contact works opposite (see-saw) to the handle. But I have seen the other way just enough to place no bets until I buzz it out (or cut a round hole so I can turn it around on test).

 

[ReRibbon]

Thanks for all yall's help. 

I was able to finally get the volume pot to work, however, it only passes about a tenth of the volume (through the volume pot signal path) as it does compared to the volume that passes coming straight off the transformer... maybe it's supposed to do that?
Additionally, I think I misread the schematic because I have two 3 lug switches hooked up instead of one 6(?) lug switch. What happens is both switches have to be flipped a certain way in relation to one another in order for it to be a clean signal off of both the transformer direct out and also the volume pot signal path.
So I'm wondering if this 1- creates this volume difference and 2- means that I should switch the two 3 lug switches to one 6 lug switch?

Thanks again for the suggestions and help in advance. i've attached a schematic of this project.

 

[ReRibbon]

Additionally, the transformer is wired to a 500 ohm load output.
if it would help this volume issue, I can drop it down to 333,200,125, or 50 ohms.

Thanks again.

 

[Whoops]

What transformer are you using?

 

[shabtek]

That is called a double-pole-double-throw switch.

Draw/show the complete schematic: it is not clear what the source is, how the transformer is connected and what its ratio and orientation is relative to source/load/switch/volume control etc.

 

[johnheath]

This might help?

regards

/John

 

[Whoops]

The title of this thread says "Motown DI build"

Are you trying to do something similar to the DI based on the UTC  transformer that was used in Detroit's Motown Studio?

 

[ReRibbon]

@Whoops- ive tried a few different ones so far. My favorite being a UTC A-12 so far.

@Shabtek - thanks for the reply.

Here is the whole thing. It was originally  called "The Wolfbox" and now it's sold by Acme Audio as the "Motown DI WB 3".

It's inventor, Ed Wolfrum (who apparently invented the DI box as a whole) seemed to have a disagreement with the guy that runs Acme Audio. Mr. Wolfrum then decided to post the schematic to his own invention in apparently in protest of the business process that Acme was using.
This is a link to Mr. Wolfrum's response. http://www.audiographicservices.com/wolfbox.html

 

[ReRibbon]

@Whoops

Also, this box was originally created using a Triad A11J transformer

 

[ReRibbon]

Here is a link to the Acme made  Motown DI.

http://acmeaudio.net/product/motown-di/

 

[ReRibbon]

Just to clarify, my use and sharing of the schematic in my posting of all of this information to the forum is for educational purposes only.

 

[ReRibbon]

@JohnHeath

Thank you Sir.

 

[ReRibbon]

@Whoops
now that I've made your day, do you have any suggestions or thoughts on my switch problem?

 

[ReRibbon]

in following the rules and request of Mr. Wolfrum in regards to his invention the "Wolfbox", here is a link to the Creative Commons License that he has granted.
http://creativecommons.org/licenses/by-nc/4.0/

No changes were made. http://www.audiographicservices.com/wolfbox.html


Thank you Mr. Wolfrum.

 

[Whoops]

EDITED    SEP/2020

It seems that the transformer used might be an UTC A-10 and not an UTC A-20,
please read post in next thread

@Whoops
now that I've made your day, do you have any suggestions or thoughts on my switch problem?

@Whoops

Also, this box was originally created using a Triad A11J transformer

I asked what transformer you were using to try to help you out, as you were not clear at all in your intentions in the first post,  others pointed that out also. But there's nothing here to make my day, I went to the beach today and that made my day.

Also the favorable DI at Motown as per Bob Olhson source (Motown Mastering Engineer) was an UTC A20 transformer connected backwards, Bob says that in a couple of threads on the internet, he also told me about that when I met him in Nashville in 2012.
Not to say that they didnt have other DI devices at the studio, they probably had, like the Mr. Ed Wolfrum DI device.
I just pointed that out because the title says "Motown DI"

As for helping you out,
sure. But I can't add more to what other people already said.

As shabtek posted, you need a DPDT switch (double pole double throw), thats what you were referring for a "6 lug switch",
So my suggestion is to buy one DPDT switch, wire it as in the schematic (B2 is the center of the switch) A and C are the sides, doesn't matter which side you use for C or A,  just choose one for A do the A connections  there and use the other side for C.

Do you have a Digital Multimeter (DMM) to use measuring continuity and resistance?

As for the volume problem, could you explain it better what you are experiencing?
The volume Pot is part of a variable attenuater circuit at the input,  before the signal hits the transformer primaries, using the pot will bring the volume down. The DPDT switch is there to insert the attenuation in the circuit or bypassing it.
With Electric and Bass guitars equiped with passive pickups you will not probably need any attenuation, but with hot signals from some keyboards, instrument active circuits, drum machines , etc it might be really useful .

 

[ReRibbon]

@whoops
I was just making a joke man. I wasn't really expecting an argumentative reply from you to be honest. If you have things in your life that make you unhappy I'm sorry for that but don't take it out on me.

 

[ReRibbon]

@Whoops

Also, I'd be interested to read those Bob Ohlsson threads. Sounds interesting. Could you post a link please?

Also, did you have any thoughts on my switch wiring issue?

You live in Nashville?

Thanks

 

[pucho812]

he has thoughts on your switch wiring issue, whooops and others have told you what's up. you need to reread their posts.

As for helping you out,
sure. But I can't add more to what other people already said.

As shabtek posted, you need a DPDT switch (double pole double throw), thats what you were referring for a "6 lug switch",
So my suggestion is to buy one DPDT switch, wire it as in the schematic (B2 is the center of the switch) A and C are the sides, doesn't matter which side you use for C or A,  just choose one for A do the A connections  there and use the other side for C.