Emt 140rk part 2... meter options

[pucho812]

The round meters I got for a couple of bucks at the surplus place work for the 140rk. However at full they are supposed to measure 1.5mA.  So they do not go up as much as I would like. Should I just get different meters or is there a way to make it more useable? Or do I not even bother and use what we got because ultimately we will go by ear not by meter.
At full I get the following as wired with  our mockup wood panel and switch.

 

[pucho812]

And here we are at minimal setting we go below the 0 on the scale. The meters are sealed and I can’t figure out how to unseal them.  I like the round look but willing to do something else if i can get more distance in the meter.
The original
Specs are 375 uA dc meter. Which is beyond impossible to find.
Suggestions?

 

[radardoug]

Well, if your meter is 1.5 mA, and the original was 375uA, you need an amplifier of about 5 times. And for the going below 0 problem, you need an offset for that end of the scale. Think meter on the UREI 1176. I seem to remember the original circuit did allow for an offset at the bottom end. First thing is, put a volt meter on the pot output from the EMT, and measure the voltage for different settings of the damper. Then build electronics to suit.

 

[PRR]

> I can’t figure out how to unseal them.

METERS: [email protected]

While brand names change, there can't be too many meter-makers in Manchester NH. (There IS another in the state, Hoyt.) This may be derived/descended from A&M MR26/MR36 Ruggedized Series. The "Meters" contact person may know who to ask.

 

[pucho812]

> I can’t figure out how to unseal them.

METERS: [email protected]

While brand names change, there can't be too many meter-makers in Manchester NH. (There IS another in the state, Hoyt.) This may be derived/descended from A&M MR26/MR36 Ruggedized Series. The "Meters" contact person may know who to ask.

thanks PRR.

 

[pucho812]

Well, if your meter is 1.5 mA, and the original was 375uA, you need an amplifier of about 5 times. And for the going below 0 problem, you need an offset for that end of the scale. Think meter on the UREI 1176. I seem to remember the original circuit did allow for an offset at the bottom end. First thing is, put a volt meter on the pot output from the EMT, and measure the voltage for different settings of the damper. Then build electronics to suit.

Yes, but trying to keep the panel passive... so might just rethink my meters and use these elsewhere.

 

[PRR]

You left the plans in another thread 

You want a current multiplier. Current mirror is another way to think about it. There are discrete CMs. But a 19 cent dual opamp and one resistor will do. You have power in the meter control board.

 

[PRR]

.

 

[mjrippe]

The meters are sealed and I can’t figure out how to unseal them. 
Specs are 375 uA dc meter. Which is beyond impossible to find.
Suggestions?

Some sealed meters are not meant to be opened - they will die if you open them.

Perhaps look for a 0.5mA meter.  Then your needle should go most of the way up.  Or a 250uA meter with a resistor in front of it.  You can them make your own dial plate to read in Seconds or whatever you like.

 

[pucho812]

Some sealed meters are not meant to be opened - they will die if you open them.

Perhaps look for a 0.5mA meter.  Then your needle should go most of the way up.  Or a 250uA meter with a resistor in front of it.  You can them make your own dial plate to read in Seconds or whatever you like.

Yes... got some inexpensive 500ua meters coming. Taking it from there...  in total between the original meters and the new ones we are looking at 12 bucks total. Taking it from there.
As for the scale  from les to mo is good enough for us. I need mo verb, I need les verb.

 

[pucho812]

Well haza haza, ordered me a new el chepo meter off amazon, boy is it awesome.  It's bigger and square but boy are the ballistics more on to what we wanted and want is needed. I can get full throw of the meter when the motors and the plates are at full open, no damping, and all the way down to  infinity when full damping. I can now print a new scale , perhaps maybe labeled MO and LES.  for MO reverb and LES reverb.  ;D

 

[mjrippe]

Moles?  Small blind rodents.  I prefer moles, over enchiladas de pollo con arroz y frijoles!

 

[pucho812]

Moles?  Small blind rodents.  I prefer moles, over enchiladas de pollo con arroz y frijoles!

I am half Mexicano, half Italian. I could never get into the mole sauce. However in the winter, Abuelita is a welcome treat.

https://en.wikipedia.org/wiki/Abuelita

 

[pucho812]

And here we are, in all it’s glory.

Works as intended. Dymo labels as a tribute to nydave.

Yes there are 2 plates, one has martech plate electronics, the other has emt solid state electronics. We also have a set of tube ones but those may be sold soon.