VU Meter recommendations / Tube preamp

[reinw33]

Hi everybody,

building my first tube preamp and there is around +250VDC on the lines of the VU meter.
What kind of VU Meter can you recommend for this purpose?
Don't they have lights also, like neon(?), incadescent (?), xeon(?), and use like 1/4 Watt @ 230V.
What about LED?
I'm very uneducated about VU-Meters in general, except they should probably have a high input impedance.
I don't shy away from looking into old trash or dusty vintage gear.
Thank you for your replies and would like to hear if you have a favourite from the bay or sth. like that.
Sth. that'll do the job is fine for now.

 

[ruffrecords]

There definitely should not be 250VDC on the lines of the VU meter. Something is very wrong. Can you post a schematic of what you have built?

Cheers

Ian

 

[reinw33]

There definitely should not be 250VDC on the lines of the VU meter. Something is very wrong. Can you post a schematic of what you have built?

Cheers

Ian

Hi Ian,
The schematics for preamps I use currently are generally or mostly incomplete in the sense that they are lacking a vu-meter.
It's not a big deal but sth. very helpful would be missing.
So it's up to you, the DIYer to put into it what he wants or prefers or needs.

Concerning your request ruffrecords, I tried to look up, but couldn't find it again.
It wasn't even a preamp IIRC where I recited out of the 250VDC but rather a compressor of some tube based decades old design, that had nothing to do with it, with what I build. Long story short.
Perhaps I'll find it again someday and then would show it to you.

Basically I am beginning to understand what options are out there, or what passive meters they used back then.
I'm just beginning to dive into the different pointers and layouts and perhaps active meters and LED-type meters but I want a classic pointer at first.
What about this one:

I don't know whether it has silicone transistor built in or none at all.
My question is,
Is it best practice to run the LEDs from the LT?
Or should I dedicate a seperate winding just for the lights?
I don't know the specs of this thing or what circuitry it requires just beginning to find out and talking is cheaper than buying and finding out.
Would a passive VU-meter in a TwinLine amp or other tube based preamp fit the topology or is it the modern way to go to make it actively driven so to speak with a TL072 for example.
What are the pros and cons?
Thanks.

 

[reinw33]

Hi everyone,
Just realized the output impedance of the source is too high, a buffer amp would be needed to avoid distortion with a seperate ground.

A tlo72 supplied with 24VDC winding should be added to my transformer and do the trick.

All in all the preamp is going to have 4 secondaries now which changes the the calculations for the psu transformer a bit and since it uses 1ma typically there is definitely wiggle room in the power consumption for this buffer.
I'll probably opt for sth. like the standard VU-meter circuit, and report back if it doesn't work out.
Thanks and happy soldering and God bless everyone.

 

[C.B. - Boudio]

It would be really handy to have some sort of a schematic. It will be so much easier to give you a meaningful answer.

 

[ruffrecords]

Tue VU meters are 100% passive devices that are designed to sit directly across a balanced output that is capable of driving a 600 ohm load. The VU itself is not a 600 ohm load but if the signal source is not capable of driving a 600 ohm load then the VU will add unnecessary distortion to the signal.

A classic VU meter is nothing more than a series resistor (about 2400 ohms) nd a germanium bridge rectifier connected directly to a meter movement. with defined ballistics.

Cheers

Ian