the Poor Man 660 support thread

[bernbrue]

21 positions correspond with the ordinary potentiometer turn (don´t know how much degree that is).
regards
Bernd

 

[Moby]

[quote author="bernbrue"]Hi,
with a VU meter you are on the save side. In my prototype I used ordinary 250mA ampermeters with a 100R resistor parallel. I compared the tracking to a Beede VU meter and there is not really a big difference. My suggestion: Build it an try various meters, in the end it´s your choice.
regards
Bernd[/quote]
So, I'm right about. It's ma meter not VU. But would it be better to use less sensitive ma meter and to add serial resistance to trim zero. BTW, can you tell me value for the current in the non GR state. That should be the max current and it will be helpful to determine meter sensitivity.

 

[[silent:arts]]

I don't think it will work without a meter - like many other vari mu compressors.
the specification for the poor man is a VU meter (and I used one in my prototype, AL39).

doesn't mean anything other could work, 1ma would be closest as far as I know.
but:
NONE OF THIS HAS BEEN ATTEMPTED IN THE FIELD WITH A PM660 :green:

 

[Moby]

I don't think it will work without a meter - like many other vari mu compressors.
the specification for the poor man is a VU meter (and I used one in my prototype, AL39).

doesn't mean anything other could work, 1ma would be closest as far as I know.
but:
NONE OF THIS HAS BEEN ATTEMPTED IN THE FIELD WITH A PM660 Mr. Green

Thanks, but can you tell me what's the static current in the 18db gain mode?

 

[khstudio]

volker ,
Is there any way you could ask Rowan about the Meters?
(I'm a little surprised we don't see him around here a little more, supporting his design.)

I have several different types laying around (as do many others here)

It would be cool to know if DC Meters are OK to use and @ what range(s)?

Thanks,
Kevin

 

[Moby]

I have several different types laying around (as do many others here)

It would be cool to know if DC Meters are OK to use and @ what range(s)?

Yes! Since this is the PM project we must use some things laying around. That's why I asked details about meter :green:

 

[[silent:arts]]

[quote author="khstudio"]Is there any way you could ask Rowan about the Meters?
(I'm a little surprised we don't see him around here a little more, supporting his design.)[/quote]
why bother rowan with questions already answered ?
he is working on something new, and there is already enough support to build this Poor Man. me and bernd have been able to build it without any support.

read bernbrues and my posts again and you can answer the meter questions.

if you want to be safe take a VU meter as suggested by Rowan.
if you want to experiment with other meters this is fine, but don't claim for support in advance.

moby, I have no direct access to my poor man at the moment, will do the measuring when it is possible (which won't be this or next week)

 

[khstudio]

Sorry man... I thought it was a simple request. :?

Your response is "try it & see"... this doesn't work out too well when I test it, then it "seems" to work OK... then I CUT my faces plate & use it, then either the Meter or the circuit fails or doesn't work properly.

#2, since a V-MU Comp relies on the meter, is it possible a DC meter could affect the performance???

Rowan could answer this in 20 seconds.

Like I said, I've got a lot of nice old DC meters so...

 

[[silent:arts]]

[quote author="khstudio"]Sorry man... I thought it was a simple request[/quote]
it might look like a simple request ...

didn't bernd answer it already ?

even rowan can't foresee what you will like best.
as said before: if you want it like rowan designed and suggested:
use VU meters

we can't test all the possible extras for 200+ builders, and we can't tell who likes what best.

but if you want to go the safe way, take it easy:
- prototypes work with VU meters
- in the schematic there is a VU meter
- in the parts list there is a VU meter
- we told you to use a VU meter
- nobody said you can't use any other meter, but we have to say:
THIS HAS NOT BEEN ATTEMPTED IN THE FIELD WITH A PM660
since it may react different, it may not work for you, it may work even better for you ...
sorry, but with support we want to be on the safer side.

 

[emrr]

A vari-mu comp will indeed work without a meter; you just don't have a meter then. Many switch a standard VU in and out between GR and VU, and even positions for external source, so nothing in the circuit is connected to it at all. So use whatever you like, but you'll have to figure it out and trim it yourself. Some do it plate side, some do it cathode side. Lots of variables to hack.

Any optional solutions should be presented over here:

http://www.groupdiy.com/index.php?topic=351648#351648

 

[khstudio]

OK, fair enough.

 

[Moby]

moby, I have no direct access to my poor man at the moment, will do the measuring when it is possible (which won't be this or next week)

Thanks, it will be really important info for me, if someone else can measure the same thing I appreciate that :grin:

 

[analag]

[quote author="khstudio"]volker ,
Is there any way you could ask Rowan about the Meters?
(I'm a little surprised we don't see him around here a little more, supporting his design.)

I have several different types laying around (as do many others here)

It would be cool to know if DC Meters are OK to use and @ what range(s)?

Thanks,
Kevin[/quote]

I work a 12 hour at night shift and lately I've been working everyday or should I say night, so if I get a little too tired to get on the forum when I know Volker is handling business...then hey.


You can use an ordinary VU meter, you just have to tweak the parallel resistance to bring it to "0" I don't see the need to go re-scaling mA meters when any old ordinary VU will do the trick.

analag

 

[Moby]

I don't see the need to go re-scaling mA meters when any old ordinary VU will do the trick.

Just to clear out...VU meters with diode bridge are excluded :?:
Please can you measure the total steady-state current for input stage in the non GR mode?

 

[[silent:arts]]

[quote author="Moby"]Just to clear out...VU meters with diode bridge are excluded :?:[/quote]
no, they are the supported meters

 

[[silent:arts]]

[quote author="Moby"]Please can you measure the total current for input stage in the non GR mode?[/quote]
will do - at the moment my prototype is in pieces since I measured different Heater resistors in different conditions, and had to clear out my "workspace" for the birthday party of my daughter next week.
when I'm back up and running I can do this measurement, but not before.
in the meantime, stuff your board, connect everything and connect your meters to see how they react.
btw, to null the VUs I connected a 5K trimmer across it.
gain reduction tracking was great :thumb:

 

[skal1]

To how it may concern c1 and c3 in the psu part list have a different value to

the ones on the silk screen,which is the correct value ,parts list or silk screen.


regards

skal1

 

[[silent:arts]]

in the parts list posted on the first page of this thread they are the same as the silk screen: 220µF / 400V
http://groupdiy.silentarts.net/PM660/PSU660_rev02-PartsList.pdf

however, the silk screen is always more important than the parts list.

 

[skal1]

[quote author="[silent:arts]"]in the parts list posted on the first page of this thread they are the same as the silk screen: 220µF / 400V
http://groupdiy.silentarts.net/PM660/PSU660_rev02-PartsList.pdf

however, the silk screen is always more important than the parts list.[/quote]

I beg to differ ,even your parts list shows the same c1,c3 as 200u, but lets not split hairs 220uf is ok....


regards

skal1

 

[[silent:arts]]

ah, overlooked that, thanks.

doesn't matter, take 200uF or 220uF.
220uF will be easier to source.