hirono

TAB V372/1D hum noise
« on: October 13, 2018, 06:53:56 AM »
Hi everybody.
I have 2 TAB v372/1D cards racked and when I increase the gain a hum noise starts, (more gain more noise)
I followed the pinout I found in Kubarths site and all 0v. pins are as in the document
The PSU is a PowerPlant from JLM Audio (feeding too a EZ1290 preamp, totally noiseless)
I got earth and 0v touching the case.

Im just a soldering skilled guy following where to solder thing but no knoledge in electronics
so if Im missing something really basic, I dont know .

Where should I start to look up to get a solution for this issue??

Thanks a lot

H.



moamps

Re: TAB V372/1D hum noise
« Reply #1 on: October 14, 2018, 05:49:03 AM »
Most probably you have problem with a ground loop.
Is the power supply placed inside the same chassis where are TABs or in a separate?
Could you post a picture of the interior?

hirono

Re: TAB V372/1D hum noise
« Reply #2 on: October 16, 2018, 04:34:25 PM »
Hi
thank you very much for your reply!
the PSU is inside the same enclosure, and 0v and ground of the V372/1D card and 0v and chasis of the PSU are touching the enclosure chasis.
Cant do the photo now, but in 2 days I could send you a photo.
I really apreciate you help.
Thank you

h.

hirono

Re: TAB V372/1D hum noise
« Reply #3 on: October 19, 2018, 02:27:57 PM »
Hi
there are the pics
This is the overall view
As you see the PowerPlant PSU is feeding with 24v (not in serie, all from the same point to the pres) the V372 and the EZ1290
and PSU 0v is  going to the Pres and to the PSU "to the case" screw, wich is connected to the Case and to the 220 plug Earth and the
Earth Pin of the V72

hirono

Re: TAB V372/1D hum noise
« Reply #4 on: October 19, 2018, 02:33:15 PM »
there is a zoom of the PSU connection

hirono

Re: TAB V372/1D hum noise
« Reply #5 on: October 19, 2018, 02:53:12 PM »
pic of the V372 0v connections

Bad photo...  linked pins are:
in ch1 ; 10-11-14
in ch2  18-21-22

pin 16 to earth

hirono

Re: TAB V372/1D hum noise
« Reply #6 on: October 19, 2018, 02:56:43 PM »
other Pic

moamps

Re: TAB V372/1D hum noise
« Reply #7 on: October 20, 2018, 07:00:30 PM »
First move all wires of 372 module as far as possible from the power transformer an test it.  Also move the white power cable to right side of chassis . You need to dress all cables more neatly.

hirono

Re: TAB V372/1D hum noise
« Reply #8 on: October 23, 2018, 04:50:29 PM »
Thank you very much for your reply!!
I will do that and try to separate audio from DC cables.
I know its  a mess
Maybe it is better To change the PSU in a horizontal way, to be far of the V372??

Thanks!!

hirono

Re: TAB V372/1D hum noise
« Reply #9 on: July 25, 2019, 05:37:23 AM »
HI!
IM a lazy bastard but dont want tovbe ungrateful.
9 months to ask in the forum, 6 months to do what you suggest and 3 months to say THANK YOU VERY MUCH
As you said the noise was made for all that cable mess.
I will try to be cleaner in my future projects, is such a difference.

Thanks again Mo Amps

H.


moamps

Re: TAB V372/1D hum noise
« Reply #10 on: July 25, 2019, 01:48:24 PM »
I’m happy to help. :)

opacheco

Re: TAB V372/1D hum noise
« Reply #11 on: July 27, 2019, 07:17:05 PM »
HI!
IM a lazy bastard but dont want tovbe ungrateful.
9 months to ask in the forum, 6 months to do what you suggest and 3 months to say THANK YOU VERY MUCH
As you said the noise was made for all that cable mess.
I will try to be cleaner in my future projects, is such a difference.

Thanks again Mo Amps

H.

BTW; Tell us, How these TAB preamp sound like compared to the EZ1290 preamp??...
Opacheco.
I love the Vaccum Tubes Sound!!!

hirono

Re: TAB V372/1D hum noise
« Reply #12 on: July 29, 2019, 04:17:21 AM »
Oh,
I think the main diference in sound is the thick bottom of the ez1290,
No one of the pres have a silky top, but the mid definition on both are superb.
Maybe a little  bit better in the hi mids for the V372.
At the beggining I thought the V372 was like some Broadcast console pres I got but,
No way, It is not this kind of voice frecuency enhance thing,
Last week I recorded a upright bass with an SDC and the low mids were strong and round.
And all the 3rd octave bass information sounds deep.

I didn't make an AB comparison, so I cant tell you nothing scientist. I prefer the V372 Sound better than my LAWO 970
which got transistors too.

On the other hand, the ez1290 gots more headroom and I think the transient response is a bit fast.

But the v372 is an easy project and for a little amount of money you can have 2 pro preams workin.

My next project is to rack in one unit another v372 and a Delta that is on the way.

I have to finish too a JML that leave me blocked doing  some weird  noise, and I have to check everything patiently.

I could record some synth with both pres in the weekend  if you are interested.

Cheers!

H.





opacheco

Re: TAB V372/1D hum noise
« Reply #13 on: July 29, 2019, 09:24:01 AM »
Oh,
I think the main diference in sound is the thick bottom of the ez1290,
No one of the pres have a silky top, but the mid definition on both are superb.
Maybe a little  bit better in the hi mids for the V372.
At the beggining I thought the V372 was like some Broadcast console pres I got but,
No way, It is not this kind of voice frecuency enhance thing,
Last week I recorded a upright bass with an SDC and the low mids were strong and round.
And all the 3rd octave bass information sounds deep.

I didn't make an AB comparison, so I cant tell you nothing scientist. I prefer the V372 Sound better than my LAWO 970
which got transistors too.

On the other hand, the ez1290 gots more headroom and I think the transient response is a bit fast.

But the v372 is an easy project and for a little amount of money you can have 2 pro preams workin.

My next project is to rack in one unit another v372 and a Delta that is on the way.

I have to finish too a JML that leave me blocked doing  some weird  noise, and I have to check everything patiently.

I could record some synth with both pres in the weekend  if you are interested.

Cheers!

H.

hirono,
Thanks for your response and time!

I think the V372 are in the top line of preamps list! and yes please show us some audio clips for these monsters preamp!!

I will wait for the audio
Thanks a lot,
Opacheco
I love the Vaccum Tubes Sound!!!

hirono

Re: TAB V372/1D hum noise
« Reply #14 on: July 30, 2019, 03:39:37 AM »
Ok, I will record something for you this weekend.
Cheerrs

opacheco

Re: TAB V372/1D hum noise
« Reply #15 on: July 30, 2019, 10:46:18 AM »
Ok, I will record something for you this weekend.
Cheerrs

Ok, we will wait them!
Thanks
Opacheco
I love the Vaccum Tubes Sound!!!


 

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