old Fostex mixer led level question

WykedPT

Member
Hi all.......Quick question about a older Fostex mixer. Picked up a model 820 at a yard sale for $50. My second one.. (it works). I hooked it up to my ADATS (Yup,I mix analog and digital..Digilog....)and started doing a recording. The mixer levels go well into the red and mostly stay there but the recorder levels stay in the normal area with no distortion. Was this a problem with Fostex mixers?
 

sweetbeats

Reel deep thoughts...
More information, please…when the meters are in the red are they monitoring the mixer outputs to the ADAT or the playback from the ADAT? And what model ADAT deck?
 

WykedPT

Member
Hi Sweetbeats....They run hot both ways. Going to and from the ADATS...I'm using two Alesis blackface units..Like I said,I can't hear any distortion and the channel peak indicators don't flash when recording. ADAT levels don't go into the red...
 

sweetbeats

Reel deep thoughts...
Am I correct in assuming you are using the 1/4” input/output jacks on the ADAT?

When is the last time you calibrated the meters on the 820?

It took awhile to find them but I found all the documents related to the 800 series consoles and I see there are trimmer access points to calibrate the meters on the backside of the meter pod.
 

WykedPT

Member
I am using the 1/4 inch jacks..I have the manual but I can't find any calibration points. The only thing on the back of the pod is a peak hold switch. I'm guessing they have probably not been calibrated in a while, I just got this one a cpl weeks ago.
 

sweetbeats

Reel deep thoughts...
Well…

That sucks.

I can’t find a service manual for the 820…odd that they included meter cal trimmers for the 812 but I see in pics it’s blanked off for the 820.

The manual includes no specifications regarding the meter specs that I can find, relative level (like what the numbers on the scale actually mean). We can *assume* “0” is -10dBv, but we don’t really know for sure. And beyond that are they averaging or peaking etc. so maybe your meters don’t need calibrating, we just need to know more about them. If everything sounds fine go with that first, it’s just unfortunate you don’t have the benefit of the useful functionality of the meters, but in your case at least their function is duplicated by the ADAT meters. If you want to check what the scale means or determine if you need to or want to go further with exploring the potential of calibrating your meters, if you have a signal generator and a good audio meter, set your tone generator to produce a 1kHz sine wave tone, connect that to your group 1 BUSS IN jack on the Fostex via a ‘Y’ cable, and to the unterminated leg of the ‘Y’ cable connect your level meter. Set the level of the 1kHz tone to 316mV AC. Now move the level meter to the group 1 output jack and adjust the group 1 fader until your level meter reads 316mV AC at the group 1 output jack. Now look at the group 1 meter. What does it display? If you do this test, repeat it for groups 2 through 8 and report back.
 
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