What's the deal with the FOSTEX 3040 noise reduction unit?

[cjacek]

This is a continuation from the following thread:
https://homerecording.com/bbs/showthread.php?t=284513

I'm just wondering, reading Tim Beck's post and also Blue Jinn's, if it's pretty much confirmed that this unit will only work (stock factory) with the A-4?

 

[Blue Jinn]

Stock factory yes, looks like just the A4, otherwise, I'm not sure yet. Ethan decoded a very simple mod for the Tascam dbx units, so I can't imagine this thing is anymore complex.

I haven't sprung the 18 bucks to get a manual for it. I have the schematics for the A4, and there appears to be a bank of transistors that appear to just send an 8 v cv to the unit to switch it from decode to encode. I think. I don't have an A4 to verify that w/ a meter.

It looks like it is pretty straightforward a control voltage. But that part of the schematic is pretty vague.

I got my eletrical engineering degree from a cracker jack box, so I'm making a lot of assumptions about how transistors work.

 

[Beck]

Yep, the Fostex 3040 is basically designed for the Fostex A-series in the same way the DX-2D and DX-4D were designed for Tascam decks. I almost bought one a few years back, but info on these things is hard to find so I passed on it. I know it could be done if one could find the documentation. I still have the two Sony outboard Dolby C units. There weren't many outboard C units made because Dolby stopped licensing them early on.

For reference the two units I have are Sony NR-500. They work great and I can even use them to decode up to four tracks on other reel-to-reel or cassette 4-tracks from other manufacturers, like Fostex, even though I don't own any Fostex tape decks.

Another outboard Dolby C unit to look for is the Nakamichi NR-200. It does Dolby B as well, so could be pretty handy around the studio.

I'm still curious about the Fostex unit, but my time is best spent on other things these days.

 

[cjacek]

Thanks guys! I ask 'cause I got the 3040 as a freebie recently and I'm not sure what to do with it.... There is some hope, however, as the guy I got it from made a home-made contraption of sorts, a DIN cable and at the end of it a push button remote where you apparently "arm" each track for encode / decode to use with any tape deck. That's what he said. I'll have to put it through its paces and see if it in-fact works but I'll first have to figure out how to connect this thing.... I'll post some photos later. Again, thanks fellas...

 

[Blue Jinn]

Thanks guys! I ask 'cause I got the 3040 as a freebie recently and I'm not sure what to do with it.... There is some hope, however, as the guy I got it from made a home-made contraption of sorts, a DIN cable and at the end of it a push button remote where you apparently "arm" each track for encode / decode to use with any tape deck. That's what he said. I'll have to put it through its paces and see if it in-fact works but I'll first have to figure out how to connect this thing.... I'll post some photos later. Again, thanks fellas...

Well, in that case it can be modded apparenlty yippeee!!!. The homemade contraption should just switch it from "decode" to "encode" can you post some pics of the inside of that contraption?

 

[cjacek]

Well, in that case it can be modded apparenlty yippeee!!!. The homemade contraption should just switch it from "decode" to "encode" can you post some pics of the inside of that contraption?

I will put up some photos in the next few days but I can tell you for sure that the remote does indeed switch from encode to decode and back again. I checked it out today. The next step is photos and to try it on program material.

 

[cjacek]

OK, here are some photos I made.

 

[cjacek]

If you need any more photos let me know.

 

[sweetbeats]

Can you get photos of the inside of the 3040?

 

[cjacek]

Can you get photos of the inside of the 3040?

Sure, no problem Cory. Will do shortly. BTW, I was surprised how heavy the 3040 is. It'd be interesting indeed to see what hardware resides within.

BTW2: is it generally the consensus that outboard noise reduction is of higher / better quality than one that's built in?

 

[cjacek]

It's all too much tech for my brain to handle but I think you'll agree that this 3040 is pretty much packed to the rafters with, what seems like quality hardware. No? I mean, all this in a Dolby C noise reduction unit? Wow.

BTW, I uploaded to an outside place for higher resolution photos (sorry Tim ).

 

[Blue Jinn]

Wow,

It looks like all the control does is short to ground or something. I'm going to run a multimeter on the middle pin and see if it is ground.

Do you know if those are momentary or on/off switches?

 

[cjacek]

Do you know if those are momentary or on/off switches?

Can you clarify? I'm not sure I understand..

 

[Blue Jinn]

Do the switches open and close like a light switch i.e. on or off, or a stomp box switch on or off or do they close only when you hold them down and then open again if you let go like a punch in pedal?

 

[cjacek]

Ah, OK..... Well, when I press a button, it doesn't stay down, doesn't lock (it pops back up). It switches the channel to decode and then, when I press again, it switches back to encode. I don't have to hold it down. It has a distinct "click" sound when I press it but, as I said, it pops back up.

 

[Blue Jinn]

They are just SPST switches. I tried this out last night with a simple jumper in the DIN jack. The transistors on the A-4 must just be simple switches as well, and the cv to turn the transistor on or off. All they do is shunt to ground to switch to encode mode. It is much less complicated a process than the DX-xD's from Tascam. It is just four switches. I doesn't look like you could just drill holes in the front panel, I'll have to look tonight, but there is another PCB in the front so there may not be enough room.

Dude, you have successfully solved this mystery.

 

[sweetbeats]

Comment of the "guts"...that looks like an awfully big main transformer in there for what this unit is handling...relatively heavy-guage shield around it too...

 

[cjacek]

Dude, you have successfully solved this mystery.

I'm glad to have helped out.

Comment of the "guts"...that looks like an awfully big main transformer in there for what this unit is handling...relatively heavy-guage shield around it too...

Yeah, I have a whole new respect for Fostex.

 

[doepferiano]

Hello Friends,

I'd like to use the fostex c 3040 with a TEAC A3440-S

Now that you have decode dthe switching mechanism for the 3040

do you have any idea about signal sent by the TEAC ?
I wish to automate the process...


Anybody with schematics ?

thank you for your help

antonio

 

[Blue Jinn]

You would need the schematic for the 3440, and figure out what the control signal is from the 3440 and then used that to open and close (could be transistors, which is all it is on the A-4) a switch.

Note that I am not sure what the 6 pins on the 3440 control cable do,.