NSM V.1 Aux Jack Addition (Performer Grand 2000)

[jd]

Has anyone successfully tried adding an input jack to a V.1 NSM without a mic adapter board?

Been trying to crack the secret of adding an input jack to my NSM Performer Grand 2000 on and off for a while. Think I've finally got it, but wanted to know if its just so obvious I'm the only dummy that hasn't figured it out yet before I hot wire the wrong thing on my central amp board. This solution seems too easy.

Found a schematic of the rare mic adapter board that did have inputs and to my surprise it directly passed the line input to the central amp board. All the onboard circuitry appears to have been for the microphone section. This means I should just be able to connect a left, right, and ground wire to the appropriate pins on the mic adapter socket and it theoretically will just work. This would also assume the stars are aligned and the Siemens TDA4390 signal processing chip was indeed set up to connect the aux input to the power amp when not playing a CD.

[Ron Rich]

Hi JD,
I don't understand your statement the "All the onboard ---for the mic section."?? Are you saying it's a pre amp for that mic ?Did NSM supply the mic, with that board--was it a low, or hi. impeadence mic ? Ron Rich

[jd]

To be honest, I don't know much about this jukebox at all. I don't think a special mic was required. The manual does say how to use the mic adapter board, but does not cover the theory of operation. It was very clear NSM was in the market to sell parts, not repair advise with their manuals.

Literally every component on the mic adapter board seems to support dropping the music level when the mic is active. The other input jacks given for a "tape unit" literally just seem to run the signal straight off the board. However, when I tried hotwiring just an input to the pins on the mic adapter plug, nothing happened. Therefore, I think one of the signal pins on the mic adapter board uses the 15v power line to alert the TDA4390 to the mic adapter's presence which then "unlocks" the input jack inputs.

I think I am just going to recreate the mic adapter from the schematic on a protoboard and give that a try. That may be the next easiest thing to making the computer happy and letting my input pass through to the amp. I could just bypass the TDA4390 entirely too, but that will not be as elegant a solution.

[Ron Rich]

Hi JD,
I think, I still have one of the "adapter boards" around here somewhere--dono if it was for a mic, as I used it for BGM. Earlier NSM phono' had that board built in-- yep--options made them more money--also cut production costs ! As for their manuals-- don't get me started on that subject ! Ron Rich

[jd]

If you do find it and it says nsm 216188A / 346 on it, i would be interested. Should have a weird 5 pin plug, 4 rca jacks, 2 pots and a pin header to connect to the amp. If not luckily the parts are all still available so it can be remade for around $25 and a bunch of effort. All I want to do with it is connect a bluetooth.

[Ron Rich]

Hi J/D,
Yep--egg-zact-lee what it says, on the board--Think I have the whole thing here, including inst. sheets !-You will need to replace the adhesive on the mounting feet--- If you would like to purchase it, contact me at : [e-mail] Ron Rich

[jd]

Well, I lucked out and found an original mic adapter board so I am taking the easy way out here. However, to make this post helpful to those who may not be so lucky, parts are available to make your own mic board. The schematic is readily available for free on the interwebs on the last page of the ES V.1 Gem - Series NSM service manual. I recommend getting a solder protoboard and just replicating the mic adapter board. It turns out the interaction between the mic adapter board and the jukebox is not as simple as it looks now that I have had time to play with the real OEM mic adapter board. Even for the input jacks that were meant for a background music tape machine, the jukebox has a permissive signal for these to work. If no CD is playing, the amp auto senses whether there is a signal on the input line. It switches on/off and ramps the cooling fan speed up and down as you press play/pause on an input. Also, the input on the mic board is faded out and a CD is faded in if you select a CD.

There are four sort of difficult to read semiconductors from the schematic (at least the copy I was reading). They currently cost around a dollar total.

1) Texas Instruments TL 074 CN
2) BC 547 NPN Transistor (ON Semiconductor BC547BTA)
3) 1N4148 Diode (ON Semiconductor)
4) 4.7v 0.5W zener diode (Vishay BZX55C4Z7-TAP)

Believe the resistors were all 1/4 watt.
Capacitors all rated at 63 V.
Not sure if the pots are linear or log however they only matter if you plan to use the mic functionality of the mic adapter board. They are for mic volume and music volume reduction adjustment when the mic is active.

Below was my resistor and cap list that I was about to purchase. (C=ceramic, F= film, E=electrolytic). In addition, four jacks, the mic plug, and a 12 pin header are required if you will be exactly recreating the mic board.

R # Value c# Pot
1 4.7k 1 100p C 500k
2 4.7k 5 27 p C 500k
3 10r 9 27 p C
4 47k 11 560 p C
5 3.3m 3 100 u E
6 22k 4 100 u E
7 22k 7 1u E
8 15k 10 47 u E
9 1k 2 4.7 n F
10 1k 6 0.1u F
11 6.8k 8 0.33 u F
12 1k 12 0.1 u F
13 1m
14 1k
15 330k
16 22k
17 33k
18 330k
19 47k
20 22k
21 10k

[digitalthunder]

I know this an older post but if anyone can answer this i would really appreciate it. I have an original mic-adapter board that I would like to plug into my main board (ESV) on my Digital Thunder NSM jukebox. It has a 12 pin ribbon cable and the only socket that it will plug into is ST11. Is this the corrct socket for this adapter. I have no instruction sheet for this board.