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Neil’s Mini Motherboard Remote /multiple input selector project similar to starfish?

Pound0sound

pfm Member
My aims:

1. To make a remote Neil Mini mother board in a Naim shoe box case with the ability to switch between 3 separate sources.
2. To ensure the best sound possible.

I’m posting on the forum with regards to this little project because while it should be simple, I’m a complete electronic novice and would prefer not to have to fix stuff after I made it go bang!

I wield a soldering iron with grace of a beached whale but metal gets stuck to metal so that’s good… :D

Here is a picture of the motherboard I am using – complete and tested, I will be using Avondale 821 boards or NJ boards:

Here is the board lay out:

http://i26.photobucket.com/albums/c114/neiljadman/NAP42 Rebuild/Revisedlayout.jpg

Here is a pic of mine:

http://i212.photobucket.com/albums/cc114/pound0sound/SAM_0297.jpg


I am using an Alps 20k remote pot as can be seen in the photo


Choosing the remote and input board

Ideally it should be fairly versatile with a RC5 remote signal:

2 analogue inputs
1 Naim DIN input –looks like I get 4 with most of these kits.

Such as:

Ebay: (looks cheap but effective)

http://cgi.ebay.co.uk/Assemble-Remo...ultDomain_0&hash=item19c497d1bd#ht_2029wt_905

Does this Alps remote kit look any good – any one tried it? Will my pot work and fit on the remote board?


Dantimax (gets a bit complex here and I think I have to build it :O best not..):

Control 1 board - (10.3cm x 4.4)
http://electronics.dantimax.dk/Kits/Control_boards/index.html

Remote 1 motor driver (10cm x 3.6)
http://electronics.dantimax.dk/Kits/Control_boards/index.html

Input 4 board (9.7cm x 5.2cm)
http://electronics.dantimax.dk/Kits/Selectors_-_attenuators/index.html



Or a high quality digital display option –same guy as in the 1st option:
http://cgi.ebay.co.uk/Upgrade-PGA23...ultDomain_0&hash=item19c4afd89a#ht_4447wt_905


Any other recommendations?

Silly money: remote stepped attenuator…..but any good?
http://www.hificollective.co.uk/components/tl_volume.html


Basically, dantimax has been recommend in other posts but can this be improved upon? Can I use a digital display remote board for the NJ board? Is it simple to install?

I have been advised that I should separately power the remote board using a wall wart plug, is there a simple way to do this from a Sonicbliss or a snaps? I would prefer not to have too many plugs etc – on the other hand I wouldn’t want interference to affect the sound.

Any suggestions would be great! I understand a few people have done this with a starfish to good effect?
 
This site contains affiliate links for which pink fish media may be compensated.
I have built the dantimax kit with motorised volume control and switchable remote control inputs and volume control and use the result every day. The kit is easy to build with a little bit of care. The result is a box with a knob and a few indicator lights. I think it is great. This goes with a B4 preamplifier board. The only criticism I would have of the kit is the earthing arrangements aren't star, but it sounds fine and there is no hum, hiss or anything. If you wish to fit only three inputs rather than the six then the earth issue can easily be sorted I would guess. The Dantimax kit has tape facilities.

In my view the Dantimax website is a little over complicated and could do with a thorough, "I built this" section for novices.

I have often thought of trying a kit with relay volume control and digital display, but I've not plucked up the courage. One of these days......

The power supplies for the remote control and the amplifier are from separate power transformers on board. The amplifier has off board regulator and the remote on board so just a small AC transformer needed. The one shown is probably over size, but it just fits in the case!

RB4innards.jpg
 
Right, it looks like Dantimax is tried and tested every time and gets results. Ill go for that. These ebay kits do look to be quite good quality but I guess I would be taking a risk.

I was looking for the "Ultimate remote control unit" but I guess Dantimax will do :D

Thanks for the input.

Ill order the parts, then my next step is building the thing in Naim Pre box!

Any idea about wiring? I suspect I should be using silver coated pure oxygen free copper wire for this, will any sort do?
 
The PGA2311 is a complete pre using digital pot subtitute as volume control. I used one with a LM3886 chip amp and it works a treat, but it'd be redundant using it with Neil's minimoherboard.
The remote control is quite short sighted, though
 
Right, resurrecting this thread - I have got one of these to go with the mother board build:

http://www.diyhifisupply.com/ultimate-volume-control

I chose this as it has a built in trafo to separate digital nasties, is small and ready built, also the company has a good reputation. It is meant to be very high quality.

Now its is just the assembly!

I had a few questions regarding this, mostly about layout...

1. What should I keep the trafo away from to minimise interference.

2. What cables/internal wiring should I keep short and what doesn't matter if it runs the length of the case?

e.g. Does it matter if mains cable runs the length of the case, past the NJ board to the remote transformer? Does it matter if its shielded?

What about the power cable from the 'hicap'?

Also - should I twist power cable chords if possible?

Now for a bit I really don't wanna mess up!

I wont be using a 20k Log pot with the NJ board now, so can I just connect the direct out from the 'selector/volume board' straight into the NJ 'signal in' (and then jumper the volume pot pins)?

OR

Can I by pass the 'buffer boards' and put a signal in straight into the 'volume pot in'

I hope someone has done something similar any input would be great

Cheers

Rob
 
Harthold and Mudlark, thanks for the input, the B4 remote kit looks very good. Luckily this remote has a built in trafo. Ill try and use the B4 topology for my build - Im still not sure if it best to keep the 'signal in' wires shortest or the 'signal out' wires.

I hear stories of high end roll off with longer wires but I don't know which signal will be worst effected. Looking at yours - and the Naim design, signal in wires are longer than signal out. I would follow this principle except that 'ultimate remote' instruction say that its output (going into the NJ Mini Board) should be as sort as possible. This will affect the way I orientate the Mother board.


Can anyone who has used a digital remote for the NJ board explain if I need to use the buffer section - what does a buffer board even do and will the NJ 729 boards work without em? (might the remote 'buffer to a degree already?)

If the NJ boards dont need a buffer can I just bypass that section on the NJ mini board and possibly use the two built in regs (that reg the buffer boards) to regulate another part?

What I don't want to do is rig it up and blow stuff up - Im a bit 'plug and play' at this stage so couldn't fix stuff if it goes bang.

Any simple principles would help

Im only on page 7 of:

http://electronicstheory.com/COURSES/ELECTRONICS/e101-7.htm

So, early days :D
 
Now for a bit I really don't wanna mess up!

I wont be using a 20k Log pot with the NJ board now, so can I just connect the direct out from the 'selector/volume board' straight into the NJ 'signal in' (and then jumper the volume pot pins)?

OR

Can I by pass the 'buffer boards' and put a signal in straight into the 'volume pot in'

The Naim (or is that now Focal?) signal path goes:

Inputs - Selector Switch - Buffers - Volume Pot - Balance Pot - 321 - Relay - Outputs...

So for true Naim style sequencing, connect the output from the remote selector switch straight to the Ch1/Ch2 signal input pins close to the 729 cards & then insert the volume sections in the place of the of the volume pot. But if it is impossible to separate the selector functions from the volume, feed the direct output to the pins adjacent to the 729s.
 
Im not sure I understand the reference to Focal - have they 'borrowed' the design?

Anyway, thanks for the response. That will enable me to use both types of cards which is great. Im assuming I can remove the resistors that are in place there and there and just plug and play.

Im waiting on a cable from Hifi Supply then I can hook it up and compare it to a modified 72 with similar cards.

The 72 bass response already goes deeper than a Marantz pearl and its more lively, the sound just loses some delicacy and clarity. Im hoping the super regs will clean things up no end and bring out the sound.

Ill post some pics and how it goes shortly!
 
Well, its all hooked up but Im getting no sound with this remote volume pot gubbins...gonna try just the NJ board and and alps pot to make sure its all working. Fingers crossed!
 
That didn't work either...

Here is a pic of my first set up...is there any reason why this wouldn't work?

http://i212.photobucket.com/albums/cc114/pound0sound/DSCF0191.jpg
http://i212.photobucket.com/albums/cc114/pound0sound/DSCF0190.jpg
http://i212.photobucket.com/albums/cc114/pound0sound/DSCF0192.jpg

I have tried attaching the signal input wires into the 'out' section (as opposed to the in) of the balanced section of the motherboard - I did this after the photo was taken but with no luck.

Then attached an alps 20k pot...this gave me no sound either, the Avondale 821 boards light up and nothing goes bang. Have I miss wired something?
 
Rob,

apologies but my post 8 above was incorrect due to the sequence. Which in turn affects the hook up. None the less the reason you have no sound is the missing relay...PM sent...
 
Brilliant! All working now with the Alps pot. Turns out I needed to add or bypass the relay. How thats done...SOUND! whoo!

Cheers Neil!

Now to get this electronic remote working :D
 
A warning to those buying from 'DIY hifi supply'.....

I purchased the remote above. It was sent with OUT the chip or cables.

I asked for the cables and chip, and they were good enough to send them no questions asked.

Since then I have been trying to get it to work - I have just discovered why it may not.

The ribbon cables I have been sent have been connected the wrong way, so pin 16 goes into pin 1 and visa versa.........in BOTH cables connecting the remote vol+ selector to the transformer (control matrix board).

Someone was having a bad day.

Do you think this has damaged my remote?
 
I took the plunge and swapped the cables - et viola! It all works! :D

It is set up as is in the first photo except that the relay is bypassed and the signal is running through the 'signal in' section at the top right of the board near the buffer cards.

In addition, I have jumpered the 'Alps' normal volume section with wire.

So it all works, and sounds very very promising.

My problem is with volume....even when the volume is set to zero, the pre amp still blasts out music. The volume control does work but it only increased the volume

....balls...so close....


So now I have to figure out how to increase the resistance some where in the volume control I think (DIY hifi supply have instructions on this).

I could also look at the NJ motherboard if that is possible? Maybe a component that crosses the 'Alps' volume section and/or even the balanced output section to reduce gain? The equivalent of a static volume Pot? What would this part be called could I simply add some resistors?
 


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