BSS DSP fan noise, especially for M2 setup

[sebackman]

Dear all,

There has been much discussion on DSP solutions for M2 clones and other setups. After having tried many different DSP units I do recommend using BSS units as I believe that their algorithms are superior. They are reasonable priced on the second hand market and very flexible. Not mentioning that for M2 cloners you can just dump the original downloaded JBL DSP file straight into them.

But this was not to be a fire speech over use of DSP, but fan noise reduction .

For those of you having looked at using BSS units and may have shy away due to the fan noise there is salvation.

The older line of Motorola based units Soundweb 3008-9088 and their offspring all have one 5v 40x40mm exhaust fan at either side.

The newer BLU16 & BLU80 also has one exhaust fan, while the bigger BLU160 and BLU800 chassis have 4 fans, two on each side. I have not had BLU100 or BLU50 units so I don’t know about them.

In all of these chassis there are Sunon 40x40mm fans that are pretty high rev and do make considerable noise.

There are many fan manufacturers that would be able to sell replacement fans and my favourite brand is Papst. They do make wonderful quality fans in all shapes and sizes and they do provide detailed specs so you know what you get, including credible noise specs.

However in these BSS units I have successfully replaced the original fans with silent Noctua computer fans. I thought they only provided 12V fans but Eureka, Noctua actually do a 40x40mm 5V fan that can be ordered on the internet..

http://noctua.at/en/products/fan/nf-a4x10-5v

The Noctua fans come in a complete kit with mounting HW. They are 3-pin configuration but here we only need red and black leads, the yellow can be cut. The cables are covered with shrink sleeve towards the contact and that will have to come off to get to the leads.

The simplest way is to cut away the Noctua contact and move the original BSS contact from the Sunon fan and just connect them (color on color) using the included cable joints in the package.

As the original Noctua contact is three pin and actually fits the BSS mother board, an alternative is to change the pin configuration in the supplied Noctua original contact so it matches the original BSS pin out. This is done by using a small screwdriver to gently press on the side of the black Noctua contact to release the actual metal contact and pull it out backwards. Remove the yellow contact (cut it off) and move the red lead to the “yellow” position so the centre is empty and the red and black is on each side. Please see attached picture.

On the BLU160 and BLU800’s I used two Noctua exhaust fans (right hand side by the Power supply) and just disconnected inlet fans on the left side. In these the fan contact is different so you will need to use the original BSS contact and cut the cables to join the old BSS contact with the new Noctua fan.

I had my BLU160 (to be used with Compact Monitor) connected on idle for 2 days with just the two Noctua exhaust fans running and there was absolutely no heat build-up. And considerably less noise.

A word of caution ! If the BLU160/BLU800 units are used in a very tight space, limited access to fresh air, heat build up from other units or in a warm location each owner needs to check that two exhaust fans are enough to keep the units cool. When I took the lid off mine after 2 full days the chips were not even felt warm when I put my thumb on them.

I know that Mr Widget in a different thread mentioned that they sometimes run BSS units with all the fans disconnected and the lid of and that should beperfectly fine.

This alternative is a rather cost effective alternative and it may be more soothing for the mind knowing that the brain in your multi thousand dollar system is not totally exposed to mother nature.

Kind regards
//RoB

[sebackman]

[4313B]

Thank you very much for this information!

[grumpy]

Great to see this. I had put those exact units on my "wish list" about 2 weeks ago.
at ~$13-14/fan I hadn't decided to pull the trigger yet. Nice to see a working example!

[grumpy]

On the BLU160 and BLU800’s I used two Noctua exhaust fans (right hand side by the Power supply) and just disconnected inlet fans on the left side. In these the fan contact is different so you will need to use the original BSS contact and cut the cables to join the old BSS contact with the new Noctua fan.

Concur/completed on BLU-160 and 120. Thanks RoB!
Subjectively quieter. Measurably, different spectrum (less intense peaks above main ~500Hz "tone", which was also ~4-5dB lower). I'm ignoring the obviously worn BLU-120 fans which seem to have led a harder life and were a bit squealy.

[Jonas_h]

What temperature are you reading after a couple of hours of use?(You can read the temperature in the control panel in london architect).

I'm using a BLU160 for my M2s and recently installed the Noctua fans mentioned. I installed 4 but added a resistor which slowered the fans. My temp-reading is 49c after some after of use, which is near the upper threshold according to the manual. I think I will remove the resistors.

Can you refresh my memory regarding stock air-flow. Is it taking cold air in at the power supply and sucking the air out on the other side? Or how is the direction of the fans?

Would it help with the temperature to remove the lid from the unit or would that just make it worse as the air is not directed the same way?

[ivica]

Hi,

Just for the reference, figure made by our Forum member mica (http://www.audioheritage.org/vbullet...php?17620-mica)
of BSS BLU80 internal DSPs. Such ADSP-21161 has almost 4 times less speed then ADSP-21369 that are in BSS BLU160

regards
Ivica

[Macovox]

Who knows which converters in old BSS BLU-80 ?

[grumpy]

I believe the cards are interchangeable in the modular BSS London BLU series (e.g., not BLU50 or 100).
Whether there have been incremental manufacturing updates (or not), is more than I know. I would expect
there would be, just based on parts availability or price over time, but that is pure speculation.

[Don C]

There are definitely at least two different revisions of the analog input boards. These that I have seem to be the later revisions. The earlier ones that I've seen don't seem to have the rows and rows of electrolytic caps in metal cans.

[sebackman]

Dear all,

There have been several design changes over the years on several cards. The older cards have push trough soldered caps (often black) and the newer are surface mount (often silver). If you provide revision numer on a card you have questions about I can find out.

There is no or very limited sonic difference in the early and the newer cards that I can find. However the newer caps are supposed to be slightly better tolerance.

BSS has also changed the DAC chip as the first model went EOL. I have both and there is no real sonic difference but the chips are not interchangable as the circuits differ slightly. Ie you cannot update an old card with a newer DAC chip even if they are pin compatible. At least as BSS state.


The fixed I/O 100 series are 3db higher noise floor but well beyond the music and most of the rest of the equipment so I would not worry about that.

All the units are 48 or 96kHz and 24bit I/O. Internally they are 41bit floating point with dual Shark DSP processors running att 100, 200 or 400 mHz.

Kind regards
//Rob

[Don C]

From looking at some cards in a current ebay auction, we can see that the older analog output cards use the AKM AK 4393VF chips.

[mica]

Dear all,

There have been several design changes over the years on several cards. The older cards have push trough soldered caps (often black) and the newer are surface mount (often silver). If you provide revision numer on a card you have questions about I can find out.

There is no or very limited sonic difference in the early and the newer cards that I can find. However the newer caps are supposed to be slightly better tolerance.

BSS has also changed the DAC chip as the first model went EOL. I have both and there is no real sonic difference but the chips are not interchangable as the circuits differ slightly. Ie you cannot update an old card with a newer DAC chip even if they are pin compatible. At least as BSS state.


The fixed I/O 100 series are 3db higher noise floor but well beyond the music and most of the rest of the equipment so I would not worry about that.

All the units are 48 or 96kHz and 24bit I/O. Internally they are 41bit floating point with dual Shark DSP processors running att 100, 200 or 400 mHz.

Kind regards
//Rob

Hello all,

Series 100 (100, 101, 102 and 103) are all 48KHz only.
Best regards.

Mica

[bubbleboy76]

However in these BSS units I have successfully replaced the original fans with silent Noctua computer fans. I thought they only provided 12V fans but Eureka, Noctua actually do a 40x40mm 5V fan that can be ordered on the internet..

http://noctua.at/en/products/fan/nf-a4x10-5v

I have this fans in my BSS BLU-160 today (2pc of them). It is this very unit talked about in this post, I guess, because I bought it from sebackman.
Still the noise is too high for me. I will try these fans instead:
https://noctua.at/en/nf-a4x20-flx/specification

They have 3dB lower noise. They are 20mm thick, instead of 10mm. They also give better airflow according to spec.

(thanks to pos for this advice)

[grumpy]

It would be interesting to know what voltage the "LNA" and "ULNA" adapters provide (presumably resistive dividers)
as the unit would be receiving 5v from the BSS vs the nominal 12v required for the a4x20... so airflow might be
comparable or less, while noise would likely also be less than the thinner fan. You might also try (as others have done)
placing small heatsinks on appropriate ICs to enhance the cooling effectiveness (vs the expected lower airflow).