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

714477144871449

[sebackman]

714507145171452

[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?

[Don C]

All of my fan were blowing into the case. There are exhaust vents at the back. I think that i's OK to unplug two of the fans if you are not using AEC cards.

[Jonas_h]

What is the temperature of your BSS units after running for a while?

I have had mine run in the rack for three hours with 4 Noctua fans where the ones near the PSU run full speed and the ones on the other side run half speed. The fans are still noisy but better than the stock fans.

74939

According to BSS spec, max temperature is 50 degrees, and I am reading 48 on mine... Don't know if I should be worried or if it is okay.

What temp are you guys reading?

[Don C]

This is with just one of the stock fans connected on the right side, both left side fans disconnected, and with the heatsink mod (http://www.audioheritage.org/vbulletin/showthread.php?37127-Experiments-with-M2-horns&p=378285&viewfull=1#post378285).
This temperature is a lot cooler than what I recorded in the "experiments" thread, mostly because I moved the DSP from sitting on top of the Bryston amp to its own shelf. Also its cold here today.

74940

[sebackman]

Dear all,

In the BLU16 and BLU80 there is only one fan and that blows air out of the box. I have changed to Noctua fans in all my units, as per above.

Please note that I have NOT used any of the rev limiting resistors that comes with the fans, they are all connected direct to the 5v from the main board.

In the BLU160 there are 4 fans and there seems like there are two verions. The one I have blows aír out of the box. I have replaced two fans by the power supply with Noctua fans blowing out of the box. The two others are still there but not connected. They are also mounted to suck air out of the box. I have not had any problems.

I did talk to a friend with a new BLU160 and it appears that the fans in that unit blows air into the box.

It is easy to spot as there is a marking on the fan indicating rotation and air flow.

The BLU100 and 102 I have both have 4 fans blowing into the box and there I have not changed any fans yet.

My BLU800 has the same configuration with 4 fans blowing into the box.

I would suggest, especially if you go with only two fans in a BLU100, 102, 103, 160 or 800 to mount them to blow air out of the box and to mount them by the power supply. The other 2 can be left in the box but disconnected.


****IMPORTANT****
I you do use the unit in a tight rack, warm environment or a room with limited ventilation please keep original fans or make absolutely clear that the reduced air flow is enough to keep your unit cold. Otherwise there is a possibility that your gear will be damaged. Please also remember that there is additional heat build up in the units that have AEC HW processing onboard.
****IMPORTANT****



When I had the box open I did put a self adhesive passive copper cooler on the dsp chips. Please se picture below. Don't know if it helps at all but it looks the part :-) . These coolers fit perfect and are for cooling memory chips on computer graphics cards.

74948


Kind regards
//Rob

[Don C]

I was looking at the specs of the BSS Blu-160 recently just from curiosity. I thought I'd record the chipset data because it doesn't seem to be available anywhere online.
On the input board, the A/D converter is a Cirrus CS5381.
On the output board the D/A converter is a AKM AK4396VF.
These should be exactly the same in any of the JBL SDEC models, such as the SDEC 3500 4500 or 5500.
I'm curious as the whether the Blu-100 and Blu-50 use the same chips. I don't have any of those to look at though.

[Jonas_h]

I was looking at the specs of the BSS Blu-160 recently just from curiosity. I thought I'd record the chipset data because it doesn't seem to be available anywhere online.
On the input board, the A/D converter is a Cirrus CS5381.
On the output board the D/A converter is a AKM AK4396VF.
These should be exactly the same in any of the JBL SDEC models, such as the SDEC 3500 4500 or 5500.
I'm curious as the whether the Blu-100 and Blu-50 use the same chips. I don't have any of those to look at though.

I know that the BOB and BOB boxes use the same converters as the cards for BLU160 (at least according to BSS). It doesn't answer your question though, but thought it could be relevant :)

[grumpy]

BLU-100 a/d and d/a: TI PCM4202 and PCM4104
16 to 24-bit, 216KHz max

76282

[Don C]

TI, AKA Burr-Brown. Looks like they have good specs.
Thanks for posting that.

[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.

[baldrick]

Is there a way of Reading out temp on a BLU100? Don't see any tempurate on mine within Control panel :(

[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).

[pos]

Here is the correct model: http://noctua.at/fr/products/fan/nf-a4x20-5v
5V, 20mm, 9.4m3/h, 14.9dB
(I hope you got this one bubbleboy76, not the 12V model you linked)

The one Richard installed is this one: http://noctua.at/fr/products/fan/nf-a4x10-5v
5V, 10mm, 8.2m3/h, 17.9dB



The original BSS fans are 5V, 20mm, around 10.5m3/h (IIRC) and 18dB (but dB figures alone do not tell the whole story of course)

[bubbleboy76]

Scheisse! (as they say in Germany)
I got the wrong NF-A4x20 then. And I bought it a long time ago, so I can not return it.
The devil is in the details....

What would likely happen if I use the 12V version with 5V input? Will it "just" spinn too slow?
In that case I could try them, and monitor the temperature?

I have heatsinks on each SHARC-processor, installed by previous owner (sebackman on this forum).
The picture in the post is of my unit, I think:
http://www.audioheritage.org/vbulletin/showthread.php?38347-BSS-DSP-fan-noise-especially-for-M2-setup&p=399897&viewfull=1#post399897

What is the highest acceptable long-term internal temperature, would you say?

[grumpy]

Hence my questions.
I'd just try it... particularly if you have the heatsinks installed.

50degC (but preferably less) is a good target for -maximum- long-term electronics temp.
Above that, component lifetime starts dropping off rapidly. Particularly consumer electronics.

[pos]

According to the spec each fan will draw max 0.6W, so you can probably use a small DC-DC converter to boost the voltage from 5V to 12V (so called step up or boost DC-DC converters, easy to find on ebay/amazon/aliexpress for a few euros)

[Don C]

You post mentions the heat-sinks on the DSP chips, but doesn't mention the FPGA. I think that the FPGA is the hottest chip. It might be under the cobranet card on your 800.

[grumpy]

According to the spec each fan will draw max 0.6W, so you can probably use a small DC-DC converter to boost the voltage from 5V to 12V (so called step up or boost DC-DC converters, easy to find on ebay/amazon/aliexpress for a few euros)

That would fix the issue of spinning the fan at the intended speed, -but- introducing a very likely noisy (EMI/RFI) DC-DC converter into a low-level/sensitive electronics system might not be the best solution. Personally, as mentioned, I'd try the fans as-is or just get the correct version... not a large investment vs. a very expensive DSP box.

[baldrick]

I read somewhere that the JBL versions often were run without fans... any reason why the BSS couldn’t do the same?

I still haven’t found a way to read temp on BLU100 :(

[Don C]

I think that it was Widget who mentioned running SDEC units without fans. But I recall that the cover was left off to aid cooling. Someone could get shocked if they put their hand in the unit. Not good if there are children around. Adding heat-sinks along with drilling holes in the cover might work out OK. I'm still an advocate for using a single stock fan with the heat-sink mod. The fan is not that loud if you only leave one connected. I have an SDEC-4500 that I'm fooling with, and I did change it to use two noctua fans, it's about as loud as a single stock fan.
The temperature on the Blu-160 is on the default control panel. Click on the unit once to highlight it. Then right click and select the control panel. But that's in Audio Architect with a Blu-160.

[bubbleboy76]

I tried the Noctua 12v-fan yesterday, and it did not work. I have ordered the correct 5v-version now "Noctua NF-A4x20 5V Premium 40mm (https://www.inet.se/produkt/5320259)".

I also installed new cards in my BSS BLU-160. I now have an all-digital unit, with 8 channels digital input and 8 channels digital output + blu-link digital output.

I will use my BSS BLU-BOB2 as DAC for now, connected via blu-link. But maybe I will buy something more fancy DAC-wise later this year.

[bubbleboy76]

Heatsinks.

[bubbleboy76]

Now, I got the new 5V-fans working.
Switching from dual Noctua nf-a4x10-5v to dual nf-a4x20-5v (sucking air out of the BSS BLU-160) gave me about -10C reduction internal temperature. And the noise is a little bit lower (subjectively). But I still can hear it from the listening position (if I stop the music playing), unfortunately.
From being around 48C internal temperature, It now have around 38C (after long-time use). That is a nice improvement.

[pos]

would a single fan be enough?
That would be a 3dB reduction, not that much...
It would probably be more interesting to slow down the fans.

[bubbleboy76]

I tried the included resistor adapter cables from the 12V-fans that should slow the fan down,
but the 5V-fan did not start with that one.

I do not think only using one fan would make a significant noise reduction for me. But I can try someday.

Attached pics shows difference of 10mm vs 20mm thick Noctua fans (NB, it is the wrong 12V-model of 20mm thick fan shown here)

[pos]

No such resistors shipped with the 5V one?
Maybe you could swap these resistors for better suited values.

[bubbleboy76]

No such thing shipped with the 5V version.

[Jakob]

I have made kind of the same trip with both my BSS 366 and BLU160 and with the small size fans never got an acceptable result. In both cases I ended up changing the top lid making a hole for a 120mm silent computer chassie fan (Noctua) driven by its own transformer (bought cheap at Biltema, a swedish Walmart). I also removed the small fans tog increase airflow.
Now I cant hear the fan one feet away, its dead silent. Internal temperature is around 40 centigrades after long term use.

[Don C]

I folded some cardboard into a U shape and duct taped it to the side of the Blu-160. Folded closed at the front, but open at the back. It forms a snorkel to draw the air in from the back of the rack, with the tape and cardboard further silencing the single fan. It helps a lot. It doesn't seem to have affected the temperature.

[bubbleboy76]

I have made kind of the same trip with both my BSS 366 and BLU160 and with the small size fans never got an acceptable result. In both cases I ended up changing the top lid making a hole for a 120mm silent computer chassie fan (Noctua) driven by its own transformer (bought cheap at Biltema, a swedish Walmart). I also removed the small fans tog increase airflow.
Now I cant hear the fan one feet away, its dead silent. Internal temperature is around 40 centigrades after long term use.

Ok. I am not prepared to do that kind of extensive modification.

Duct-taping a snorkel/hose to it I might try someday though :)

[Jakob]

It wasnt that much of a hassle really. I went to the local glass shop and ordered an acrylic glass plate the same size as the top lid where I mounted the fan. The original top lid is still intact.
For me it was important to have a completely quiet solution since i sit close to the equipment. I also use it to HT as well and in movies there are a lot of quiet passages.

[Fitero]

an acrylic glass plate the same size as the top lid where I mounted the fan. The original top lid is still intact..

That is a good idea! ;)

I was about to bring the top of my SDEC-3500 to my machinest buddy to cut out a hole to mount a fan to. I prefer keeping the lid intact as you did. I'll get a piece of acrylic as you did and mount the fan to it.

[bubbleboy76]

It wasnt that much of a hassle really. I went to the local glass shop and ordered an acrylic glass plate the same size as the top lid where I mounted the fan. The original top lid is still intact.
For me it was important to have a completely quiet solution since i sit close to the equipment. I also use it to HT as well and in movies there are a lot of quiet passages.

A picture would be welcome, if possible. How did you fasten it to the chassis? This acrylic plate has the exact same shape as the original lid?

[Jakob]

The lid has the same outer dimensions but is thicker than the steel original and (of course) isnt bent to connect to the back plate. I was able to fit some of the original screws and used electric tape to make an air tight seal around the edge between the lid and the box. Not as pretty as the original but it works. Sorry for the bad picture, the unit is located at the bottom of my equipment rack.

[Ian Mackenzie]

Hi Jacob,

The larger fans are going to be quieter with the lower velocity.

It’s a bit left field but have you considered a heavy Perspex case to block the noise with larger quiet fan(s) at the rear for ventilation?

Another option that might work. Analyse the fan noise and create a similar noise in anti phase to cancel the offensive noise.

[Fitero]

I haven't been able to make the trip to the local plastic store, so until then I decided to implement a temporary solution.

I propped up the 200mm fan with some bamboo sticks. The blue leds in the fan add to the mystique :D.

8136581366

[Jakob]

Hi Jacob,

The larger fans are going to be quieter with the lower velocity.

It’s a bit left field but have you considered a heavy Perspex case to block the noise with larger quiet fan(s) at the rear for ventilation?

Another option that might work. Analyse the fan noise and create a similar noise in anti phase to cancel the offensive noise.

Hi Ian,
Im really happy with the result I have, thank you for the tip though! I use the adapter cable with resistors so the fan isnt running at full speed. It really is dead silent.

[Fitero]

I finally got the lid made and fan mounted to it. I still have to track down a few more screws so that I can secure the stainless steel grill piece to the top of the fan.

The Internal Ambient Temperature is 38 degrees.

[bubbleboy76]

Looks cool :)

[baldrick]

Any idea if Solution like this could work with BSS Units? I’m thinking running without BSS fan but with this on top.

edit: link:) https://www.amazon.com/AC-Infinity-Rear-Exhaust-Receivers-Components/dp/B01LW1Q429

[Jonas_h]

Any idea if Solution like this could work with BSS Units? I’m thinking running without BSS fan but with this on top.

edit: link:) https://www.amazon.com/AC-Infinity-Rear-Exhaust-Receivers-Components/dp/B01LW1Q429

I don't see why is shouldn't work - but won't that just move the fan noise from the BSS to the new unit?

[pos]

This is an interesting unit, I had no idea such things existed !
A bigger fan will be more silent than smaller ones when moving a given quantity of air, but why not simply put a big fan on the top of the BSS like Fitero did?
The BSS already has (several) temperature sensors and the coupling will be better that way compared to an additional unit on top of the BSS. You would have to drill holes on the top cover of the BSS anyway for this system to work.

[rodec]

What is the temperature of your BSS units after running for a while?

I have had mine run in the rack for three hours with 4 Noctua fans where the ones near the PSU run full speed and the ones on the other side run half speed. The fans are still noisy but better than the stock fans.

74939

According to BSS spec, max temperature is 50 degrees, and I am reading 48 on mine... Don't know if I should be worried or if it is okay.

What temp are you guys reading?

Following your track, I use only one fan over the four of the blu160 and my finger says OK.
To officially check it is ok, how to read real time the temperature of the blu device with London Architect? I did find the control panel in off line, but not anymore in online. Thanks in advance.

Also, in case I will go with a wide slow noisyless fan, would be any reason not to put it inside the BLU box instead on top of the top panel as I may want to pile devices?

[Fitero]

There is not enough room inside the case of the BSS unit to mount the large fan. This is why I mounted mine on top.

I am sorry that I cannot help you with regard to finding the internal temperature of the BSS unit. I can't recall how I accessed the information on mine. It now just appears as one of the pages I see on London Architect.

[rodec]

There is not enough room inside the case of the BSS unit to mount the large fan. This is why I mounted mine on top.

I am sorry that I cannot help you with regard to finding the internal temperature of the BSS unit. I can't recall how I accessed the information on mine. It now just appears as one of the pages I see on London Architect.

OK, clear Fitero, I thought it would fit.
For temperature, no worry, I switched to Audio Architect and I've found it in 30sec.

[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

[ivica]

71452

Hi,

Just for the reference, figure made by our Forum member mica (http://www.audioheritage.org/vbulletin/member.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

[RLRB]

hello,
my bss is noisy. can i remove the fan or is not safe? bss 336 has no fan.
i am going to use in home audio, not in a rack

thanks

[RLRB]

Hello

I dont know where i wrote in the thread. But i repeat: is safe to use a BSS 366t without fan in domestic audio? 336 model does not have fan

THanks

[Riley Casey]

The 366T has quite a bit more processing under the hood than the 336. Possible solutions could be to replace the top cover with a metal screen and ensure adequate air flow above and / or use a larger, lower speed fan to ensure that air flow with the lid off. I've seen lower noise /lower CFM fans available but not sure I'd count on the lower CFM to do the job given how warm the processor gets. Too hot to touch if I remember correctly.


hello,
my bss is noisy. can i remove the fan or is not safe? bss 336 has no fan.
i am going to use in home audio, not in a rack

thanks

[RLRB]

Hello.
I have a 366 and a minidsp opendrc Di. Would the blu 16 better than minidsp? How many for taps accept London blu16. Is valid for all Freq filtering? I don't want to filter the full range horns, I tried with minidsp and removes air and immediacy.
Thanks