I am really struggling with the noise of the fans. Any advice will be appreciated.
I am using a new speaker cable,
Confirmed matched impedance with the speaker cab (8 ohms).
Speaker cab is a Suhr PT-15 (brand new)
I am running mono but only using channel A
I have it installed in a dedicated 5 RU Rack sitting in the middle with no other devices in it.
Three questions if that’s OK.
Is it OK to run it mono and not bridge with channel B- would this cause the unit to run any hotter?
Could I remove channel B’s power tubes to reduce heat, maybe that is a stupid idea.
Is there anyway to turn the fans off selectively during recording live, this is causing an issue when recording as I don’t have an isolation room.
Happy to provide any additional information if that would help.
The LXII is a tight package so it needs cooling to manage the heat coming off the power tubes. We went to great lengths to source the quietest fans available, but the priority is safety and maximum air flow.
That said, the temperature sensitive switch that controls fan speed is sensing heat from the far left tube in CH A. Using only Channel B and keeping A on standby would probably keep the fans operating in low speed for a longer duration.
as I am a bit of a maniac and worried about the reliability of the equipment (especially in concert), I make sure that my rack is well cooled so that the equipment suffers as little as possible.
I have a SYN50/50 (but it is technically the same as the LX),
from a certain temperature, the fan accelerates and becomes really noisy!
to avoid this, (and avoid turning my rack into an oven) I mounted 2 good quality and very quiet fans (papst very good ventilation equipment) on the back panel.
result, I have a very bearable ventilation noise, and the SYN fan never accelerates. (except maybe on outdoor stages and heat waves)
I recently received an LX II. Against all expectations, compared to the Synergy 50/50, the fan accelerates much earlier on the LX, and it’s also noisier (it probably spins faster).
I’m waiting for the hardware I ordered to install a grille on the back of the rack where the LX is installed, with two 230V 80mm fans, coupled and connected to a Furman.
Generally, 230V fans can be found in 110V (I assume that’s the voltage in your area).
I installed a pair of Motraxx RAH8025S1 fans on the Synergy rack.
They’re really quiet, but not necessarily the most efficient (24m² per hour, 20dB).
For the LX, I’m going to test it with the same ones, then with a pair of PAST 8850 N 9274014213 (36 m² per hour, 24 dB).
I tried a set of three ARCTIC P9 Silent - PC fan, 92 mm 1900 RPM’s pushing air through and into the LX with a rack space above and below it. Unfortunately this didn’t stop the fans kicking into what seems to be a second stage of RPM. The only way I have been able to mitigate the noise is by running the LX in stereo mode and connecting to channel B. The fan sensors are closer to channel A’s power tubes so this stops the fans moving into the higher RPM stage. Good luck, if you have any luck getting this to work I would love to try it.
If the Lx is in a static rack in a home studio, perhaps removing the top cover, along with additional fans on the front or rear to dissipate heat, should be sufficient.
And since the heat will radiate upwards with the cover removed, I don’t think unplugging the small fans would be harmful to the unit. (Check with a laser thermometer.)
Since I’m using this amp in a rack for live performances, I won’t be removing this cover for obvious safety reasons.
But I might replace the metal sheet with a grille of the same dimensions.
I tested it by opening the LX case for maximum ventilation in the rack, with free space above and below. I installed two quiet 80mm fans on the front to ventilate the rack. It doesn’t get any better than this…
The LX fans still activate and accelerate quickly as soon as the standby mode is turned on.
When I opened the case, I quickly realized that my fun experiment would be pointless because the temperature sensor is very, very close to the first tube of channel A (as David explained in a previous post). As soon as the power is turned on, the tube heats up, and the ventilation speeds up, which is inevitable. A safety feature, except in case of failure of this first tube…
So the option remains to wire it in stereo and only engage channel B.
However, I’m still afraid of accidentally engaging channel A. Like all Fryette amps, there’s no standby indicator light. Mistakes happen quickly, and you can play for a long time before realizing it!
I made myself some small boxes with a 50W 8-ohm power resistor, which I take to my concerts and wire to the back of the amps in case someone forgets to connect it to the speaker during quick and stressful band changes on stage.
So I plug it into channel A as a precaution.
Question: I understand that you shouldn’t remove the unused channel tubes (this will increase the voltage on the remaining tubes).
But is it possible to permanently remove the 500mA fuse on the front of the unused channel? Does it have the same effect as removing the tubes?
