I'm sorry, my previous post post wasn't exact.
My (not so) old LM3886 was sitting on a shelf, now back in use.
The measurement I did ( 1 Volt peak to peak input voltage from my DAC preamp ) was done with another amplifier, with a 17,5 factor gain.
Giving a large enough amount of power for my sound system.
JM
My (not so) old LM3886 was sitting on a shelf, now back in use.
The measurement I did ( 1 Volt peak to peak input voltage from my DAC preamp ) was done with another amplifier, with a 17,5 factor gain.
Giving a large enough amount of power for my sound system.
JM
OK, so no FO M voltage issue needs to be resolved. Anyway FO M could operate at +/-30 V with few resistor's values change. At this rails voltage level you would get app. 50 Vpp on 8 Ohm load.
L.C.
P.S. Still some FO M on the stock.
OK, to be more precise, I just pulled my oscilloscope and made some measurements with my LM3886 amplifier.
I'm under 1 volt peak to peak input (from my DAC preamp) and a maximum of 40 volts peak to peak output to keep my ears safe.,
Is this feasible with the 1.4M module, and my present voltage rail ?
JM
I'm under 1 volt peak to peak input (from my DAC preamp) and a maximum of 40 volts peak to peak output to keep my ears safe.,
Is this feasible with the 1.4M module, and my present voltage rail ?
JM
OK, so no FO M voltage issue needs to be resolved. Anyway FO M could operate at +/-30 V with few resistor's values change. At this rails voltage level you would get app. 50 Vpp on 8 Ohm load.
L.C.
P.S. Still some FO M on the stock.
50 Volts pp will be more than enough according to what I just measured.
Will you make the resistors mods yourself ?
JM
Thanks for kind words, I'm so glad you like it.
Please read FO M User manual instructions very carefully, make exact actions according to all manual's steps and follow FO M connection schematics. In this way there will be no issues whatsoever.
L.C.
Your ears are on the safe side since FO M has +27,75 dB of voltage gain.OK, to be more precise, I just pulled my oscilloscope and made some measurements with my LM3886 amplifier.
I'm under 1 volt peak to peak input (from my DAC preamp) and a maximum of 40 volts peak to peak output to keep my ears safe.,
Is this feasible with the 1.4M module, and my present voltage rail ?
JM
Done.
L.C.
Great!
Would it be better and cheaper than two M versions in parallel?
Cheers,
M.
Calibrating my modules ...........
Hi !
I received my 2 FO 1.4M modules a few days ago.
It took me some time to install the 1st one on its radiator.
Now I've been trying to adjust the 0 Volt offset no problem playing with TR1 and TR2.
The problem is the voltage I get between TP1/TP2 and TP3/TP4 : I can get the same 21,80 mV on each side, and O volt offset,
but never the 180mV you mention on the 1.4M manual.
Is this somehow related to the mod you've done on my modules
(adjusted to my 30 - 31Volts to be precise) rail ?
Thanks ......
JMK
Hi !
I received my 2 FO 1.4M modules a few days ago.
It took me some time to install the 1st one on its radiator.
Now I've been trying to adjust the 0 Volt offset no problem playing with TR1 and TR2.
The problem is the voltage I get between TP1/TP2 and TP3/TP4 : I can get the same 21,80 mV on each side, and O volt offset,
but never the 180mV you mention on the 1.4M manual.
Is this somehow related to the mod you've done on my modules
(adjusted to my 30 - 31Volts to be precise) rail ?
Thanks ......
JMK
Good news
Hi,
I've been very coutious installing the 1st module in my chassis previously used with Lm3886 modules in a dual mono configuration.
I left the LM3886 on the right channel, and installed the 1st FO 1.4M on the left channel.
It took me a while to properly calibrate it, it will be easy for the next one !
My left channel is MUCH BETTER than the LM3886 channel, specially in the mid/bass range.
I must say that my big floor standing 3 ways speakers are pretty dificult to drive properly, and it looks like it will be excellent - but still some work to do to install the 2nd module.
More details in a couple of days !
Cheers
JMK
Hi,
I've been very coutious installing the 1st module in my chassis previously used with Lm3886 modules in a dual mono configuration.
I left the LM3886 on the right channel, and installed the 1st FO 1.4M on the left channel.
It took me a while to properly calibrate it, it will be easy for the next one !
My left channel is MUCH BETTER than the LM3886 channel, specially in the mid/bass range.
I must say that my big floor standing 3 ways speakers are pretty dificult to drive properly, and it looks like it will be excellent - but still some work to do to install the 2nd module.
More details in a couple of days !
Cheers
JMK
Hi Everyone,
in the past days I had the chance to test my dual FO 1.4M with 2 smps from audiopower.it version DPS-400/S1 and I thought I could share some info and picture.
I knew this supply from a previous project 2 years ago, and till then they have revised this smps with a new transformer and the overall power is said to be supporting 600watt and more than 600ma continuous current (bias) wihout any overload problem.
I wanted to keep the overall temperature of the amp below 50°C and then I have chosen a 2x52V version, which is 10V less than hypex, so the overall dissipation (without signal) is 29watt per heatsink instead of 35watts, reducing the heatsink temperature of about 3 degrees.
The result is amazing good soundwise. with the 2 smps, obviously the result is better than with 1 big hypex!. I can hear more séparation across the 2 speakers. for the bass, it is a mater of volume listening.
the SMPS is quite compact (105x105) and can be fixed on a standard 2U 300x80 heatsink, with the FO.
the only drawback I see is that the supply do not have the posibility to directly connect a DC current protection (as sold by LC) as its standby mode is not "latched" so if your concerned by DC protection you have to add a traditional relay based protection.
here we are with another alternative to make compact dual mono system, for example using the "mini dissipante" case.
in the past days I had the chance to test my dual FO 1.4M with 2 smps from audiopower.it version DPS-400/S1 and I thought I could share some info and picture.
I knew this supply from a previous project 2 years ago, and till then they have revised this smps with a new transformer and the overall power is said to be supporting 600watt and more than 600ma continuous current (bias) wihout any overload problem.
I wanted to keep the overall temperature of the amp below 50°C and then I have chosen a 2x52V version, which is 10V less than hypex, so the overall dissipation (without signal) is 29watt per heatsink instead of 35watts, reducing the heatsink temperature of about 3 degrees.
The result is amazing good soundwise. with the 2 smps, obviously the result is better than with 1 big hypex!. I can hear more séparation across the 2 speakers. for the bass, it is a mater of volume listening.
the SMPS is quite compact (105x105) and can be fixed on a standard 2U 300x80 heatsink, with the FO.
the only drawback I see is that the supply do not have the posibility to directly connect a DC current protection (as sold by LC) as its standby mode is not "latched" so if your concerned by DC protection you have to add a traditional relay based protection.
here we are with another alternative to make compact dual mono system, for example using the "mini dissipante" case.
An externally hosted image should be here but it was not working when we last tested it.
