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First One - mosFET amplifier module

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since i used funs at the heatsinks i was wondering what would be the optimal temperature operation.
When i was technical manager of recording studios, very often, manufacturers asked us to test one of their amps. I received them nicely, but when i saw fans, unpacking the amp, i used to say: no way, we will not even try-it.
Why to try to have 110db of signal noise ratio when you get > 30db of acoustic noise in your room during mixages or listenings because the noise of the fans ?
 
First One GB members ordered modules and chassis

Hi all :wave2:

To all GB members ordered chassis and modules I can firmly present information about the shipment date:

- all black and silver chassis together with modules ordered will be shipped out latest on 30th June ;)

Because of a bit delayed production each chassis set will include two DC sense PCB-s as a gift. :)

Best regards, L.C. :cheers:
 
When i was technical manager of recording studios, very often, manufacturers asked us to test one of their amps. I received them nicely, but when i saw fans, unpacking the amp, i used to say: no way, we will not even try-it.
Why to try to have 110db of signal noise ratio when you get > 30db of acoustic noise in your room during mixages or listenings because the noise of the fans ?

i have two modules at each side and the temp too high even with big heatsinks.
maybe later when economics allow i will buy even bigger heatsinks.
for now the funs are low noise 120mm and they work at 300 rpm.
it,s imposible to hear them even if you go close not from listening position.
room noise floor is higher.
 
Hi all :wave2:

To all GB members ordered chassis and modules I can firmly present information about the shipment date:

- all black and silver chassis together with modules ordered will be shipped out latest on 30th June ;)

Because of a bit delayed production each chassis set will include two DC sense PCB-s as a gift. :)

Best regards, L.C. :cheers:

Hypex power supplies are waiting for them.... :eek::sax:
 
LC,is it possible to post photos of the black chassis?Relaixed boards, on the other hand, would fit nicely into the existing chassis?

Yes of course as soon as I'll get them pics will follow. ;)

No, Relaixed is too big to fit, similar one could, working on this subject. :)

BTW Relaixed powered and tested according to specs, now it's time to connect it to First One. :cool:
 

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L.C. I want to thank you for this wonderful amp!

I finished 1 of the monoblocks this evening. "Old" earth connection wiring. (waiting for the MUR160 to arrive) But COMPLETELY silent this way. (probably due to galavanic isolation from the output transformers in my DAC/preamp) Don't know if the "new" earth connection can improve the sound?

Wired both of my Maggie 1.6 speakers (in parallel) to the mono amp and connected the left output of my DAC/preamp to the F.O. input. Played some well known music and I only could say WOW!

Dynamics, openness, detail, very tight and powerful bass, everything is there! And NO WAY the openness and detail are making it harsh sounding, absolutely not. Instruments are sounding very realistic. Goosebumps all over the place while playing Eva Cassidy - Ain't no Sunshine, the voice sounds REALLY good.

Those are my first impressions from 1 mono amp running only one channel from my DAC/preamp. I can immagine the amp will even sound better after a while. I REALLY can't wait to listen to my set with both mono First One amps in place.

I've owned quite a few amps lately, most of them with very good reviews, but don't think any of them did have ALL positive things in one package. To mention a few amps I've owned or still own: NAD M2, Marantz SM11-S1, LUA Alborada MK2, Hypex NCore mono's, Holton NxV-201PS mono's. The LUA's are REALLY good (Push Pull 211 full tube mono's with more than 200W of power available), but I REALLY don't like the tube replacement every now and than and I am always "tube rolling".... ;) The M2 is REALLY dynamic, open, really good bass, but lacking some "natural" tone on voices and instruments.

Happy with the F.O. for now! :)
 
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L.C. I want to thank you for this wonderful amp!

You're welcome Mark :)

I finished 1 of the monoblocks this evening. "Old" earth connection wiring. (waiting for the MUR160 to arrive) But COMPLETELY silent this way. (probably due to galavanic isolation from the output transformers in my DAC/preamp) Don't know if the "new" earth connection can improve the sound?

Yes, new grounding scheme will improve the sound significantly. ;)

Wired both of my Maggie 1.6 speakers (in parallel) to the mono amp and connected the left output of my DAC/preamp to the F.O. input. Played some well known music and I only could say WOW!

Dynamics, openness, detail, very tight and powerful bass, everything is there! And NO WAY the openness and detail are making it harsh sounding, absolutely not. Instruments are sounding very realistic. Goosebumps all over the place while playing Eva Cassidy - Ain't no Sunshine, the voice sounds REALLY good.

Now two Maggies in parallel on one First One channel sounds good, that's real 2 Ohm load, imagine each on its own channel and new GND sch, even more goosebumps. :cloud9:

Those are my first impressions from 1 mono amp running only one channel from my DAC/preamp. I can immagine the amp will even sound better after a while. I REALLY can't wait to listen to my set with both mono First One amps in place.

Report when finished. :up:

I've owned quite a few amps lately, most of them with very good reviews, but don't think any of them did have ALL positive things in one package. To mention a few amps I've owned or still own: NAD M2, Marantz SM11-S1, LUA Alborada MK2, Hypex NCore mono's, Holton NxV-201PS mono's. The LUA's are REALLY good (Push Pull 211 full tube mono's with more than 200W of power available), but I REALLY don't like the tube replacement every now and than and I am always "tube rolling".... ;) The M2 is REALLY dynamic, open, really good bass, but lacking some "natural" tone on voices and instruments.

Vocals on First One are indeed very natural, can mislead someone the Singer is in the room. :sing: :drool:

Happy with the F.O. for now! :)

:cool:

Regards, L.C. :cheers:
 
I've owned quite a few amps lately, most of them with very good reviews, but don't think any of them did have ALL positive things in one package. To mention a few amps I've owned or still own: NAD M2, Marantz SM11-S1, LUA Alborada MK2, Hypex NCore mono's, Holton NxV-201PS mono's. The LUA's are REALLY good (Push Pull 211 full tube mono's with more than 200W of power available), but I REALLY don't like the tube replacement every now and than and I am always "tube rolling".... ;) The M2 is REALLY dynamic, open, really good bass, but lacking some "natural" tone on voices and instruments.

Naturalness of the sound profile has a lot to do with distortion linearity across the audio bandwidth, meaning THD is frequency independent. In such amp audio bandwidth has linear OLG, usually drops -3 dB at over 40 kHz or more, so naturally error signal (subtraction between feedback and input signal) is linear too, meaning amp has no more hard work on higher frequencies than in lower spectrum. The result is natural like sound, neutral too. :)
 
Naturalness of the sound profile has a lot to do with distortion linearity across the audio bandwidth, meaning THD is frequency independent. In such amp audio bandwidth has linear OLG, usually drops -3 dB at over 40 kHz or more, so naturally error signal (subtraction between feedback and input signal) is linear too, meaning amp has no more hard work on higher frequencies than in lower spectrum. The result is natural like sound, neutral too. :)

Hi LC,

What values did you measure for open loop gain and bandwith of First One?

Regards,
John
 
Very interested by your conclusion about balanced / bi-amp question :cool:



Did a non-exhaustive test. Compared to a stereo bi-wired set of speakers similar to ATC50, bi-amping is definitely the winner. Balanced sounded serene and slightly muddy in comparison. Kept test conditions as similar as possible by feeding either balanced signal from a transformer coupled preamp, or just one polarity from the same transformer. Shorting both channels inputs kept me a bit apprehensive as input impedance came down to just over 5k, but the preamp did not seem to mind. Different set of speakers/cables may of course produce different results.