thank you fluid
yes i have big heatsink and i don,t need much power.i was just was afraid if there is problem when they all start at the same time but i guess it can handle them.
yes i have big heatsink and i don,t need much power.i was just was afraid if there is problem when they all start at the same time but i guess it can handle them.
Yes. Tested on Thiel CS2.4, minimum impendance 2.8 ohm, and also Thiel CS3.7, minimum impendance 2.4 Ohm.
Amp is stable and can go quite loud with them.
FO revive
Previously I accidentally created firework during calibration of right channel of the FO.
I was worried that there will be a major different when replacing with new one. 
After receiving the new module from LC, within 1 hour doing for the replacement.
Viola! the amp was revived like the phoenix and singing gracefully again!😀 The output DC offset is still well maintained for left side at 1mV and for right side at 4mV which are very good with just plug and play.
After few days of listening, the worry is gone. both side are still identical. The amp is still dead quite, analytic and good bass performance even though with single SMPS.
LC! Thanks again for such a good masterpiece!
Best Regards,
James
Previously I accidentally created firework during calibration of right channel of the FO.
I was worried that there will be a major different when replacing with new one. After receiving the new module from LC, within 1 hour doing for the replacement. Viola! the amp was revived like the phoenix and singing gracefully again!😀 The output DC offset is still well maintained for left side at 1mV and for right side at 4mV which are very good with just plug and play.
After few days of listening, the worry is gone. both side are still identical. The amp is still dead quite, analytic and good bass performance even though with single SMPS.
LC! Thanks again for such a good masterpiece!
Best Regards,
James
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Just out of interest I measured the voltage I am getting from the SMPS1200A180 with nothing connected and then with 4 modules at idle.
+/-47.7 V with nothing connected and +/-47 with four amps idling.
Only a 0.7V drop with nearly 1A of Bias current. I think this is a good result for the Hypex supply!
+/-47.7 V with nothing connected and +/-47 with four amps idling.
Only a 0.7V drop with nearly 1A of Bias current. I think this is a good result for the Hypex supply!
Anyone perform the v1.3 upgrade?
I just got the parts from farnell and prepare for the upgrade.
Is it needed to do calibration after upgrade?😕
James
I just got the parts from farnell and prepare for the upgrade.
Is it needed to do calibration after upgrade?😕
James
Hi, my first post on this forum, although I am reading it for quite some time now.
I ordered FO modules, case and Hypex modules. But I am not shure for this on/off switch ( interrupteur 19mm inox cercle bleu + logo 250v 5a ). Is rated 230V 5A enough for two 1200w Hypex modules?? Will they exceed rated 5A current?
Tnx for your help.
I ordered FO modules, case and Hypex modules. But I am not shure for this on/off switch ( interrupteur 19mm inox cercle bleu + logo 250v 5a ). Is rated 230V 5A enough for two 1200w Hypex modules?? Will they exceed rated 5A current?
Tnx for your help.
Hi all 
KR Audio Kronzilla, very good tube power amp, although pricey. No direct comparison to FO made.
Probably yes, better the source better the sound. Lately I'm listening to Benchmark DAC2 HGC, very satisfying.
10 k logarithmic curve recommended.
No it's not, looking to RMS constant power it is the match to FO. Some even use one SMPS1200A180 to supply four FO modules.
In this case the chassis from the link is OK.
Yes, definitely four power mosfets per channel version (400 W/4 Ohm) at the end of this R&D journey.
Agree completely.
Yes, without any problem.
Yes.
Yes of course, just e-mail me to esl@siol.net
No, not needed. Parts modified not influences DC conditions.
Take 10 A/250 V switch, SMPS inrush current can be very high for the first few periods of mains.
4 Channel First One Finished
I have finally finished my 4 channel version of the First One!
First impressions are very good and I am pleased. The noise level from interference is very low and the sound from first switch on is very nice.
So far my tests have only been with two channels and small Sonus Faber speakers as I have yet to set up the main active system these will be used with.
I have enjoyed listening with the First One as it is very nice to listen to across a wide range of music. I have some tracks that can sound harsh and unpleasant with some power amplifiers. The First One seems to smooth these out a little and makes them much easier to listen to without resorting to turning the volume down or skipping them entirely!
After an hour or so of listening at normal levels the heatsinks are hot but not so hot that you can't hold them for a long time.
I don't notice much difference between the heatsink with the side that was playing vs the side that was idling so I think that the bias is setting the general level of heat when listening at moderate levels and the heatsinks I chose are working well enough in this configuration.
I have finally finished my 4 channel version of the First One!
First impressions are very good and I am pleased. The noise level from interference is very low and the sound from first switch on is very nice.
So far my tests have only been with two channels and small Sonus Faber speakers as I have yet to set up the main active system these will be used with.
I have enjoyed listening with the First One as it is very nice to listen to across a wide range of music. I have some tracks that can sound harsh and unpleasant with some power amplifiers. The First One seems to smooth these out a little and makes them much easier to listen to without resorting to turning the volume down or skipping them entirely!
After an hour or so of listening at normal levels the heatsinks are hot but not so hot that you can't hold them for a long time.
I don't notice much difference between the heatsink with the side that was playing vs the side that was idling so I think that the bias is setting the general level of heat when listening at moderate levels and the heatsinks I chose are working well enough in this configuration.
Attachments
keep'n it ...cool
What are the dimensions of those sinks... maybe 150mm x 300mm x 50mm ?
Cheers
What are the dimensions of those sinks... maybe 150mm x 300mm x 50mm ?
Cheers
Nearly, they are 300mm (L) x 115mm (H) x 50mm (D)
These are the same 1pcs Aluminum E Heatsink for Amplifier 300MM×115MM×50MM | eBay
Finally done the upgrade from V1.2 to V1.3 and from early listening tests, I find a few things have changed
- Bigger stage, actually deeper than before, keeping the width as it was. This creates a greater immersion
- More air, everything seem to breath better. Not a huge difference but it seems better on that side, however bass seems to have dropped a tiny bit (seems better, tighter though), maybe because the amp has a better grip on the bass driver and it is not exaggerated?
- and quieter background, better micro-details.
Nice upgrade! I still have to run some more tests though and will re-confirm those findings. I have another source, preamp and pair of speakers to test.
Ciao!
Do
- Bigger stage, actually deeper than before, keeping the width as it was. This creates a greater immersion
- More air, everything seem to breath better. Not a huge difference but it seems better on that side, however bass seems to have dropped a tiny bit (seems better, tighter though), maybe because the amp has a better grip on the bass driver and it is not exaggerated?
- and quieter background, better micro-details.
Nice upgrade! I still have to run some more tests though and will re-confirm those findings. I have another source, preamp and pair of speakers to test.
Ciao!
Do
Finally done the upgrade.... I still have to build V1.2! But it is nice to know that it can be made even better in the future....
But there is some progress on my First One ... I am building some stuff (Dac/Pre and Shigaclone MKII) for a friend and the payment will be the missing parts for my First One.
The aluminium for the case is already in the pocket! Heat-sinks are next and hopefully the Power supply will soon follow..
I have 2 sources with their own volume control- surround preamp and DAC with build-in volume control. Both of them must be connected directy to FO (because of SQ reasons). So I need 2x stereo inputs on FO.
How to implement this into FO? I was thinking of installing rotary selector, something like this:
Elma 2 pole 6 way switch, 04-1264 | Hifi Collective
alps selecteur 2x5 positions stro
slecteur de source alps srrn152000 5 positions 2 voies
So here I have some problems for picking the optimal one.
Is there much difference in SQ between ALPS and Elma? Because Elma is 10x more expensive … It needed to be non shorting, breake before make type, is that wright?
Finnaly, is this type of selector any good or is there better way to switch between 2 inputs?
Tnx for your help
How to implement this into FO? I was thinking of installing rotary selector, something like this:
Elma 2 pole 6 way switch, 04-1264 | Hifi Collective
alps selecteur 2x5 positions stro
slecteur de source alps srrn152000 5 positions 2 voies
So here I have some problems for picking the optimal one.
Is there much difference in SQ between ALPS and Elma? Because Elma is 10x more expensive … It needed to be non shorting, breake before make type, is that wright?
Finnaly, is this type of selector any good or is there better way to switch between 2 inputs?
Tnx for your help
Congratulations, very good four channel amp and it runs on one SMPS1200 wow
Hi, not yet, work in progress, still hehe
So now FO is not the worst from your amp's list, hopefully 🙂
Please report when done. 😉
FO v1.4 beta on the test bench, a lot of testing on stability in progress, since I don't want to deal with any reclamations issues later in the process. Don't worry, good things in life takes time. 🙂
Can we have an idea of your schematic, even with no values if you want to keep some secrets ;-) ?
It has never been on the bottom of the list LC, and those on my top 5 list are to me the best for my personal taste. You have a VERY GOOD amplifier!
Keep up the good work!
Do
DC coupled modified diamond, enhanced VAS, mosfet output, nothing special but very fine tuned HF compensation to ensure stability in all conditions. 🙂