I have updated my review of the FO using dual DPS-500/UR with temperature after 4 hours of moderate-high sound level.
Check it out here:
Amplificateur FO (First One) avec alimentation AudioPower SMPS - Page 6
This is still for V1.2 since I wanted to get the latest DPS-500/UR model with the latest 1kW transfo in comparison of the DPS-400/S2-LV. Now I will modify the FO to V1.3 and retest everything for sound differences.
Very good results!
Do
Check it out here:
Amplificateur FO (First One) avec alimentation AudioPower SMPS - Page 6
This is still for V1.2 since I wanted to get the latest DPS-500/UR model with the latest 1kW transfo in comparison of the DPS-400/S2-LV. Now I will modify the FO to V1.3 and retest everything for sound differences.
Very good results!
Do
Hi Fred
Yes of course it would be easier with the help of sch but that was cleared so many times here, also we are in vendor's part of the forum for known reason.
Look, voltage drop on R16, R17 indicates the input current is present at normal level, TP1-TP2 and TP3-TP4 indicates zero VAS bias current, so most likely T5 (KSA1381) and T6 (KSC3503) are dead.
I suggest to set multimeter to Diode conductance test position, measure all transistor's B-E, B-C diodes voltage drop on broken channel and compare the results with the good one. Best is done by direct comparison of same transistor's position on both channels simultaneously. Very soon you'll notice which transistors said goodbye.
T1 (KSC1845) and T2 (KSA992) should be glued faces together prior soldering to PCB in a case if they too have to be replaced.
Best of luck, L.C.
Hi Do
Very good First One assembly, nice testing plan also in a terms of different SMPS-s applications.
You'll be amazed how different v1.2 and v1.3 sounds. Looking forward to hear your opinion.
Best regards, Andrej
First One v1.4 beta sound test
First One v1.4 beta in testing for more than a week. Just an opening of v1.4 so testing and development is continuing. So far I can only say it is gaining from previous versions and I like it very much. It was built in a completely the same environment as v1.3 and listening in the same system (Pioneer CD transport, Benchmark DAC2 HGC, Zu audio Soul Supreme) so the comparison is relevant.
I had a lot of company's work in Jan 2015, therefore the delay.
First One v1.4 beta in testing for more than a week. Just an opening of v1.4 so testing and development is continuing. So far I can only say it is gaining from previous versions and I like it very much. It was built in a completely the same environment as v1.3 and listening in the same system (Pioneer CD transport, Benchmark DAC2 HGC, Zu audio Soul Supreme) so the comparison is relevant.
Attachments
I had a lot of company's work in Jan 2015, therefore the delay.
First One v1.4 beta in testing for more than a week. Just an opening of v1.4 so testing and development is continuing. So far I can only say it is gaining from previous versions and I like it very much. It was built in a completely the same environment as v1.3 and listening in the same system (Pioneer CD transport, Benchmark DAC2 HGC, Zu audio Soul Supreme) so the comparison is relevant.
How about a few more photos of the pre-amp? What does the entire stack look like?
Mr Cat
Is there a wiki for FO ? A single place where I can find out the heatsink, power requirements, sound quality comparisons and reviews ?
There are so many projects available, from build yourself to ready made modules like your FO. It would be good to read some people's experiences.
Thanks
Is there a wiki for FO ? A single place where I can find out the heatsink, power requirements, sound quality comparisons and reviews ?
There are so many projects available, from build yourself to ready made modules like your FO. It would be good to read some people's experiences.
Thanks
Hi Do
Very good First One assembly, nice testing plan also in a terms of different SMPS-s applications.
You'll be amazed how different v1.2 and v1.3 sounds. Looking forward to hear your opinion.
Best regards, Andrej
Thanks LC!
I guess I'll also have 1.4 to test soon!
Ciao!
Do
Entire stack looks like as seen in the pics, under First One v1.4 amp you can see First One preamplifier, Soul Supreme speakers are visible only in a small portion - lower edge corner.
Preamp pics I could upload soon.
Unfortunately nobody form wiki site information for the First One modules yet. Some more info here
Detailed "How to assemble" info in User manual instructions.
All caps except PSU decoupling and HF compensation gone. First step to eliminate caps made, evalueted, now's time to go to more complex CCS, VAS, DC servo etc.Looking good LC, feedback caps seems gone guess this means group delay now same timing from DC-HF, wish you good tech investigation and development + listening.
PS Solid core cat5 also good sounding as speaker cable, one core enough at low SPL, high SPL add more cores
Actually I use CAT6 pairs for the input connections, speaker's cable is ultra low Z Hi Diamond, minimally disrupting amp's dumping.
After First One v1.4 final iteration VSSA will be adopted to its front-end, so VSSA v1.5 will be just a matter of designing new PCB layout, not delayed by R&D.
Good for you, expecting some pics-report soon.
Best AC & PSU connection wires from SMPS1200A400 to the First One module is SMPS1200 cable set which could be ordered in Hypex Webshop. DC sense connection cable is also in this cable set package.
For input connection solid core CAT6 pair is best to use. Better option could be a pair of pure silver wires in teflon isolation.
Yes, hopefully soon.Thanks LC!
I guess I'll also have 1.4 to test soon!
Ciao!
Do
Hi Mark
Very nice idea indeed, but hehe ...there's always some butt involved
First group buy of 25 chassis sold out quickly, for the next GB, lets call it spring GB, I would need at least 10 chassis confirmed to give my manufacturer green light ... but in silver only. Black is too demanding to produce in such small quantities so he asked for the time beeing to order only the silver ones. If there's interest we can go for C1 Silver Chassis GB, as befits I'll wait a while to forum members to decide.
Regards L.C.
I had a lot of company's work in Jan 2015, therefore the delay.
First One v1.4 beta in testing for more than a week. Just an opening of v1.4 so testing and development is continuing. So far I can only say it is gaining from previous versions and I like it very much. It was built in a completely the same environment as v1.3 and listening in the same system (Pioneer CD transport, Benchmark DAC2 HGC, Zu audio Soul Supreme) so the comparison is relevant.
L.C., Count me for 2 modules v1.4 please
LC dropped by today. Brought a 1.4beta with him.
We had a listen. Then listenned to some more songs and then some more. We planned 1 hour which then manifested in 3 hours.
I can say that the difference between 1.2 and 1.3 is much smaller than to 1.4 beta.
It was really good to hear how the 1.4 opened the sound, becoming same character of the sound from the bass to treble.
After this demo I would say that 1.3 sounds more like tube amp and 1.4 more like studio amp. While I can understand the reasons for tube like sound, studio is more for me.
1.4 was able to reveal more detail which we never heard before in a soundtrack. It is better in bass department, has more insight in middle and treble region. The chimes are now more steely as before.
There are still some hiccups, but bear in mind that this is a prototype build on 1.2 pcb. I believe that 1.4 production will be even better.
I asked LC to modify my 1.2 to 1.4 beta. I asked really nice and used a lot of please and pretty please words. He just smiled. I guess that I'll have to wait for final 1.4 pcb.
We had a listen. Then listenned to some more songs and then some more. We planned 1 hour which then manifested in 3 hours.
I can say that the difference between 1.2 and 1.3 is much smaller than to 1.4 beta.
It was really good to hear how the 1.4 opened the sound, becoming same character of the sound from the bass to treble.
After this demo I would say that 1.3 sounds more like tube amp and 1.4 more like studio amp. While I can understand the reasons for tube like sound, studio is more for me.
1.4 was able to reveal more detail which we never heard before in a soundtrack. It is better in bass department, has more insight in middle and treble region. The chimes are now more steely as before.
There are still some hiccups, but bear in mind that this is a prototype build on 1.2 pcb. I believe that 1.4 production will be even better.
I asked LC to modify my 1.2 to 1.4 beta. I asked really nice and used a lot of please and pretty please words. He just smiled. I guess that I'll have to wait for final 1.4 pcb.
Looking good LC, feedback caps seems gone guess this means group delay now same timing from DC-HF, wish you good tech investigation and development + listening.
PS Solid core cat5 also good sounding as speaker cable, one core enough at low SPL, high SPL add more cores
I use 3 wires for plus and 3 wires for minus. They are able to drive my Thiel speakers very well.
I use telephone wires for interconnects.
So far this combination is unbeatable at the price.