...just placed an order for FO "M"... hope they weren't sold out in the mean time..
FO M not sold out yet, sending out quotations over the weekend.
Some uses tubes still, no complaints on my side, it's completely up to designer and his preferences, to me mosfets rules in this position; in other interstages BJTs, FETs ... were brought in.
More here.
Exactly, no reason to join ground connections between stereo channels after the source/preamp. Power amps like to operate solo, the results are much better in this way, tested. GND lift is even greater upgrade, all in the same respect.
DC Sense is great companion saving speaker's lives in most easiest way, thanks to Hypex's DC error latched input. R&D of FO L - my lab speakers KEF Cresta wouldn't survive rough testing phase without DC Sense beeing on the watch.
Hi !
You're right, as you can see on the pict, I do have a speaker protection - BUT it is NOT linked to the gnd at all, that is not clear on the pict, because I left some unused old wires on the bottom of the case.
OUT signal merely goes through the 2 relays, no gnd connection between this protection board and anything but AC power.
I don't have any hum or any hiss in my speakers, perfect silence.
But, I have one more question :
You've changed one resistor on my boards because I have a low voltage on my rail. What is now the DC voltage acceptable for my boards with your special mod ? Anything between 30V and 60V ? More ? Less ?
Just in case I want to one day change my PSU .........
I'm very happy with the sound I get from my speakers, much more presence and consistence in the bass range, very well balanced sound globaly.
Goes very well with the big improvement I have since I have a xmos usb/spdif adapter in my system.
Cheers
J-M
Hi again,
Hi-end wise ........ difficult to say, was already very good before.
Stage: maybe a bit deeper, more coherent and sweeter.
All in all, globaly excellent. Never heard many systems as good ...........
As I removed my previous regulation stage, I now have 37V DC on my rails.
One question though : would you recommend to perform another calibration control after some time ? 10 hours ? 1 month ? or pointless ?
Cheers
JM
FO M not sold out yet, sending out quotations over the weekend.
Nice, thanks!
I already put in an order with audiopower.it for 2x DPS-600/S2-52V (yes, the 400/S1 would have been sufficient and was recommended, but I wanted to oversize), and was very pleased by both the prices and the informative and friendly communications there. Thanks to maxidcx for the tip!My plan is to build monoblocks during autumn, with balanced inputs to FO M provided by Lundahl 1540s, as described elsewhere in this thread.
Attachments
Sharing some progress
Hi !
GBatokai I m sure you will be pleased with such a gear !
well guys, I thought I could share more about a special version I m doing around quad FO 1.4M modules this is not finished but the FO is also a very nice toy and kind of swiss knife for me and sharing this is also a way to push me on going faster..
So the project is a compact and ultimate quad amplifier in order to bi-amp a pair of loudspeaker, and it integrates a "lossless"volume control inside the amp.
As I have passive filters, I could choose between bridge or biamp. At the moment this will be configured as biamp as my plan is to quickly move to active biamping. But I m sure a bridge configuration would be awesome and I may try that sooner or later.
So we have a 240mm wide front panel with on each left and right side a dual bloc of 2 heat sink (80mm x 300mm each) containing 1 (vertical) hypex smps1200a400 and 2 FO1.4M.
The 2 FO are one above the other and the wiring is organized so that the input connectors are facing each other. I ve manager to directly solder the wire on the hypex PCB and then the wires exit from 3 holes drilled in the L aluminium plate... (not really industrial but fully compatible with DIY approach).
you can see the 4 output and 2 RCA on the right side of the picture.
For the volume controle, I ve design a small PCB using the DAC8812 and an Attiny85. the PCB is organised so that it fits in between the 2 FO so that the output of the R2R MDAC can reach the input connectors with the shortest length possible.
there is a controle panel with an encoder, an IR and 3 digits display, which comunicates with up to 2 R2R board in serial (4800 baud) optocoupled) so that there are no comon GND in between the Rigth and Left chanel.
when the hypex is loaded with 2 FO1.4M, it becomes quite hot and the connection to the heatsink is welcome here. Now comes the problem of the comon ground between the 2 modules , and you know I have designed a differential input module to solve that. but here this would be overkill as we have already a PCB for the R2R volume. So, after many hours of simulations, I decided to modifiy one of the 2 FO so that the Feedback divider network goes to the ground of the first / botom module. You can see the mod on the 3rd picture : the 2 small 47ohm resistor have been unsoldered and moved over the 2 x 2200 ohm (see blue circle). Then I can connect a silver wire from these 47R down to the botom module GND. same stuff needed on the In- connection to be perfect. And then the 2 GND Speaker connection must be taken at the same point on the botom module.
Here we go, this is all in progress and I hope I can finish and listen that say next week. if all is OK I will order all the parts for the other side of the amp in order to complete a fantastic biamp bridegeable unit.
cheers
Hi !
GBatokai I m sure you will be pleased with such a gear !
well guys, I thought I could share more about a special version I m doing around quad FO 1.4M modules
this is not finished but the FO is also a very nice toy and kind of swiss knife for me and sharing this is also a way to push me on going faster..So the project is a compact and ultimate quad amplifier in order to bi-amp a pair of loudspeaker, and it integrates a "lossless"volume control inside the amp.
As I have passive filters, I could choose between bridge or biamp. At the moment this will be configured as biamp as my plan is to quickly move to active biamping. But I m sure a bridge configuration would be awesome and I may try that sooner or later.
So we have a 240mm wide front panel with on each left and right side a dual bloc of 2 heat sink (80mm x 300mm each) containing 1 (vertical) hypex smps1200a400 and 2 FO1.4M.
The 2 FO are one above the other and the wiring is organized so that the input connectors are facing each other. I ve manager to directly solder the wire on the hypex PCB and then the wires exit from 3 holes drilled in the L aluminium plate... (not really industrial but fully compatible with DIY approach).
you can see the 4 output and 2 RCA on the right side of the picture.
For the volume controle, I ve design a small PCB using the DAC8812 and an Attiny85. the PCB is organised so that it fits in between the 2 FO so that the output of the R2R MDAC can reach the input connectors with the shortest length possible.
there is a controle panel with an encoder, an IR and 3 digits display, which comunicates with up to 2 R2R board in serial (4800 baud) optocoupled) so that there are no comon GND in between the Rigth and Left chanel.
when the hypex is loaded with 2 FO1.4M, it becomes quite hot and the connection to the heatsink is welcome here. Now comes the problem of the comon ground between the 2 modules , and you know I have designed a differential input module to solve that. but here this would be overkill as we have already a PCB for the R2R volume. So, after many hours of simulations, I decided to modifiy one of the 2 FO so that the Feedback divider network goes to the ground of the first / botom module. You can see the mod on the 3rd picture : the 2 small 47ohm resistor have been unsoldered and moved over the 2 x 2200 ohm (see blue circle). Then I can connect a silver wire from these 47R down to the botom module GND. same stuff needed on the In- connection to be perfect. And then the 2 GND Speaker connection must be taken at the same point on the botom module.
Here we go, this is all in progress and I hope I can finish and listen that say next week. if all is OK I will order all the parts for the other side of the amp in order to complete a fantastic biamp bridegeable unit.
cheers
Attachments
Looking good... Looking really good!!! Hehehe
Ciao!
Do
Looks good LC...
And thanks for answering my question from previous post "why not decoupling the electrolytics with smaller ones ending with pp ones - one decoupling would be enough for the entire banks and mimic even better caps"...
VERY interesting, hope only the duelund doesn't bust the budget...
Keep up the excellent work
Claude
And thanks for answering my question from previous post "why not decoupling the electrolytics with smaller ones ending with pp ones - one decoupling would be enough for the entire banks and mimic even better caps"...
VERY interesting, hope only the duelund doesn't bust the budget...
Keep up the excellent work
Claude
Ok Ive goot it uo and running. Very nice sound, playing Yello now)) will try more. Now I am curious how good 1.4 M amd L are will need tp chose one of them once ready. This sounds really good and looking towards the improvements in the newer models.
Thanks to LC for the njce amplifier and to Cresent for his smps
Sent from my ONE A2003 using Tapatalk
will need tp chose one of them once ready. This sounds really good and looking towards the improvements in the newer models. Thanks to LC for the njce amplifier and to Cresent for his smps
Sent from my ONE A2003 using Tapatalk
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