> But with 1,5A my amp is hotter than hell.
> (6 seconds by hand test, ambient temperature 32 Cº)
Well, it was designed to heat sink temperature of 65°C for 22°C ambient.
I guess where you live and with ambient of 32°C, you should retain bias at 1.5A to keep the temperature reasonable.
The other solution would be a slow blowing fan. This will reduce temperature drastically.
> (The top panel is much hotter that the heatsinks).
That IS the case for the CRC, as Nic already reported.
This will improve when you have the regulator version later.
Another alternative would be to go back to the wire-mesh top plate, as this allows better ventilation.
Patrick
> (6 seconds by hand test, ambient temperature 32 Cº)
Well, it was designed to heat sink temperature of 65°C for 22°C ambient.
I guess where you live and with ambient of 32°C, you should retain bias at 1.5A to keep the temperature reasonable.
The other solution would be a slow blowing fan. This will reduce temperature drastically.
> (The top panel is much hotter that the heatsinks).
That IS the case for the CRC, as Nic already reported.
This will improve when you have the regulator version later.
Another alternative would be to go back to the wire-mesh top plate, as this allows better ventilation.
Patrick
Would be a shame change the top plate, is super pretty.
I'll remain with 1.5A in summer and 2A the rest of the year
Thank you!
Take my word and consider using one slow blowing fan for each main heat sink in the summer.
They will easily lower heat sink temperature by 10~15°C.
And if you do it right, you will not hear ANYTHING.
I use one of these for testing myself.
Noctua.at - sound-optimised premium components "Designed in Austria"!
Patrick
They will easily lower heat sink temperature by 10~15°C.
And if you do it right, you will not hear ANYTHING.
I use one of these for testing myself.
Noctua.at - sound-optimised premium components "Designed in Austria"!
Patrick
No such thing as dumb questions.
The GB2 people have a revised protection board based on revised Gerber from Alexis, but I have not tested that myself.
If you promise to test for us, we'll send you one at nominal cost (postage).
It is AFAIK also 1.6mm. Why would you want thicker ?
If there is demand for 2mm, we can run an extra batch as a GB.
Contact Gogowatch by email if you want a test board.
Patrick
The GB2 people have a revised protection board based on revised Gerber from Alexis, but I have not tested that myself.
If you promise to test for us, we'll send you one at nominal cost (postage).
It is AFAIK also 1.6mm. Why would you want thicker ?
If there is demand for 2mm, we can run an extra batch as a GB.
Contact Gogowatch by email if you want a test board.
Patrick
No such thing as dumb questions.
The GB2 people have a revised protection board based on revised Gerber from Alexis, but I have not tested that myself.
If you promise to test for us, we'll send you one at nominal cost (postage).
Patrick
I promise, I'll test the board
Last edited:
No such thing as dumb questions.
Why would you want thicker ?
Patrick
There was a concern with the board flexing with the pcbs onboard push button mechanism thingy.
... from memory.
A board of 1.6mm FR4 mounted on 120x90mm grid with 4x M3 screws.
And the force to actuate a tiny winny push button switch ........
How many Newtons ? Now many µm deformation ? Have you actually try ?
We'll do you one last service and make a batch 2mm for you if there are more than 30 subscribers.
Price tbd. (Not sure we can get small batch 2mm economically.)
Best to be distributed via the local distributors, so we only have a few packets to send.
More donkey work for WK again ........
Patrick
And the force to actuate a tiny winny push button switch ........
How many Newtons ? Now many µm deformation ? Have you actually try ?
We'll do you one last service and make a batch 2mm for you if there are more than 30 subscribers.
Price tbd. (Not sure we can get small batch 2mm economically.)
Best to be distributed via the local distributors, so we only have a few packets to send.
More donkey work for WK again ........
Patrick
I have the amp running. Now is without protection board. Feedbacks uncrossed, direct to ground.
I have polarized to 1.5 A and the power is a + -18.9 V after power resistors.
I put jumpers on board, so if unplug the jumpers the feedback is crossed and the amplifier go supersymetric. I can adjust bias without removing the board on heatsink.
I hope make the protection board this weekend.
I have polarized to 1.5 A and the power is a + -18.9 V after power resistors.
I put jumpers on board, so if unplug the jumpers the feedback is crossed and the amplifier go supersymetric. I can adjust bias without removing the board on heatsink.
I hope make the protection board this weekend.
An externally hosted image should be here but it was not working when we last tested it.
For all those protection board subscribers :
Alexis tested the finished protection board for fit onto the case. Everything works as expected, but he felt that the PCB flexing when he pushes the push-button. The push-button force is only the 1N or so required to engage the micro-switch. So functionally there is no reliability issue. But it is true that there is no mechanical limiter to prevent you from exerting more force than required.
What I suggest is that before building the entire protection board, just solder on the micro-switch, mount the PCB onto the front panel and test it with the push button. If many of you feel that you do not have delicate enough fingers, and need a more rigid PCB, we can arrange a new batch made (at cost) to 2mm FR4 instead of the current 1.5mm This will increase the stiffness by a factor of 3.
Even though we consider this a physiological issue rather than technical, all future batches will automatically get 2mm PCBs, just to avoid any issues of the kind.
Patrick
Just to jolt the memory...
WK forgot, I did not check. So our fault.
We all have too much to do for the normal job for the next years to come.
So we shall not do this again (F5X GBs), thus it will not happen again in the future.
But as said, we'll make a batch of 2mm, at cost, if there is sufficient demand.
I do not consider 1.6mm a design error.
Patrick
We all have too much to do for the normal job for the next years to come.
So we shall not do this again (F5X GBs), thus it will not happen again in the future.
But as said, we'll make a batch of 2mm, at cost, if there is sufficient demand.
I do not consider 1.6mm a design error.
Patrick
Last edited:
Good to know someone is making progress.
Before you float the X, check that you can adjust output DC offset to zero (<10mV), and it is stable with time. Gnd the inputs first of course.
Then feed the input with a square wave, say 1kHz, and measure the output response.
Some load will help stability, say 4 ohm 50W power resistor.
When testing single ended, of course connect dummy load from output to star ground.
When all goes well, then change to floating X, repeat the same, and then time to play music.
Patrick
Before you float the X, check that you can adjust output DC offset to zero (<10mV), and it is stable with time. Gnd the inputs first of course.
Then feed the input with a square wave, say 1kHz, and measure the output response.
Some load will help stability, say 4 ohm 50W power resistor.
When testing single ended, of course connect dummy load from output to star ground.
When all goes well, then change to floating X, repeat the same, and then time to play music.
Patrick
My F5X without protection board, running at 1.5A (This weekend go to 2A), sounds great. This weekend I'll try to do some measurements (Distortion, noise....) and a critical listening against a regular F5 and a XA30.5.
By the moment I burned a R from the CRC (Acted like a fuse) (Beginner's luck).
As oneoclock I left a pins for shortcut by jumpers for adjust, but my unit is working with crossed feedback
By the moment I burned a R from the CRC (Acted like a fuse) (Beginner's luck).
As oneoclock I left a pins for shortcut by jumpers for adjust, but my unit is working with crossed feedback
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
why not one of that fan Inside the case - at the back plate
what C/W are regulator heatsinks
which Fischer model are they
Last edited:
If you only have lost one R, you can try to get a replacement here in Europe.
MPC71 1R is much easier to get, e.g. :
4 Widerstand MPC71 Hochlast 1Ohm 5Watt Metallband 1R 5W 850701 | eBay
Patrick
MPC71 1R is much easier to get, e.g. :
4 Widerstand MPC71 Hochlast 1Ohm 5Watt Metallband 1R 5W 850701 | eBay
Patrick
I lost the board also, the pcb is burnt and bended
I have new resistors, I bought here https://www.buerklin.com/default.asp
Diodes board tilts and bends the legs of LEDs with rigid transformer cable.
I made a new rectifier board for the LEDs fixed with 2 screws to the heatsink.
I made a new rectifier board for the LEDs fixed with 2 screws to the heatsink.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Bias 1.5 A and output DC ofset <1 mV stable all time.
It seems to have a good result for a 3 Amp. Class A amplifier.
I will measure distortion for this 1,5 A. bias before and after the X float this weekend.