@ma_coule: Peter Daniel may have boards left.
@snokker: I got the point with the 100Ohm resistor. Shortcutting the inrush ntcs seems tzo be a point for class a/b amps - or??? otherwise we shouldn't use CRC filtering...
But what I didn't get right: How can signal currents flow over the mains ground??? And how can the thermistor avoid this? I therefore don't understand the reason for using a thermistor at all - I know that we must be referenced to ground due to the input signal. But I would guess, that a 100k ohm resistor would be sufficient - or??? If my input shield is grounded, I wouldn't need a ground reference anyway???
Dirk
@snokker: I got the point with the 100Ohm resistor. Shortcutting the inrush ntcs seems tzo be a point for class a/b amps - or??? otherwise we shouldn't use CRC filtering...
But what I didn't get right: How can signal currents flow over the mains ground??? And how can the thermistor avoid this? I therefore don't understand the reason for using a thermistor at all - I know that we must be referenced to ground due to the input signal. But I would guess, that a 100k ohm resistor would be sufficient - or??? If my input shield is grounded, I wouldn't need a ground reference anyway???
Dirk
[QUOTE
I got the point with the 100Ohm resistor. Shortcutting the inrush ntcs seems tzo be a point for class a/b amps - or??? otherwise we shouldn't use CRC filtering...
But what I didn't get right: How can signal currents flow over the mains ground??? And how can the thermistor avoid this? I therefore don't understand the reason for using a thermistor at all - I know that we must be referenced to ground due to the input signal. But I would guess, that a 100k ohm resistor would be sufficient - or??? If my input shield is grounded, I wouldn't need a ground reference anyway???
Dirk[/QUOTE]
-For steady state situations the PS current of SE designs is indeed constant. But with signals (not near the) mains freqeuncy flowing through the PS there is interaction between PS and amplifier circuitry (remember kirchhoff's second law!). For example, place an oscilloscope over de R of the CRC you mentioned while playing a loud white noise or multisine through your F3 and you'll be surprised
-To be clear, I ment mains ground currents not flowing over the signal grounds. For your information, Bill Whitlock from Jensen is doing really good work on this subject. His whitepapers are free download on:
JENSEN TRANSFORMERS, INC. - APPLICATION PAPERS AND SCHEMATICS
AN004 might clear the fog.
Every hour designing the groundpath is worth it!!
Succes!
I got the point with the 100Ohm resistor. Shortcutting the inrush ntcs seems tzo be a point for class a/b amps - or??? otherwise we shouldn't use CRC filtering...
But what I didn't get right: How can signal currents flow over the mains ground??? And how can the thermistor avoid this? I therefore don't understand the reason for using a thermistor at all - I know that we must be referenced to ground due to the input signal. But I would guess, that a 100k ohm resistor would be sufficient - or??? If my input shield is grounded, I wouldn't need a ground reference anyway???
Dirk[/QUOTE]
-For steady state situations the PS current of SE designs is indeed constant. But with signals (not near the) mains freqeuncy flowing through the PS there is interaction between PS and amplifier circuitry (remember kirchhoff's second law!). For example, place an oscilloscope over de R of the CRC you mentioned while playing a loud white noise or multisine through your F3 and you'll be surprised
-To be clear, I ment mains ground currents not flowing over the signal grounds. For your information, Bill Whitlock from Jensen is doing really good work on this subject. His whitepapers are free download on:
JENSEN TRANSFORMERS, INC. - APPLICATION PAPERS AND SCHEMATICS
AN004 might clear the fog.
Every hour designing the groundpath is worth it!!
Succes!
Last edited:
Hi Snokker,
so first build it using a CL60 to ground, then make a better ground design???
I could quite easy construct a voltage regulator instead of the capacitance multiplier. So I wouldn't have to care for bridging the inrush limiters???
What is the reason for CL60 to ground instead of direct connection to ground??? What ca a CL60 heal???
Thanks for your patience,
Dirk
so first build it using a CL60 to ground, then make a better ground design???
I could quite easy construct a voltage regulator instead of the capacitance multiplier. So I wouldn't have to care for bridging the inrush limiters???
What is the reason for CL60 to ground instead of direct connection to ground??? What ca a CL60 heal???
Thanks for your patience,
Dirk
Dirk,
Please read Bill Whitlock's papers!! The (one and only?) connection between the chassis- and signal ground is the V- from the rectifier (as F3 only uses single voltage..). Any difference in potential between the two points wil cause a current. The function of the CL60 is just damping that current as it induces voltage. In the past we used a 10 Ohms resistors to do the same.
The trick is to avoid any current flowing through the shield from the RCA of your input to this point.
Books are written on this subject!
Have fun playing around with this
Last edited:
Hi Dirk,
Here again
What do you think a series regulator is?? Exactly, a device that causes voltage drop due to current flowing through it. Does that sound familiar??
I would go for a normal CRC and choose the R on the findings. And you only need one R (per channel) so that's easy to play with. Maybe try a CRCRC? Making the sum of R's lower then original.
In the F5 thread is a (much too long) discussion on this.
Happy building this weekend!
Hi all, I'm selling extra F3 PCB and parts :
- 2 Peter DANIEL PCB sets (F3+PSU)
- 1 x IRFP 240 (2x3 matched) + 2 matched LU 1014D
Here's the link : http://www.diyaudio.com/forums/swap...pnotize-mezmerize-lightspeed.html#post2176341
Thanks
- 2 Peter DANIEL PCB sets (F3+PSU)
- 1 x IRFP 240 (2x3 matched) + 2 matched LU 1014D
Here's the link : http://www.diyaudio.com/forums/swap...pnotize-mezmerize-lightspeed.html#post2176341
Thanks
from exact experience with these cases :
4U is just good enough
5U is good
remember that F3 is burning 100W per side
I have a list of all the parts for the power supply of the F3
could some one give a feedback on the selection?
For the resitors I choose a 5w, the size should not matter, but a bigger one should bether release the head
diod´s
GBPC2501-E4/51 Vishay Semiconductors Bridge Rectifiers
Cap:
BFC233820332 Vishay/BC Components Suppression Film Capacitors
R9+R10
286-2.2K-RC Xicon Metal Oxide Resistors
C1-C8
UKW1V153MRD Nichicon Aluminum Electrolytic Capacitors - Leaded
R1-R8
RW74UR470FB12 Vishay/Dale Wirewound Resistors - Through Hole
I tryed to get all from one store as the postage to Czech Republic will not be cheap so I preffer to pay it only once
could some one give a feedback on the selection?
For the resitors I choose a 5w, the size should not matter, but a bigger one should bether release the head
diod´s
GBPC2501-E4/51 Vishay Semiconductors Bridge Rectifiers
Cap:
BFC233820332 Vishay/BC Components Suppression Film Capacitors
R9+R10
286-2.2K-RC Xicon Metal Oxide Resistors
C1-C8
UKW1V153MRD Nichicon Aluminum Electrolytic Capacitors - Leaded
R1-R8
RW74UR470FB12 Vishay/Dale Wirewound Resistors - Through Hole
I tryed to get all from one store as the postage to Czech Republic will not be cheap so I preffer to pay it only once
Hullo Daniel,
I see you are having a bit of trouble with the Power supply - it IS a bit confusing and the reason it's done that was it's a general purpose pcb to also suit the +/- rails of the F4 and F5 amps - from the cct diagram, notice that in the centre there is a common connection between all the caps which means that they are in Series, so the supply is actually 7,500uF/50v - 0.12R - 7,500uF/50v (the capacitance halves and the voltage doubles - the F3 has the single 48volt rail) If this is still confusing, draw the cct out on a peice of paper and just join up all the common connected points and it then is more obvious.
Component choice: Well, there is a supply house in Prague called GES-Electronics at Myslikova 31, 110 00 Praha1 that has nearly everything that you need.
I don't know if you are using the Mali heatsinks - the HR400 at 150mm high, will be fine
First - They have the higher current ones in stock if using a single Bridge - suggest seperate shottky diodes - they are the MBR20100CTG ones - will need the insulating washers and things kit - mount on seperate bracket or small heatsink - cooler the better.
2nd; This is a "snubber cap" for the AC, not critical, but check the voltage. they should have plenty - take the power supply diagram with you for reference.
3rd ; Same thing with the "discharge resistor" - not critical value - about 2.2kR and yes, 2 watts will do (2 parallel 5kR/ 1 watt, fine)
5th, jumped the Caps : They have Metal Film resistors for this - again, 4 X 0.47R is about 0.12R and a total of about 10 watts - I use single 0.1R/6watt Dale metal film SMD and soldered "legs" on it - best sound - noticeably smoother - again, they have plenty of options.
Now, 4th: those damn caps - if Suds didn't add anymore room on the pcb for bigger caps, you're in trouble - the original design was the Panasonic 15,000/25v UPs and are about 12 mm dia - those UKW Nichicons are about 25mm diameter and just not going to fit - Nichicons are much better sound IMO, but you're either going to forget the pcb, and go discrete build, or search for smaller caps - unfortunately, in this case, even the new types of smaller caps aren't as good for this amp, but just my opinion - the smaller Panasonics are available everywhere.
I hope this is of assistance .... James
Your CZ (Praha) address caught my attention as I have been trying to get longer lengths of that extraordinary Magnatan resistance wire from GES-Electronics (and also without paying that 100Euro minimum quantity fee!)
I see you are having a bit of trouble with the Power supply - it IS a bit confusing and the reason it's done that was it's a general purpose pcb to also suit the +/- rails of the F4 and F5 amps - from the cct diagram, notice that in the centre there is a common connection between all the caps which means that they are in Series, so the supply is actually 7,500uF/50v - 0.12R - 7,500uF/50v (the capacitance halves and the voltage doubles - the F3 has the single 48volt rail) If this is still confusing, draw the cct out on a peice of paper and just join up all the common connected points and it then is more obvious.
Component choice: Well, there is a supply house in Prague called GES-Electronics at Myslikova 31, 110 00 Praha1 that has nearly everything that you need.
I don't know if you are using the Mali heatsinks - the HR400 at 150mm high, will be fine
First - They have the higher current ones in stock if using a single Bridge - suggest seperate shottky diodes - they are the MBR20100CTG ones - will need the insulating washers and things kit - mount on seperate bracket or small heatsink - cooler the better.
2nd; This is a "snubber cap" for the AC, not critical, but check the voltage. they should have plenty - take the power supply diagram with you for reference.
3rd ; Same thing with the "discharge resistor" - not critical value - about 2.2kR and yes, 2 watts will do (2 parallel 5kR/ 1 watt, fine)
5th, jumped the Caps : They have Metal Film resistors for this - again, 4 X 0.47R is about 0.12R and a total of about 10 watts - I use single 0.1R/6watt Dale metal film SMD and soldered "legs" on it - best sound - noticeably smoother - again, they have plenty of options.
Now, 4th: those damn caps - if Suds didn't add anymore room on the pcb for bigger caps, you're in trouble - the original design was the Panasonic 15,000/25v UPs and are about 12 mm dia - those UKW Nichicons are about 25mm diameter and just not going to fit - Nichicons are much better sound IMO, but you're either going to forget the pcb, and go discrete build, or search for smaller caps - unfortunately, in this case, even the new types of smaller caps aren't as good for this amp, but just my opinion - the smaller Panasonics are available everywhere.
I hope this is of assistance .... James
Your CZ (Praha) address caught my attention as I have been trying to get longer lengths of that extraordinary Magnatan resistance wire from GES-Electronics (and also without paying that 100Euro minimum quantity fee!)
Just a followup on the Nichicon caps - there are some 8,200/50v KG (Gold Tune) caps at "the Hifi Collective" in England that are about 6 pounds ea - they are about 35mm dia but as you only need 1, not 2 in series, they will fit okay and have the same 10mm terminals - have to do some links, etc on the pcb but no real problems ....
If the budget will stand it, the Super Thru are also available and at about 19 pounds ea (not a bad price, actually) - these are the top of the range - excellent results but only if you match them with good diodes, resistors, wire, etc.
I started with a single 300VA transformer, then used 2 seperate 300 va ones, and went back to a 500VA single for both channels -> seperate supplies (diodes, C - R - C, etc,) per channel - better stereo image -
GES has 53 pages of transformers and I'm pretty sure they'll have a 2 X 18 volt (or maybe 36 volt) secondary in there somewhere.
they also have some Super thru ones 10,000/50v at about 20 quidhas
If you
If the budget will stand it, the Super Thru are also available and at about 19 pounds ea (not a bad price, actually) - these are the top of the range - excellent results but only if you match them with good diodes, resistors, wire, etc.
I started with a single 300VA transformer, then used 2 seperate 300 va ones, and went back to a 500VA single for both channels -> seperate supplies (diodes, C - R - C, etc,) per channel - better stereo image -
GES has 53 pages of transformers and I'm pretty sure they'll have a 2 X 18 volt (or maybe 36 volt) secondary in there somewhere.
they also have some Super thru ones 10,000/50v at about 20 quidhas
If you
Well thanks for the detailed info.
But im still confused... you know im not really electronics knowleadgeable.
SO far I understand your replies im fine with the selection, except for the c1-c8 caps.
Is this right?
I would like to stay with the PCB, it was not cheap and its gold plated. Would you be so nice a link me the caps you would recommend me if I stay with the pcb?
I know GES unformtunately I dont get there all I was looking for, never the less is there a way I could help you with the Magnatan resistance wire, if so just send me a message
But im still confused... you know im not really electronics knowleadgeable.
SO far I understand your replies im fine with the selection, except for the c1-c8 caps.
Is this right?
I would like to stay with the PCB, it was not cheap and its gold plated. Would you be so nice a link me the caps you would recommend me if I stay with the pcb?
I know GES unformtunately I dont get there all I was looking for, never the less is there a way I could help you with the Magnatan resistance wire, if so just send me a message
Okay, from the diagram C1 - 8 are the power caps and if you draw the cct again with all the -ve terminals of C3,4,7,8 connected directly to the +ve terminals of C1,2,5,6, you can see that C1,C2 are in series with C3,C4 - as each of them is only 25volt device, adding them in series allows them together to work at twice that voltage, or 50 volts - however, when you put 2 caps in Series, the effective capacitance halves and so your 15,000uF in series becomes 7,500uF. Putting 2 in Parallel (C1 and C2 etc) just doubled the capacitance and brings the total back up to 15,000uF again.
It takes 4 of the 25 volt caps to equal one 50 volt cap of the same capacitance.
Not a good way of doing things normally and I'm surprised that the Suds supply pcb didn't include the option of using it for 2 seperate channel supplies, on the same board - you can still do it, but it needs a bit of modding.
If you would like to use the Nichicon caps, I would suggest you get 4 of the 10,000uF/50 volt Nichicons (2 per channel) from Hifi Collective (the Gold Tune ones) or if you like, they have some 10,000/50v Mundorf Mlytics at about same price - both will fit okay. Totals to about 40 pounds, not too bad for good caps.
There are quite a few other capacitor types on the market that will do the job and fit the pcb okay.
You need to google the HiFi Collective (I haven't managed to master this linking thing) and go to the capacitors, then select nichicon and this, unfortunately, gets you a page about Black Gates but at the top (in red letters) there is the next clue on this hunt called nichicon and down bottom right corner is the KG list - bit of a PIA, but it's a pretty good mob - worth the trouble. (the Mundorfs are under the Mundorf Mlytic heading.
On the pcb, these are fitted as C3, and C7 for each channel on the pcb - you can mod the pcb so C1 and C5 can be a seperate supply for the other channel - the caps will still fit on the brd. If you want, there is still room to add some fancy bipass caps ....
Scper the diagram called First watt PS O R1, You join the 2 inner wires of the transformer secondary windings together to get 2 x 18 volts secondary winding voltage and you only need the one bridge (or 4 discrete diodes) - this will give you the required 48 volts at the V+ terminal and the 0Volt GND goes to chassis earth via the TH1 thermistor.
If you use 4 parallel resistors R5,6,7,8, they need to be 0.47 ohms/ 2watt. If you use 2 resistors, they need to be 0.22 ohms/3+watts - 1 resistor needs to be 0.1 ohm and at least 6watts - those Mills power resistors are pretty good and easy to find - wirewound power resistors have to be "non inductive" type - not the cheap ceramic rectangular type ones.
Hope this is a bit clearer - not so good at the description thing.
That GES-Electronics aren't all that helpful - perhaps, if you have a spare few minutes, you could ring the Praha office to see if you can talk to someone that knows if it's possible to either get bigger quantities of their ODM 55R4 wire or better still, see if you can find out where the stuff actually comes from - I think it's probably old stock of the Isabellenhuette wire but perhaps someone is still making it in CZ. Could use about a 300gm reel of the 55ohm/metre wire - best resistors there is - like those really expensive Z foils resistors but with a more analogue sound - effortless detail!
... Jh
It takes 4 of the 25 volt caps to equal one 50 volt cap of the same capacitance.
Not a good way of doing things normally and I'm surprised that the Suds supply pcb didn't include the option of using it for 2 seperate channel supplies, on the same board - you can still do it, but it needs a bit of modding.
If you would like to use the Nichicon caps, I would suggest you get 4 of the 10,000uF/50 volt Nichicons (2 per channel) from Hifi Collective (the Gold Tune ones) or if you like, they have some 10,000/50v Mundorf Mlytics at about same price - both will fit okay. Totals to about 40 pounds, not too bad for good caps.
There are quite a few other capacitor types on the market that will do the job and fit the pcb okay.
You need to google the HiFi Collective (I haven't managed to master this linking thing) and go to the capacitors, then select nichicon and this, unfortunately, gets you a page about Black Gates but at the top (in red letters) there is the next clue on this hunt called nichicon and down bottom right corner is the KG list - bit of a PIA, but it's a pretty good mob - worth the trouble. (the Mundorfs are under the Mundorf Mlytic heading.
On the pcb, these are fitted as C3, and C7 for each channel on the pcb - you can mod the pcb so C1 and C5 can be a seperate supply for the other channel - the caps will still fit on the brd. If you want, there is still room to add some fancy bipass caps ....
Scper the diagram called First watt PS O R1, You join the 2 inner wires of the transformer secondary windings together to get 2 x 18 volts secondary winding voltage and you only need the one bridge (or 4 discrete diodes) - this will give you the required 48 volts at the V+ terminal and the 0Volt GND goes to chassis earth via the TH1 thermistor.
If you use 4 parallel resistors R5,6,7,8, they need to be 0.47 ohms/ 2watt. If you use 2 resistors, they need to be 0.22 ohms/3+watts - 1 resistor needs to be 0.1 ohm and at least 6watts - those Mills power resistors are pretty good and easy to find - wirewound power resistors have to be "non inductive" type - not the cheap ceramic rectangular type ones.
Hope this is a bit clearer - not so good at the description thing.
That GES-Electronics aren't all that helpful - perhaps, if you have a spare few minutes, you could ring the Praha office to see if you can talk to someone that knows if it's possible to either get bigger quantities of their ODM 55R4 wire or better still, see if you can find out where the stuff actually comes from - I think it's probably old stock of the Isabellenhuette wire but perhaps someone is still making it in CZ. Could use about a 300gm reel of the 55ohm/metre wire - best resistors there is - like those really expensive Z foils resistors but with a more analogue sound - effortless detail!
... Jh
just to make the discussion visible:
here is a photo of the original from 6moon:
http://6moons.com/audioreviews/firstwatt4/2_open2.jpg
and here the clone PCB
http://hex.dan.sweb.cz/F3/DSC_0795.JPG
here is a photo of the original from 6moon:
http://6moons.com/audioreviews/firstwatt4/2_open2.jpg
and here the clone PCB
http://hex.dan.sweb.cz/F3/DSC_0795.JPG
To jameshillj: you got a privat message regarding the Wire...
I would preffer it not to mod the caps and resistors, ist really bad that there is no kit for the power supply,... as there is for the amp it self.
What do you think of these caps:
Mundorf M-Lytic - Condensateur Mundorf M-Lytic 35V 15000µF
they are 15000uF and 35V, the voltage should not be the prolem, does it?
I would preffer it not to mod the caps and resistors, ist really bad that there is no kit for the power supply,... as there is for the amp it self.
What do you think of these caps:
Mundorf M-Lytic - Condensateur Mundorf M-Lytic 35V 15000µF
they are 15000uF and 35V, the voltage should not be the prolem, does it?
Correction: Nelson used Panasonic TSHA 25V 15000uF
I am quite sure it was this one Digi-Key - P6577-ND (Manufacturer - ECO-S1EA153CA)
Which has a diameter of 25mm
But it is possible Nelson used this one
Digi-Key - P6578-ND (Manufacturer - ECO-S1EA153EA)
Which has a diameter of 35mm
