I said I am more unprofessional so no worries, I do worse all the timeYou saying I am unprofessional?
I have a few questions about the FSP and building recommendations. I hope this is the best thread.
I have hopes to build an FSP in the near future. It seems I've missed the boat on boards and kits, but I'd like to add my name to the group buy list for the next round and in the meantime perhaps order some parts I will need now since I am placing an order for odds and ends I need for my current project which is the DCB1.
I've been reviewing both the early and more recent version of the build manuals and using search to try and find bits of information that I'd like to have sorted for placing my order on the GB list and ordering parts not offered in the GB.
The earlier MM/highMC build guide stated a 28V transformer should be used. I desire flexibility, so I thought I would use a head amp I have that could be added and removed when needed with this variation of the build when I want to use my low output MC. So it makes sense to build the FSP for MM/highMC gain.
The newer manual states a 36V transformer or one with dual secondary 18-0-18V of at least 30VA should be used. The number of transformers required is listed as "2".
I also found information early on in this thread I believe stating that only one RAW power supply board is required for the build.
I've seen quite a few images when I google the FSP of the main boards assembled and mounted in various cases, but haven't yet found pictures of what members of the GB are actually putting together for their power supplies. I have found what looks like clones of the FSP or perhaps they just different phono designs with dual boards that also have what look like dual mono power supplies in separate cases. In those instances the power supplies appear to be true dual mono with separate transformers, rectification and capacitor banks.
I will be ordering a transformer from Antek for my DCB1' and I thought I would save on shipping by ordering the transformers for a FSP build at the same time.
How many transformers do I need to order for the FSP? They will have to be the 18-0-18V 50VA variation with dual secondaries as that is all Antek appears to have available.
Also, is it even possible to build a dual mono power supply for the FSP with the RAW boards? Do I only require one RAW board even if I wanted to go overboard and pursue that option?
Thanks in advance.
Kevin
I have hopes to build an FSP in the near future. It seems I've missed the boat on boards and kits, but I'd like to add my name to the group buy list for the next round and in the meantime perhaps order some parts I will need now since I am placing an order for odds and ends I need for my current project which is the DCB1.
I've been reviewing both the early and more recent version of the build manuals and using search to try and find bits of information that I'd like to have sorted for placing my order on the GB list and ordering parts not offered in the GB.
The earlier MM/highMC build guide stated a 28V transformer should be used. I desire flexibility, so I thought I would use a head amp I have that could be added and removed when needed with this variation of the build when I want to use my low output MC. So it makes sense to build the FSP for MM/highMC gain.
The newer manual states a 36V transformer or one with dual secondary 18-0-18V of at least 30VA should be used. The number of transformers required is listed as "2".
I also found information early on in this thread I believe stating that only one RAW power supply board is required for the build.
I've seen quite a few images when I google the FSP of the main boards assembled and mounted in various cases, but haven't yet found pictures of what members of the GB are actually putting together for their power supplies. I have found what looks like clones of the FSP or perhaps they just different phono designs with dual boards that also have what look like dual mono power supplies in separate cases. In those instances the power supplies appear to be true dual mono with separate transformers, rectification and capacitor banks.
I will be ordering a transformer from Antek for my DCB1' and I thought I would save on shipping by ordering the transformers for a FSP build at the same time.
How many transformers do I need to order for the FSP? They will have to be the 18-0-18V 50VA variation with dual secondaries as that is all Antek appears to have available.
Also, is it even possible to build a dual mono power supply for the FSP with the RAW boards? Do I only require one RAW board even if I wanted to go overboard and pursue that option?
Thanks in advance.
Kevin
Chromenuts,
When we are talking about true dual mono power, than using two transformers would be best.
Then you wire at 18-0-18-0 like from Antek and wire in series, then you get one 36v out.
Does that make sense?
You could other use one 36-0-36-0 and run one transformer secondary to each input on the raw power supply.
When we are talking about true dual mono power, than using two transformers would be best.
Then you wire at 18-0-18-0 like from Antek and wire in series, then you get one 36v out.
Does that make sense?
You could other use one 36-0-36-0 and run one transformer secondary to each input on the raw power supply.
As Tea mentioned there are AnTek double secondaries models with peripheral magnetic shielding of higher separate voltages that some have used for space and money economy. Using the double mono principle only up to the separate secondaries extent as a good enough compromise. 36V transformers many times proved stronger than anticipated and 20 Ohm RD/Link dropping resistors were called for so 32+32V seems practical for delivering what we aim for on most mains standards. Still 0.47-1 Ohm 2-5W RD/Link are good for filtering some EMI even if the raw DC level at 100mA load is OK (43-50VDC). Model AS-1232 (100VA) would do. Two completely separate 30-50VA transformers will be full double mono but there is nothing ready made available between 15+15V and 18+18V hence the original 36V combined in series spec in the guide.
dual mono requires two ISOLATED supplies.
That could be from two separate transformers, or from one transformer with duplicated windings.
A pair of 50VA transformers to provide the supplies for a pair of channels will be isolated.
A four secondary 100VA transformer will also provide supplies for a pair of channels and they will be isolated.
The questions then become:
will the two higher regulation transformers perform better, or the same, or worse, than one lower regulation transformer?
Will using regulators between the transformers and the load, hide any performance differences between the two arrangements?
That could be from two separate transformers, or from one transformer with duplicated windings.
A pair of 50VA transformers to provide the supplies for a pair of channels will be isolated.
A four secondary 100VA transformer will also provide supplies for a pair of channels and they will be isolated.
The questions then become:
will the two higher regulation transformers perform better, or the same, or worse, than one lower regulation transformer?
Will using regulators between the transformers and the load, hide any performance differences between the two arrangements?
OK...so it seems that a single RAW power supply board in any case has accommodations for two transformer inputs whether they be from separate transformers or a single transformer with dual secondaries...correct? And the same RAW board has two outputs for the two main boards which are normally separated.
The power regulation happens on the main boards.
As there have been some issues with the level of DC output from 36V transformers in combination with variations in mains supply, provisions for RD/Link dropping resistors on the boards have been provided and used to trim the DC and add some filtering to the output of the RAW board?
Salas recommended the Antek AS-1232 which is a 100VA toroid with dual 32V secondaries to avoid having to use larger dropping resistors to reduce the possible high DC output of a 36V variation. A small value dropping resistor is desirable for some added filtering.
If one wanted dual mono the closest one would get would be to buy two 18V transformers with dual secondaries that would require the secondaries be wired in series and then connect each to one of the two inputs on a single RAW PSU board. The output of these transformers would very likely be too high and larger dropping resistors would have to be used on the RAW board to compensate and bring the voltage into acceptable limits.
Just an exercise in thought...suppose you really wanted to go nuts, could you completely isolate your power supplies for each channel by using two RAW boards and only use one input and output on each board?
The power regulation happens on the main boards.
As there have been some issues with the level of DC output from 36V transformers in combination with variations in mains supply, provisions for RD/Link dropping resistors on the boards have been provided and used to trim the DC and add some filtering to the output of the RAW board?
Salas recommended the Antek AS-1232 which is a 100VA toroid with dual 32V secondaries to avoid having to use larger dropping resistors to reduce the possible high DC output of a 36V variation. A small value dropping resistor is desirable for some added filtering.
If one wanted dual mono the closest one would get would be to buy two 18V transformers with dual secondaries that would require the secondaries be wired in series and then connect each to one of the two inputs on a single RAW PSU board. The output of these transformers would very likely be too high and larger dropping resistors would have to be used on the RAW board to compensate and bring the voltage into acceptable limits.
Just an exercise in thought...suppose you really wanted to go nuts, could you completely isolate your power supplies for each channel by using two RAW boards and only use one input and output on each board?
OK...Since this is the GB thread I figured I'd bump it as I added my request to the list and it seems no one else on the list is requesting the FSP right now.
I thought I would get the quad of 2SK369 in case in the future I would decide to change my mind and populate it for MC gain.
In the mean time, if anyone decides to bail on their FSP project or has extra boards/kits please let me know as I would be interested in buying them.
I thought I would get the quad of 2SK369 in case in the future I would decide to change my mind and populate it for MC gain.
In the mean time, if anyone decides to bail on their FSP project or has extra boards/kits please let me know as I would be interested in buying them.
Hi all
OK, I was lucky enough to close my deal on a fairly complete FSP kit over the long holiday weekend.
I've spent time sorting through things doing inventory and using the build guide and group buy info as reference material.
I'm left with a few questions that I'd like to answer so that I might be able to take advantage of the sale that Parts Connection is running through today so I can pick up the caps, resistors and other bits I might want from them.
The seller had the PRP RIAA resistor option offered in the group buy. I'm a bit confused by it. It has (2) 47K and (2) 6.754K 25ppm resistors in it.
In the build guide I find the 47K spec quoted for R1 and R14 with the note that they are both important and to use naked Z-Foil for them if possible.
The guide specs 6.8K for R5 and R10.
Where am I supposed to use the PRP 25ppm resistors? Am I supposed to have two sets?
The mini kit that came with the boards had a few other differences from what I found quoted.
One was that it contained what appears to be (6) 100pF polystyrene caps. I'm assuming this was just a different offering for C2Y than the (2) WIMA 150pF + (2) poly 100pF mentioned?...and that I can similarly use them piggyback as mentioned in the build guide to trim C2? Is the WIMA + poly a better option?
I didn't get the (6) BC 550s mentioned in the mini kit description and in build guide as "7% hfe match, the higher the better". They may have been misplaced. The seller is offering some from his stash. I'm not sure they would meet this spec. How important is it?
I received a pair of 22uF 100V ELNA SILMIC along with a set of ELNA for the electrolytics in the circuit. I'm assuming they are for the Elcap option mentioned in the build guide. Has it been determined that this is a better option than using C2x and R5x?
If not, and I want to stick to C2x + R5x, the spec for C2x is "4.7uF>63V" in the build guide. Does this mean use a cap (such as WIMA illustrated in guide) that is greater than 4.7uF with a rating of at least 63V?
I also got a set of what looks like 4 heat sinks that will slide onto jfets that wasn't mentioned in the guide or group buy info. They are in addition to the Wakefield sinks that I did get for the Mosfets. Has a use for them been mentioned/discussed?
Some plastic isolator washers were in the bag of transistors bundled with the mini kit. There were only 3. They seat properly in the mounting holes of the IRF9610/9530. Are they required to mount the heat sinks properly? If so, I'm one short.
I didn't get any 2SK170BL either. Tea said he has the LSK170B, and I will probably have to get a few other things from him. The 2SK170BL are available from alweit on eBay, and he says he would be able to provide them within spec. Is it worth the trouble to get the Toshibas?
Thanks in advance for the feedback.
Kevin
OK, I was lucky enough to close my deal on a fairly complete FSP kit over the long holiday weekend.
I've spent time sorting through things doing inventory and using the build guide and group buy info as reference material.
I'm left with a few questions that I'd like to answer so that I might be able to take advantage of the sale that Parts Connection is running through today so I can pick up the caps, resistors and other bits I might want from them.
The seller had the PRP RIAA resistor option offered in the group buy. I'm a bit confused by it. It has (2) 47K and (2) 6.754K 25ppm resistors in it.
In the build guide I find the 47K spec quoted for R1 and R14 with the note that they are both important and to use naked Z-Foil for them if possible.
The guide specs 6.8K for R5 and R10.
Where am I supposed to use the PRP 25ppm resistors? Am I supposed to have two sets?
The mini kit that came with the boards had a few other differences from what I found quoted.
One was that it contained what appears to be (6) 100pF polystyrene caps. I'm assuming this was just a different offering for C2Y than the (2) WIMA 150pF + (2) poly 100pF mentioned?...and that I can similarly use them piggyback as mentioned in the build guide to trim C2? Is the WIMA + poly a better option?
I didn't get the (6) BC 550s mentioned in the mini kit description and in build guide as "7% hfe match, the higher the better". They may have been misplaced. The seller is offering some from his stash. I'm not sure they would meet this spec. How important is it?
I received a pair of 22uF 100V ELNA SILMIC along with a set of ELNA for the electrolytics in the circuit. I'm assuming they are for the Elcap option mentioned in the build guide. Has it been determined that this is a better option than using C2x and R5x?
If not, and I want to stick to C2x + R5x, the spec for C2x is "4.7uF>63V" in the build guide. Does this mean use a cap (such as WIMA illustrated in guide) that is greater than 4.7uF with a rating of at least 63V?
I also got a set of what looks like 4 heat sinks that will slide onto jfets that wasn't mentioned in the guide or group buy info. They are in addition to the Wakefield sinks that I did get for the Mosfets. Has a use for them been mentioned/discussed?
Some plastic isolator washers were in the bag of transistors bundled with the mini kit. There were only 3. They seat properly in the mounting holes of the IRF9610/9530. Are they required to mount the heat sinks properly? If so, I'm one short.
I didn't get any 2SK170BL either. Tea said he has the LSK170B, and I will probably have to get a few other things from him. The 2SK170BL are available from alweit on eBay, and he says he would be able to provide them within spec. Is it worth the trouble to get the Toshibas?
Thanks in advance for the feedback.
Kevin
The 6.754K 25ppm is for R5 needing no R6 in parallel. Its a special custom value to avoid producing it through parallelism. So you solder it for R5 and you use no R6.
There must be 15nF C2 + C2Y in pF for making a combined value to your precisely preferred in system treble balance. Usually 15nF + 100pF is adequate.
BC560C 7% matching is not truly important as long as high hFE units are used in both channels. Especially Fairchild ones normally have very high hfE
Elcap or C2x + R5x is a matter of your own preference. Most used the latter without experimenting so we don't have feedback on statistical preference. I suggest you start with elcap and migrate to R+C after many hours of play when familiar so to draw a personal conclusion.
The spec for the C2x 4.7uF MKP in more than 63V is just because you will not find such a capacitor in small voltage. Higher voltage in still proper dimensions is a good thing due to thicker film inside.
The mini-sinks are an aid to stabilize Q1 Q2 little better thermally in non well ventilated enclosures. Normally there is not a real issue occurring so to make you use them. There are other methods too if there is a real issue. More in the build thread when the time comes. This GB thread is not proper for extensive technical discussion.
No isolation is required in mounting the MOSFETS to their sinks. The sinks are not touching ground traces or chassis. Just a little bit of thermal paste is all you need in FSP and you avoid isolation hardware and its thermal resistance.
LSK or 2SK are both adequate as long as they are hand picked to the IDSS bracket mentioned in the guide and not just matched as a pair to a percent but out of that bracket.
There must be 15nF C2 + C2Y in pF for making a combined value to your precisely preferred in system treble balance. Usually 15nF + 100pF is adequate.
BC560C 7% matching is not truly important as long as high hFE units are used in both channels. Especially Fairchild ones normally have very high hfE
Elcap or C2x + R5x is a matter of your own preference. Most used the latter without experimenting so we don't have feedback on statistical preference. I suggest you start with elcap and migrate to R+C after many hours of play when familiar so to draw a personal conclusion.
The spec for the C2x 4.7uF MKP in more than 63V is just because you will not find such a capacitor in small voltage. Higher voltage in still proper dimensions is a good thing due to thicker film inside.
The mini-sinks are an aid to stabilize Q1 Q2 little better thermally in non well ventilated enclosures. Normally there is not a real issue occurring so to make you use them. There are other methods too if there is a real issue. More in the build thread when the time comes. This GB thread is not proper for extensive technical discussion.
No isolation is required in mounting the MOSFETS to their sinks. The sinks are not touching ground traces or chassis. Just a little bit of thermal paste is all you need in FSP and you avoid isolation hardware and its thermal resistance.
LSK or 2SK are both adequate as long as they are hand picked to the IDSS bracket mentioned in the guide and not just matched as a pair to a percent but out of that bracket.