Gentlemen, I have ordered 20 FC-100 PCBs (see image 1) a minute ago.
So: "the show goes on".
Concerning the FC-100 frontend - PSU:
I have done a very nice layout (as I think
) for it, which is based on a dual LT3062 - LDO - regulator (see image 2).
I have measured its "hum" on my prototype - regulator: it is lower than 3mV, and I am sure that the "hum" of the current layout will be even significantly lower.
But there is one drawback.
The LT3062 - package is very, very small (MSOP8), and I (and I think most of you) will not be able to solder it.
A German DIY-friend of mine is able to solder it however! He owns a solder stencil and a solder-oven and has successfully soldered my LT3062 prototype PCBs.
But it takes him a lot of time and material to solder and he won't do it "for nothing".
His offer to solder the LT3062 - PCBs is 5€ per PCB.
I have contacted Mihai and asked him, if it is possible (wise) to power both channels of the FC-100 from a single frontend-PSU.
Mihai did not yet answer my question.
@Adrian: what do you think? Do you have a closer contact to Mihai than me?
I then contacted ALWEIT (ebay-seller).
ALWEIT sold me very well matched quads (!) of 2SK170 input-differential transistors several years ago, when I did the 1st group buy for the FC-100.
Mihai recommends to use 2SK170 with an IDss of >= 9mA.
I am looking forward to ALWEIT's answer.
May I order MPC74 - 0R1 emitter resistors for all of you?
BUERKLIN does currently have the needed amount of resistors (120) on stock!
I will keep you informed about the progress of this group buy.
Best regards - Rudi_Ratlos
So: "the show goes on".
Concerning the FC-100 frontend - PSU:
I have done a very nice layout (as I think
) for it, which is based on a dual LT3062 - LDO - regulator (see image 2).I have measured its "hum" on my prototype - regulator: it is lower than 3mV, and I am sure that the "hum" of the current layout will be even significantly lower.
But there is one drawback
.The LT3062 - package is very, very small (MSOP8), and I (and I think most of you) will not be able to solder it.
A German DIY-friend of mine is able to solder it however! He owns a solder stencil and a solder-oven and has successfully soldered my LT3062 prototype PCBs.
But it takes him a lot of time and material to solder and he won't do it "for nothing".
His offer to solder the LT3062 - PCBs is 5€ per PCB.
I have contacted Mihai and asked him, if it is possible (wise) to power both channels of the FC-100 from a single frontend-PSU.
Mihai did not yet answer my question.
@Adrian: what do you think? Do you have a closer contact to Mihai than me?
I then contacted ALWEIT (ebay-seller).
ALWEIT sold me very well matched quads (!) of 2SK170 input-differential transistors several years ago, when I did the 1st group buy for the FC-100.
Mihai recommends to use 2SK170 with an IDss of >= 9mA.
I am looking forward to ALWEIT's answer.
May I order MPC74 - 0R1 emitter resistors for all of you?
BUERKLIN does currently have the needed amount of resistors (120) on stock!
I will keep you informed about the progress of this group buy.
Best regards - Rudi_Ratlos
Attachments
Hi Rudi,
I suggest you ask FetAudio for the matched quads of 2SK170.
FET Audio | Hi-End Audio Projects
He's well known at DIYaudio
I can solder my own LT3062 and I will also source my own 0R1 resistors as I wanted to use something else
I'm happy to see that I can get that Tamura transformer at Digikey (MT2129-ND)!
Thanks
Do
I suggest you ask FetAudio for the matched quads of 2SK170.
FET Audio | Hi-End Audio Projects
He's well known at DIYaudio
I can solder my own LT3062 and I will also source my own 0R1 resistors as I wanted to use something else
I'm happy to see that I can get that Tamura transformer at Digikey (MT2129-ND)!
Thanks
Do
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Hi markus22ch,
There isn't any reason that you can't use more than one transformer with one soft start circuit as long as the combined load does not exceed what the soft start circuit can handle. You should be fine.
The aspect that you should watch for is the inrush current for each power supply. Higher capacitance increases the load on any soft start circuit. The steady state requirements are normally not a problem.
-Chris
There isn't any reason that you can't use more than one transformer with one soft start circuit as long as the combined load does not exceed what the soft start circuit can handle. You should be fine.
The aspect that you should watch for is the inrush current for each power supply. Higher capacitance increases the load on any soft start circuit. The steady state requirements are normally not a problem.
-Chris
I want to inform you about a change, concerning the PSU for the FC-100's frontend.
I have done a nice layout for the LT3062 - PSU and presented it in the "Power Supply sub-forum."
But: none of the visitors of my thread has any experience with the LT3062 LDO.
Moreover: Manuel, who has soldered a LT3062 - prototype - PCB, has measured the ripple/hum on its output (being loaded by a 1K resistor) and shown me the result (snapshot of his scope).
The picture has shown a hum of about 3mV.
I doubt that using a scope is an accurate way to measure the performance of the LT3062 LDO and am no more certain to recommend it.
To be on the "safe side", I will therefore offer you the original shunt regulator, designed and calculated by Mihai and used in my first rounds of group buy for the FC-100.
See attached image 1.
The price of a shunt regulator is equal (even less?) to the price of the LT3062 PSU.
I have also attached the current order list.
There is a new item on the order list, called "Frontend PSU transformer".
I remember that I have ordered special transformers (toroid with 4x34VAC, ?VA, primary for both 110 and 230 VAC)) to drive Mihai's shunts in the first rounds of group buy.
I will contact BADEL (the transformer company) and will ask them, if I can again order a couple (depending on the demand) of these transformers from them.
I will tell you the price. Five years ago it has been about 20€.
I will order 10 SPO-PCBs. If somebody does not want to have one, I will distribute the spare PCBs as demanded.
A SPO-PCB is normally only needed, if the power of connected transformers (at most 3 transformers can be connected to my SPO-PCB) exceeds in sum the value of 500VA.
To fully use the capabilities of the SPO-PCB (for example: remote power-off/on via a IR control-unit), you need a RC5-based IR-controller.
I offer to order quads of well-matched 2SK170 with Idss >=9mA from ALWEIT, who is an ebay-seller and from whom I ordered the 2SK170 transistors in the first rounds.
I do this to save you the shipping.
Best regards - Rudi_Ratlos
I have done a nice layout for the LT3062 - PSU and presented it in the "Power Supply sub-forum."
But: none of the visitors of my thread has any experience with the LT3062 LDO.
Moreover: Manuel, who has soldered a LT3062 - prototype - PCB, has measured the ripple/hum on its output (being loaded by a 1K resistor) and shown me the result (snapshot of his scope).
The picture has shown a hum of about 3mV.
I doubt that using a scope is an accurate way to measure the performance of the LT3062 LDO and am no more certain to recommend it.
To be on the "safe side", I will therefore offer you the original shunt regulator, designed and calculated by Mihai and used in my first rounds of group buy for the FC-100.
See attached image 1.
The price of a shunt regulator is equal (even less?) to the price of the LT3062 PSU.
I have also attached the current order list.
There is a new item on the order list, called "Frontend PSU transformer".
I remember that I have ordered special transformers (toroid with 4x34VAC, ?VA, primary for both 110 and 230 VAC)) to drive Mihai's shunts in the first rounds of group buy.
I will contact BADEL (the transformer company) and will ask them, if I can again order a couple (depending on the demand) of these transformers from them.
I will tell you the price. Five years ago it has been about 20€.
I will order 10 SPO-PCBs. If somebody does not want to have one, I will distribute the spare PCBs as demanded.
A SPO-PCB is normally only needed, if the power of connected transformers (at most 3 transformers can be connected to my SPO-PCB) exceeds in sum the value of 500VA.
To fully use the capabilities of the SPO-PCB (for example: remote power-off/on via a IR control-unit), you need a RC5-based IR-controller.
I offer to order quads of well-matched 2SK170 with Idss >=9mA from ALWEIT, who is an ebay-seller and from whom I ordered the 2SK170 transistors in the first rounds.
I do this to save you the shipping.
Best regards - Rudi_Ratlos
Attachments
@gwrskin: the mains-DC-filter caps are rated at 10.000µF/6.3V and cost about 90 cent!
The FC-100 backend-PSU power caps are more expensive. They shall be rated at >40V.
Patrick: it is hard to describe a "sound", even in my mother-tongue.
Moreover: my old ears "hear differently" than your young ears, and my musical taste is different from yours as well.
But what you will notice at once is: the FC-100 plays very fast, no smearing at all, and is producing a very relaxed sound.
Gentlemen: if I had your EMail-adresses, I would be able to distribute the documentation (Builder's Guide, BoM, Drill Templates, ....).
Please send me a PM giving your EMail-address.
Best regards - Rudi_Ratlos
P.S. Find attached the current order.
The FC-100 backend-PSU power caps are more expensive. They shall be rated at >40V.
Patrick: it is hard to describe a "sound", even in my mother-tongue.
Moreover: my old ears "hear differently" than your young ears, and my musical taste is different from yours as well.
But what you will notice at once is: the FC-100 plays very fast, no smearing at all, and is producing a very relaxed sound.
Gentlemen: if I had your EMail-adresses, I would be able to distribute the documentation (Builder's Guide, BoM, Drill Templates, ....).
Please send me a PM giving your EMail-address.
Best regards - Rudi_Ratlos
P.S. Find attached the current order.
