Hello Marc,
Would this transformer be acceptable for the 6N1P Preamp MK2?
http://www.antekinc.com/content/AS-05T240.pdf
Thank you,
Vunce
Would this transformer be acceptable for the 6N1P Preamp MK2?
http://www.antekinc.com/content/AS-05T240.pdf
Thank you,
Vunce
Bonjour Vunce,
Yes, this will be more than needed and you can use a regulated power supply like on the picture... The tube shield are not required, I have just tested them but that does not change anythings, there is no noise anyway
Rgds,
Marc
Yes, this will be more than needed and you can use a regulated power supply like on the picture... The tube shield are not required, I have just tested them but that does not change anythings, there is no noise anyway
Rgds,
Marc
Attachments
Hi Sunil,
Except if you want to make mono blocs, it is useless to separate power supply for each channel and if you do that you should also separate 50 V AC power supply because one of the line is connected to ground !
As you say it's a waste of time and money
Regards,
Marc
Cheers Marc. I'll go with the single like you've done.
regards,
sunil
Hello Marc,
I’ve successfully fired up the 6N1P preamp you shared. I’m listening now as I compose this message. A steaming iPhone as a source and an Icepower class D amp complete the testing combo. The sound is sweet, no harshness and very quiet background.
Here’s a little information about the preamp project:
Antek AS-05T240 trafo is utilizing the 240vac HV tap and the 6.3vac secondaries are paralleled for max filament current. The PSU board includes both the HV and LV supplies. What’s really cool about this board is it uses an ultra low dropout regulator for the filament heater supply which enables you to use your 6.3vac trafo secondary and still get a regulated 6.3vdc. Not possible with a “regular” voltage regulator. The 240vac tap yields approximately 315vdc and with a turn of the trim pot it’s spot on 300vdc. The schematic called for an IRF740 MosFet but, I used an On Semi FQFP2N60C that was listed on the Bom, I hope that will not be an issue?
My main purpose for this preamp project was to give my Big MoFo a different “flavor”. The MoFo is paired with an AKSA Lender Preamp and sounds amazing. I just wanted to try a tube pre with it. So, the next step will be to try that combination
Thank you Marc for sharing this preamp design!
Cheers,
Vunce
I’ve successfully fired up the 6N1P preamp you shared. I’m listening now as I compose this message. A steaming iPhone as a source and an Icepower class D amp complete the testing combo. The sound is sweet, no harshness and very quiet background.
Here’s a little information about the preamp project:
Antek AS-05T240 trafo is utilizing the 240vac HV tap and the 6.3vac secondaries are paralleled for max filament current. The PSU board includes both the HV and LV supplies. What’s really cool about this board is it uses an ultra low dropout regulator for the filament heater supply which enables you to use your 6.3vac trafo secondary and still get a regulated 6.3vdc. Not possible with a “regular” voltage regulator. The 240vac tap yields approximately 315vdc and with a turn of the trim pot it’s spot on 300vdc. The schematic called for an IRF740 MosFet but, I used an On Semi FQFP2N60C that was listed on the Bom, I hope that will not be an issue?
My main purpose for this preamp project was to give my Big MoFo a different “flavor”. The MoFo is paired with an AKSA Lender Preamp and sounds amazing. I just wanted to try a tube pre with it. So, the next step will be to try that combination
Thank you Marc for sharing this preamp design!
Cheers,
Vunce
Attachments
Hello Vunce,
Thanks for your feedback
I am pleased that you like the sound of your test bench with this tube preamp
Don't worry about the value of the MOSFET on the schematic, I took the IRF740 because it was in the EAGLE library and I forgot to change the name later, but the FQFP2N60C is the good one, it has very low Crss of 4.3 pF instead of 120 pF for the IRF740 and that is important when used in Audio as Merlin Blencowe explained in his very good book "Designing High-Fidelity Tube Preamps" and he also recommended the 2N60
I am sure the result will be even better with the MoFo ...
Cheers,
Marc
Thanks for your feedback
I am pleased that you like the sound of your test bench with this tube preamp
Don't worry about the value of the MOSFET on the schematic, I took the IRF740 because it was in the EAGLE library and I forgot to change the name later, but the FQFP2N60C is the good one, it has very low Crss of 4.3 pF instead of 120 pF for the IRF740 and that is important when used in Audio as Merlin Blencowe explained in his very good book "Designing High-Fidelity Tube Preamps" and he also recommended the 2N60
I am sure the result will be even better with the MoFo ...
Cheers,
Marc
Hi again Vunce,
I forget to ask you, what are the red resistors you are using on your board, are they PR9372 Audio Resistor manufactured in Mediapolis ( https://hfc-fs.s3-eu-west-1.amazonaws.com/s3fs-public/pr9372_datasheet_0.pdf ) or an other type ?
Cheers,
Marc
I forget to ask you, what are the red resistors you are using on your board, are they PR9372 Audio Resistor manufactured in Mediapolis ( https://hfc-fs.s3-eu-west-1.amazonaws.com/s3fs-public/pr9372_datasheet_0.pdf ) or an other type ?
Cheers,
Marc
Hi Marc,
Thanks for the kind words
Yes, they are PRP 9372 series, 1/2watt resistors and fit the pad space perfectly.
I’m using a pair of low quality 6N1 tubes at the moment, I’m waiting on a set of matched 6n1p-ev tubes. By moving the SV1 jumper this will allow the use of 12au7 tubes correct? I have several of those to choose from.
Regards,
Vunce
Thanks for the kind words
Yes, they are PRP 9372 series, 1/2watt resistors and fit the pad space perfectly.
I’m using a pair of low quality 6N1 tubes at the moment, I’m waiting on a set of matched 6n1p-ev tubes. By moving the SV1 jumper this will allow the use of 12au7 tubes correct? I have several of those to choose from.
Regards,
Vunce
Hi Vunce and Marc,
I searched around the forums for info on the 6N1P MK2 preamp befoer asking...
Are there any pcbs available for this preamp. If no pcbs available, I will search and see if some similar preamp is offered in the group buy section. Any recommendations to look for?
Thanks for the help,
Myles
I searched around the forums for info on the 6N1P MK2 preamp befoer asking...
Are there any pcbs available for this preamp. If no pcbs available, I will search and see if some similar preamp is offered in the group buy section. Any recommendations to look for?
Thanks for the help,
Myles
Hello Myles,
There is no current GB for this board. Marc was kind enough to post the Gerbers for individuals use. I had a small batch made. For some reason the parts value was not stenciled on the pcb? (Maybe a glitch in the files sent)
Not a big deal though, just follow the schematic.
Regards,
Vunce
There is no current GB for this board. Marc was kind enough to post the Gerbers for individuals use. I had a small batch made. For some reason the parts value was not stenciled on the pcb? (Maybe a glitch in the files sent)
Not a big deal though, just follow the schematic.
Regards,
Vunce
No, I added 2mm thickness and 2oz copper options which bumped the price up. But, I figured it was wise to do since the board will be handled more with tube swapping
Bonjour,
Here is a slightly modified version where I corrected the MOSFET reference and added round corners
You can also find the value of the components on the silk screen They were not on the PCB because my previous board manufacturer removed them !
While I was looking at the PCB, and since now I produce them by PCBWay I was thinking to shrink the board to reduce the size to 100 x 80 mm to have a better price of 5 $ for 10 PCB
If I have time I will look at it, by example the second output capacitor can be 25 V only since it is protected by the zener diode...
Regards,
Marc
Here is a slightly modified version where I corrected the MOSFET reference and added round corners
You can also find the value of the components on the silk screen
They were not on the PCB because my previous board manufacturer removed them !While I was looking at the PCB, and since now I produce them by PCBWay I was thinking to shrink the board to reduce the size to 100 x 80 mm to have a better price of 5 $ for 10 PCB
If I have time I will look at it, by example the second output capacitor can be 25 V only since it is protected by the zener diode...
Regards,
Marc
