They are North Creek Borialis, George Short was designing speakers for them and he was a very talented engineer. They use ScanSpeak drivers and he modified the D25 tweeter and designed the crossover. The construction was Baltic birch/MDF/ glop a combination of ncs glue and drywall. They ended up being about 60 lbs and finished in Birds Eye maple with 8 coats of lacquer. They have been my reference speaker, my living room now is a little small for them now and I am almost done building XRK’s XSD dipole speaker. It will be intersecting how it will compare. Thanks for such a great preamp, it sounds great, is dead silent a pleasure to use and the Headphone amp is a joy to my wife ( she can watch tv while I listen to music in the living room).
Bill
Bill
Does the 12v trigger have a delay to turn on the amps? 2 of my amps have SMPS that have a 12 V trigger function built in. Another 2 amps have linear power supplies that need have the AC switched or build in a 12 switching function, either a SSR or relay. The worst that could happen with a relay would be the contacts fused closed and the amp would not shut off.
I should have gotten back to you on this - apologies.
The trigger output goes active 3 seconds after the amplifier comes out of standby - ie after you power it up via the remote or by depressing the Select dial.
When you put the preamp into standby, the trigger is deactivated first, and then 3 seconds later the preamp.
Typically, you would use the trigger output to drive a 12V DC 35mA DC coil current 16A 250VAC contact rating relay (like a good quality Tyco, Schrack or Potter and Brumfield industrial component - $3-4 on mouser) to switch the main amplifier power. Since you are switcing AC, the relay's are quite capable, although I would always recommend you use some sort of softstart.
I am not an expert on SMPS's (although I did design a few flyback types when in development decades ago), but presume on modern units mains DC offset is not a problem - the main issue is standard linear PSU's using large toroids. Rod Elliot has a nice discussion on this on his website.
Hope this helps
Regards
A
The trigger output goes active 3 seconds after the amplifier comes out of standby - ie after you power it up via the remote or by depressing the Select dial.
When you put the preamp into standby, the trigger is deactivated first, and then 3 seconds later the preamp.
Typically, you would use the trigger output to drive a 12V DC 35mA DC coil current 16A 250VAC contact rating relay (like a good quality Tyco, Schrack or Potter and Brumfield industrial component - $3-4 on mouser) to switch the main amplifier power. Since you are switcing AC, the relay's are quite capable, although I would always recommend you use some sort of softstart.
I am not an expert on SMPS's (although I did design a few flyback types when in development decades ago), but presume on modern units mains DC offset is not a problem - the main issue is standard linear PSU's using large toroids. Rod Elliot has a nice discussion on this on his website.
Hope this helps
Regards
A
Yep I read his article and checked out his read on SSRs that’s why I figures in the long run a relay was probably the way to go. My linear power supplies all have soft starts so they are good. I think I will go with a good relay on the amp s ac outlets. I was going to add a dc blocker but the amp that hummed so bad was not the toroid but a low voltage mean we’ll power supply in it. Also a 5V and 12V power supply will help clean up mess behind amps.
Attachments
Chris/Andy
1. HPA-1 Headphone amp - R14 and R23 must be 470 Ohms as in the schematic and on the silkscreen; PCB and schematic are indeed 1N4148
2. MC/MM module - R1,2,30,34 are 270 Ohms. I will update the schematic and BOM; C15,16 and 17 must be 1uF devices 0805 same as C22 and C23 Mouser 187-CL21B105KBFNNNG or equivalent
I'll update the relevant docs later tonight.
1. HPA-1 Headphone amp - R14 and R23 must be 470 Ohms as in the schematic and on the silkscreen; PCB and schematic are indeed 1N4148
2. MC/MM module - R1,2,30,34 are 270 Ohms. I will update the schematic and BOM; C15,16 and 17 must be 1uF devices 0805 same as C22 and C23 Mouser 187-CL21B105KBFNNNG or equivalent
I'll update the relevant docs later tonight.
Last edited:
Misson (almost) accomplished 🔥 . Just waiting on the extra RCA jacks for the AUX and the headphone socket board to arrive. Wow it turned out amazing is all I can say right now. This project was not a small undertaking by any means, but the final outcome makes the last couple days of wiring worthwhile. I ran into a few hiccups here and there, but is to be expected with any project that has this many parts.
Thanks @Bonsai for another great project!! I can't wait to get my Phone preamps hooked up to this and get it all in my system.
Thanks @Bonsai for another great project!! I can't wait to get my Phone preamps hooked up to this and get it all in my system.
Attachments
-
PXL_20230614_123126453.jpg -
PXL_20230614_123142567.jpg -
PXL_20230615_180958603.jpg -
PXL_20230615_181257222.jpg -
PXL_20230615_181304476.jpg -
PXL_20230615_181325155.jpg -
PXL_20230615_181332435.jpg -
PXL_20230615_181343255.jpg -
PXL_20230615_181357482.jpg -
PXL_20230615_181413827.jpg -
PXL_20230615_181426580.jpg -
PXL_20230615_181432844.jpg -
PXL_20230615_185152646.jpg -
PXL_20230615_185159091.jpg -
PXL_20230615_185212029.jpg -
PXL_20230614_123107546.jpg