Hi All,
I finished my build of a B3 pre following 6L6's excellent build guide. I used Fairchild mosfets as per the BOM posted because I couldn't find the Toshiba's, and at first I couldn't get the thing to bias up. Then I read Nelsons B3 article and took his advise and changed out P1 & P2 to 1K pots. I used a long 3U galaxy chassis, and things are squeezed in pretty tight because of the size of the PSU. In any event it is singing now. Very quiet, and transparent swapping out my other SS preamp that I was using with my Aleph J was like removing a veil. Verrrry nice preamp. Thanks Nelson.
PJN
I finished my build of a B3 pre following 6L6's excellent build guide. I used Fairchild mosfets as per the BOM posted because I couldn't find the Toshiba's, and at first I couldn't get the thing to bias up. Then I read Nelsons B3 article and took his advise and changed out P1 & P2 to 1K pots. I used a long 3U galaxy chassis, and things are squeezed in pretty tight because of the size of the PSU. In any event it is singing now. Very quiet, and transparent swapping out my other SS preamp that I was using with my Aleph J was like removing a veil. Verrrry nice preamp. Thanks Nelson.
PJN
Attachments
Looks like the SSR03 super regulator: Sjöström Audio - SSR03 Sjöström Super Regulator Power Supply
Your right, that's the one. I picked up a few boards in a group buy a while ago and this was the first time I had the chance to use one.
Intermittent problem
I have a strange intermittent problem with my BA3 preamp. It's more than a year since I built my BA3 preamp and has been working wonderfully. Recently I have noticed that when I power on the preamp, only one channel works and the other channel makes a very faint distorted noise. If I power off and power on the pream again couple of times, then both channels work normally. This is happening intermittently and not everytime.
What could be the problem. The power supply is a single power supply and not two power supplies to suspect.
Need help in rebugging this new problem.
Thanks in advance.
Cheers
Anil
I have a strange intermittent problem with my BA3 preamp. It's more than a year since I built my BA3 preamp and has been working wonderfully. Recently I have noticed that when I power on the preamp, only one channel works and the other channel makes a very faint distorted noise. If I power off and power on the pream again couple of times, then both channels work normally. This is happening intermittently and not everytime.
What could be the problem. The power supply is a single power supply and not two power supplies to suspect.
Need help in rebugging this new problem.
Thanks in advance.
Cheers
Anil
I'm going to buy a set of matched 2SK2013/2SJ313 for this project, and the vendor is asking me the operational current they'll be used at (for the purposes of proper matching I imagine). What do I answer?
45-50ma as per the Pass article.
This is similar to the one used in the build guide:
GlassWare PS-19 Bipolar Power Supply Kit
GlassWare PS-19 Bipolar Power Supply Kit
I'd think you would want to use a regulated supply with the ba3 as a preamp. Especially with 20-30db of gain.
Plus, the universal power supply board is gonna be HUGE for a preamp. Space will probably be an issue.
If you want to support the store buy the super reg board (although you will need rectifiers and caps before it).
Simplest solution is a lm317/337 or 78xx setup.
Plus, the universal power supply board is gonna be HUGE for a preamp. Space will probably be an issue.
If you want to support the store buy the super reg board (although you will need rectifiers and caps before it).
Simplest solution is a lm317/337 or 78xx setup.
Salas BIB boards or the store regulator boards. Happy campers for both. I have used the Salas boards in my build and am very happy with them and especially the support received.
nash
Bias is 50ma per channel. You need twice that in the shunt so 200ma for both channels.
I see you have an electrolytic and poly cap on the output. You only need the 10uf poly caps. The electrolytics will probably make the sound worse.
Also, you wont need that much heatsink but if you use them make sure they are insulated from the mosfet or make sure they don't touch each other of the chassis.
Looks nice though.
I see you have an electrolytic and poly cap on the output. You only need the 10uf poly caps. The electrolytics will probably make the sound worse.
Also, you wont need that much heatsink but if you use them make sure they are insulated from the mosfet or make sure they don't touch each other of the chassis.
Looks nice though.