BOSEWA vs BOZ
I have decided not to pursue the BOSEWA beacause it is really a copy of the Aleph L 1.2. I have decided not to make pcb offerings of Nelson's commercial designs (discontinued or not), as there are just as good (if not better) projects that are open source. Right now I am working on a industrial quality BOZ board that will be my main preamp for the next decade or so. It is really the one preamp to beat IMHO. Earlier this summer I made a prototype of the BOZ circuit proposed in the SEWA thread today, and I found it to be better than the X2 and (from my memory) the BZLS as well. The Aleph L/BOSEWA can not possibly be better than the BOZ. The only advantage as I see it is the lower output impedance and the fact that it is non-inverting. However, it introduces an extra transistor in the signal path, and I am of the sincere opinion that LESS IS MORE when it comes listening to music. This means (single ended) class A, no (or very little) feedback, highly sensitive speakers and normal listeing levels.
As a side note; the SEWA/OTA designs do not require a low impedance source becase of the common drain configuration of the MOSFET. As far as I have been able to measure it has an input capacitance in the range of a couple of hunded pF.
I have decided not to pursue the BOSEWA beacause it is really a copy of the Aleph L 1.2. I have decided not to make pcb offerings of Nelson's commercial designs (discontinued or not), as there are just as good (if not better) projects that are open source. Right now I am working on a industrial quality BOZ board that will be my main preamp for the next decade or so. It is really the one preamp to beat IMHO. Earlier this summer I made a prototype of the BOZ circuit proposed in the SEWA thread today, and I found it to be better than the X2 and (from my memory) the BZLS as well. The Aleph L/BOSEWA can not possibly be better than the BOZ. The only advantage as I see it is the lower output impedance and the fact that it is non-inverting. However, it introduces an extra transistor in the signal path, and I am of the sincere opinion that LESS IS MORE when it comes listening to music. This means (single ended) class A, no (or very little) feedback, highly sensitive speakers and normal listeing levels.
As a side note; the SEWA/OTA designs do not require a low impedance source becase of the common drain configuration of the MOSFET. As far as I have been able to measure it has an input capacitance in the range of a couple of hunded pF.
Like this:
http://www.diyaudio.com/forums/attachment.php?s=&postid=840640&stamp=1139436029
Only you need a 2x30VAC for 40VDC, again use what you have
http://www.diyaudio.com/forums/attachment.php?s=&postid=840640&stamp=1139436029
Only you need a 2x30VAC for 40VDC, again use what you have
If you're out shopping, might I humbly suggest to get 2 300-600VA 2x18VAC transformers and series the secondaries. This will give you rails in the 45V region and is very flexible for future use. You don't actually need this big transformers, but they sound much better and runs cooler. I bought 2 600VA 2x18VAC transformers for my first project (SOZ) and I have made countless amps recycling these in various configurations Right now I am listening to a minimalist GC on steroids (wirth one of the transformers mentioned) and it is a lot of fun. 
Right now I am listening to a minimalist GC on steroids (wirth one of the transformers mentioned) and it is a lot of fun.
Hy Mad_K ,
Thanks for your transformers suggests , I think I will buy something like that !
I olso realised erlier a GC with LM3875 . It is svisible here :
http://idefixes.phpnet.org/sections.php?op=viewarticle&artid=36
It's in french .
@ + Philippe.
Thanks for your transformers suggests , I think I will buy something like that !
I olso realised erlier a GC with LM3875 . It is svisible here :
http://idefixes.phpnet.org/sections.php?op=viewarticle&artid=36
It's in french .
@ + Philippe.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.