Hi, finally i got myself to test the long completed unbalanced balanced line stage. After measuring with scope and multimeter I hooked it up to my Zen V2 and it sounds quite good already, even though the power supply (metal box and print next to it up side down) isn't finished yet. Also the gain is to high and I use a 50k ALPS pot i had found in my stock. I will replace that with a 10k as soon as possible. Also the decoupling caps are MKT which have to be replaced with better ofcourse.
btw, these bias resistors (3W) get really really hot and smell like burning hair after some minutes, is this normal? The ones in my boz get also really hot but they don't smell that bad. The bias resistors in my Zen are 25W, they can cope with some dissipation
Finally an image, it sounds better than it looks
the blue case beneath the amp is supposed to contain this linestage when finished...
greatings from Enschede, Netherlands,
Hans-Willem
btw, these bias resistors (3W) get really really hot and smell like burning hair after some minutes, is this normal? The ones in my boz get also really hot but they don't smell that bad. The bias resistors in my Zen are 25W, they can cope with some dissipation
Finally an image, it sounds better than it looks
the blue case beneath the amp is supposed to contain this linestage when finished...
greatings from Enschede, Netherlands,
Hans-Willem
An externally hosted image should be here but it was not working when we last tested it.
indeed, where are the pictures? they WAS one...
still not packed in a nice housing...
An externally hosted image should be here but it was not working when we last tested it.
still not packed in a nice housing...
Enschede
OK, so there ARE a lot of DIYers from Enschede here
HanzWillem, Maybe we could come together once and have a nice evening of tweaking and so on, I myself am currently fiddling with a nice preamp to drive my somewhat old QUAD 405, mr. Pass told me BoSoZ would do fine...
Greetz,
Merijn
OK, so there ARE a lot of DIYers from Enschede here
HanzWillem, Maybe we could come together once and have a nice evening of tweaking and so on, I myself am currently fiddling with a nice preamp to drive my somewhat old QUAD 405, mr. Pass told me BoSoZ would do fine...
Greetz,
Merijn
we could certainly meet sometime, and exchange some experience or something. Are you already working on your bosoz?
The preamp is now fully functional, although I still haven't wired the blue LEDs. In the picture you can see the 4x3 ELMA switch for source selection and the 2x24 ELMA volume attenuator.
I replaced the heatsink with a bigger one (it really was very very hot). Also the MKT outputcaps (7uF) are replaced with silmic 100u, they really sound much better.
All signal wiring is done with twin pure silver wire. The power wiring is ordinairy copper stuff. No need for fancy wire there
The sound is really amazing, I can vertainly recommend this preamp to everyone. Simple, cheap and sounds very good.
Thanks again to Nelson for sharing this with the world!
the pic...
The preamp is now fully functional, although I still haven't wired the blue LEDs. In the picture you can see the 4x3 ELMA switch for source selection and the 2x24 ELMA volume attenuator.
I replaced the heatsink with a bigger one (it really was very very hot). Also the MKT outputcaps (7uF) are replaced with silmic 100u, they really sound much better.
All signal wiring is done with twin pure silver wire. The power wiring is ordinairy copper stuff. No need for fancy wire there
The sound is really amazing, I can vertainly recommend this preamp to everyone. Simple, cheap and sounds very good.
Thanks again to Nelson for sharing this with the world!
the pic...
An externally hosted image should be here but it was not working when we last tested it.
Not a wire soldered, but collecting FET's and elna-switches...
Allso I am not sure what to build, Aleph L is allso in the race, as are the BoSoZ in balanced mode and Aleph P, there is not this much difference in price when u are hardwiring the pre. The point in the max output at 0 dB attenuation. my quad needs onely 0,5 Volts to give max amplification (old english 0,73 V standard?). So I need a really good active pre with onely a little gain... Problems, problems...
Allso I am not sure what to build, Aleph L is allso in the race, as are the BoSoZ in balanced mode and Aleph P, there is not this much difference in price when u are hardwiring the pre. The point in the max output at 0 dB attenuation. my quad needs onely 0,5 Volts to give max amplification (old english 0,73 V standard?). So I need a really good active pre with onely a little gain... Problems, problems...
Merijn,
after reading all the threads I´ve decided to build an X-BOSOZ.
But when you´ve got the +-60V power supply you can also build the BOSOZ and even the version with cascodes and no output cap.
I´ve got all of the parts now except for the transformers (wich are ordered) so I think it´ll play before christmas (at least in prototype form).
I will build it with fairly standard parts (no fancy resistors or caps) and see how it works. If it beats my current pre (OPA627GP based) I will probably rebuild it with tantalum/black gate etc.
william
after reading all the threads I´ve decided to build an X-BOSOZ.
But when you´ve got the +-60V power supply you can also build the BOSOZ and even the version with cascodes and no output cap.
I´ve got all of the parts now except for the transformers (wich are ordered) so I think it´ll play before christmas (at least in prototype form).
I will build it with fairly standard parts (no fancy resistors or caps) and see how it works. If it beats my current pre (OPA627GP based) I will probably rebuild it with tantalum/black gate etc.
william
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