My Take on X-BOSOZ

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#681
beppe61,

:clown: choky seems to put a lot of humor in his posts.! I have no doubt he cares how something sounds..as do we all. I have not yet finished mine so I cannot comment. I chose to build the Bosoz because of all the wonderful comments I have read. Search for posts on completed Bosoz projects and you will probably find more comparisons and comments than you know what to do with! Most are extremely favorable....

regards

edit: ...and regarding the kit discussed in this thread.. it's very nice and well thought out.
 
#682
mpmarino said:
beppe61,
:clown: choky seems to put a lot of humor in his posts.!
I have no doubt he cares how something sounds..as do we all.

- Ok! Thank you Sir.
No doubt that this project could have its place in an audio gallery expo. Very nice indeed !

> I have not yet finished mine so I cannot comment.
I chose to build the Bosoz because of all the wonderful comments I have read.
Search for posts on completed Bosoz projects and you will probably find more comparisons and comments than you know what to do with!
Most are extremely favorable....

- So you suggest to me to use the key words - "completed" -"Bosoz" - "projects" ?

> regards
edit: ...and regarding the kit discussed in this thread.. it's very nice and well thought out.
- As I said no doubts about that.

Thank you very much indeed.
Kind regards,

beppe
Click to expand...
 
#683
Steen made a very nice one 😀

http://www.diyaudio.com/forums/showthread.php?postid=783930#post783930

Early on Steen was very kind to buid a prototype of this circuit for us. I believed he was pleased with it. 😀

I have been listening to mine for a little while now, but I would prefer to let others give their subjective opinions. 😀 I love it, but then I would have to wouldn't I? :hphones:

I doubt anyone will be dissapointed.:drink: 😎

Cheers!
Russ
 
#685
Re: Steen made a very nice one 😀

Russ White said:
http://www.diyaudio.com/forums/showthread.php?postid=783930#post783930
Early on Steen was very kind to buid a prototype of this circuit for us.
I believed he was pleased with it. 😀
I have been listening to mine for a little while now, but I would prefer to let others give their subjective opinions. 😀 I love it, but then I would have to wouldn't I? :hphones:
I doubt anyone will be dissapointed.:drink: 😎
Cheers!
Russ

Dear Sir,

my sincere congratulations for your excellent product.
Very nice indeed.
I will go to your web site for some more info.

Kind regards,

beppe
Click to expand...
 
#686
Somwhere in my original thread on the progression of my one-off design that led to the Twisted BoSoZ, I posted about comparing it to a Levinson pre where it compared very favourably. I will be taking my pre to the RAWFest DIY meet in late February where I will have another chance to compare it to some Theta gear and perhaps others. I'll let you all know what the comments of the attendees are.

Cheers, Terry
 
#687
listening impressions of these wonderful preamp
Click to expand...
Hi beppe. Well I am not to good at this HiFi mumbo-jumbo talk😀 , but this preamp is really good indeed. It is the best sounding pre I heard in my system. Very, very musical. Detailed and crisp sound with firm bottomend, but still with the very pleasant sound signature of the BosoZ family😎 I am sure I will keep the Twisted for a very long time in the main system 🙂 All I need now is an Aleph-J to crown the work😎

Steen🙂

BTW, thanks for elaborating on the pot placement earlier in this thread😉
 
#688
metalman said:

> Somwhere in my original thread on the progression of my one-off design that led to the Twisted BoSoZ, I posted about comparing it to a Levinson pre where it compared very favourably.
- Thank you so much Sir.
I could not find the exact post anyway.
Which Levinson model was ?

> I will be taking my pre to the RAWFest DIY meet in late February where I will have another chance to compare it to some Theta gear and perhaps others.
I'll let you all know what the comments of the attendees are.
Cheers, Terry
- Thanks a lot very interesting indeed.
I wonder if this preamp can also act as a balanced to unbalanced adapter because I have a DAC with xlr outputs but my present power amp is unbalanced (RCAs inputs).

Thank you very much again.
Kind regards,

beppe
Click to expand...
 
#689
steenoe said:

> Hi beppe.
Well I am not to good at this HiFi mumbo-jumbo talk😀 , but this preamp is really good indeed.
It is the best sounding pre I heard in my system.
Very, very musical.
Detailed and crisp sound with firm bottomend, but still with the very pleasant sound signature of the BosoZ family😎
I am sure I will keep the Twisted for a very long time in the main system 🙂
All I need now is an Aleph-J to crown the work😎
Steen🙂

Dear Mr. Steen,
your extremely kind, valuable and appreciated reply leaves me with no doubts about the quality of the Twisted preamp indeed.
Very fine piece of audio art !

> BTW, thanks for elaborating on the pot placement earlier in this thread😉
- First of all I have to declare that my skills in electronics are very very basic.
That said some years ago a friend of mine built me a Bride of Zen preamp following completely the original project.
Then I start "to modify" it.
I place a 100K Black Beauty Alps pot in front of it and started experimenting with different power supply solutions.
As you can see from the schematics, and as Nelson Pass says in his article, with a pot in front of the BOZ any noise from the PS is found at the ouput unchanged in level and then is amplified by the power amp.
With any different solution of PS the effect of the power supply was so obvious that, when I have some spare time for experimenting, I use that BOZ as a testing tools to test the quality of power supplies I am trying to "fine-tune".
My opinion is that with a really good power supply (and I mean really good, i.e. very low noise) the resulting sound could be exceptional by any terms rivalling very expensive commercial unit.
I am quite interested about the Twisted because I understand that the balanced solution acts as a PS noise cancelling device.
Am I right ?

Thank you so much indeed.
Kind regards,

beppe
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#690
beppe,

If I recall correctly, it was a No.326 we compared against, but it has been awhile, so I can't say for certain.

And yes, you can use this design for balance to unbalanced conversion. In fact you can use any combination of input to output. The best performance is balanced in to balanced out, and the least performance is unbalanced in to unbalanced out, but even unbalanced to unbalanced it compares well against the Levinson gear.

Cheers, Terry
 
#691
metalman said:
Dear Mr. Terry, thank you so much for your kind and valuable reply.

> beppe,
If I recall correctly, it was a No.326 we compared against, but it has been awhile, so I can't say for certain.
- Wow! what a reference. I think one of the best line pre around.
Very interesting.

> And yes, you can use this design for balance to unbalanced conversion.
In fact you can use any combination of input to output.
The best performance is balanced in to balanced out, and the least performance is unbalanced in to unbalanced out, but even unbalanced to unbalanced it compares well against the Levinson gear.
- Your words do not leave any doubt about the quality of the Twisted. Very fine unit indeed.

> Cheers, Terry
- Thank you very much again.
Kind regards,

beppe
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#692
Assembled 2 power supplies over the weekend, everything was labeled, easy to assemble, very well done.

The zeners in the ps are 75v and 24v so I need a few volts higher than that coming from my secondaries, yes?

I bought the Parts express 55-0-55, 16-0-16 toroid, which won't work for the negative rail.

Can I get a lower zener for the negative rail without affecting the circuit, or would I need to change some other components as well?

If I can't use this toroid, what is the status of the avels?

Please pardon my inexperience and Thanks!
 
#693
Hi Joster,

If you are planning on using 16VAC into the negative rail a 12V zener should work just fine you could probably even go up to 14-15V zener. There is no problem running like that, certainly it will have an effect but things should still be just great.

We are still mulling over the avels, it is a lot of money for us to layout on trafos and we still have a lot of figuring to do. 🙂

Cheers!
Russ
 
#694
joster said:
Assembled 2 power supplies over the weekend, everything was labeled, easy to assemble, very well done.

The zeners in the ps are 75v and 24v so I need a few volts higher than that coming from my secondaries, yes?

I bought the Parts express 55-0-55, 16-0-16 toroid, which won't work for the negative rail.

Can I get a lower zener for the negative rail without affecting the circuit, or would I need to change some other components as well?

If I can't use this toroid, what is the status of the avels?

Please pardon my inexperience and Thanks!
Click to expand...

I was in the same situ as I had a trafo on hand with lower voltage as you do. Thanks to Steenoe's suggestion I was able to maximize my negative voltage by replacing the IRF9610 on the neg side with a pnp bipolar transistor. It got me almost 3 volts more on the neg. side due to the much lesser voltage drop across the bipolar.....

My preamp's not near done but I am getting -14v on the psu under load and my trafo secondaries are only 12.7vac. I forget the zeners I ended up with but it did require some fiddling...

🙂 thanks Steen🙂
 
#696
It is working.

I have a 128 step (.5db) 64db total attenuation prototype working.

The attenuator can be controlled any way you like, but with the controller I am using here in the photo it behaves exactly like a true one turn log pot when controlled by a 5K linear pot to the PIC's ADC.

So far it is working pricisely as designed with no nasty surprises. The software worked on the first try, but then it is super simple.

I expect this thing to be in full swing here very soon.

Remember the picture is of a prototype, the real thing will be much more polished.

Cheers!
Russ
 

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#698
Hi Guys,

I'm a bit confused about the power supplies. I bought the Parts Express transformer that was suggested earlier. It is 55-0-55, 16-0-16. That should give a rectified +77VDC, -22VDC. Is this a problem? Do I need to change some things to get this to work with the parts supplied with the kit?

Thanks, Terry
 
#699
still4given said:
Hi Guys,

I'm a bit confused about the power supplies. I bought the Parts Express transformer that was suggested earlier. It is 55-0-55, 16-0-16. That should give a rectified +77VDC, -22VDC. Is this a problem? Do I need to change some things to get this to work with the parts supplied with the kit?

Thanks, Terry
Click to expand...


I am not the most expert on this, but I know for sure you will need to adjust the zener diodes. On the positive rail I would try to get somethng around 70-72V (combine zeners if necessary). For the negative rail I would use ~15V(14-16V) should be just fine.
 
#700
thanks Steen
Click to expand...
You are most wellcome, Marc🙂 Happy to help out when I can🙂
That should give a rectified +77VDC, -22VDC.
Click to expand...
Depending on your mains stability, I wouldnt like to use a zenerstring over 65 volts. You need a little safety margin to make sure the regulator has a bit "over"voltage to regulate from. I would use 7 pcs of 9,1V zeners myself for added stability. the mosfet regs throws off a couple of volts also, so that nets you around 60v. Whatever combination suits you, just remember that the zeners should have approx. the same value (you cant use a 5v together with a 60v) The worst case you can have is a "starving" zenerstring. Its not pretty to listen to at all:xeye: I guess you could use a 70v zener, but then you would have to trust that your mains dont "dip" too much🙂 Whatever, I am running my Twisted from 60V on the pos rail with good results indeed (actually using a 55v trafo also) I have nothing to complain about😉

Steen🙂
 
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