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PostPosted: 01 Nov 2010, 19:22 
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Very nice Mark. The engraving turned out very nice. So what is WWW wire?
Cheers

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PostPosted: 01 Nov 2010, 19:59 
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Gio wrote:
Very nice Mark. The engraving turned out very nice. So what is WWW wire?

It took me a little while to work it out too. Wire wrap wire (WWW). I made a whole micro-computer with the stuff. It took me months. Have you ever used it? You need a skilled hand to strip it with side cutters that's why they make a special tool for it. I use side cutters 'cause I have used it extensively in the past.

Got some measurement for BoZ:

-3db points into 10Kohm load @ 2Vp2p => 5hz to 180khz

35V PS with 2Vp2p input @ 1khz into 10kohm load max voltage swing: 13Vp2p

into 1k: 6Vp2p.

Current drain 15mA @ 36V
Attachment:
20khz.jpg
Attachment:
TTF.jpg


Image


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PostPosted: 10 Nov 2010, 05:38 
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I have compared the B1 with BoZ on a few different configurations of my system. Each time the B1 appears to fit better with the rest of the system.

I took both the B1 and BoZ to two other peoples place's for a listen in their system. Both agreed BoZ was supreme (not in my system it's not). It appears BoZ rules??

I must admit on both of my friend's systems BoZ did sound better. B1 now resides with my new Oppo BDP-83SE and SET amp.

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PostPosted: 10 Nov 2010, 13:06 
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mwhouston wrote:
I have compared the B1 with BoZ on a few different configurations of my system. Each time the B1 appears to fit better with the rest of the system.

Maybe i'm wrong, but i see these two constructions as a preamp vs. buffer ...right ? If this is right, i guess there is no comparison, because they've got different purposes.

But anyway Mark, it's great you've done both constructions and found the one you like best. :thumbsup:

I would only go for a buffer, where long signal wiring is necessary, or sources poor of current.

Actually "some, good sources" output ( expensive cd players, tuners, aso. ), gives both lot of voltage and current. For those, a simple potentiometer/attenuator, would sometime benefit more to good sound ( directly into a power amp ), than a preamp included. When this is said, it depends ...and it's always worth, to try different compositions. :wizard:


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PostPosted: 10 Nov 2010, 15:56 
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KrammeAcoustics wrote:
mwhouston wrote:
I have compared the B1 with BoZ on a few different configurations of my system. Each time the B1 appears to fit better with the rest of the system.

Maybe i'm wrong, but i see these two constructions as a preamp vs. buffer ...right ? If this is right, i guess there is no comparison, because they've got different purposes.

But anyway Mark, it's great you've done both constructions and found the one you like best. :thumbsup:

I would only go for a buffer, where long signal wiring is necessary, or sources poor of current.

Actually "some, good sources" output ( expensive cd players, tuners, aso. ), gives both lot of voltage and current. For those, a simple potentiometer/attenuator, would sometime benefit more to good sound ( directly into a power amp ), than a preamp included. When this is said, it depends ...and it's always worth, to try different compositions. :wizard:

You are absolutely right. The B1 is a buffer/driver. But if you agree with Pass you should never just place a pot in your system to control volume. There are a number of reasons Nelson outlines and that is why the B1 is a better form of attenuation.

For me I struggle with over-all volume level in my system. An upgraded Oppo only putting out 1Vp2p and a 3W amp. I have since upgraded to the Oppo BDP-83SE with full output swing. The B1 now works even better in my system and I can drive my SET to full power.

In both the B1 and BoZ I used exactly the same parts. But of course the B1 is a source follower with a CCS and the BoZ a straight class A. I thought I would have to build more B1 after yesterday but BoZ won the day.

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PostPosted: 11 Nov 2010, 09:53 
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Mark,

Till today, I haven't found a truly good buffer or preamp for my Aussie Amps Nxv200. Which do you think is more suitable for the amp :- Boz or B1 ?

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PostPosted: 11 Nov 2010, 15:45 
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Popular consensus says the BoZ is better. I was playing the B1 with the new Oppo BDP-83SE player last night and there is still not enough volume. I may have to go to the BoZ myself. I have to build one more BoZ.

One thing for sure there is plenty of gain with BoZ and with the two being hard to choose between BoZ maybe the way to go. It will work with your ZCA better also. It appears BoZ may run from a Jaycar 24V SMPS - wall wart. Yet to prove but on an earlier test with a 15V Jaycar wall wart it was dead quiet but not enough voltage.

Because the Oppo has an output cap I could make one for myself without out an input cap. It may improve the sound slightly and saves on an expensive cap. I could almost build one without a pot. Alps Blue velvets are not cheap and again it may improve the sound.

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PostPosted: 11 Nov 2010, 23:51 
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Hi Mark,

Thanks. I may build up a BoZ soon! The Jfets will be a little tough to get , expecially matched.
(or do they need to be matched? I still to do a lot of reading.)

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PostPosted: 14 Nov 2010, 15:25 
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I have been listening to the new Oppo BDP-83SE a bit lately to get some hours up on it and eval. how it sounds. It is far more natural than my upgraded Oppo 980H. What has been confirmed in this short listening period is that even with the extra output voltage of the new Oppo I still cannot get enough volume with some CDs. I'm currently using the B1 which is the first of the Pass preamp/drivers I made.

I have nearly finished another BoZ. The cct. brd. is complete, case is drilled and I am at the point of assembly. While it is apart it would be a good idea to make another cct. brd. and finally a BoZ for myself. The BoZ for me would not require input caps as the BDP-83 has an output cap. And I could even drop the Alps pot as the Oppo has volume level on the remote. If I dropped the $AU53 Hammond Al enclosure a cut down BoZ would be a very cheap preamp.

I have also discovered that though the original BoZ I made whistled with the old Toshiba SMPS the SMPSs I am getting from the local electronics shop, where I work, runs dead silent. A friend who comes in often use to design and make SMPSs for a living. He claims that the modern SMPS is a far cry from earlier design and they run at much higher frequencies these days. Thus being out of the audio band. Big names are now producing power amps with SMPSs and are getting good reviews for there products.

So a SM wall wart should be OK as a PS for the cut down BoZ.

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PostPosted: 15 Nov 2010, 23:45 
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For those building BoZ and using the B1 front-end to the PS, in other words the two 15000uf caps and a one ohm resistor to feed the first: rate that 1 ohm resistor 3W as the cct. just suggests. I have blown two one ohm 1W resistors now. Because the the filter caps are so big they look like a short at switch on. A wire wound 5W may be a better selection.

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