Heatsinks for Bosoz?

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What is the purpose of the C4 and C5 caps? Is it only for DC blocking or it has any other function? My intended purpose for Bosoz is to use them in addition with Lundahls 1674 after DA converters in DCX2496. Lundahls are great because they completely kill DC and X Bosoz will provide needed gain (about 10dB needed). Obviously I will prefer not to use these caps if I do not need them in this configuration.
Also I do not have much luck finding original article from Pass lab on Bosoz, so if anyone has link I would appreciate it a lot.
Thank you
AR2
 
steenoe said:
BosoZ article here: http://www.passdiy.com/legacy.htm .
C4 and C5 are DC blockers, I think the circuit can do without them.

Steen.:)

As long as what you connect it to can deal with the ~30VDC (non cascoded version) If your amp has capacitors on its inputs then strictly speaking you don't need C4-C5, but you'll end up with 30V on your interconnects. The results might be colorful if you disconnect the cables from the amp when the preamp power is on and they touch ground. :bigeyes:

If you intend to use your transformer at the output of your BOSOZ, you'll still need the caps or you'll be grounding that 30V through your transformer's primary.
 
Bob,
thank you for the detailed and logical explanation. I would rather stick with pair of capacitors than add more active parts. All that I wanted to achieve is to loose capacitors from the signal path, since I already have Lundalhs. As I mentioned they are really awsome, and they cut DC to 0V, with minimal sonic signiture. I certainly would prefer them over caps, but thanks to your explanation I am affraid that 30V could be too much for them.
I appreciate everybody's opinion very much
Thank you
AR2
 
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Joined 2002
Coulomb said:
Just to clarify, ...

Aoh... but, don’t worry too much.
One man can not redirect the river flow.
They will make this amp and enjoy more than I do.
I am using electrolytic output caps of unknown quality.
Still the sound is too good to blame the caps.

You know?
Some weeks ago, when someone pulled out the live RCA plug
connected between my CD player and BOSOZ, it gave a shot
to my speaker, giving death to the gain transistor, IRF510,
of my BOSOZ. This happened because I did not have the input
protection zeners, I thought. I wanted immediate repair. But, the only
transistors that time I had were IRF620s, which had high capacitances
often claimed as bad by high-end diyers. With no other choices,
I had to use them for the repair.

I did almost throw away twenty IRF620s, but recollected them
into my safe locker. I saved them and could drink that much of beer.

:cool:

Regards
 
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Kari
 
Kari said:
Wiki is updated. Those of you that have a status of NO on the IV sent is because you haven't registered your email on diyaudio.com, please email me asap so we can fix that.

Also ALWAYS include your diyaudio.com nick in your paypal payment so i can check that you have paid. I now have a couple that have paid but are marked as not paid on the wiki, please email me and i'll fix that.

If possible please send me the funds before Monday next week so i can order the boards.

Thx,

Kari

Yeah, I did that too sorry Kari.

Regards

Anthony
 
I am considering for C4/C5 some paper in oil caps. Does anyone have any thoughts on an approach like that. My idea was to use 3x10uF papercaps parralelled, each one bypassed by a 0,1uF teflon cap, on each +/- out. That is my initial idea, to try something different. Or is this just crazy?:) Any thoughts?

Steen.
 
steenoe said:
I am considering for C4/C5 some paper in oil caps. Does anyone have any thoughts on an approach like that. My idea was to use 3x10uF papercaps parralelled, each one bypassed by a 0,1uF teflon cap, on each +/- out. That is my initial idea, to try something different. Or is this just crazy?:) Any thoughts?

Steen.


My experience of bypassing output caps in the past has not been good. I prefer a single regular Solen polyprop than multiple “hi end” caps. Multiples tend to degrade low freq, lacks integration and sound bright too.

But you never know, you may like it different in your system.
 
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