My Take on X-BOSOZ

[steenoe]

Darn..

Cheer up mate You will have so much more satisfaction from a real NP system, that you will forget about all your previous.................. Do I need to say more, just let me know
All the chipamp guys will get surprised

Steen

 

[apassgear]

Coming in a bit late I guess...

This might be the best layout by far I’ve seen for this preamp. Excellent work Russ, please receive my congratulations, I like those FET’s aligned to the side of the board which makes them easy on heatsinking, at least from my humble DIY point of view.

One thing I noticed on the schematic is the lack of protection on Q4/5 gates. I know many of us don’t like zeners there but being a passive devise as long as the voltage is not exceeding the zener rating it does not intrude on the signal.

If this is going to be a group buy I would suggest having the opinion from other members interested on the boards. I would vote to add them and if someone doesn’t like these just don’t solder them.

I’m in for a couple of boards

 

[Nisbeth]

Russ, what is the lead spacing of the C4/C5 caps on the amplifier board? If I'm reading it right it's 15mm and finding a 10uF film cap in that package is hard to say the least. Did you have a specific part in mind when you chose that footprint?


/U.

 

[steenoe]

If this is going to be a group buy I would suggest having the opinion from other members interested on the boards. I would vote to add them and if someone doesn’t like these just don’t solder them.

That is correct Tony! How was that to be missed?

Steen

 

[zei]

No worries
i,m looking forward to get my hands on these boards.

sub or no sub..--- i want one

/Z

 

[Russ White]

Russ, what is the lead spacing of the C4/C5 caps on the amplifier board? If I'm reading it right it's 15mm and finding a 10uF film cap in that package is hard to say the least. Did you have a specific part in mind when you chose that footprint?


/U.

Hi Nisbeth,

I have some MKPs that fit, but I am willing to add some more pads for bigger radial type caps.

I actually plan on using 33uf axial foil caps.

EDIT forgot to mention that the LS is for 10 or 15mm caps, which you can get.

Cheers!
Russ

 

[Russ White]

Re: Coming in a bit late I guess...

One thing I noticed on the schematic is the lack of protection on Q4/5 gates. I know many of us don’t like zeners there but being a passive devise as long as the voltage is not exceeding the zener rating it does not intrude on the signal.

First of thank you so much. I have been having a lot of fun with this project. Great designs naturally inspire interesting layouts.

This is my first ever Pass design, and yes even my first ever FET design, so I am not sure how to implement what you are asking for as far as the Q4/5 gate protection zeners. Let me take a stab at it.

A quick description would be very helpful.

Cheers!
Russ

 

[steenoe]

A quick description would be very helpful.

The zeners would be connected from +in to gnd and -in to gnd.
Take a look at the BosoZ paper here: http://www.passdiy.com/pdf/balzenpre.pdf
Oh, by the way that reading is pure gold

Steen

 

[Russ White]

The zeners would be connected from +in to gnd and -in to gnd.
Take a look at the BosoZ paper here: http://www.passdiy.com/pdf/balzenpre.pdf
Oh, by the way that reading is pure gold

Steen

Thanks Steenoe, thats exactly what I thought, but I wanted to be sure. Thanks!

Cheers!
Russ

 

[apassgear]

Russ, just as Steen has pointed, add a B2B 9V zeners parallel to R16/17, this will protect the gates from static electricity when you connect signal cables from the source.

 

[Russ White]

New improved safer version.

Here you go. I actually like this much better!

Cheers!<---Guinness
Russ

 

[jleaman]

Re: New improved safer version.

Here you go. I actually like this much better!

Cheers!<---Guinness
Russ

Looks super nice .. Is this a stereo channel or mono ?

 

[Russ White]

Balanced mono. Thanks.

 

[jleaman]

is the inut balanced or single ended ?

 

[Russ White]

Fixed couple mistakes.

If you did not see them, I will not tell.

 

[Russ White]

is the inut balanced or single ended ?

Balanced, but I believe you should be able to tie In- and GND together and use it single ended. I will defer to the experts though for the final answer.

Cheers!
Russ

 

[jleaman]

Balanced, but I believe you should be able to tie In- and GND together and use it single ended. I will defer to the experts though for the final answer.

Cheers!
Russ

I'd Be interested in 2 boards plus the psu board

 

[hayenc]

Definitely Twisted.

Sign me up for two boards and a psu board. I'll do beta again if you want to take them through the cycle.

 

[metalman]

Originally posted by Russ White
Balanced, but I believe you should be able to tie In- and GND together and use it single ended. I will defer to the experts though for the final answer.

Exactly correct. In fact, you can run single ended in to single ended out if you attach both the -in and -out to ground. If anyone is interested, I put together an arrangement that allows me to switch between SE and Bal inputs and outputs from the front panel in my old CC-CCS-X-BZLS thread. This circuit is very, very flexible, part of the reason I like it so much.

Cheers, Terry

 

[jleaman]

Exactly correct. In fact, you can run single ended in to single ended out if you attach both the -in and -out to ground. If anyone is interested, I put together an arrangement that allows me to switch between SE and Bal inputs and outputs from the front panel in my old CC-CCS-X-BZLS thread. This circuit is very, very flexible, part of the reason I like it so much.

Cheers, Terry

Ya i like it.. ill have to build one so i can hear the change in sound from my tube pre-amp to this pass labs pre-amp.