Bosoz

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Jump to Latest
K

kennethrl

Member
Joined 2005
I just rounded up the parts for the BOSOZ. I ordered the Diode bridge from Digikey (for the power supply) #2KBP02M-ND. It appears to be a 4 pin rectifier and my PCB is set up for a two device. Any suggestions?

Also I am planning to make a wooden case for the Preamp. Does it need a metal case around it for shielding?
 
H

harryeng

Member
Joined 2004
steenoe said:
I have no experience with wooden enclosures. You might want to think about where you place the preamp, on top of a big trafo in your poweramp might not be the best place.
Someone else with knowledge on this?

Steen:)
Click to expand...

Hi Steen, I have some experience with wood. Some people in Holland think it has a big impact on the sound, so they do everything in wood (including re-packing the capacitors in wood).

Some experiments with some of my own DIY gave an enlighting view and a somewhat confused sound. :drunk: In the end I bought myself an experiment kit with Mu-metal and started rebuilding my Pass Ono case with lots of aluminium, copper and Mu-metal for the trafo's. The trafos do influence the sound, especially with small signals in pre-amps.

Greetings, Harry
 
steenoe

steenoe

Member
Joined 2004
Hi Steen, I have some experience with wood. Some people in Holland think it has a big impact on the sound, so they do everything in wood (including re-packing the capacitors in wood).
Click to expand...
Repacking caps in wood:xeye: Wow, I heard of skinning caps, but not packing them in wood:eek: Is that sounding any better? Okay I know you can go to great measures to shield out EMI and so with MU-metal! I never heard of the wood thing, though. Thanks for replying, Harry:) I am sure our friend Kennethrl, is happy too;) As for preamps, I have had the best results connecting the circuit GND to the chassis. That would be more ore less useless, with a wooden chassis.

Steen:)
 
steenoe

steenoe

Member
Joined 2004
Kenneth, 3 feet away makes you pretty safe;) Normally you dont have to shield the psu from the circuit itself. Just put the trafo in one corner and the preamp board itself in the opposite corner, so to speak. The more dist. between the two, the better!
If you need more info, speak right out.
Happy building and best of luck :)

Steen:cool:
 
K

kennethrl

Member
Joined 2005
Thanks for the help!!

I have another question I am going to have rotary switch to select inputs (CD, radio,etc). My local parts supplier told me that the negative inputs are put together(for both channels) and the positive are separate in the switch (it is a 3 pole 4 position switch is this a common and is it the right way to go?
 
steenoe

steenoe

Member
Joined 2004
I have another question I am going to have rotary switch to select inputs (CD, radio,etc). My local parts supplier told me that the negative inputs are put together(for both channels) and the positive are separate in the switch (it is a 3 pole 4 position switch is this a common and is it the right way to go?
Click to expand...
As I understand it, your supplier missed the fact that this is Balanced circuit!! Normally with single-ended input you just tie the GND's together! Do you have any balanced input sources?
If you do have a balanced source, you do not want to tie the neg. signal to ground! Please tell me a bit more:) If you have only single-ended input, you just put a jumper in the board from -in to gnd! Right and left channel are kept seperate.

Steen:cool:
 
K

kennethrl

Member
Joined 2005
As I understand it, your supplier missed the fact that this is Balanced circuit!! Normally with single-ended input you just tie the GND's together! Do you have any balanced input sources?
Click to expand...

I don't have any balanced inputs. My CD and tuner has just RCA connectors.

On other subject, I know alot has been written on this...but what is the best way of connecting the pots so I have one main knob controlling the volume and a way to control the channel balance.

Thanks
 
D

dms

Member
Joined 2002
Volume pot(s) after BOSOZ

This is a problem I am grappling with. I am planning a multi-channel unit to drive a bi-amped surround sound system. From a design standpoint it is best to have the pots or attenuators after the gain stage to lower the noise as Pass did in his pre-amps. Pass used relays and resistors to maintain CMRR. One clever guy found you can just short the out of phase outputs with a single pot (per channel) so that may be worth looking at. I have been checking all my surplus sources for the 36 or so relays for Pass style attenuation. or 72 relays if my preamp is after the crossover(s). I would like to try a passive crossover made with coils and caps. So my idea at this point is a source switch matrix, then the crossovers, then the amplification, then the volume control. There are some impressive multi-channel efforts on this site. Hope mine is as good!
Don
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Top Bottom