BALANCED LINE DRIVER,PCB layout share

[juluska]

Originally posted by AndrewT

is this AC output a combination of noise and/or hum?
Have you listened to it.
an ordinary speaker will reveal much about it.
A pair of headphones will reveal it at very loud level.

i think there's no problem, if the output voltage of my cdp layer is 2v and the bridge adapter has 10mv output that means an attenuation of 200. i have measure the output voltage in my passive preamplifier ( 100 k), and the attenuation is much lower, from 2v in the cd output to 80mv in the passive pre output. I think it can't be audible.

[digi01]

for those interested in make bridge driver with universal opamps,i have a completed design last year.
here is the device photos,sch,bom:
bridge preamp

http://assemblycraft.com/bridge_preamp.html


-Zang

[digi01]

Originally posted by juluska

i think there's no problem, if the output voltage of my cdp layer is 2v and the bridge adapter has 10mv output that means an attenuation of 200. i have measure the output voltage in my passive preamplifier ( 100 k), and the attenuation is much lower, from 2v in the cd output to 80mv in the passive pre output. I think it can't be audible.

i guess your passive preamplifier (100k) without decoupling caps in the signal route.

[juluska]

Originally posted by digi01
for those interested in make bridge driver with universal opamps,i have a completed design last year.
here is the device photos,sch,bom:
bridge preamp

http://assemblycraft.com/bridge_preamp.html


-Zang

nice work. What is the price for a complete stereo kit with components?
thanks

[col]

I thought I'd try the Jaycar KC5469 bridging kit just to see if it was any good.

It was extremely easy to build with all hole-through components widely spaced (too widely spaced, PCB is a bit big). It seems to work fine though. It comes with a LM833 opamp. Also, there is an option on the PCB for using the amps PSU to power it with 2 x 15v 1W zeners and 4x 1W resistors, that are a different value depending of the voltage of the amps PSU.

One drawback is that it only has a mono input. I would like to use it to power a sub. So I need to sum a stereo pair and use some kind of low pass to filter it down to 200hz before the input. Is it possible to use a PLLXO type filter with this?

col.

[digi01]

Hi col,nice try with the thread hijack there but a pretty commerce project is not where we're at right now

juluska,you can drop me a mail for the service

--
Zang

[col]

opps sorry digi01, no hijak intended! just similar issues....

Will your boards run on 15v?

col.

[digi01]

Originally posted by col
Will your boards run on 15v?

the board supply with +/-18VDC to +/-30VDC,it have fixed regulator chips LM78L15,LM79L15.

here is the sch&bom:
http://assemblycraft.com/0903img/bridge-v1.1.GIF

all the best,
Zang

[juluska]

I've just finished my first bridging adapter for the bpa300 following the digi01 schematic in a quad opamp. It works really good, see here the results.
http://ignatiusprojects.blogspot.com/
In the next board i will mount the regulated PSU and adapter in the same board.
BPA300 amplifier sounds superb.
Thanks to all.

[qweetz]

hello digi01, hope its not to late to post here.

I wonder (as i am very new to this) why does your pcb have a positive and a negative voltage regulator? All the circuits i have experimented with recently have just used a positive regulator. Will this drv134 chip only work with a + and - regulator connected to pins 5 and 6?

thanks for any info : )