Balanced XLR source RIAA

[Stee]

hello
see my idea to have perfect balanced signal
from MC cartridge
with new cable
and four channel RIAA

 

[analog_sa]

This doesn't fill me up with confidence.

 

[mlloyd1]

indeed ...

that is a lot of components to match and there are likely more elegant and higher performance approaches available.

but, who am i to say. 🙂
give it a go and let us know how it works out ...

best regards,
mlloyd1

 

[Stee]

Balanced Source is the Way

yes sure

I will test and upgrade...

really the news is
connect MC in balanced mode

to have better performance
also for filter and other chain...

 

[SY]

Running the cartridge balance is a very good idea (says the guy who runs his cartridge balanced). These are just not good implementations. The second one will have degraded noise performance.

There are (to my knowledge) two good ways to do it. One is to build a fully differential phono input, the other is to use a transformer at the input and run the primary balanced. The secondary can then drive the input of a conventional single-ended stage. You get 99% of the balanced advantage that way.

 

[Stee]

thanks <SY>

do you have a schematic of fully differential one?

http://www.esafono.it/diff.jpg
this is just a project with OPA1632

 

[SY]

Only with tubes, but I'll bet there's a transistorized one around the forum somewhere. The "search" function is your friend.

Here's an example of a tube one:

http://www.vacuumstate.com/schematics/rtp3c_s.gif

edit: The one you linked to looks much better.
edit edit: "Better" than the first one, not better than the Vacuum State one; sorry to be ambiguous.

 

[analog_sa]

You can get some good, working ideas here

 

[Stee]

thesis: balancing improves

to see if the hypothesis is correct
I did a simple test that anyone can repeat at home

steps:

listen a preferred song only from one channel
for example the right channel

turn off everything

connect the left channel wire on cartridge instead of ground wire
and connect the negative pole of right loudspeaker
on left output of the amplifier

push on everything

hear the same song...

I believe the difference is very significant :

the sound is more dynamic
treble are more crystalline
the noise is reduced!

 

[analog_sa]

Lovely picture 🙂

It seems you are listening to the entire chain balanced now, not just the phono. Difficult to know how much of the improvement is due to the phono stage but interesting all the same. No hum?

 

[Stee]

an uneconomic improvement

certainly difficult to discriminate between contributions...

now I have an economic turntable - kenwood
with economic MM head and shielded container (on the ground)
no hum

test you also
it's easy with great satisfaction

But attention
must buy a second complete electronics once heard this quality!
(or build a fully differential one)

 

[Stee]

sorry the output of last schematic is unbalanced

ideal for unbalanced input amp but with balanced out
http://www.esafono.it/Esafono_Tandem.pdf
😉

 

[mzperx]

FullyDiff (MC) RIAA

At the moment I'm thinking in building of this version with fully smd technology.

 

[Stee]

very intresting

thanks 😉

 

[jackinnj]

Only with tubes, but I'll bet there's a transistorized one around the forum somewhere. The "search" function is your friend.

Here's an example of a tube one:

http://www.vacuumstate.com/schematics/rtp3c_s.gif

edit: The one you linked to looks much better.
edit edit: "Better" than the first one, not better than the Vacuum State one; sorry to be ambiguous.

Differential DIY OPAMP -- Scott Wurcer posted under "Measuring Low Noise" -- instead of 2SK170 uses BF862.

 

[Stee]

good idea

but what is his complementary? 🙄

 

[jackinnj]

This is from Tubecad http://www.tubecad.com/2007/09/blog0120.htm

adapted a bit for the situation -- so full credit to Broskie

An externally hosted image should be here but it was not working when we last tested it.

 

[mzperx]

This circuits has very poor CMRR at low frequency. And C1/C5 pairs have to be well matched in order to avoid further CMRR degradation and to keep theoretical 40dB CMRR.
//That's why I choose OPA1632 into 2nd position.

 

[Stee]

more easy is have twice preamp

hello
an easy solution to have balanced signal
and more and more harmonics?

but two NAD PP2 phono preamplifier
and modify your connection to the pick-up

need also two amplifier😉 🙄

 

[EUVL]

> Differential DIY OPAMP -- Scott Wurcer posted under "Measuring Low Noise"

Can you kindly post a link please.


Thanks,
Patrick