Balanced phono stages: input to output

puroagave

puroagave

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Hi there, who else is using a fully-balanced phono stage from input to output?

I recently inserted a Rowland Cadence into my system, I had to re-terminate my phono cables with XLRs (not so easy when its stiff Yamamura cable hardwired directly to the tonearm). The effort was well worth it! I'm running a re-built Ikeda with a very low output of .17mV. Normally carts like that have special needs with respect to amplification, and any gain associated with carts having a low internal impedance and miniscule outputs are often obscured or swamped by phono stage 'noise'.

Enter the Cadence, I have >74 db of very quiet gain, possible IME because of its balanced design. The input only 'sees' the +/- halves of the cartridge output and the cable's shield or drain wire is not tied to the neg half, but the chassis ground (pin #1 of the XLR), completely removing spurious noises from the signal. Jeff's circuitry is fully complimentary and balanced from input to output the result is the blackest backgrounds I've ever experienced. what you don't hear is the 'electronic haze' often associated with single-ended phono stages, particularly when pushed to amplifying something as low as the Ikeda.

I'm a 'balanced' convert forever!
 
Yes. I am using balanced phono (trinity phono)
As mentioned in other threads on this topic, one of the clear and direct advantages for me has been the extra gain and low noise which is what i was after for my LOMC (allaerts finish).
In terms of phono cabling, i admire that you reterminated. I am adept at lots of things but reterminating phono cables is not one i have trusted myself to attempt. I use the balanced stealth hyperphono.
 
I currently am with the new Doshi 3.0 phono.

Nick gives an explanation:

A couple of points :

1- MC cartridges are differential devices - this simply means that both +/- are floating (not tied to ground) and that they have signal present in equal magnitude and opposite phase.
2- A differential amplifier amplifies the signal present on both the positive and negative legs of the cartridge. it is better able to reject common mode noise and since it is not referenced to ground, is relatively immune to ground noise. If I believed SE technology would suffice, I would have used it.
3- The Transparent phono cable that Josh developed uses transparent networks in differential mode thus preserving the transmission of the signal to the Phono input. Feel free to contact Josh at transparent for further information
4- there are no transformers used in the cable on in the input of the Doshi MC stage.

6- I did a demonstration at Paragon where the only change was the cable, maybe the folks at the demo can relay what they heard.

And this can be done with an RCA at the table end since ....the RCA is agnostic to the signal. If the female jack is floating on the equipment side, then there is no contact with ground....If is it a (balanced) or differential input, then the separate ground wire from the arm provides ground reference.
 
Myles B. Astor said:
I currently am with the new Doshi 3.0 phono.

Nick gives an explanation:

A couple of points :

1- MC cartridges are differential devices - this simply means that both +/- are floating (not tied to ground) and that they have signal present in equal magnitude and opposite phase.
2- A differential amplifier amplifies the signal present on both the positive and negative legs of the cartridge. it is better able to reject common mode noise and since it is not referenced to ground, is relatively immune to ground noise. If I believed SE technology would suffice, I would have used it.
3- The Transparent phono cable that Josh developed uses transparent networks in differential mode thus preserving the transmission of the signal to the Phono input. Feel free to contact Josh at transparent for further information
4- there are no transformers used in the cable on in the input of the Doshi MC stage.

6- I did a demonstration at Paragon where the only change was the cable, maybe the folks at the demo can relay what they heard.

And this can be done with an RCA at the table end since ....the RCA is agnostic to the signal. If the female jack is floating on the equipment side, then there is no contact with ground....If is it a (balanced) or differential input, then the separate ground wire from the arm provides ground reference.
Click to expand...

this is true provided your cable is twin-axial (separate and equal twisted wire runs) for each separate L/R channel and the shield doesn't touch the neg. leg anywhere from the cart at the junction box (i'm thinking VPI here). 5-pin din plug (Graham, SME, etc) to XLR can be wired the same way.

I tied the shield to pin #1 on the XLR and ran an additional drain wire from Pin 1 and joined them in a Y configuration to a spade connector. The spade is ground to the post on the Cadence's chassis.
 
tunes said:
Yes. I am using balanced phono (trinity phono)
As mentioned in other threads on this topic, one of the clear and direct advantages for me has been the extra gain and low noise which is what i was after for my LOMC (allaerts finish).
In terms of phono cabling, i admire that you reterminated. I am adept at lots of things but reterminating phono cables is not one i have trusted myself to attempt. I use the balanced stealth hyperphono.
Click to expand...

I have close to 30-yrs of practice terminating my own wire:) I cut my teeth with silk wrapped litz wire (MIT) and a 600 degree solding pot. I haven't bought pre-terminated wire in years...only my eyesight has deteriorated, I rely on strong 'readers' and/or andoer loupes.
 
puroagave said:
this is true provided your cable is twin-axial (separate and equal twisted wire runs) for each separate L/R channel and the shield doesn't touch the neg. leg anywhere from the cart at the junction box (i'm thinking VPI here). 5-pin din plug (Graham, SME, etc) to XLR can be wired the same way.

I tied the shield to pin #1 on the XLR and ran an additional drain wire from Pin 1 and joined them in a Y configuration to a spade connector. The spade is ground to the post on the Cadence's chassis.
Click to expand...

According to Nick, he hasn't encountered an arm where this isn't true.
 
I run full balanced I am no expert on which is best but I like what I have and the sound I am getting. XLRs seem like a better way to go and feel better as they lock in. To each his own . No tubes no RCA and I still manage to play a little music.
 
Of course the phono cable has a bearing too (and it's electrical proprties.). Balanced certainly won't make a silk purse out of a sow's ear. But will running in a balanced configuration make a good balanced cable sound better than an excellent SE? Then there are the cost considerations between the two versions.

Sent from my SM-G900V using Tapatalk
 
Myles B. Astor said:
According to Nick, he hasn't encountered an arm where this isn't true.
Click to expand...

except that having an RCA 'plug' and corresponding 'jack' are the worst connector I can think of in a balanced phono loom between the cartridge clips and XLRs. I'm now listening to an RPM-2 arm/'table, Allen Perkins also saw this as the weak link and splices the main phono cable directly to the tonearm wire.

Allen later dropped this on the Spiral Groove/Centroid 'arm b/c so many customers were bent on 'improving' it with the interconnect of their choosing.
 
puroagave said:
except that having an RCA 'plug' and corresponding 'jack' are the worst connector I can think of in a balanced phono loom between the cartridge clips and XLRs. I have an RPM-2 arm/'table, Allen Perkins also saw this as the weak link and splices the main phono cable directly to the tonearm wire.

Allen later dropped this on the Spiral Groove/Centroid 'arm b/c so many customers were bent on 'improving' it with the interconnect of their choosing.
Click to expand...

Nothing, unfortunately, is without compromise.

You could like some owners did run the same wire directly from the cartridge to phono without any junctions. Of course, this limits cartridge interchangeability and defeats wand interchangeability. Not to mention, sometimes RFI and hum creeps in.

Or you could try something like Bob's Devices SUT that replaces the junction box altogether. Then the arm wand plugs directly in reducing the phono wire length to nil. But it it is a SUT.

Or, arrange your gear so you use the shortest possible wire length between the arm and phono section. To me, those losses outweigh any issues with connectors.

It's easy enough on the VPI to just order another junction box with balanced connections but Nick felt this solution was fine having RCA on one end and XLR on the other. And he's measured noise and other parameters using this connections and the noise levels are scarily close to what is theoretically possible. Don't quote me on the numbers but it was something like -120 or -130 DB. I can confirm with Nick.


Sent from my iPad using Tapatalk
 
Same can be said about the tape repro heads and thus the advantage of implementing balanced head input for his tape head preamp.

It works well. Not sure about the sound (don't have the golden ears) but surely far less noise issues especially when one has to route the head wires through the deck body around several servo amps and motors.

Myles B. Astor said:
I currently am with the new Doshi 3.0 phono.

Nick gives an explanation:

A couple of points :

1- MC cartridges are differential devices - this simply means that both +/- are floating (not tied to ground) and that they have signal present in equal magnitude and opposite phase.
2- A differential amplifier amplifies the signal present on both the positive and negative legs of the cartridge. it is better able to reject common mode noise and since it is not referenced to ground, is relatively immune to ground noise. If I believed SE technology would suffice, I would have used it.
3- The Transparent phono cable that Josh developed uses transparent networks in differential mode thus preserving the transmission of the signal to the Phono input. Feel free to contact Josh at transparent for further information
4- there are no transformers used in the cable on in the input of the Doshi MC stage.

6- I did a demonstration at Paragon where the only change was the cable, maybe the folks at the demo can relay what they heard.

And this can be done with an RCA at the table end since ....the RCA is agnostic to the signal. If the female jack is floating on the equipment side, then there is no contact with ground....If is it a (balanced) or differential input, then the separate ground wire from the arm provides ground reference.
Click to expand...
 
Ki Choi said:
Same can be said about the tape repro heads and thus the advantage of implementing balanced head input for his tape head preamp.

It works well. Not sure about the sound (don't have the golden ears) but surely far less noise issues especially when one has to route the head wires through the deck body around several servo amps and motors.
Click to expand...

Great point as usual!
 
I have a question. I am confused a bit on some of the references in this thread regarding the use of xlr versus rca plus ground for a balanced input on a phono. My phono is fully balanced but uses rca and ground as the input. Are folks implying here that this approach is inferior to xlr. It is my understanding that all mc's are naturally balanced and so are phono cables regardless of din to xlr or din to rca plus ground. (I am not meaning to accuse; I honestly just looking for more clarity on this point.) Thx.
 
Traditionally, RCA connections were always considered the inferior connector type. (Remember XLRs also were popular because studios ran balanced and wanted quick disconnect connectors!) Wiith the advent of the newest generation of RCAs, no one has done a good comparison of the to types of connectors.
 
Myles B. Astor said:
Traditionally, RCA connections were always considered the inferior connector type. (Remember XLRs also were popular because studios ran balanced and wanted quick disconnect connectors!) With the advent of the newest generation of RCAs, no one has done a good comparison of the to types of connectors.
Click to expand...


Thanks Myles, that is my understanding as well, but to be clear, using an rca with a ground wire is still a 100% balanced connector, correct?? (This of course assumes the balanced phono preamp is designed to receive the balanced signal via rca.)
 
FlexibleAudio said:
Thanks Myles, that is my understanding as well, but to be clear, using an rca with a ground wire is still a 100% balanced connector, correct?? (This of course assumes the balanced phono preamp is designed to receive the balanced signal via rca.)
Click to expand...

Yes, as Nick said, the RCA is agnostic. :)
 
FlexibleAudio said:
Thanks Myles, that is my understanding as well, but to be clear, using an rca with a ground wire is still a 100% balanced connector, correct?? (This of course assumes the balanced phono preamp is designed to receive the balanced signal via rca.)
Click to expand...

this is true except the majority of RCA plugs are still designed with co-ax in mind (neg phase is grounded to a massive barrel (and inferior metallurgy to boot). just about all interconnect cable we would consider hi-end is and has been twin-axial (equal twisted pair of conductors for +/- legs) and a shield of some sort (usually braid and/or foil). AFAIK, the only RCA plug on the market today that treats the +/- phase of the signal *equally* are the Eichmann bulletplugs. WBT nextgen jack works well with this plug, and embraces similar design principles.
 
More views on what is meant by balanced rca vs balanced xlr

http://forum.audiogon.com/cgi-bin/fr.pl?eanlg&1431030622&openfrom&1
 
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