Sherbourn 5/1500A Owner Opinions? (1 Viewer)

[Randy G]

pssst...

ya know what...the "balance" version ain't really alllll that balanced, but the "A" version does have some other technical improvements over the older version.

 

[Tony Genovese]

ya know what...the "balance" version ain't really alllll that balanced, but the "A" version does have some other technical improvements over the older version.

Does anyone know whay Randy G means here? I was thinking of buying some balanced cables to mate with my Integra Research RDC-7, but won't if there are zero benefits. Anyone know for sure?

Thanks

 

[Dan Driscoll]

Does anyone know whay Randy G means here? I was thinking of buying some balanced cables to mate with my Integra Research RDC-7, but won't if there are zero benefits. Anyone know for sure?

The Sherbourn has XLR connectors, but is not actually a balanced amp. FWIW, the RDC-7 isn't balanced either. In fact, very few of the components with XLR connections are truly balanced and even fewer are full differential, especially in the mid-fi market. In balanced and differential circuits there are actually 2 signals, of opposite polarity (or 180* out of phase). This requires a lot more circuitry than traditional single ended designs and can be cost prohibitve for all but the most expensive components.

The one benfit to having XLR connetions on mid-fi equipment like the Sherbourn amp is when there may be long cable runs. Balanced cables are very good for rejecting RFI/EMI, even when the actual electronics are single ended designs. Remember that the Sherbourn was originally designed for custom installations, where the amp may be quite a distance from the processor and the cables may be run in bundles. Using balanced interconnect cables in that type of installation makes a lot of sense. But in most standard home set-ups it is unlikely that you will gain anything audible from using XLR cables.

 

[Tony Genovese]

The Sherbourn has XLR connectors, but is not actually a balanced amp. FWIW, the RDC-7 isn't balanced either.

Integra Research in their manual lists the pin positions as follows: Pin 1 Ground, Pin 2 +, Pin 3 -. Isn't this what you describe above as a "truly balanced" circuit? And is the Sherbourn wired this way like the Integra?

Thanks for the help.

 

[Chas_T]

Dan..

I've pasted this before written by Brian F. Is it safe to write then the Sherbourn is a fake adapter balanced amp?

Still learnin'

Charles

**************

Fake "adapter" Balanced - the preamp/amp has an XLR input, but pin 3 is grounded. Electrically, this is nothing more than a convenience connection. Euh!

True Balanced - The XLR I/O have an op amp inverter to take advantage of common mode rejection. The negative phase is inverted and added to the positive phase (if it's an input), to cancel interference picked up by the cable. Both phases go through the op amp, not just the negative phase. Bottom line: If you want to reject noise pickup in long interconnects, then this is for you.

Full Differential - what so many people seem to think they want when all they're really after is True Balanced connection. This is used in sensitive lab gear etc., and more expensive audio gear (including I believe some of Sonic Frontier's 2-channel tube stuff). It requires twice the circuitry, since each phase is amplified separately. What's the advantage? Rejection of interference

generated under the hood. If a SE circuit with a real balanced input is laid out properly and the S/N ratio is already acceptable, there's no reason to pay through the nose for a full differential circuit, because you don't gain anything...or at very least you don't gain enough to come even close to justifying the enormous increase in cost. And if each side of the circuit is not absolutely

matched, you will actually be worse off! This means even more cost...

 

[Dan Driscoll]

Charles,

Was Brian referring specifically to Sherbourn? I would have to check the circuit diagrams to determine if he is correct.

Tony,

Where do the pins actually connect on the RDC-7? If pin 3 goes through an inverter and then is summed with the signal on pin 2, then yes, it is a balanced connection. If that's the case then I was mistaken, I thought the RDC-7 just had the XLR connectors, without the circuitry.

 

[Chas_T]

Hey Dan.. He was writing about the Anthem AVM-20 as the discussion when he posted was if the AVM-20 was a True Balanced piece. The AVM-20 is in that category.

Now I assumed that his description and definition was for ALL audio products that can provide a potential balanced connection. Assumption can be dangerous and maybe in this situation it is.

This was his complete comment as I ommited the words AVM-20 and MCA from the previous post as I thought it was irrevelent. Maybe it's not in this case.

True Balanced - what the AVM20 and MCA use: The XLR I/O have an op amp inverter to take advantage of common mode rejection. The negative phase is inverted and added to the positive phase (if it's an input), to cancel interference picked up by the cable. Both phases go through the op amp, not just the negative phase. Bottom line: If you want to reject noise pickup in long interconnects, then this is for you.

Still learnin'

Charles

 

[Doug_NHT]

Does anybody know where to purchase Sherbourn amps??? I've been trying to get a price on one from a place in KC(Ron Fone pointed me there) but they haven't given me a price yet and when I call back, the sales guy is always out. I'm near St. Louis, MO if that helps any.

Doug

 

[Bobpaul]

I have the Sherbourn 5/1500A for $900 floor sample off Yahoo Shopping.

WOOOOOOOW! This beast rocks. It does amplify so smoothly and quietly that you want to cry listening to classical in SACD. My next step is to get me hands on a B&K REF50 and balanced cables.

Bob

 

[ChadLB]

It is hard to find used 5/1500a's>>>

 

[Al Holland]

Doug,

You will probably be happy with either.

I have the Sherbourn mated with a Rotel 1066. These are the only components that I have never considered selling and I have owned many (too many).