Thanks Ralph, I get it now. My many questions have been answered. |
Thanks for the comments so far. When I referred to balanced designs I was talking about fully differential, not simply an XLR connection. I would include Peter’s designs wbere there is a conversion after input stage in the discussion. |
Thanks for the comments, Al and Ralph. @atmasphere , on a side note, I discovered the Yr album by Steve Tibbetts in 1980 while working at my college radio station and flipped out over his music. We put it into Heavy Rotation. That's where I got my start in audio engineering, since Syracuse was a top broadcast school, engineers were full-time employees and required to have an FCC license. Now, getting back to my SE design question regarding CJ, is this a case of the company finding a design that reproduced very high quality sound and stayed with it since their products were and are still are so successful? @almarg made a related comment... I'd imagine that a factor in many cases is that designers tend to use
approaches they are familiar with, and that build upon their previous
work, unless there is a compelling reason to change. And the fact that
any given design is likely to be used in many systems in conjunction
with associated components that are single-ended would seem to make the
case for change less compelling. |
why do reviewers not "call out" the equipment manufacturers, with "fake" balanced connections? That’s true. We know from the review that the unit is not a balanced design. They could say "this amp has RCA and XLR inputs." |
bdp2The Tim Paravicini-designed EAR-Yoshino tube circuits are all single ended, the pre-amps and power amps having transformers on the XLR/balanced inputs and outputs. This brings up an interesting concept that I have been thinking about. In the case of a SE designed preamp, what would be the preferred way to send the signal to the amp; use unbalanced RCA cables, or go thru transformers with XLR’s which will be converting the signal back to single-ended? And depending on the type of transformer, the gain may be increased on the output, or it may be a 1:1 conversion. Seems like an unnecessary step. But if the preamp was fully differential, then it would be advantagous to output a balanced signal to the amp’s XLR/balanced inputs. Am I correct? |
Yes Charles, I'm getting much more info than I expected. And very pleased that a discussion about the different designs has happened.
Glad that some of brightest minds on the forum have joined in.
Jim |
@herman , I appreciate you participating in the discussion, but in viewing the archive threads I did not find an answer to my original question. I wanted to find the reason a manufacturer designs a SE component and why in today’s HiFi environment (which includes many fully-balanced components), does not offer a balanced option in their product line.
I’m referring to fine companies such as Conrad Johnson, Consonance, Coincident, and Bob Carver’s tube amps. CJ builds amps that sell for $20-$39K, so their design is not driven by cost.
I appreciate everybody’s comments and learned that I should have planned out my system more carefully. In my case, I have a balanced source and amp, but my preamp is SE. My next purchase will be a new amp and learned that maybe I should go for SE tubes, rather than one of the many fully-balanced amps that are available.
There has been evidence provided that staying single-ended may be the best direction for me.
|
Full disclosure; my preamp is the Atma-sphere UV-1, single-ended. I decided to buy this unit based on it's sonics and simple design. To me, it does everything right; wide and deep soundstaging, realistic imaging, deep bass extension. It presents a clear, yet classic sound using 6SN7 tubes.
My CDP and DAC are a balanced design, thus the reason I posted my question. If this preamp or a CJ or Coincident offered a balanced input thru a transformer, it might introduce artifacts thru the circuit. |
How much potential sonic performance would I lose by using my SE preamp into the unbalanced inputs of a fully differential amp? e.g., my UV-1 preamp into the SE input of an Atma-sphere amp, or using this preamp with a Pass Labs amp.
There’s an impedance difference between fully-balanced and SE inputs, but in what way would sonics be different using unbalanced in a fully-differential design?
Or is it recommended to use a fully-balanced preamp to gain high quality sound?
|
An addition to my post;
The unbalanced cable runs would be short, 1 to 1.5 meters. |
@atmasphere , thanks, that's the answer i was hoping to hear.
"my guess would be that finding a fully balanced preamp providing sonics that are as much to your liking as those of the UV-1, for a comparable price, would be a tall order if not impossible"
Al, that is quite true. |
It is correct that some manufactures use a jumper pin from 1 to 3 when a input are configured with two options - XLR and RCA. IMO there is several issues with this. First one being that pin 1 of a XLR should have Chassis ground (earth) potential - not signal ground which is what the inverting amplifiers input needs connected to when only feeding the non inverting amplifier to get a balanced output. When using a SE input to a differential amp, I thought the ground was tied to pin 1 of the XLR input and to the chassis. What are the consequences of also being tied to the safety ground? I was offered a Pass amp at a great price, but don’t know if I should use a SE pre with their fully-differential design. |
@pbnaudio , Thanks, I’m familiar with the Whitlock paper, probably time for me to read it again. Typically Signal ground is isolated from chassis ground with a dual diode in reverse parallel and a resistor - or something similar. Signal ground should not be present on pin 1 of the XLRs Peter, your components are magnificent. I like the toggle between balanced and RCA on the back of the amps. I appreciate the info provided by yourself, Ralph and Al. It makes me realise that the design of an amplifier needs to be examined carefully before making a purchase. It’s easy to check for a balanced signal, or for fully-differential by reading the specs, but how an amp deals with safety and signal ground is not always disclosed. Atma-Sphere states clearly that their amps use a star grounding topology. |
i have a balanced preamp and XLR inputs into my power amp, but the amp inputs are likely not balanced at all (Jolida 502p). Thus when I hooked up a pair of balanced Mogamis to replace whatever the unmarked weird green XLRs (that sound fine by the way) are that came with my preamp, the Mogamis sounded awful… If the Mogami's are truly balanced and the Jolida shorts pins 1 and 3 of the XLR inputs, could this cause a change in sonics? |
