Eddie Current Equilibrato

[zippy2001]

Eddie Current Equilibrato

- two unbalanced inputs

- will drive headphones true floating balanced, or unbalanced

- external power supply, same as the ZD and ZDT

- solid state rectifier

Tubes - (1) Tung Sol 12SN7, (2) Sophia Electric PX4

I'll get more details when I pick it up on Saturday

[uberburger101]

Wow, looking good. It's not listed on the site though, prototype?

[Voltron]

Very cool Steve. What is "true floating balanced or unbalanced"?

[Dusty Chalk]

"prototype" -- Yes, it's (currently) one of a kind.

"...floating..." -- ah, nice, clear and accurate even for the pedants (I.E. me).

EDIT: Well, I thought it was clear -- I took "floating balanced" to mean it was balanced up until the wires went out to the headphones without the third ground wire.

Edited January 6, 2010 by Dusty Chalk

[HeadphoneAddict]

Hmmm...

[zippy2001]

This is the first production version of this amp.

And yes, it is not on the Eddie Current site yet. I'm not sure when Craig was planning on announcing it.

At first it was to come with a 6SN7 tube and a pair of 300B tubes.

Then it changed to the 12SN7 / 300B combination.

As of today, he offered to set it up with the 12SN7 / PX4 tubes and this may become the standard configuration.

[zippy2001]

Very cool Steve. What is "true floating balanced or unbalanced"?

I'm not sure what "true floating balanced" is, but Craig posted a whitepaper on his site.

"To Balance or Unbalance - that is the question..."

I believe he is refering to headphone output as setup for balanced (4pin XLR) and single ended. It looks like how the ZDT has both balanced and single ended headphone outputs.

[909]

congrats!

looks very cool, steve.

i hope to hear it this weekend.

[zippy2001]

congrats!

looks very cool, steve.

i hope to hear it this weekend.

Thanks, I hope you can make it over to Craigs to give it a listen.

[spritzer]

The amp is certainly SE only but if it has a transformer output then that can be balanced.

[zippy2001]

The amp is certainly SE only but if it has a transformer output then that can be balanced.

And it does indeed have a transformer output.

[spritzer]

Center tapped output transformer then, same as the TTVJ amp.

[n_maher]

Center tapped output transformer then, same as the TTVJ amp.

That'd be my guess.

[spritzer]

That does bring up a question in my mind, why doesn't Craig transform one of these amps into a Stax amp by simply using different output transformers? Many people like to use the SRD units with SET amps so why not cut out the two high ratio transformers and just use one low ratio unit.

[n_maher]

Not sure.

I'm still trying to figure out the illuminated "Input" switch.

[kevin gilmore]

The input switch changes color when you push it in and out.

(it actually does this mechanically)

craig just loves to use antique parts that are generally not available.

[spritzer]

Edit: Ahh ok.

Edited January 6, 2010 by spritzer

[morphsci]

Very nice. I just love the design aesthetic of the EC amps, not to mention Craig's attention to detail on both the circuit and chassis design. Congrats on a very nice amp Zippy.

[Bidoux]

The amp is certainly SE only but if it has a transformer output then that can be balanced.

I think DNA's sonet is like this to. Do you think the sound is different SE vs balanced ?

[spritzer]

No idea, way too many variables.

[zippy2001]

I think DNA's sonet is like this to. Do you think the sound is different SE vs balanced ?

According to Craig if you have a balanced headphone, you can easily put a dummy plug into the SE plug and it puts the amp into unbalanced single ended mode. So you can easily compare balanced vs unbalanced, and he claims that it does definitely sound better balanced with both his AD2000 and RS1s.

[Bidoux]

According to Craig if you have a balanced headphone, you can easily put a dummy plug into the SE plug and it puts the amp into unbalanced single ended mode. So you can easily compare balanced vs unbalanced, and he claims that it does definitely sound better balanced with both his AD2000 and RS1s.

If you have time it would be great to do a quick test.

[nikongod]

What is "true floating balanced or unbalanced"?

It means that the transformer is "floated" (not grounded) as opposed to grounded.

Transformers were historically ALWAYS grounded somewhere so that heaven forbid the insulation in the transformer fails any voltage that finds its way out of where you want it goes straight to ground. Newer transformers make failures far less likely with better materials and construction techniques, but for historical reference.

The problems with center tapping the transformer come at you from a few directions. The first is that the center tap is not always perfectly centered on the windings so the 2 phases are not always equal in every respect and not as well balanced as they could be. Better transformers avoid this with better construction, but thats $$$$. The second is that switching from "balanced" to "single ended" with a center tapped transformer requires yet another switch which must be switched properly (if you float the transformer its very easy to hook up to SE). The last thing is that by grounding the transformers you have introduced "ground" into the signal path where you are going from component to component: no ground connections between components=no ground loops! Going back to the telephone example or long runs of cable like at a concert, ground loops become very dificult to deal with any other way when dealing with stuff that is being run on different power grids.

By floating, the balance is set by the load to ground which can be controlled far more accurately than a center tap. In the case of stuff that is not grounded (headphones, speakers, the output/input transformers in audio components, etc) there is no ground connection at all, and the balance is set by random looses. This random junk is actually MUCH better than it would seem to be as it effects EVERYTHING equally. Balanced is no longer balanced when the 2 phases are not equal in every respect.

As a quick example of floating, I have run an MC cartridge into an MC SUT fully floated without shields and gotten acceptable noise pickup (it was barely audible, but a somewhat contrived test: I have heard noisier things set up "right") . no shield, 0.3mv signal. It is better with a shield but

Now that all of that is out there, Im not convinced floating/grounding the transformer matters either way for SQ on the output of a POWER amplifier except in providing certain types of feedback, which is not an issue here. I have heard some arguments for noise getting into the system through the outputs, but that seems to be more of a problem for amps with global feedback loops than open loop amps.

[bhd812]

who was that headfier in ohio who had lots of moth/eddie current stuff back in the day. i met him at the Ohio meet..?

i forgot his username and name

[recstar24]

who was that headfier in ohio who had lots of moth/eddie current stuff back in the day. i met him at the Ohio meet..?

i forgot his username and name

Mikey01 I believe...I hope he is doing okay, I know he sold off a lot of his EC Moth stuff way back when because he was having some serious health issues.