Eddie Current Equilibrato

[Parafeed]

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.

My own "experiments" with floating the secondary of a headphone amp transformer have shown no SQ advantage (that I could hear anyway) over grounding the secondary. I'm not sure how comfortable I would be with an amp, especially a 300B amp with a series feed transformer, high voltage B+ on the primary and the secondary not tied to ground. Regardless of the improvements in constructions techniques and materials, it makes me nervous. Not so bad if it is a parafeed configuration, where one end of the primary is tied to ground in any case, and of course there is the DC blocking cap, but series feed .....

[dsavitsk]

I'm not sure how comfortable I would be with an amp, especially a 300B amp with a series feed transformer, high voltage B+ on the primary and the secondary not tied to ground.

I think it is a terrible idea, and something I won't do for myself or anyone else. Particularly in the case of something you are connecting to your head Your 100volt plus moment - Page 2 - diyAudio

[n_maher]

I can't believe that any commercial product would be made with the output floating, that's actually pretty scary.

[Parafeed]

Let's hope that EC's idea of "floating" the secondary is not what we think it to be. The more I think about this, I can't believe that a commercial manufacturer, (even a relatively small boutique one), would do this. Craig is way too wise to do this.

Although safety seems not to be taken as seriously as it once was. No names mentioned, but I have issues with people who should know better selling amps without a bleeder resistor to discharge the HT caps, or with an output plug instead of a socket, (exposed high voltage pins without the umbilical connected) on the chassis of a standalone PSU unit or better still, an amp that came my way last week for a mod - metal chassis, not grounded - earth tag on the IEC - no connection to it. That's one way to ensure your equipment doesn't have an issue with ground loops!

[909]

instead of speculation why not inquisition? it's simple -- ask craig...

[dsavitsk]

an amp that came my way last week for a mod - metal chassis, not grounded - earth tag on the IEC - no connection to it. That's one way to ensure your equipment doesn't have an issue with ground loops!

That's how my Melos was until I fixed it.

I have no problem with floating transformer secondaries, or even floating outputs, in low voltage circuits, but definitly not in anything over 24V or so.

[909]

i believe steve mentioned this thread to craig and he asked i post this tidbit.

The A Designs Audio Reddi, MP-1, and MP2 mic pres are single ended floating balanced designs. They have CE certification which is an international safety agency approval for fire, and shock. I can give you hundreds of more examples of balanced floating outputs on Professional, and Commercial electronic equipment, all UL, or CE certified.

A Designs Audio - Reddi Tube Direct Box

[dsavitsk]

i believe steve mentioned this thread to craig and he asked i post this tidbit.

CE certification is a floor, not a ceiling. Just because something is approved by a certification body doesn't mean it is safe: http://en.wikipedia.org/wiki/Rofecoxib. And, the Reddi is not strapped to anyone head.

[909]

This is OK too, [snip] there are lots of current production floating balanced Commercial offerings out there, with safety approvals.

A floating balanced line terminated with a load is less likely to have primary to secondary short because there is no ground reference to punch through to. A transformer secondary grounded on one end but not loaded is the most likely to get a punch through because the voltage differential is the highest between primary and secondary. In addition if there was a short between primary and secondary on a floating secondary nothing would happen because there is no circuit to complete the short. In a grounded secondary the short can go through the load to ground blowing out the load. Seems to me a floating balanced line is best.

i am done being a conduit

[dsavitsk]

if there was a short between primary and secondary on a floating secondary nothing would happen because there is no circuit to complete the short.

i am done being a conduit

You might not be, as you could be the conduit to ground. The probabilities are certainly low of anything happening, but it just doesn't seem like a risk worth taking, particularly for no demonstrated benefit.

[Parafeed]

You might not be, as you could be the conduit to ground. .

LOL.

But seriously, I'm surprised. Insulation can fail over time. That's a fact, it does happen. I've seen it on older gear. While it is extremely unlikely and CE certification or not, my common sense dictates that especially in this instance, (primary with high B+ and secondary connected to an object that is fixed to your head), safety is the only consideration, no matter how small the percentage chance of something failing! Why take the risk? (Even if Craig has listened with and without the secondary grounded, and deemed not to ground it for SQ reasons, I would hope that he is at least giving customers of this "floating" design a warning, even if he considers the risk infinitesimal, and the option of grounding the secondary for safety reasons.)

[zippy2001]

[recstar24]

Nice score zippy! Beautiful amp.

Some info I gleaned from Craig for any interested parties.

"Equilibrato, and SE. Standard is $1760.00 including Sophia PX-4 tubes, and NOS 12SN7. Two input selector switch, unbalanced inputs, balanced, and unbalanced headphone jacks. Regulated power supply, regulated DC heaters. Very quiet amp.

The SE uses the BA dual vacuum tube power supply, and dual high frequency isolated heater amplifier. It has two balanced inputs, two unbalanced inputs. Two three pin balanced outputs, and 1/4" unbalanced outputs. That amp is $2800.00."

[zippy2001]

I met David (909) at Craig's house on Saturday to pick up my Equilibrato and all I can say is that I am extremely pleased with this amp. David was kind enough to bring over his L3000s, a really great sounding cartridge and phono preamp. We did quite a bit of listening to both CD and vinyl on Craigs Sony PSX70 turntable.

The Equilibrato with the PX4 sounds great, it is very musical. Listening to some vintage vinyl really made me want to setup my turntable and get my analog system setup again. I've been listening to music digitally through my Lavry DA11 quite a bit lately and although it is convenient and does sound great with the Equilibrato, I do miss the analog sound.

In regards to balanced versus unbalanced, I did listen to the AD2000 and RS1 balanced vs unbalanced, and there is a noticeable difference in soundstage and definition. The balanced setup definitely sounded better to my ears. Now to I need to get my headphones balanced.

The input switch on the front lights up when you turn on the amp, it glows a nice amber / orange color that almost matches the glow of the tubes. Very cool. It does not change color, just goes in and out to switch between the two single ended inputs. Nice, now I don't need a seperate preamp. I can use one input for digital and one for analog.

The Sophia Electric PX4 sounds great, it is a little bit microphonic, but nothing that I can hear in normal listening. I didn't compare it to any 300Bs, but am quite happy with my decision. Although I do want to listen to the much more expensive KR tubes, Craig says that they sound better overall and have better bass.

This amp is a huge leap forward in performance over my DM-2 prototype, it is better in everyway from detail, soundstage, etc.

[zippy2001]

Nice score zippy! Beautiful amp.

Some info I gleaned from Craig for any interested parties.

"Equilibrato, and SE. Standard is $1760.00 including Sophia PX-4 tubes, and NOS 12SN7. Two input selector switch, unbalanced inputs, balanced, and unbalanced headphone jacks. Regulated power supply, regulated DC heaters. Very quiet amp.

The SE uses the BA dual vacuum tube power supply, and dual high frequency isolated heater amplifier. It has two balanced inputs, two unbalanced inputs. Two three pin balanced outputs, and 1/4" unbalanced outputs. That amp is $2800.00."

Thanks, I am loving it

I would say that if I can get 90% of the BA sound at 50% the cost, its a bargain.

[909]

with respect to whether a floating balanced line offers any sonic improvements, here's my take, which i posted over on head-fi back in september of 07....

here's the entire post

Mini Meet at Eddie Current 9/15 - Page 2 - Head-Fi: Covering Headphones, Earphones and Portable Audio

here's the excerpt

[snip] So here's my impressions...

The biggest surprise had to be the audible differences going single-ended to balanced. I've never heard it make such a noticeable change in the sonic presentation both on speakers and headphones. In the past I've listened to the GS-X both single-ended and balanced on the HD-650 and preferred balanced, but never felt it was night and day. Even with the Dynamite going between single-ended and balance with the HD650s I thought I could easily live with the the Dynahi (single-ended version). I don't know if it is just the HD650s, those SS balanced amps, the source or combo of factors, but it seemed at the time not as drastic an improvement. Listening to the HD2, however, was a completely different story.

Reimyo --> HD2 (singled-ended to balanced) Cicadas*, K-1000s and L3000:

Cicadas (*exception Moth Audio DAC):

I listened to a Willie Nelson track showcasing primarily his voice and his acoustic guitar. As a guitar player I felt I could really appreciate this track. The biggest difference, going balance offered much better control and focus. The vocals and guitar had a superior level of transparency and imaging. Overall both were excellent, but balanced on the HD2 truly raised the bar to a level I could no long merely classify as slightly more than negligible. [snip]

now fast forward to january 09, 2010...

i've not seen craig or steve since canjam 09 -- it's been a long while since i hung out with these guys and it was great chewing the fat, which i did a heck of a lot more than listening.

the equilibrato

probably as most of you, i am taken by the look of this amp. i really like the industrial retro look and black on black color scheme. the chassis looks even more impressive in person.

my time with the equilibrato wasn't all that long and listening was what I'd deem critical, but given the vast majority of important components were my own, i can safely say this is one fine sounding headphone amplifier and considering the price, a huge bang for the buck. while listening to "in my room" by the beach boys, it made the hairs on my arm stand at attention, which is always a good sign because to me that means it's sounding close to the real thing or what i'd imagine it to sound like. a nice surprise was that this was the very first time i liked the w5000s after numerous auditions and i'd wholly attribute that to the way the equilibrato drove them.

i've spent a fair amount of time listening to the ZD, albeit a long, long time ago, and based on my audio memory, for what it's worth, the equilibrato doesn't really remind me of ZD. the only production BA i heard was at canjam 09 and the room was so freaking loud i couldn't gleam much of anything... however, i've heard a few BA prototypes and though, i didn't like it with the 45s or 300bs, i seriously wanted to buy one after i heard it with the 307As. the equilibrato seems to be more of a sonic cousin to the BA than the ZD, but the 307A BA (proto that i heard) i believe scaled higher than them both.

Edited January 12, 2010 by 909

[some1x]

It is a real shame this amp can't drive speakers too.

[n_maher]

It is a real shame this amp can't drive speakers too.

Your comment makes no sense to me. When an amp can, it's a bonus, when it can't I don't see any reason to feel awful about it.

[Smeggy]

congrats zippy, that thing looks sweet. Dunno how he always manages to make his stuff look so damn awesome.

It's a real shame it can't drive my car.

[Dusty Chalk]

Dunno how he always manages to make his stuff look so damn awesome.

A hint towards your answer lies here:

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.

...but it's a whole esthetic thing.

[some1x]

Your comment makes no sense to me. When an amp can, it's a bonus, when it can't I don't see any reason to feel awful about it.

Well, it uses tubes that are typically used for speaker amps. So, why not Is it too much to wish for a Si2A3 replacement?

[recstar24]

Is it too much to wish for a Si2A3 replacement?

Yes.

[tkam]

Well, it uses tubes that are typically used for speaker amps. So, why not Is it too much to wish for a Si2A3 replacement?

You could always just ask Craig....

[zippy2001]

congrats zippy, that thing looks sweet. Dunno how he always manages to make his stuff look so damn awesome.

It's a real shame it can't drive my car.

Thanks, I do love it. And the styling of his stuff is great, I love the use of the red lights on his BA and transcription amplifier.

[zippy2001]

Well, it uses tubes that are typically used for speaker amps. So, why not Is it too much to wish for a Si2A3 replacement?

The ZDT will drive speakers. This headphone amplifier was intended as a limited production amp for critical heaphone listening.