The Ergo AMT Review. (56k, Dont Even Try)

[Duggeh]

So that would in fact be a L/R split biamp setup (doubling the wattage per channel) with an interim phase inverter between the amp output and the transformer input?

The next question, naturally, is "Where does one look for such device?" but thatd be getting ahead of myself.

The easier option would be to reterminate the cord with XLR connector as employed with normal dynamic headphones, but then I'd have to use something else to EQ the driver elsewhere in the equipement chain. This is something I'd definately like to avoid.

Your suggestion for the T-amp makes sense, trouble is they are a lot more expensive to get ahold of in the UK than elsewhere and for a bit more I could get a new integrated Denon. Or stagger buy, one amp to run the AMT as is, then a second one later to try the balanced arrangement...

[wualta]

Originally Posted by Duggeh

Do you see any advantage to running the AMT balanced wualta?

Let's just say that I am yet to be convinced. So many things to do before that.

[Carl]

Oh by the way, has anyone tried the TakeT piezoelectric heil drivers?

http://www.taket.jp/about2/about2.html

[Duggeh]

1500 bucks is a lot of money for something that looks like that. The principle seems interesting though. If im reading the article with its mish mash english correctly, its a heil driver made from a peizo element.

Suitable for dogs cats and bats everywhere then.

[setmenu]

Originally Posted by Duggeh

As for you EQ in the amp suggestion. I believe the AMP2 is a full class A with a meticulously designed EQ curve. The Amp1 imho could use a lift of a few db at around 40hz to give the sound a bti more meat. This might be accomplished with a beefier power supply, but given the amps topology I doubt it..

Hi Duggeh
Great review,nice to see the 'guts' of the amp and phones.
Regarding bass, it would be interesting to see whether the amps output is
filtered or the transducers themselves limit the bass.[I could not see
evidence of additional filtering at the traducer end of things]
My experience with my own Planar magnetic transducers [ribbon type]
was that they were capable of very powerful raw low end output.
This resulted it quite a large excursion of the ribbons.
I reduced output to achieve less excursion and a better balanced sound.
The Heil design design looks like it would become very mechanically noisy if
the pleats moved to far when doing bass duties.
Besides the loss in sound quality excessive movement may well create a
higher risk of metal fatigue in the conductors at the relatively sharp bends in
the pleats.
So it could be wise to exercise caution if you do decide to go the 'bass
boost' route, they may sound a better but at the risk of early failure.
I am only guessing here, so it might be worth asking the manufactures for
their views as to the potential risk.


.

[Duggeh]

Wise words setmenu, thank you. Im not cranking the bass dial all the way to 11 though, just sloping it slightly. And I dont ever use the AMT for listening to drum and bass type music. Turning the bass up a little gives a better effect to listening than reducing the treble does. Although my NAD only has 1 dial for each and is not a proper graphic eq.

I will probably shoot an email off to the Precide though, just to get their own feedback on eq. I think ill ask them about possible sonic improvments to the Amp1 when its used with a beefier power supply. At the minute its on 16V 500ma, but the rear panel says it will take 18V.

As for the EQ of the equipment itself, its definately the Amp and transformer that have the EQ applied to them to correct for the headphones. Althoguh which part of the Amp1 performs this function I've no idea. In the transformer im lead to believe its to do with the coils (oe of which had disconnected).

[setmenu]

The phones are around 4 Ohm impedance if I recollect?
Sounds like a nice candidate for diy amp project!
You could then build in your eq specifically aimed at the frequencies of interest.

.

[Duggeh]

Building my own amp doesnt really interest me. Ill stick with the home made headphones for now.

[wualta]

Originally Posted by Carl

Oh by the way, has anyone tried the TakeT piezoelectric heil drivers?

Way to volunteer, soldier. Pick up a set at your neighbourhood TakeT agent's and report back.

Oh darn, they're talking about a Hyle driver. Never mind.

I don't know how or why you found that, Carl, but it reminded me of something I'd completely forgotten. Way back in the late '70s I ordered a developer's kit of PVDF film from Pennwalt (who were then manufacturing PVDF film. No relation) to make that very thing, a self-powered Heil. Imagine an AMT with no honking big magnet structure to get in the way. Unfortunately, the kit went missing during a move. I'm glad someone's finally taken up the idea and is running with it. There's still the capacitive nature of a piezo driver to deal with, but it's an encouraging development.

They make a speaker AMT too. Nifty! They call that one the TAKET-BATPRO.

The headphones are a little pricey at $2300 for the 'phones and transformer box. Still..

[Carl]

Originally Posted by wualta

Way to volunteer, soldier. Pick up a set at your neighbourhood TakeT agent's and report back.

Oh no, I wouldn't want to deprive our neighbourhood isodynamic and AMT fan the chance to be first. That would be too cruel and ill-meaning ever for myself!

Well, maybe in a year or two when I actually have some money.