Orthodynamic Headphones & all things planar

[gurubhai]

^ya, that kind of thing happens to lot of us :lol:

 

[anm]

I was not able to extend listening session last night, as my kid woke up and started crying. I hope I will do some better comparisons today.
For now I feel yamaha >~ tp > hd 650 in musicality. Bass on TPs was initially less, but with some increase in volume, it caught up, coming close to yamaha.

 

[gurubhai]

@anant : Do you even sleep at all or are you an early bird?

 

[anm]

late night is the only time you can have to yourself. That is the reason I am focusing more on headphone system than on speakers.

 

[gurubhai]

Rotel RH-930 back-electret headphones

I haven't posted in a while since I have been a bit busy.
Today I present a rather unique & rare planar headphone : Rotel RH-930 back-electret headphones.
This is an OEM version of Toshiba HR-910.

The transformer is built into the TRS plug & so it can be used with usual dynamic amplifiers.

Some of you would know that the Electrets are cheaper versions of electrostatic headphones.Most electrets are considered infereior to the 'electrostats' but back-electrets are a bit different. Check this wikiphonia link for electret driver principle:

From an engineering standpoint, the ideal diaphragm material is a polyester called boPET, biaxially-oriented polyethylene terephthalate film, aka Mylar or Hostaphan or Melinex. Problem is, boPET doesn't make a very good electret. So an engineer must either accept a compromise in the sound, or he can re-engineer the typical electrostatic headphone layout by metallizing a boPET diaphragm and applying the audio signal to it and relegating the electret material to the stators where its inferior mechanical properties won't matter. This inside-out or back-electret design was used by only two manufacturers: Toshiba (most notably the HR 910; Rotel also marketed an OEM model) and Audio-Technica (the ATH-8, aka the Signet TK33).

About the Sound :
The first thing that struck me was how smooth they were in mids & treble. I can't seem to pick any major peak/dip in there frequency response.I can play them as loud as I can from my amp & they don't get shouty.
The Treble is very extended & without a hint of that plasticky sound that seems to bug most dynamic cans.
In the stock form they have significant bass roll-off starting from 175 Hz & lower meaning that one would miss the mid-bass & that the male vocals sounded a bit thin.
I improved the backwave seal of the cans & that has cured the vocals. The bass still rolls off but most of it is now in sub-bass region & doesn't hurt the the timbre of most instruments.
All in all, a welcome addition to the planar family at my home.

 

[grubyhalo]

Looks very classy, I'm sure it sounds that way too!

 

[gurubhai]

I usually say that my headphones sound much better than they look. In this case, they look good too.

 

[Brendon]

Wow ! That looks like a really classy set of cans. So in the interim which cans did you get rid off ?

 

[iaudio]

Interesting! How did you come across these, gurubhai?

 

[gurubhai]

Wow ! That looks like a really classy set of cans. So in the interim which cans did you get rid off ?

Look in the 'Classifieds' Section.

Interesting! How did you come across these, gurubhai?

Months of search across the globe !

 

[gurubhai]

Just a heads up for folks her.
I shall be putting couple of my headphones on sale in the next few days.
1)Yamaha HP50S (ortho)
2)Rotel RH-930 ( Back-electret)
Those interested, kindly PM me.

 

[anm]

interested in the nads

 

[gurubhai]

^ 25k & then maybe I can think about it.

 

[anm]

don't get too greedy Maybe you can lend it for a few days in that case. The amp now sits on my office desk paired with hp50s and streamer II dac. I can now find some time to listen to it.
Any progress on dac build?

 

[gurubhai]

Even that price doesn't dissuade you from trying.

You are welcome to drop by & listen to NAD as much as you want but It isn't going to leave my place for even a day. Sorry !

About the DAC : the newly released Buffalo III has added alot more to the cost of building.
It would cost atleast $600, which is beyoound my current budget.

 

[anm]

can we live happily with older buffalo?

 

[gurubhai]

Yes but buffalo II is not available anymore.

 

[anm]

aiwa hp 500 is here !

 

[gurubhai]

Great News, Ananth !
Didn't see the post earlier because there is something wrong with thread subscription link.

Pics & impression please.

 

[anm]

impressions are great. Lots of details, midrange is great. don't find any shortcoming in limited listening till now. And they are much more efficient than yamahas. I hope to listen more to it in next few days.

The amp we have is VERY good too