[YungOmbat]

Dear All,

I am very glad to announce the formation of the new brand of true-ribbon headphones, RAAL 1995.

The new brand stands on the shoulders of RAAL Advanced Loudspeakers, the brand that I have founded for manufacturing tweeters and RAAL-requisite, the brand that I have co-founded with Danny McKinney of Requisite Audio Engineering and Standel fame, for manufacturing of headphones.

RAAL 1995 will, at first, focus to headphones and later to loudspeakers, with aim to push the limits of True-Ribbon technology in different applications.

I'll start from the beginning, with an intro to the technology that we use:

Over the decades past, all kind of rectangular-diaphragm drivers were called ribbons, but that's not really what they were.
Most of the time, they were mass-produced planars in a long(ish) form factor. A really good True-Ribbons can not be mass produced and need ancillary components to work, but they carried the fame, so the need to rub-off on some of that fame by twisting the names was pronounced in audio marketing.

We follow the specifics of the tech, as I believe that this is the best loudspeaker technology that has ever existed.

Here's a short pictograph of what are the differences between True-Ribbons vs Planars (regardless of their form-factor):




So, no matter what you do to a planar, unless you make it long, narrow, place the magnets at the sides of it, clamp it only at top and bottom, regardless of it's resistance, or percentage of plastic foil area covered with conducting layer, it won't become a ribbon.
The exception are quasi-ribbons, like Apogee Acoustics used to make, that are ribbons, but using a plastic substrate foil to carry the conducting layer that is etched to form many traces connected in series, for increasing the resistance.

A True-Ribbon is only pure metal foil, with no plastic substrate, hanging in magnetic field. They are exactly what is used in ribbon microphones, only reinforced to work as speakers, but the purity of it's acoustical vicinity (the stuff placed around the sound-radiating element) remains.
This is what I was developing for the past 29 years and together with Danny McKinney, 5 years ago, introduced the True-Ribbons as a new headphone technology.

After showing the technology, more about the new headphones later...

any hints of the release date?

 

[Aleksandar R.]

Unfortunate to hear there will be only one impedance per interface. Having 16Ohm and 32Ohm is really useful on my TI-1b interface since my speaker amp has 16Ohm taps and my headphone amp likes the 32Ohm option.

I suppose if I order, I should get the 8Ohm interface and keep my old TI-1b for use with my headphone amp or just not get any interface and continue using my TI-1b.

For DIY purposes would you be willing to share the specs of the transformers such as their winding ratios? I suppose I could also just tear open my TI-1b and look myself. I built a transformer box out of jumbo Lundahl transformers for my STAX headphones and would be interested in doing this for the Immanis as well potentially.


I'll likely be bringing my CA-1a to CanJam NYC if anyone wants to try it.


And I will be there listening to them! (multiple times)

You won't have any problems with your 40W amp at 16 ohms if you use it with 32 Ohm Interface, as you develop "only" 20W, with lower distortion...

The problem with tube amps appears when you go lower with the load impedance than what their output transformers are made for, never if you go higher (within reason, like up to 4x that).

Transformer ratio is very easy to determine:

Come in at primary with say, 1V at 1k and measure the voltage at the secondary, that's the windings ratio.
Impedance is converted by the square of that ratio.
If you know the resistance of cable+headphones (~0.3 Ohms) you need to multiply that by ~110 to get to 33 Ohms, so square root of 110 is the needed ratio.
And you can calculate any needed ratio like that, easy-peasy, basic stuff.

Anyhow, if knowing just the ratio would be a secret to a high performance transformer, any audio transformer maker would be out of their job, but like anyone else, I won't share the "tricks of the trade".

 

[gammi]

You won't have any problems with your 40W amp at 16 ohms if you use it with 32 Ohm Interface, as you develop "only" 20W, with lower distortion...

The problem with tube amps appears when you go lower with the load impedance than what their output transformers are made for, never if you go higher (within reason, like up to 4x that).

Transformer ratio is very easy to determine:

Come in at primary with say, 1V at 1k and measure the voltage at the secondary, that's the windings ratio.
Impedance is converted by the square of that ratio.
If you know the resistance of cable+headphones (~0.3 Ohms) you need to multiply that by ~110 to get to 33 Ohms, so square root of 110 is the needed ratio.
And you can calculate any needed ratio like that, easy-peasy, basic stuff.

Anyhow, if knowing just the ratio would be a secret to a high performance transformer, any audio transformer maker would be out of their job, but like anyone else, I won't share the "tricks of the trade".

Yup, didn't expect you to give me any tricks of the trade, just wanted to know the winding ratio (which can be measured anyway and isn't a secret). I already know the Lundahl transformers are flat out to 20kHz and very high performance, no need to figure out any secret performance tricks, I'll just buy one of those off the shelf if I build my own interface.

Thanks for the transformer calculation.

 

[Aleksandar R.]

Yup, didn't expect you to give me any tricks of the trade, just wanted to know the winding ratio (which can be measured anyway and isn't a secret). I already know the Lundahl transformers are flat out to 20kHz and very high performance, no need to figure out any secret performance tricks, I'll just buy one of those off the shelf if I build my own interface.

Thanks for the transformer calculation.

Just be careful with total resistance of the secondary circuit.
That is winding resistance+cable+headphones.
It is quite usual that tube OTP's have 0.3 ohms resistance in the secondary curcuit.
In that case, you need a ratio for 0.6 Ohms, and be fine with 6dB of losses on that alone.
More importantly, if the parasitic inductance of the secondary is greater than 2 microHenry, for a 0.6 Ohms of total circuit resistance (and they are much greater in OTPs), you will start to audibly roll-off the highs.
Basically, any transformer is designed with what will be the actual load value in mind, and their specs apply to that situation only.
20k is OK if you terminate the OTP transformer with 8 Ohms, but invalid for other loads.

In other words, that idea is not going to work, unless you ask them to do a custom job.

 

[gammi]

Thanks for the extra info. I've been using Lundahl 1630-PP transformers for my STAX headphones and those have worked well, I need to check the spec sheet again to see if they meet the ribbon requirements. Windings are 14:1 so that's within acceptable range (a bit higher than ideal), as for the parasitic inductance I don't think I've seen that listed but I have seen them measured to 20kHz and there's no roll off.

This is all a big maybe anyway. Most likely will keep using the TI-1b, just thought I already have these $500 ultra high quality audio transformers that I'm using for my STAX, would be nice if I can add a second ribbon circuit to them to switch between and use that for 8Ohm amps and the TI-1b for 16-32Ohm

 

[Aleksandar R.]

Thanks for the extra info. I've been using Lundahl 1630-PP transformers for my STAX headphones and those have worked well, I need to check the spec sheet again to see if they meet the ribbon requirements. Windings are 14:1 so that's within acceptable range (a bit higher than ideal), as for the parasitic inductance I don't think I've seen that listed but I have seen them measured to 20kHz and there's no roll off.

This is all a big maybe anyway. Most likely will keep using the TI-1b, just thought I already have these $500 ultra high quality audio transformers that I'm using for my STAX, would be nice if I can add a second ribbon circuit to them to switch between and use that for 8Ohm amps and the TI-1b for 16-32Ohm

Yeah, totally different usage scenario, like basically no current flows there, and load resistance is like an open circuit, so inductance won't matter...dealing with voltage...

You can certainly try it in a ribbon circuit, why not!
Nothing bad will happen and you'll have a nice experiment to do, lots of fun!
It'll definitely work, the problem is how, so you will have some first-hand experience, and that is always rewarding.

 

[adornoWest]

According to 6moons: "With Jotunheim R and VM-1a no more, it in fact seems that for direct-drive options only the solid-state SAEQ HSA-1c remains which Alex feels isn't yet refined enough for his 1995 lot."

Would be interesting to hear more from Alex about which amplifiers he recommends.

 

[jlbrach]

I have to imagine the SAEQ HSA-1c is far more refined than the Jot R

 

[Aleksandar R.]

According to 6moons: "With Jotunheim R and VM-1a no more, it in fact seems that for direct-drive options only the solid-state SAEQ HSA-1c remains which Alex feels isn't yet refined enough for his 1995 lot."

Would be interesting to hear more from Alex about which amplifiers he recommends.

There is an update to this, but I'll start from the beginning.

I did the voicing of the headphones on several amps:

SAEQ Hyperion Ge (at 32 Ohms),
Firstwatt J2 (at 32 Ohms) and
VM-1a in Triode Mode,
representing a group with very similar "organic" sound, where J2 is a bit "bigger" sounding that the other two (which are very, very similar, almost identical sounding amps).

Then,
RAAL-requisite HSA-1b, VM-1a in Pentode Mode and Benchmark AHB2 (at 32 Ohms), serving as a "control" amp.

And recently, Solaja dropped by with 300B² prototype (used with 32 Ohms Interface), which was very interesting and Dragan from SAEQ with his new uber-amp prototype
which (used with 32 Ohms Interface) sounded really accurate, smooth yet lively...I liked both a lot.
Dragan from SAEQ also brought the SAEQ HSA-1c that was not strictly developed to sound best only on ribbon headphones, like RAAL-requisite HSA-1b, but to inject more life into planars, for more versatility, and I listened to it on XLR inputs and it was a bit too open for me, like Benchmark, which is not my favorite amp any more.

I wanted to explore more about this C version, so I tried it on RCA inputs and things settled down nicely. Plugged in a smoother sounding cable and that was it.
Then, I've had a panel of 4 listeners, my control group of local audiophiles, speaker listening guys, to see what they say about Hyperion Ge vs. HSA-1c.
The listening was at pretty high SPL.
The result was 50/50. Half preferred SAEQ HSA-1c and half preferred Hyperion Ge. My vote didn't count, but I'm in Hyperion Ge camp.

So, it was just like what you could expect.
I'll explain...
Amps can have even-order, 2nd harmonic-dominant or odd order, 3rd harmonic-dominant distortion characteristics.
It is known that people's preference in distortion characteristics of amplifiers are about 50/50 in preference to even/odd distribution of generated harmonics.
The HSA-1c is not a typical representative of odd order group, it has a good amount of 2nd, but it is close enough to be sorted in that group and Hyperion Ge is typical representative of even order 2nd harmonic-dominant distortion content with almost logarithmic envelope of all other harmonics up to 5th and practically no higher harmonics than that.

Now, if you listen to headphones softly, you will likely not hear much of a difference.
It takes speakers to really load beefy amps like these, but at power levels for headphones, especially with people that listen softly, it is more likely that you will rather hear the general tone balance of the amps, more influenced by the choice of caps and wiring type and wire layout inside...

So, to show that I'm serious, we will do the WOH Heidelberg with SAEQ HSA-1c, properly driven at RCA input with the right cable for the job.
There will also be other amps to test, of course, it's a show...

 

[Aleksandar R.]

As for amplifier recommendations for Magna and Immanis, it is not a clear cut like with SR1.

These do not require a big, warm sounding amp to complement their tone balance, so now the choices are far greater.
It's more about personal preferences, what camp you're in, not about what the headphones may need.

 

[ThanatosVI]

As for amplifier recommendations for Magna and Immanis, it is not a clear cut like with SR1.

These do not require a big, warm sounding amp to complement their tone balance, so now the choices are far greater.
It's more about personal preferences, what camp you're in, not about what the headphones may need.

Did you ever have the chance to try your new creations on a Feliks Envy eith 32 Ohm Interface?

 

[Aleksandar R.]

Did you ever have the chance to try your new creations on a Feliks Envy eith 32 Ohm Interface?

We tried it in '22 with CA's and it was not compatible at that time.
Changing the setting didn't help. I will revisit that in Heidelberg.

 

[ThanatosVI]

We tried it in '22 with CA's and it was not compatible at that time.
Changing the setting didn't help. I will revisit that in Heidelberg.

In what way not compatible?

 

[Aleksandar R.]

In what way not compatible?

Heavy distortion at any level. Guys from Felix were there and we couldn't find the setting that was OK, but it was nor the time or the place to dwell deeper into it, so we just gave up, to be revisited at a later date.

 

[ThanatosVI]

Heavy distortion at any level. Guys from Felix were there and we couldn't find the setting that was OK, but it was nor the time or the place to dwell deeper into it, so we just gave up, to be revisited at a later date.

I see, hopefully this can be fixed. Since the Envy is the amp I'm using.