[Aleksandar R.]

When are you guys gonna have more info on the small tube amp for planars/dynamics? Like price and such.

Hello Pete,

The retail price will be $1900.

The interest for it is greater than we expected, so right now we're increasing the batch we want to assemble. It will be at the shops by the end of October if everything goes well with our vendors for parts, transformers, chassis...

The specs are:
Tubes: input and driver triodes 6N6P, DC coupled to power output triode: 6AS7, no overall feedback, capacitor coupled output (0V DC offset or drift).
Linear power supply, oversized.
Power voltage: 115-230Vac, easy rewiring for 100V (Japan)
Headphones impedance: 32-600 Ohms
Input connectors: RCA
Input impedance: 220k
Output connectors: 4-pin XLR in parallel to 1/4" TRS.
Frequency response: 10Hz-100kHz (-3dB)
S/N: >80dB
Output power (<1% THD) : 50 Ohms - 245mW
600 Ohms - 180mW
It's a well proven design by Solaja Audio, the sound that we really wanted, then it was pushed up a notch or two

 

[Aleksandar R.]

Have you had any success experimenting with angling the drivers during the SR2a enclosure design phase?

The soundstage and imagining could be TOTL in the right configuration.

Angled them for 15°, pretty much like I wear the SR1a's and moved them forward, so they shoot from the front towards the ears.

 

[FLTWS]

How about the specs on VM-1a?
I'm also curious about how the auto-bias is accomplished (as I see no pots for manual adjustment).

 

[Aleksandar R.]

I know that, though they look similar to see, the tech behind Ribbon is really different from AMT, but I remember that HEDD explained US they had to use huge pads to separate the driver from the ear canal by a lot.
Actually, HEDD managed in a rather reasonable price to offer probably the most convincing bass impacts of the market without any loudness effect. HEDDphones are ugly too ... but they work rather fine, though they are many issues.

As HEDDphone are using lot of plastics, they are rather fragile for an everyday use (plastics are getting old very soon, in less than 18months in my case), I hope RAAL will manage to solve 3 major issues :
-> more durability with less plastics than HEDD
-> less bulky than HEDD
-> make the SR1A tech transportable in our home or even outside at office. They should build an adapted portable Amp, like it exists with Electrostatics Headphones (Stax SRM-D10 or Kingsound M03) or Less Bx2+ for AMT tech.
That would be a nice target.

Bass impact without loudness effect is a very commendable feat! Kudos to HEDD! I really mean that.

Well, we'll be using very thick 2.5 to 3mm (depending on the part) of fiberglass reinforced ABS and the cup is wrapped in leather. the goal was to make a very solid piece that doesn't vibrate or ring and deaden it up some more with leather wrapping.

Working now on the "fork" mount for the cups, much less bulky than the show prototypes, will be less bulky than HEDD.

We certainly have the adapted portable amp, the Jotunheim R, which works for both SR1a (open baffle EQ on, or for SR2a -EQ off) and developed two cables that do not provoke the JotR into ringing or weird distortion, keeping it at it's preferred 0.4 Ohms load with minimal possible parasitic inductance of the cable, transforming the combo into a very, very respectable sound...

...All the while we're working on a impedance matching transformer interface that should (in theory) allow our ribbon headphones to be driven with any amp that is capable of making 6W at 32 ohms. I say "in theory", because such an anp, while having the required specs, may not be thermally capable of sustaing that power for more than a few minutes. If proper heatsinking is built in, then there will be no problem.
The actual testing of thermal capability of a very popular amp is scheduled in 10 days.

 

[Aleksandar R.]

Please make them easily swapable and offer several options.
From dolphin to blue whale

Thank you for your input - will do!

 

[Aleksandar R.]

Hi Aleksander
Maybe a little early but do you have idea on when the VM-1a will be in the shops and an indication on prices? Less then the HSA-1b, more then HSA-1b or much more then HSA-1a.

Hi RickyV,

Hopefully, by mid-November we'll have dealers covered. Until then, 3 units will be available though our direct sales in about 3 weeks.
the price will be >/=$5500.

 

[PeteSTRADAMUS]

Hello Pete,

The retail price will be $1900.

The interest for it is greater than we expected, so right now we're increasing the batch we want to assemble. It will be at the shops by the end of October if everything goes well with our vendors for parts, transformers, chassis...

The specs are:
Tubes: input and driver triodes 6N6P, DC coupled to power output triode: 6AS7, no overall feedback, capacitor coupled output (0V DC offset or drift).
Linear power supply, oversized.
Power voltage: 115-230Vac, easy rewiring for 100V (Japan)
Headphones impedance: 32-600 Ohms
Input connectors: RCA
Input impedance: 220k
Output connectors: 4-pin XLR in parallel to 1/4" TRS.
Frequency response: 10Hz-100kHz (-3dB)
S/N: >80dB
Output power (<1% THD) : 50 Ohms - 245mW
600 Ohms - 180mW
It's a well proven design by Solaja Audio, the sound that we really wanted, then it was pushed up a notch or two

Thanks for the info.

 

[Aleksandar R.]

How about the specs on VM-1a?
I'm also curious about how the auto-bias is accomplished (as I see no pots for manual adjustment).

No manual adjustment, all auto. Has to be like that, as toroidal output transformers are very easy to saturate with bias unsymmetry. The transformers are designed by Menno van der Veen and we have strictly followed the recommendation about autobias.

I can say about Vandeveen transformers is that they have the least sound of "iron" I've ever experienced! Also, the response at the end of the bandwidth (~32kHz) is a very nice and wide low-Q knee, without any traces of ringing. A very remarkable achievement for a 100 :1 transformer (10000x impedance conversion) for both bandwidth and lack of parasitic reactive components. It's bonkers and it sounds like an OTL with ba..s!
As the loading of the transformers is basically the cable resistance of 0.4 Ohms, we've made sure that cable parasitic Inductance is kept to a minimum, the same requirement as for the JotR. Not recommended to use with any other cables, as the cable is the actual load (ribbon is only 0.018 ohms) and you don't want unknown inductance to be multiplied 10000x and load the anodes as voltage-spiking reactance.

The amp is Class AB (70% of possible swing is class A) Push-Pull with a pair of EL34's, driven with high current/voltage swing capability of another EL34 that doubles as a phase splitter.
The input tube is 6SL7 triode, loaded with a CCS.
No overall feedback.
Output power at 0.4 Ohms is 21 Watts, about 3dB higher than what SR1a and SR2a can use cleanly, so basically, it all works in Class A, until you overload the headphones.
Input is only XLR with awesome Cinemag transformers, for audio ground isolation from source gnd and best possible CMRR.

Initially, we've had the speaker output, BUT...the sound of the feedbackless amp was so enchanting on SR1a that we ditched the speaker output as that can't work without feedback.
So, audio purity at it's finest all the way!
The one that got broken in shipping to the show was my piece and I'm still weeping over it's sudden death! However, it's martyrdom made me redesign the transformers mounting and it will be rock solid, worthy of MIL-spec hardware. Also, packaging is getting redesigned so it will arrive safely to any point on the planet, with all modes of transport.

We're really rushing to get the VM-1a into sales, and we'll do everything humanly possible to shorten that amount of time!

Again, circuitry is designed by Solaja Audio, with parts choice input by Danny and me and the sound is brought to the very summit through several iterations. And I'm so glad we all did it!

 

[FLTWS]

Thanks, interesting info, looking forward to this amp.
Heard from David today, they shipped out my "Deluxe Ribbon" and "Premium Ribbon" cables today so I'll have all 4 to play with when the amp is available.

Ah, I see re-reading the above, looks like the VM-1a will come with the "Deluxe". Well, I can still use this one coming with my JOT R and see what I like best with my HSA-1b.

Your post above also answers my question about that 3rd power tube.

 

[paradoxper]

Bass impact without loudness effect is a very commendable feat! Kudos to HEDD! I really mean that.

Well, we'll be using very thick 2.5 to 3mm (depending on the part) of fiberglass reinforced ABS and the cup is wrapped in leather. the goal was to make a very solid piece that doesn't vibrate or ring and deaden it up some more with leather wrapping.

Working now on the "fork" mount for the cups, much less bulky than the show prototypes, will be less bulky than HEDD.

We certainly have the adapted portable amp, the Jotunheim R, which works for both SR1a (open baffle EQ on, or for SR2a -EQ off) and developed two cables that do not provoke the JotR into ringing or weird distortion, keeping it at it's preferred 0.4 Ohms load with minimal possible parasitic inductance of the cable, transforming the combo into a very, very respectable sound...

...All the while we're working on a impedance matching transformer interface that should (in theory) allow our ribbon headphones to be driven with any amp that is capable of making 6W at 32 ohms. I say "in theory", because such an anp, while having the required specs, may not be thermally capable of sustaing that power for more than a few minutes. If proper heatsinking is built in, then there will be no problem.
The actual testing of thermal capability of a very popular amp is scheduled in 10 days.

Let me prototype, my CFA3 headamp will throw 16W into 50 ohm which no other headamps come close to. Of course a Kevin Gilmore design.
It also drives the SR1a.

 

[Aleksandar R.]

And I didn't explain the very important thing about VM-1a...
VM stands for Variable Mode, meaning that after you turn it off, you can change the output tubes operational mode from Ultra-Linear ( local feedback between output tubes and transformer), to Triode, to Pentode.
Now that is something I can't live without now! I get the politeness and accuracy of UL, lushness of T or slam and attack of P...all in just one amp!

You know, we design things that we will be happy to use ourselves and we definitely understand what it's like to have to make a choice about the type of tube amp you want to buy for a hefty amount of money. The trouble is that whatever choice you make, you'll be wrong in certain areas of sound, so this way, you'll always get it right, regarding your taste or what the musical choice requires.
Tubes are incredibly rewarding as an audio experience, but the circuit topology choice will limit the performance for some music and enhance it for some other and you can't have it all, but this way you can and I love that! It's the first time I really started to want a tube amp after many, many years as an audiophile.

 

[Aleksandar R.]

Thanks, interesting info, looking forward to this amp.
Heard from David today, they shipped out my "Deluxe Ribbon" and "Premium Ribbon" cables today so I'll have all 4 to play with when the amp is available.

Ah, I see re-reading the above, looks like the VM-1a will come with the "Deluxe". Well, I can still use this one coming with my JOT R and see what I like best with my HSA-1b.

Your post above also answers my question about that 3rd power tube.

Correct, the amp will come with a "Deluxe" cable. That one and Star67 are the options for VM-1a.

 

[normie610]

The input tube is 6SL7 triode

Just slap in Tung Sol 6SU7GTY or RCA 5691 red base, I bet it’s gonna sound even more amazing

 

[Aleksandar R.]

Let me prototype, my CFA3 headamp will throw 16W into 50 ohm which no other headamps come close to. Of course a Kevin Gilmore design.
It also drives the SR1a.

I gladly will, BUT...the SR1a that you own (thank you!) need the open baffle EQ.
There was no plan to provide the built-in passive EQ inside the transformer interface box, as that would introduce a drop of 4.5dB of SPL and there's not enough power available (except with your amp) to have this drop and still have a rewarding SPL.
The idea is to offer the transformer interface only without EQ circuit, basically limit it's usability to SR2a only, as there will be no penalty in SPL with 5-6W/32 Ohms amps.

However, you could use a passive line-level EQ circuit at your RCA input. Can be made as a female-male RCA adapter that you plug into your amp's input and then plug you RCA interconnecting cable in it.

if that would be a product thatpeople might be interested in, I'm willing to work on it.

 

[Aleksandar R.]

Just slap in Tung Sol 6SU7GTY or RCA 5691 red base, I bet it’s gonna sound even more amazing

Oh, we did try the NOS RCA 6SL7 and its great! I have noted your suggestion, thank you!
Tube rolling is definitely a good thing about tube amps!