[Uncle Erik]

Donald North is right - I still need to learn more. I also think he's near me in LA; I need to find some time to get him lunch some time and find out about these finer points. He also designed a very interesting amp I'd love to hear.

About the Moth Si2A3, it has output transformers and does well with Grados if you change the taps. They're not easy to come by, unfortunately. I haven't heard the ZDT or Balancing Act, but expect both to be at CanJam. They're high on my list to hear.

 

[Donald North]

Quote:

Originally Posted by Uncle Erik /img/forum/go_quote.gif Donald North is right - I still need to learn more. I also think he's near me in LA; I need to find some time to get him lunch some time and find out about these finer points. He also designed a very interesting amp I'd love to hear. About the Moth Si2A3, it has output transformers and does well with Grados if you change the taps. They're not easy to come by, unfortunately. I haven't heard the ZDT or Balancing Act, but expect both to be at CanJam. They're high on my list to hear.

Hi Erik, sure I'd enjoy meeting up on a weekend. Always fun talking music and hi-fi with fellow enthusiasts.

 

[moonboy403]

Any picture of the DNA Sonett vacuum tube headphone amplifier? Pricing?

 

[Donald North]

Quote:

Originally Posted by moonboy403 /img/forum/go_quote.gif Any picture of the DNA Sonett vacuum tube headphone amplifier? Pricing?

The only photo I have is of the prototype. The production units will be the same blue and with a nice machined aluminum faceplate. They're literally being laser cut, powder coated, and machined as we speak

I hope to have a photo of the final unit next week.

There will be 2 versions available:
Traditional single ended output with 1/4" stereo jack
Balanced output with dual XLR jacks

They will look identical except having different faceplates and output connectors.

Pricing for both versions is $1200. I will be offering a show special of $1000 to everyone who places an order at Can Jam.

 

[Covenant]

Quote:

Originally Posted by Donald North /img/forum/go_quote.gif I am suggesting the headphone should be powered by an amplifier with output impedance which the headphone's designer intended and used to tune them.

I see, thank you for your insights into the matter. The only issue is, how often do headphone designers or manufacturers specify the output impedance their phones are designed for?

I don't think I've ever seen that mentioned on the technical specs of a headphone. Without that knowledge, is there any way we can gauge how to amp-match any given set of headphones from a technical standpoint?

 

[Tridacnid]

Quote:

Originally Posted by Covenant /img/forum/go_quote.gif I know in the case of the WA6/SE there are impedance switches and whatnot, but wouldnt it make more sense to use the topology designed to match your headphones?

This is just a guess, but the switch may let you chose to use either the primary side of the output transformers or the secondary side of the output transformers.

The primary side would be better paired with a high Z headphone because it would essentially be an OTL design with more resistance in series due to the natural resistance of the transformer. This may in fact be a better thing to do than OTL, since it would appear to the tube that a much higher load is on the output side (headphone impedance + the transformer impedance), more properly matching the output impedance of the tube to the impedance of the load.

The secondary side would be better for Low Z phones because the transformer makes the low impedance of the headphones "appear" as a much higher load to the tube.

Someone tell me if this is heresy.

 

[Donald North]

Quote:

Originally Posted by Covenant /img/forum/go_quote.gif I see, thank you for your insights into the matter. The only issue is, how often do headphone designers or manufacturers specify the output impedance their phones are designed for? I don't think I've ever seen that mentioned on the technical specs of a headphone. Without that knowledge, is there any way we can gauge how to amp-match any given set of headphones from a technical standpoint?

Good question! When I have searched the various headphone manufacturer websites, I find little information. On beyerdynamic's website I do see their headphone amplifier has an output impedance of 100 ohm.

Here's the rule of thumb I use: If the headphone has impedance greater than 100 ohms, it might be tuned around the IEC spec. If the impedance is less than 100 ohms, it might be tuned and intended for low impedance drive. Again this is a just rule of thumb, and ideally you should listen both ways and select what sounds best to you.

 

[limpidglitch]

Is it sensible to assume that Beyers with 80/250/600 ohm impedance all is designed for the same output impedance (viz. IEC)?

 

[Covenant]

Completely OT, but I love your signature, limpidglitch

 

[Happy Camper]

Quote:

Originally Posted by Skylab /img/forum/go_quote.gif Great posts, Donald North and Uncle Erik. I am saving and compiling some of this information so that when it gets asked again in a few months

This should be put in Boomana's starter sticky.

I think Unc was alluding to the ZD using low impedance output tubes vs other designs, not that the ZD is the only OTL capable of driving Grados. My Extreme is an OTL and drives the RS-1s on my head very well and heating is not an issue.

 

[limpidglitch]

Quote:

Originally Posted by Covenant /img/forum/go_quote.gif Completely OT, but I love your signature, limpidglitch

You're no strag, I see.

 

[Donald North]

Quote:

Originally Posted by moonboy403 /img/forum/go_quote.gif Any picture of the DNA Sonett vacuum tube headphone amplifier? Pricing?

Here are photos of the first production units which will be on display at Can Jam

 

[Frihed89]

What? No silver C Core output transformer?

 

[Frihed89]

Quote:

Originally Posted by Frihed89 /img/forum/go_quote.gif What? No silver C Core output transformer?

That must be the Signature version!

On another front: what is between the tube and the output transformer? (I wish I had xray vision).

 

[Donald North]

Quote:

Originally Posted by Frihed89 /img/forum/go_quote.gif That must be the Signature version! On another front: what is between the tube and the output transformer? (I wish I had xray vision).

Yes, custom signature versions can be made all the way up to Audio Note double C core output transformers with nickel cores and silver windings

I don't fully understand your question. The 6H30 tube is directly connected to and loaded by the output transformer, same as you do in SET power amps.