[triod750]

Civilized people have their music either on cd or vinyl or both!

 

[Paladin79]

Civilized people have their music either on cd or vinyl or both!

I have both as well as at least 55,000 HD albums stored on hard drives. My classical music collection was lacking so I enhanced it.

 

[L0rdGwyn]

These comments have me really wondering whether an Atrium might not be a better choice next year than a Caldera????

Atrium is a very good pairing with Airmid, I haven't heard Caldera yet so I can't be certain exactly how they pair, sounds like a case of two different flavors to me.

The Caldera and Atrium will require different amps to sound stellar.
Although I have yet to hear the new amp that Keenan debuted at canjam.

I will be a bit shocked if it tops the Airmid for driving high impedance headphones

The two amps are just different, I think each has its pros and cons, but the pentode amp does run high impedance headphones very well. We'll just have to see what you think!

Caldera had better bass (to my taste), and faster / tighter sound all around.
I did not test on Keenan's pentode - it was being used every single time I stopped by the ZMF room (and I was too busy and/or impatient to wait for it to become available).

Seems a lot of people listened to it, but I haven't seen / heard a peep as far as good or bad impressions other than from Zach. Maybe they are yet to come.

I have never heard either of these amps from Keenan. The Airmid may very well be enough for most people for both cans as you can use the 6336B tubes which is a great plus.

Whether or not it can make the Caldera sound as full as on the pentode amp vs how the Atrium sounds on the pentode amp.

I am just guessing here, but I expect the pentode amp to be the best all around amp, so to speak. It should not have any issues powering most headphones.

A good OTL and high impedance headphones do have a wonderful synergy going on.

I am sure Keenan will explain this all better than I can.

Hey Keenan?

What would the 6336B take the Airmid's output impedance down to ? Would that be a better choice for an output tube with the Caldera?

Thanks,

jgwtriode

With a pair of 5998, the Airmid has an output impedance of around 30ohms, so a little over a 2:1 damping ratio with a 65ohm planar. With 265uF output capacitance, that gives a -3dB low frequency rolloff point of around 9Hz, so low frequency extension is not an issue. It would probably sound pretty good, but not optimal. My 6336 OTL can hit an output impedance of 15ohms for a 4:1 damping ratio, which is better, but I still think a transformer coupled amplifier would be the best option for running a relatively low impedance planar like the Caldera. Airmid cannot use 6336 / 6528 tubes as they draw double the heater current of a 6AS7G and bias at around double the current, so these tubes really need to have a circuit designed around them to be high performing.

 

[triod750]

I have both as well as at least 55,000 HD albums stored on hard drives. My classical music collection was lacking so I enhanced it.

Note to self; nobody is perfect.

 

[Paladin79]

Note to self; nobody is perfect.

I have been involved with audio since the 60’s, somewhere I still have reel to reel tapes and possibly cassette tapes. No four track or 8 track but I once owned some.

I may run two turntables after I build more racks.

 

[triod750]

cassette tapes

me too

 

[Paladin79]

As far as turntables and records, I still have one of these brand new in the box, sans tone arm. It is in storage with other gear about 100 miles away but I may get a tonearm and set it up. The Pioneer PLC-590. This is just a representative photo, I would most likely mount an SME tonearm.

 

[jgwtriode]

I could be mistaken, but I do not believe the Airmid can use the 6336. Keenan's custom 1-of- a- kind OTL Spinosaurus uses the 6336, but it's a different amp than the Airmid

Yeah I was a bit confused for a minute about that, got temporarily excited. But actually do remember that was the tube in the Spinosaurus. But thought I would ask. Oh well
I thing we are just looking at going Atrium and being happy for quite some time. Not about to do another Amp with my budget and priorities. If my DAC does not show up soon I may just get a stock Gustard R26, which would likely work quite well for streaming, supports roon, as well as being an R2R DAC with DSD capability. A few folk are saying it's the best R2R under 3.5k. Very interested even if my moded X26 pro ever does show.

Happy listening,

jgwtriode

 

[Monsterzero]

The Glenn OTL can use 6336 tubes, but iirc, it isnt optimized for the use of 6336. When I had my GOTL, planars didnt sound bad on it, but there was some grain in the sound that I knew wasn't supposed to be there.

The only low impedance headphone that blew my mind on the GOTL w/ 6336s in place was the AKG K701. That combo was absurdly good.

 

[UntilThen]

I've had a good time with GOTL with various headphones - HD800, Verite Open and LCD3. GOTL was special to me because it was my first custom amp and Glenn reach out to me whilst I was still on Euforia's thread. I spent a long time on Glenn's thread in my audio journey. I really wish him all the best where ever his is and hope all is well.

My GOTL is still with @paramesh I believe.

 

[JazzVinyl]

I have been involved with audio since the 60’s, somewhere I still have reel to reel tapes and possibly cassette tapes. No four track or 8 track but I once owned some.

I may run two turntables after I build more racks.

Me, three...

 

[Xcalibur255]

The Glenn OTL can use 6336 tubes, but iirc, it isnt optimized for the use of 6336. When I had my GOTL, planars didnt sound bad on it, but there was some grain in the sound that I knew wasn't supposed to be there.

The only low impedance headphone that blew my mind on the GOTL w/ 6336s in place was the AKG K701. That combo was absurdly good.

The K701 has a weird affinity with OTL amps that has never really made sense. Long ago I used my GOTL exclusively with a pair until a naughty 5998 tube blew them up.

Side note: the K712 does not have the same magic that the K701 did. It sounds passable on the GOTL but something about the midrange rubs me the wrong way. On my transformer coupled amps it sounds even worse. Given it's reputation has a "fuller and warmer" K701 it really feels like I'm hearing a different headphone than those people.

 

[L0rdGwyn]

A while back I talked about how I designed the pentode headamp to be easy to build, a relatively simple circuit with new production available tubes, all for the sake of either commercial or DIY viability. A few times my thoughts have strayed to how I would build a cost-no-object version of this circuit without those constraints. Yesterday I was on a run and the idea came back to me. I got pretty excited about how this amp would sound, so I think I am going to build one for myself, seeing as I will have a Caldera at some point, I need a personal amplifier that can run planars. The gist of it is it would be interstage transformer coupled as opposed to capacitor coupled, use E810F input tubes as opposed to 6SL7, LED biased instead of cathode biased, use solid state rectification and a voltage regulated power supply. I shot an email to Dave Slagle about some transformers for this amplifier. If he can make what I need, then I'll go for it.

Here is a pair of E810F. These are more ideal tubes for the application, but of course they are not available new production, so I designed around 6SL7 instead.



I need to talk to Zach about how things went with the original pentode headamp at CanJam. Don't take this as a firm decision, but I am starting to lean toward making it a DIY project. The way it was designed, DIY makes more sense than commercial. It would have to be redesigned with transistors to make it a commercial amplifier in my mind. Maybe that will still happen and I can release the "old school" version as a DIY project. It wouldn't be cheap, but relative to the price of a comparable commercial amp, it would be a steal. Should have an answer in the next couple weeks.

 

[Paladin79]

A while back I talked about how I designed the pentode headamp to be easy to build, a relatively simple circuit with new production available tubes, all for the sake of either commercial or DIY viability. A few times my thoughts have strayed to how I would build a cost-no-object version of this circuit without those constraints. Yesterday I was on a run and the idea came back to me. I got pretty excited about how this amp would sound, so I think I am going to build one for myself, seeing as I will have a Caldera at some point, I need a personal amplifier that can run planars. The gist of it is it would be interstage transformer coupled as opposed to capacitor coupled, use E810F input tubes as opposed to 6SL7, LED biased instead of cathode biased, use solid state rectification and a voltage regulated power supply. I shot an email to Dave Slagle about some transformers for this amplifier. If he can make what I need, then I'll go for it.

Here is a pair of E810F. These are more ideal tubes for the application, but of course they are not available new production, so I designed around 6SL7 instead.



I need to talk to Zach about how things went with the original pentode headamp at CanJam. Don't take this as a firm decision, but I am starting to lean toward making it a DIY project. The way it was designed, DIY makes more sense than commercial. It would have to be redesigned with transistors to make it a commercial amplifier in my mind. Maybe that will still happen and I can release the "old school" version as a DIY project. It wouldn't be cheap, but relative to the price of a comparable commercial amp, it would be a steal. Should have an answer in the next couple weeks.

I have always preferred the 6sn7 over the 6sl7 and I have a few amps that run both. I did more extensive tests with 6sn7's so maybe there are some wonderful 6sl7's out there I have missed along the way.

 

[raindownthunda]

A while back I talked about how I designed the pentode headamp to be easy to build, a relatively simple circuit with new production available tubes, all for the sake of either commercial or DIY viability. A few times my thoughts have strayed to how I would build a cost-no-object version of this circuit without those constraints. Yesterday I was on a run and the idea came back to me. I got pretty excited about how this amp would sound, so I think I am going to build one for myself, seeing as I will have a Caldera at some point, I need a personal amplifier that can run planars. The gist of it is it would be interstage transformer coupled as opposed to capacitor coupled, use E810F input tubes as opposed to 6SL7, LED biased instead of cathode biased, use solid state rectification and a voltage regulated power supply. I shot an email to Dave Slagle about some transformers for this amplifier. If he can make what I need, then I'll go for it.

Here is a pair of E810F. These are more ideal tubes for the application, but of course they are not available new production, so I designed around 6SL7 instead.



I need to talk to Zach about how things went with the original pentode headamp at CanJam. Don't take this as a firm decision, but I am starting to lean toward making it a DIY project. The way it was designed, DIY makes more sense than commercial. It would have to be redesigned with transistors to make it a commercial amplifier in my mind. Maybe that will still happen and I can release the "old school" version as a DIY project. It wouldn't be cheap, but relative to the price of a comparable commercial amp, it would be a steal. Should have an answer in the next couple weeks.

DIY!?? Where do I sign up?? So excited to follow the progress on this project. Have you thought about chassis supply at all? Curious on whether or not it would be feasible to have a standard pre-built chassis available to order.