[Coran]

The classifieds. I happen to hook them about 10 minutes after they dropped. How many are you looking for, I'll keep my eyes open for you.

I appreciate it. All I need is one.

 

[zach915m]

Before i post my initial impression of the Caldera, I would like to ask if anyone here powers their caldera with a GSX mini? This amp gave me a completely unexpected sound signature with the caldera. Please share any info regarding this setup.

I have a GSX MK ii and it really seemed to turn the Caldera into a very neutral, fast and technical headphone. A bit higher impedance and/or other solid states like the Wells make them more girthy and beefy.

 

[ColSaulTigh]

I believe you can get the EMLs here http://tubesusa.com/ELtubes.html

Audio Art also has them in stock: https://artaudio.us/collections/emission-labs/products/emission-labs-5u4g-mesh-each I've bought from them in the past. @Coran give them a shot.

 

[Coran]

Audio Art also has them in stock: https://artaudio.us/collections/emission-labs/products/emission-labs-5u4g-mesh-each I've bought from them in the past. @Coran give them a shot.

They say they are out of stock. Have for some time too. Supply can't keep up with demand in a lot of areas these days.

 

[ColSaulTigh]

They say they are out of stock. Have for some time too. Supply can't keep up with demand in a lot of areas these days.

Oh, I missed their OOS banner. Have you emailed them to see when they'll get more in?

 

[Coran]

Oh, I missed their OOS banner. Have you emailed them to see when they'll get more in?

I did a few months ago. There was no real estimate. Never hurts to try again.

 

[Sharppain]

Tonight's been good

Stunning look

 

[iamoneagain]

Shoot, now my Caldera is not scheduled to arrive until the 26th. I guess I’ll be spending time with my family on Christmas . Good thing I have no plans the rest of the week I’m off.

 

[dfiled]

Shoot, now my Caldera is not scheduled to arrive until the 26th. I guess I’ll be spending time with my family on Christmas . Good thing I have no plans the rest of the week I’m off.

Hope for the best and prepare for the worst. There is a huge blizzard moving through the Midwest that will likely slow shipping.

 

[ColSaulTigh]

I need to find someone who's needing to fund a caldera by selling an Atrium. I think after reading your post that Atrium could be my end game after enjoying my Auteurs for quite a while.

Here's another one:

https://www.head-fi.org/classifieds/zmf-atrium-mint-for-dca-expanse-plus-cash.32384/

 

[iamoneagain]

Hope for the best and prepare for the worst. There is a huge blizzard moving through the Midwest that will likely slow shipping.

Good to know. It’s going to be 75 here in San Diego on Christmas Day and the day after. As much I’m looking forward to the headphones, I guess I can enjoy a local vacation too. I work from home, so the Caldera will still get plenty of head time.

 

[jlawso13]

https://www.head-fi.org/classifieds/zmf-atrium-shisa-stabilized-7-norne-vygarde-cable.36017/

https://www.head-fi.org/classifieds/zmf-atrium-cherry-with-wooden-case.35085/

They pop up in the Classifieds fairly often, or you can always hit up the ZMF website and see what kind of deals there are on B-Stock...

Thanks, my friend!

 

[L0rdGwyn]

They're not recommended as the circuit wasn't designed for it as voltage will sag.

There you go.

Voltage sag isn't really a thing in class A amplifiers. The B+ voltage will be lower due to the higher voltage drop of the rectifier, so the operating points of the tubes will change, but this is not significantly detrimental, you might see a marginally higher output impedance. Using a higher Vdrop rectifier will add more resistance to the power supply, which is really only a problem in amplifiers that have a variable DC current draw, i.e., class AB amplifiers. In class A, the current draw is constant, so the voltage drop is constant, so the operating points are steady state as opposed to being variable. This variable operating point in class AB amplifiers is what is referred to as "sag". In these types of amplifiers, it is a design goal to have a relatively "stiff" power supply, meaning a low resistance supply such that the voltage drop across it will not significantly change with variable DC current draw. But again, not an issue in single ended class A tube headphone amps where the current draw is constant.

I explained it in more detail here: https://www.head-fi.org/threads/hea...t-for-all-300b-tube-amps.962932/post-17193287

 

[karangovil]

A higher voltage drop rectifier might sound "slow" compared to a lower voltage drop rectifier as the tubes are at a colder bias point (i.e., lower plate voltage, lower bias current), which means higher internal resistance, which means a slightly higher output impedance and likely higher distortion.

Quoting this from your explanation in the other thread. I had asked Craig about using 274B in Studio B and this was his response - "The 274B rectifier has a much larger voltage drop and will play with less power slightly spongy sound, but will work". This seems to be in-line with what you mentioned.

 

[L0rdGwyn]

Quoting this from your explanation in the other thread. I had asked Craig about using 274B in Studio B and this was his response - "The 274B rectifier has a much larger voltage drop and will play with less power slightly spongy sound, but will work". This seems to be in-line with what you mentioned.

Yes, it's not a matter of functionality, but the operating points will change, and as such the sound will change. Whether the change is good or bad will be highly subjective. These amplifiers have an excess of power for headphones, so the slight loss of peak power output that will never be utilized by any headphone is a non issue. The more significant audible effect is the change in operating point of the tube as it will affect distortion and output impedance slightly.