[L0rdGwyn]

After hearing the Aegis this past weekend, I can only imagine how amazing this amp must be. @zach915m I am sure you are in for a treat!

@L0rdGwyn you are a Wizard!

Thanks, Wes, glad you liked it so much! The goal of the Aegis design was to get close to the sound of a more complex amplifier (like this 2A3 amp) with a relatively simple circuit that was commercially / DIY viable.

I haven't compared Aegis directly to this amp, but you'd be surprised, it compares very favorably to higher end stuff. I'll listen to them side-by-side when Aegis gets back! And try it out with my autoformer volume control.

 

[L0rdGwyn]

Toroidy is going to leave the polished steel housings of the toroids I ordered blank, without their logo, which I am grateful for. I hope they didn't take the request personally! I prefer a minimalist look without branding / logos. Looking forward to getting those into the HY69 amp, it should improve the noise floor tremendously.

 

[Galapac]

I've made all the tweaks and adjustments I'd like to this amplifier, it is done done. The clarity, resolution, and imaging with the Caldera is off the charts. I won't be shipping this beast, going to visit ZMF HQ in a few weeks and drive it to Zach.

@L0rdGwyn you should record the moment so we can see Zach's jaw drop to the floor!

 

[AnyDave]

I've made all the tweaks and adjustments I'd like to this amplifier, it is done done. The clarity, resolution, and imaging with the Caldera is off the charts. I won't be shipping this beast, going to visit ZMF HQ in a few weeks and drive it to Zach.

FWIW, I plan to meet you there, too.

 

[L0rdGwyn]

FWIW, I plan to meet you there, too.

Looking forward to it!!

 

[zach915m]

And by then, the commercial version of Aegis should be on the market, which should occupy some time.

Oh yes I've been so busy I forgot to talk about it on this thread. I'm hoping to have some Aegis units at least by Canjam NYC, and likely sooner. I don't think this amp needs a lengthy review tour for people to know how awesome it is.

The likely list price will be $3499 with significant discount for ZMF owners who have bought direct, but all of this is still up in the air and all that.

I've made all the tweaks and adjustments I'd like to this amplifier, it is done done. The clarity, resolution, and imaging with the Caldera is off the charts. I won't be shipping this beast, going to visit ZMF HQ in a few weeks and drive it to Zach.

After hearing the Aegis this past weekend, I can only imagine how amazing this amp must be. @zach915m I am sure you are in for a treat!

@L0rdGwyn you are a Wizard!

Oh my - it's going to be the most exciting day of the year! I will make sure to get Air Mountain and 2A3 pics... @L0rdGwyn quick think of a fun name for the 2A3!

 

[zach915m]

Thanks, Wes, glad you liked it so much! The goal of the Aegis design was to get close to the sound of a more complex amplifier (like this 2A3 amp) with a relatively simple circuit that was commercially / DIY viable.

I haven't compared Aegis directly to this amp, but you'd be surprised, it compares very favorably to higher end stuff. I'll listen to them side-by-side when Aegis gets back! And try it out with my autoformer volume control.

Aegis definitely has a sound that is so unique - people were pretty bewildered with it at Canjam. It was a fun time.

FWIW, I plan to meet you there, too.

Some of you have emailed me, and we will plan on having regular demo hours once we're in our new building by spring time at some point so that we can share the awesomeness of this stuff.

 

[LXMc]

The likely list price will be $3499 with significant discount for ZMF owners who have bought direct, but all of this is still up in the air and all that.

I can already see my future internal struggle over whether to first get an Atrium Closed or an Aegis...

*edit - assuming I can even figure out where I'd put an Aegis*

 

[L0rdGwyn]

Oh my - it's going to be the most exciting day of the year! I will make sure to get Air Mountain and 2A3 pics... @L0rdGwyn quick think of a fun name for the 2A3!

Air...UNIVERSE.

 

[L0rdGwyn]

Oh yes I've been so busy I forgot to talk about it on this thread. I'm hoping to have some Aegis units at least by Canjam NYC, and likely sooner. I don't think this amp needs a lengthy review tour for people to know how awesome it is.

The likely list price will be $3499 with significant discount for ZMF owners who have bought direct, but all of this is still up in the air and all that.

Oh and I'm going to try to make it to CanJam NYC, so that would be fun!

 

[zach915m]

Air...UNIVERSE.

 

[heliosphann]

I've made all the tweaks and adjustments I'd like to this amplifier, it is done done. The clarity, resolution, and imaging with the Caldera is off the charts. I won't be shipping this beast, going to visit ZMF HQ in a few weeks and drive it to Zach.

Just remember on your way Zach, to swing down to Indy and let me have a listen.

 

[Zachik]

Oh my - it's going to be the most exciting day of the year! I will make sure to get Air Mountain and 2A3 pics... @L0rdGwyn quick think of a fun name for the 2A3!

Do you read this @BooUrns ? Not your birthday... not your anniversary... THIS is going to be the most exciting day of the year!

P.S. feel free to contact me for couples counseling. $300 / hour special rate for you and Zach

 

[Zachik]

Oh and I'm going to try to make it to CanJam NYC, so that would be fun!

Looking forward to meeting with you once again, my friend!

 

[L0rdGwyn]

I don't think I discussed it, but one change I made to the 2A3 amp in the last round of tweaks was chaning the input stage from LED bias to a typical cathode bias with a Jupiter Cosmos electrolytic bypass cap.

In the past, I've been very critical of electrolytic bypass caps, there are numerous electrolytics that sound very bad. However for the Aegis circuit, I had to use an electrolytic bypass given the high plate resistance of the 6SL7; it was a necessity to get good bandwidth out of choke loading that stage. I did a shootout of several "audio grade" electrolytics and the Jupiter Cosmos were my favorite, followed by the Elna Silmic II, well beloved in the DIY community for their sound. Not only were the Jupiter caps the best, but they actually sounded REALLY good, so good in fact that I compared them to LED biasing in a spud amplifier I was prototyping at the time. What I found as by and large I actually preferred the Jupiter Cosmos over my favorite LEDs. So, I made it a point that I should give them a shot in this 2A3 amp before I declare it completed.

I did that the other day. Subjectively though, it was no contest, the Jupiter Cosmos sound better than the LED biasing in this amp. Also, given that the bypassed cathode will lower the effective internal resistance of the input stage tube, relative to the LED, I expected to see improved bandwidth.

Here is an example. The bandwidth is now very impressive, -3dB from 7Hz to 34kHz. This is the benefit of using very well-made transformers.



I also measured the output impedances for the three taps:

120ohm tap: 41ohm output Z
32ohm tap: 8.5ohm output Z
8ohm tap: 2.7ohm output Z