Apogee Full range

[christoph]

It’s a mistake think all Apogees are amp killers. The Duetta and the Diva don’t have the horrendous impedance curves of the Scintilla. They are inefficient but that is easily sorted by bi-amping.

The Studio Ribbon Array/Studio Grand (panel only) are probably some of the easiest to drive speakers you can find anywhere.

• 87 dB/watt in 3 meters distance (due to the Dipole Line Array radiation pattern)
• Rulerflat 6 ohm impedance over the whole frequency range, an almost purely resistive load, easiest load for any amp.

I drive the Studio Grand with 30 SET tube watts from a KR amp to stupendous volume levels and the combination of ribbons and SET is sonically a match made in heaven

 

[iansr]

I’ve never heard of the Studio Ribbon Arrays before. Can you point me to some information about them?

 

[iansr]

Sorry ignore that - google was my friend!

 

[christoph]

I’ve never heard of the Studio Ribbon Arrays before. Can you point me to some information about them?

The Studio Ribbon Array is only the panel of the Studio Grand or vice versa, the Studio Grand is a Studio Ribbon Array mounted on a dual 10 inch subwoofer box.
If you scroll up in this thread, you see a picture of my Studio Grands next to my (completely refurbished and heavily modified) ex-Scintillas.

 

[Golum]

The Studio Ribbon Array/Studio Grand (panel only) are probably some of the easiest to drive speakers you can find anywhere.

• 87 dB/watt in 3 meters distance (due to the Dipole Line Array radiation pattern)
• Rulerflat 6 ohm impedance over the whole frequency range, an almost purely resistive load, easiest load for any amp.

I drive the Studio Grand with 30 SET tube watts from a KR amp to stupendous volume levels and the combination of ribbons and SET is sonically a match made in heaven

I can confirm Chris finding regarding SET + Studio Grand . Great combo!

 

[kwashabc]

I have new Apogee Full Ranges that I used for two months before storing them in a temperature controlled basement for 37 years.

I first heard the Apogees at a meeting of the Westchester Audiophile Society and was very impressed with their sound and design. I subsequently purchased them from Lyric HiFi in New York shortly before relocating from Chappaqua to Atlanta. I am a tube person, but loved the design of the Apogees and was hopeful of finding a reasonable way to drive them with tubes. However I never found the time to set them up so they have languished in my basement since 1986.

I have communicated with most of the authoritative sources regarding the probable status of the low frequency panel damping foam. There are, unsurprisingly, many different opinions about their potential condition, but after extensively researching the issue, I believe that the panels will be fine for many years. Consequently I am including a two year warranty on the panels to the speakers' purchaser.

Anyone that might be interested in acquiring them can find them listed on the typical sites.

 

[Brian Beck]

It’s been almost 2 years since anyone has posted to this thread. Let me drop a note in April 2025.

I recently built up four channels of Dr. Bruno Putsey’s Purifi 1ET9040BA “Eigentakt Gen. 2” Class D power amps. I hooked them up to my Full Range speakers, which require biamplification. These amps make about 800 W per channel into 4 ohms and almost twice that much into 2 ohms.

Wow! Seemingly a match made in heaven. The sound is smooth as silk, yet vivid with transients as quick as needed by the music, with a complete absence of the expected harshness or etched quality. Details are evident hidden deep in the mix. Dynamics can be truly shocking. And all this is coming from a tube guy. This may be the best $5K or so that I’ve ever spent in my long audiophile journey.

I’ll just leave it there…

 

[Ron Resnick]

It’s been almost 2 years since anyone has posted to this thread. Let me drop a note in April 2025.

I recently built up four channels of Dr. Bruno Putsey’s Purifi 1ET9040BA “Eigentakt Gen. 2” Class D power amps. I hooked them up to my Full Range speakers, which require biamplification. These amps make about 800 W per channel into 4 ohms and almost twice that much into 2 ohms.

Wow! Seemingly a match made in heaven. The sound is smooth as silk, yet vivid with transients as quick as needed by the music, with a complete absence of the expected harshness or etched quality. Details are evident hidden deep in the mix. Dynamics can be truly shocking. And all this is coming from a tube guy. This may be the best $5K or so that I’ve ever spent in my long audiophile journey.

I’ll just leave it there…

Interesting, Brian!

How did you come across Purifi?

Out of curiosity have you compared these amps to any other Class D amps, such as Ralph Karsten's (Atma-Sphere) or Alberto Guerra's (AGD) Class D amps?

What were your incumbent amps?

 

[bonzo75]

Interesting, Brian!

How did you come across Purifi?

Out of curiosity have you compared these amps to any other Class D amps, such as Ralph Karsten's (Atma-Sphere) or Alberto Guerra's (AGD) Class D amps?

What were your incumbent amps?

They are also used on horns by people who don't want to use valves

 

[Ron Resnick]

They are also used on horns by people who don't want to use valves

Why Purifi in particular?

(If I wanted to explore Class D personally I would start with Ralph.)

 

[Brian Beck]

It’s been almost 2 years since anyone has posted to this thread. Let me drop a note in April 2025.

I recently built up four channels of Dr. Bruno Putsey’s Purifi 1ET9040BA “Eigentakt Gen. 2” Class D power amps. I hooked them up to my Full Range speakers, which require biamplification.

Wow! Seemingly a match made in heaven. Smooth yet vivid, with a complete absence of the expected harshness or etched quality. Details are evident hidden deep in the mix. And dynamics can be shocking. And all this coming from a tube guy. This maybe llthe best $5K or so I’ve every spent in my long audiophile journey.

Interesting, Brian!

How did you come across Purifi?

Out of curiosity have you compared these amps to any other Class D amps, such as Ralph Karsten's (Atma-Sphere) or Alberto Guerra's (AGD) Class D amps?

What were your incumbent amps?

Hi Ron,

I had been using two stereo Audio Research D-250 MkII Servo amps with much enhanced power supplies to provide the four channels needed for biamplification. They worked quite well, but the amps are just now showing signs of needing re-tubing. All the tubes test as good and bias correctly but they are not providing the best possible to the demanding Apogees anymore. There are forty 6550s in the output stages and in the screen regulators! Do the math. So I decided to try Class-D for about the same price as buying new tubes, thinking that if the Class-D amps didn’t work out I would just sell them for a small loss.

As an electrical engineer I have been studying the developments in the Class-D field with great interest, and in particular the efforts made by Putseys to eliminate the last vestiges of Class -D “character”, such as eliminating the hysteresis distortion in ferrite materials.

No I have not had the luxury to compare the Purifi amps to anything else. Ralph Karsten’s GaN amp sounded pretty fine at Munich but they may not have enough power for the hungry Apogees.

Have either you or Florian tried any Class-D amps driving a pair of Clarysis speakers?

 

[Ron Resnick]

Hi Ron,

I had been using two stereo Audio Research D-250 MkII Servo amps with much enhanced power supplies to provide the four channels needed for biamplification. They worked quite well, but the amps are just now showing signs of needing re-tubing. All the tubes test as good and bias correctly but they are not providing the best possible to the demanding Apogees anymore. There are forty 6550s in the output stages and in the screen regulators! Do the math. So I decided to try Class-D for about the same price as buying new tubes, thinking that if the Class-D amps didn’t work out I would just sell them for a small loss.

As an electrical engineer I have been studying the developments in the Class-D field with great interest, and in particular the efforts made by Putseys to eliminate the last vestiges of Class -D “character”, such as eliminating the hysteresis distortion in ferrite materials.

No I have not had the luxury to compare the Purifi amps to anything else. Ralph Karsten’s GaN amp sounded pretty fine at Munich but they may not have enough power for the hungry Apogees.

Have either you or Florian tried any Class-D amps driving a pair of Clarysis speakers?

Until I remembered that my friend, JimFord's, Class D amps are sitting on my floor here collecting dust I didn't put 1 + 1 together until I read your post.

I have no experience with Class D on Clarisys. I do not know if Florián does.

But it might be interesting to try Class D on the Clarisys woofer ribbons when I bi-amp.

 

[Zero000]

It’s been almost 2 years since anyone has posted to this thread. Let me drop a note in April 2025.

I recently built up four channels of Dr. Bruno Putsey’s Purifi 1ET9040BA “Eigentakt Gen. 2” Class D power amps. I hooked them up to my Full Range speakers, which require biamplification.

Wow! Seemingly a match made in heaven. Smooth yet vivid, with a complete absence of the expected harshness or etched quality. Details are evident hidden deep in the mix. And dynamics can be shocking. And all this coming from a tube guy. This maybe llthe best $5K or so I’ve every spent in my long audiophile journey.

Hi Ron,

I had been using two stereo Audio Research D-250 MkII Servo amps with much enhanced power supplies to provide the four channels needed for biamplification. They worked quite well, but the amps are just now showing signs of needing re-tubing. All the tubes test as good and bias correctly but they are not providing the best possible to the demanding Apogees anymore. There are forty 6550s in the output stages and in the screen regulators! Do the math. So I decided to try Class-D for about the same price as buying new tubes, thinking that if the Class-D amps didn’t work out I would just sell them for a small loss.

As an electrical engineer I have been studying the developments in the Class-D field with great interest, and in particular the efforts made by Putseys to eliminate the last vestiges of Class -D “character”, such as eliminating the hysteresis distortion in ferrite materials.

No I have not had the luxury to compare the Purifi amps to anything else. Ralph Karsten’s GaN amp sounded pretty fine at Munich but they may not have enough power for the hungry Apogees.

Have either you or Florian tried any Class-D amps driving a pair of Clarysis speakers?

I'm glad you posted this I was thinking of doing the same. Been looking at it a lot.

That said the last class D I tried on my Duetta rebuilds just inspired nothing but disdain and hate, really. Merrill audio monos were the items in question.

Post a link(s) to what you bought. I suspect I know, but to alleviate any ambiguity I'd really appreciate it!

 

[Brian Beck]

I'm glad you posted this I was thinking of doing the same. Been looking at it a lot.

That said the last class D I tried on my Duetta rebuilds just inspired nothing but disdain and hate, really. Merrill audio monos were the items in question.

Post a link(s) to what you bought. I suspect I know, but to alleviate any ambiguity I'd really appreciate it!

 

[Brian Beck]

The Purifi modules are intended to be integrated into a custom amplifier environment by a commercial enterprise, but a reasonably technically-minded individual can do it. And kudos to Purifi for making it available to individuals. Here is the kit with the main amp module plus the input buffer module. (using the exceptional OPA1656 opamp):

EVAL4 Mono 1ET9040BA Eval Kit

purifi-audio.com

I used this upgraded supply (larger than the typical Hypex supply):

SMPS1K-SN – MicroAudio

micro-audio.com

Plus extra supply capacitance:

Extra Capacitors PCB (Fully Populated) – MicroAudio

micro-audio.com

 

[Brian Beck]

The Purifi modules are intended to be integrated into a custom amplifier environment by a commercial enterprise, but a reasonably technically-minded individual can do it. And kudos to Lurifi for making it available to individuals. Here is the kit with the main amp module plus the input buffer module. (using the exceptional OPA1656 opamp):

EVAL4 Mono 1ET9040BA Eval Kit

purifi-audio.com

I used this upgraded supply (larger than the typical Hypex supply):

SMPS1K-SN – MicroAudio

micro-audio.com

Plus extra supply capacitance:

Extra Capacitors PCB (Fully Populated) – MicroAudio

micro-audio.com

Or… you could just buy these, foregoing a few premium features from the DIY version:

Buckeye Amps

Buckeye Amps utilizes the most advanced audio amplifier technologies available. Authorized seller for Hypex and Purifi Class D amplifiers. Based in the US. Free shipping and worldwide service!

www.buckeyeamp.com

 

[Zero000]

Thanks Brian.

Don't want to seem too negative I had a Hypex NC400 DIY effort in my system some years ago with a linear power supply and it wasn't too bad.

Messing around with class D amps at the moment trying to build a novel power supply for an AC Pabst motor used in my Michell record player using Grok to assist me. Just ordered a 3e TDA3255 315W module to do the job as the 50W board I was using didn't have the balls to do the job. AD9833 signal generator and SMPS power supply plus an Arduino board. Really enjoying playing around with it all

 

[Brian Beck]

Here are two amplifiers for the left channel which I mounted into some nice chassis I found on eBay, Chinese of course. They are seen sitting atop the recently deposed ARC tube amp.

 

[Zero000]

Class D madness and a shot of the Chinese chassis it might fit in. Maybe. Waiting for 3e and a different SMPS.

Those Chinese aluminium cabs are nicer than you might think for the money. This one is like a MacMini almost. £60.

 

[tennisod]

Thanks Lee.

Hello Brian,
I read your your posting and I also wanted to join in and be a part of this since I have a similar setup. FR 2 Accuphase A65 in Parallel for woofers driven directly, Pass Labs 600.5 for Mids/High are driven through the updated transformer box. Graz Mids/highs, bass foil from reputable source.