Apogee Full range

[bonzo75]

Wow Brian, this looks awesome. What's your room size?

I completely agree with the purity of mids on FR and scintilla, haven't been that mesmerized anywhere else. And the bass and might of FR is much higher than divas.

 

[Ron Resnick]

We talk and post a lot here about this exact course of action and result, and you went out and actually did it -- and with tube amps (on which I always insisted, even for the Full Range)! Congratulations!

 

[Brian Beck]

What's your room size?

Thanks guys. My room size? Never big enough It is 18’4” W x 12’ H x 26’ L. The rear of the room is irregular and actually goes off into larger spaces. I think it will be fine with the Full Ranges after I tame some reflection modes. I have the speakers about 6’ out from the front wall and my listening position is well out from the rear wall. That will change as I find the optimal placement.

 

[spiritofmusic]

Brian, I must commend you for sticking to your guns on persisting with tubes on Apogees.
How confident are you this can be practically realised w those low impedance FR bass ribbons?

 

[RBFC]

From personal experience, I will tell you that directly driving the bass panels will provide a big improvement. Wonderful write-up!

Lee

 

[Brian Beck]

How confident are you this can be practically realised w those low impedance FR bass ribbons?

Pretty confident, but I have to prove that to myself. The future configuration that I posed would be 1-ohm amplifier taps directly driving 1.8 ohm woofers. So the amp will be very happy, but max power may be reduced a bit. I will also try the 4-ohm taps directly driving the 1.8 ohms. That reverses the mismatch, but maybe it would work. The amp does not have 2-ohm taps, which would have been ideal.

Another option is to put the two D-250 channels in parallel. The 4-ohm taps then become 2-ohm taps and the power goes up to 500 W in one combined channel. That would probably work exceedingly well driving the woofers. I would then need more amps for the mids and tweeters, but I know where I can find two more D-250s. Like I need even more glowing 6550s in my room! I do have to say that one 250 W channel of the D-250 driving a woofer through the interface transformer seems to have enough power. I was able to just reach clipping on loud bass drum whacks, but that level was very, very loud.

Who knows what will work best? Audio can be full of humbling surprises. I will keep you posted if anyone is interested in my progress with these speakers and these amps.

 

[Brian Beck]

From personal experience, I will tell you that directly driving the bass panels will provide a big improvement. Wonderful write-up! Lee

Thanks Lee.

 

[Tango]

I will keep you posted if anyone is interested in my progress with these speakers and these amps.

Dear Sir,

I am very much interested in reading your experiences with the FR. Pls, keep us posted.

Kind regards,
Tang

 

[Brian Beck]

Dear Sir,

I am very much interested in reading your experiences with the FR. Pls, keep us posted.

Kind regards,
Tang

OK, I shall, if only irregularly is possible.

 

[Ron Resnick]

Wow! Those are great room dimensions!

With the disclosure of this secret project you have instantly catapulted yourself into being one of our most fascinating systems!

I came close to taking the exact same path you did (although with different tube amplifiers -- your choice is much more clever) so I will be eager to hear your reports.

There is a lot of scepticism here that this project could be implemented with tube amplifiers! (I was not one of the sceptics.)

 

[bonzo75]

Brian, you had the micro Seiki 5000 right? Do you still have that?

 

[spiritofmusic]

Ron, you reserve all your energies on skepticism for fuses LOL.

 

[Brian Beck]

There is a lot of scepticism here that this project can be implemented with tube amplifiers! (I was not one of the sceptics.)

Even if I never improved this initial system set-up, I can confidently attest that tubes can work with Full Ranges. At least with this one particular tube amp, but I am sure that others such as your big VTL would work too. I have long been an unabashed fan of Audio Research’s sound quality (with notable exceptions), especially from their products made during their glory days when Bill Johnson ran the company and designed the products. Also Rich Larsen knew how to design superior output transformers.

I remain skeptical, but open-minded, about using big SETs such as the NAT amps. I hear what I think people like in SETs, and it is second harmonic distortion. I do not mean to step on toes with that comment. And no, I have not heard NATs on Apogees, so you may discount my thoughts. Whatever “floats your boat” is fine with me. It just seems contrary to me to drive a speaker with such exquisitely low inherent distortion with a distortion generator, even if it is quite euphonic.

 

[spiritofmusic]

Brian, I don’t want your thread to descend into a “you can/you can’t drive Apogees with tubes”. It’s evident that you’re confident “you can”. I have to say after being truly bowled over by a very special pair of Graz Duettas run on high current 80W 211s in an 18x12x9 room, I would love to have considered these spkrs in my 4x larger room. But I can’t shift the feeling that this is asking just a bit too much (my amps are 70W 211s), and after some recent visits to systems run on SS, I absolutely will never move away from 211s.

 

[Brian Beck]

Brian, you had the micro Seiki 5000 right? Do you still have that?

Yes. I had a 50-pound 316L stainless-steel platter made with a different cross-section to break up resonances. I then topped that with a MS CU-180 copper mat which quenches any lingering resonance by constrained-layer damping. I clamp the record directly onto the copper mat with no squishy mat in between. I am not alone in finding this set up to work quite well. I also regulated the motor power supply.

 

[Brian Beck]

Brian, I don’t want your thread to descend into a “you can/you can’t drive Apogees with tubes”. It’s evident that you’re confident “you can”. I have to say after being truly bowled over by a very special pair of Graz Duettas run on high current 80W 211s in an 18x12x9 room, I would love to have considered these spkrs in my 4x larger room. But I can’t shift the feeling that this is asking just a bit too much (my amps are 70W 211s), and after some recent visits to systems run on SS, I absolutely will never move away from 211s.

The 211 and its sister the 845 are great tubes. How much power do you want? A parallel push-pull (dirty words) amp using 211s could be devised with as much power as you like. Bias it deeply into Class A if desired. I have played with 833s too (hence my avatar).

 

[LL21]

Dear Sir,

I am very much interested in reading your experiences with the FR. Pls, keep us posted.

Kind regards,
Tang

+1...this is a great thread particularly with Brian's posts today...

 

[spiritofmusic]

It’s not so much the q how much power do I want.
It’s how much power is needed, and more so, how much is ideal.
In my nr 800 sq ft/5000 cub ft room, 70W 211s are great on my true 101dB full range drivers down to 40Hz.
But I still need 300W Class D on my 90dB eff subs to truly energise my space.

 

[bonzo75]

And how much current and impedance handling

 

[LL21]

The 211 and its sister the 845 are great tubes. How much power do you want? A parallel push-pull (dirty words) amp using 211s could be devised with as much power as you like. Bias it deeply into Class A if desired. I have played with 833s too (hence my avatar).

Hi Brian,

Have you ever seen the post below from a number of years ago...does the brief description of the design mean anything to you? Was just curious given discussions here about power and SET.

http://www.audioaficionado.org/showthread.php?t=9814&page=12


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Remember this from CES 2003. Apparently cj have enough parts to make several pairs.



conrad-johnson GAT Amplifier ($38,000) is the company's first venture into 300B tube amplification. This is the only 300B amplifier that outputs 1,000 watts (not a typo). A low ratio transformer is coupled to a push-pull buffer. This keeps the voltage gain characteristics of a 300B but the current gain of the output buffer stage."