Announcing the Ultra Double 550 Amplifier

oneinthepipe · « **Reply #20 on:** 10 Jan 2009, 09:31 pm »

martyo:

The AVA t-shirt is a nice touch. Nice report, too.

(I wonder if he wears that t-shirt every day.)

Wayner · « **Reply #21 on:** 10 Jan 2009, 11:32 pm »

I think he had them printed up! aa

Wayner

orthobiz · « **Reply #22 on:** 12 Jan 2009, 12:09 am »

Quote from: sueata1 on 8 Jan 2009, 01:39 am

Frank,,,
I use 2 Ultra 550's bridged mono,,,
Any advantage to going with the 1 Double version instead of the 2 bridged amps in this case??

Happy listening,,,
Mel

I'm interested in this answer, too.

Paul

rlee8394 · « **Reply #23 on:** 12 Jan 2009, 02:57 am »

Two Ultra's bridged gives you twice the voltage across an 8 ohm load. Theoretically that would yield 4 times the output power. In actuality, the increase in power is closer to 3 times due to the current limitation of the power supply in the amp. Going to a single Double Ultra would give you better load driving capability, say down to a 1 or 2 ohm load. The output power is still defined by the overall output voltage of the power supply. While the Double Ultra does provide a bit more voltage due to the extra current capability of the new double current Exicon devices, and therefore a bit more power, it is still way less output power than a bridged unit that you already have. If your looking for extra performance based on the new double current devices, and it sounds like you are, your best bet would be to have Frank replace the current Exicon devices in both of your bridged amps with the new double current devices. If you are technically capable, you could order them from Profusion Logic and replace them yourself. I've done this with a couple of my Hafler based amps. Take proper ESD precautions and you should be fine. Of course you may validate your warranty. Check with Frank. In the past he has allowed users to make minor changes to their amps without affecting the warranty. He also may hand match the devices as well, which would be an advantage to having AVA perform the update.
Hope this helps.
Ron

avahifi · « **Reply #24 on:** 12 Jan 2009, 01:17 pm »

The upgrade is not quite that simple. Gate resistors may require changing, as will some compensation circuits. Bias adjustments are required too. Its not a do it yourself project.

Regards,

Frank Van Alstine

tonyptony · « **Reply #25 on:** 12 Jan 2009, 02:47 pm »

Quote from: tonyptony on 8 Jan 2009, 12:35 am

Frank, will this have any effect on the ability of the design to drive low impedance loads? You may recall in my case, my speakers are nominally 4 Ohms but go down to a little under 2 Ohms at some points.

Does it change the overall gain at all?

I've found over the years that some high power amps are not as good as lower power jobs in the areas of delicacy, microdynamics, and timbre. Not the Ultra 550, but I'm wondering if you've been able to evaluate the Double in these areas as well.

Any change to the effective bandwidth?

Frank, any info on these questions?

martyo · « **Reply #26 on:** 12 Jan 2009, 03:38 pm »

Quote

Quote from: tonyptony on 12 Jan 2009, 02:47 pm
Quote from: tonyptony on 8 Jan 2009, 12:35 am
Frank, will this have any effect on the ability of the design to drive low impedance loads? You may recall in my case, my speakers are nominally 4 Ohms but go down to a little under 2 Ohms at some points.

Does it change the overall gain at all?

I've found over the years that some high power amps are not as good as lower power jobs in the areas of delicacy, microdynamics, and timbre. Not the Ultra 550, but I'm wondering if you've been able to evaluate the Double in these areas as well.

Any change to the effective bandwidth?

Frank, any info on these questions?

Tony, yesterday my session was interupted after one cut. I really do need more time to evaluate, but all 3 of us Friday night heard deeper, more powerful, and more defined lowend than the stock 550 and we also thought the image was more precise.
If you are familiar with Jack DeJohnette's playing in the Keith Jarrett trio, he is very tidy. With his use of the cymbals in particular, delicacy, microdynamics, timbre, and decay are improved over my original 550.

I'll have more after more time in front of the set.

avahifi · « **Reply #27 on:** 12 Jan 2009, 05:02 pm »

The Ultra Double 550 has significantly better ability to drive low impedance loads - it has double the load driving capability.

The overall voltage gain is not changed, it remains a voltage gain of 25 (1V in yields 25V out).

Effective bandwidth does not change as measured, still flat from about 8 Hz to about 100K Hz, but the amp has even better bass control and musicality and better microdynamics and delicacy yet, just a feeling of effortlessness driving my 85dB 6 ohm Salk HT3s.

You will like it.

Frank

mark funk · « **Reply #28 on:** 12 Jan 2009, 08:17 pm »

I got to hear the first Double 550 for a few hours last Friday night at Martyo's, and the Insight 440H ( I heard the 440H a few times over the last few weeks ). I was really impressed with the 440H! If I never heard a 550 I would be more then happy with the 440H but when Martyo changed to the Double 550, the 440H has a good low end but 300+ watts and double the current seams to make a little difference in the low end and every where else. Both the 440H and the 550 or D-550 are fine amps, I like the 550 it seams to bring you a little closer to real and the D-550 a little more with the HT-3s but I don't know if every one needs this upgrade for most speakers this high current amp may be just a little over kill.

tonyptony · « **Reply #29 on:** 13 Jan 2009, 12:20 am »

Quote from: martyo on 12 Jan 2009, 03:38 pm

If you are familiar with Jack DeJohnette's playing in the Keith Jarrett trio, he is very tidy. With his use of the cymbals in particular, delicacy, microdynamics, timbre, and decay are improved over my original 550.

I'll have more after more time in front of the set.

Sweet! AAMOF I am quite familiar with that particular Jarrett trio, so I have a good sense of what you are describing. Can't wait to hear more of your assessment!

tonyptony · « **Reply #30 on:** 13 Jan 2009, 12:22 am »

Quote from: avahifi on 12 Jan 2009, 05:02 pm

The Ultra Double 550 has significantly better ability to drive low impedance loads - it has double the load driving capability.

The overall voltage gain is not changed, it remains a voltage gain of 25 (1V in yields 25V out).

Effective bandwidth does not change as measured, still flat from about 8 Hz to about 100K Hz, but the amp has even better bass control and musicality and better microdynamics and delicacy yet, just a feeling of effortlessness driving my 85dB 6 ohm Salk HT3s.

You will like it.

Frank

As the great one said: "hamena hamena hamena hamena!"

Tone Depth · « **Reply #31 on:** 15 Jan 2009, 03:56 am »

Frank,

Can the "double die" Exicon mos-fets be installed in the Insight 440H amplifier output circuits also?

rcag_ils · « **Reply #32 on:** 15 Jan 2009, 05:05 pm »

Do those speakers come with front grills to protect the components?

martyo · « **Reply #33 on:** 15 Jan 2009, 05:36 pm »

Quote

Quote from: rcag_ils on 15 Jan 2009, 05:05 pm
Do those speakers come with front grills to protect the components?

They are Salk HT3's and you can order them with full or 1/2 grills. I didn't, but I don't know that the grills would "protect anything". They are more for home theatres and just for looks, I believe.
However, there is a screen that protects the ribbon.

Jim Salk can usually accommodate whatever needs you might have

I don't want to cover any of the wood.

charmerci · « **Reply #34 on:** 15 Jan 2009, 05:52 pm »

I always figured the grills were to keep dust and prying fingers off of the tweeters and woofers - and for looks. Though I do seem to recall that some loudspeaker companies adjusted the sound of speakers to compensate for the way that the grills changed the sound.

oneinthepipe · « **Reply #35 on:** 15 Jan 2009, 06:03 pm »

Salk advises against attaching the grills for serious listening. Hence, I suspect that there is a large supply of unused Salk Sound speaker grills. My grills are still in the wrappers.

avahifi · « **Reply #36 on:** 15 Jan 2009, 06:55 pm »

Could the double die Exicon mos-fets be installed in the Insight series solid state amplifiers?

The answer is yes, there is no reason why they could not be installed. However, we have not tried that yet and so cannot be sure if there would be any sonic benefit inasmuch as the output circuit in the solid state amplifiers is a very different configuration as the hybrids, with a much different power supply configuration too.

We certainly will try this one of these days soon just for fun. I suspect an Insight 440H with a dozen double die devices would be a really killer amp for very difficult loads. I have a "demo" Insight 440H on hand right now in brand new condition (just returned from Martyo). If anyone wants to buy it, ($1899 plus $40 shipping) I will install the big devices in this particular amp at no extra charge!

In the meantime a great client is sending me a Dyna FM-5 with AVA boards in it from the 1980s for me to play with all for myself. I did one for another client with outstanding results, now I want one for myself.

Regards,

Frank Van Alstine

mark funk · « **Reply #37 on:** 15 Jan 2009, 10:46 pm »

Frank, Just what kind of circuit are you going to put in the tuner, Insight or Ultra or some thing else?

avahifi · « **Reply #38 on:** 18 Jan 2009, 10:42 pm »

I am playing with some very much better active devices in the tuner's audio circuits.

Regards,

Frank

I will try and find my rebuild notes in my paper archives (labeled "stuff") and see if there is anything rational I can do to a Hafler 330 tuner, either one we rebuild years ago or a stock one.

I am nearly finished with the Insight one piece line - power supply board. It will almost certainly be too big to fit in a Hafler 330 tuner chassis unfortunately.

tonyptony · « **Reply #39 on:** 19 Jan 2009, 12:21 am »

Quote from: martyo on 12 Jan 2009, 03:38 pm

Tony, yesterday my session was interupted after one cut. I really do need more time to evaluate, but all 3 of us Friday night heard deeper, more powerful, and more defined lowend than the stock 550 and we also thought the image was more precise.
If you are familiar with Jack DeJohnette's playing in the Keith Jarrett trio, he is very tidy. With his use of the cymbals in particular, delicacy, microdynamics, timbre, and decay are improved over my original 550.

I'll have more after more time in front of the set.

Marty, you can't expect us to wait a whole week before hearing from you again, can you?