[floresjc]

I'm going to go with an Insight 240 and Insight 240/3 for my Salk Songtower based home theater. I don't listen at ear bleeding levels, and those speakers aren't really hard to drive. Just wondering if anyone thinks there would be a real benefit to shelling out $168 to retrofit a used 240 with the new MOSFETs, given that Songtowers are pretty easy load. Brand new its a no brainer IMO, its only half the cost of the retrofit price. Thanks much for your input.

[Tone Depth]

I've been quite satisfied with mine (Double 440H), giving extra dynamic headroom at normal listening levels and I think even better sound, however, I may be oversensitized to transient distortion.  WGH wasn't sure if he could hear a difference.  Frank commented that with the Double upgrade, he didn't hear much of a difference between the Double Insight and the Double Ultra.  Here's a thread of my experiences:

http://www.audiocircle.com/index.php?topic=64826.0

I suspect the double die MOS FETS provide better performance than the standard MOS FETS.

[Lefty052347]

I have a OmegaStar 240EX in a Dynaco ST150 chassis.  When I drive my 90db efficient speakers to my normal listening levels the heat sinks become warm to the touch but not hot.  However, when I drive my 85db efficient speakers to the same levels they get quite hot.  Both units are rated a 6 ohms.  The SongTowers are rated at 88db and 4 ohms.  Since the 240 is rated down to 4 ohms a single die Insight 240 would be adequate, but the single die devices would tend to run hotter than double die devices.  Also the double die devices would be good down to 2 ohms and thus able to deliver more current. 

Based on your total investment I don't see an additional $168 as excessive for twice the current capacity and around 10% more power for driving 4 ohms speakers.

Disclaimer:
As well as being a long time AVA customer (the ST150 was originally purchased in 1979) I have started working part time for Frank.

[avahifi]

Good advice, Lefty.  The double die upgrade certainly should not be a "deal breaker" in the overall scheme of things.

Its kind of like when I take a long vacation trip, I go for the best seats possible at the concert or play.  The increased cost is negligible compared to the overall cost of the trip.

Of course after doing this several times on my recent vacation trip - the first one in years, (from Venice to Barcelona on the Celebrity Summit) those nice "extra costs" sure did add up.

Regards,

Frank

[rcag_ils]

This part is only true when you order a new amp as "build to order", adding the extra cost for the "double-die" would not be a big deal.

But for the folks who already have the amp and need to "upgrade" them to the double-die, the extra cost, in my humble opinion, is not worth it, that's why I am not even considering it, not to mention I don't really need it.

The most sensible way to handle this is keep using the exsiting amp for at least twenty years, when the triple-die or quadruple die option come out, then do the upgrade.

[mark funk]

Did you go by Maranello and check out the Ferrari plant or see any F1 or F2 on your trip?


                                                   

[vintagebob]

I just ordered the Double 240/3 for my Salk Sound HT set which Jim is still working on.  I was just planning on driving my surrounds with my existing Pioneer SC-05, which will also serve as the preamp/processor.  Are you running a sub with your setup?

[floresjc]

vintagebob-

I'm doing essentially the same thing you are. I'm going with a double 240/3 for the front of my ST home theater and letting my Outlaw 1070 handle the rear 2. I do have a sub coming, Jim is building me a 15" Rythmik with dual 15" passive radiators.

I also ordered a double 440 and Insight EC preamp for my HT3's.

[savefarris]

i just ordered a pair of salk HT1s and a HTC, i was thinking about the 240/3 double die option.  what is the watts per channel after this upgrade? 

[vintagebob]

i just ordered a pair of salk HT1s and a HTC, i was thinking about the 240/3 double die option.  what is the watts per channel after this upgrade?

From AVA site:
"This option uses the newest Exicon "double-die" mos-fet output devices. Each device is rated at 250 watts, 16 amps, and 250 volts. The power and current ratings are twice that of the standard production devices. It is the same as using twice as many standard high current mos-fets in each amplifier. The result are even more powerful amplifiers with stunning dynamics and purity. Recommended for very difficult loads and for those that want to play unreasonably LOUD. The option price is approximately $22 additional per output mos-fet at the time of new production, or $42 per device as a retrofit to existing AVA Insight or Ultra amplifiers."

http://www.avahifi.com/

[floresjc]

i just ordered a pair of salk HT1s and a HTC, i was thinking about the 240/3 double die option.  what is the watts per channel after this upgrade?

Frank can correct me if I'm wrong, but as I understand it, the double die doesn't add so much in terms of watts. So a 240/3 at 125 or so watts per channel will probly go up a bit, but it will be capable of so much more current output and thermal capacity. The ability to push all that current is what makes it capable of driving tough loads during music playback.

[savefarris]

ok, pardon my ignorance but im not sure if im understanding that.  will it enable me to listen to music louder or will it make it more effortless while i am listening?  also will it do anything to add dynamics to home theater?

[JerryM]

ok, pardon my ignorance but im not sure if im understanding that.  will it enable me to listen to music louder or will it make it more effortless while i am listening?  also will it do anything to add dynamics to home theater?

I'm guessing it will do all of the above.

In another thread, Frank said this:

No, it is not a doubling of the rated power.  Power is higher because the output impedance of the mos-fet output device arrays are cut in half, so less voltage drop from the same source supply voltage and thus higher power.  This is different than the normal output impedance value, which already was very very low.  The advantages are that the power is shared by twice as much die area so that current, and power handling ratings go way up.  The result is a more "effortless" amplifier.

It could be done with a 350, but since the power there is lower, the benefits would not be as marked.

Regards,

Frank Van Alstine

The entire thread can be seen here.

Have fun with your choice, 
Jerry

[charmerci]

ok, pardon my ignorance but im not sure if im understanding that.  will it enable me to listen to music louder or will it make it more effortless while i am listening?  also will it do anything to add dynamics to home theater?

It will make the speakers play louder if they are inefficient and your amp runs out of peak power. I have 60 watts/channel AVA amp and my speakers are the limiting factor - not the power from the amp. I have this thing about not letting the woofers bottoming out. It's rather scary to see the woofers go so far in and out.

[floresjc]

Wow, crazy. I wonder how rocking you can get an HT3 on a double 440. Its a lot of power, but its a darn inefficient speaker. I'll have to see what kind of crazy woofer action gets going when I turn it up.

[Wayner]

If I may interject this here, amplifier power goes by the squared principal. to get something twice as loud from 1 watt you need 10 watts, twice as loud again, you need 100 watts, twice as loud again, you need 1,000 watts.

However, the extra power will give you more dynamic "headroom" for large musical bursts. That is what makes AVA so fun (and sometimes, scary) in their ability to drive a very dynamic engagement without any strain.

Also, every 3 db of gain in speaker effiency will also bring perceived amplifier gain. I have 2 different sets of speakers that are rated at 91 db, and require very little volume control to achive a relatively large sound field.

Wayner