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Pass Aleph Questions

I know I've posted a few questions about the Aleph 3 thus far, and I both own and love this amplifier. Even the bass is sufficient with my Proac 2.5's. But I'm about to upgrade to an Aleph 5 for a couple of reasons. The following are a combination of reasons and questions - any experience, insight, or info would be greatly appreciated.

1. The low power of the Aleph 3 (30 wpc Class A) requires that I have to turn the volume up to 3 o'clock on my Rogue 66 preamp. I don't think it causes any detriment to the sound, but don't know. Is it a bad thing to have to crank the volume control on the preamp up that high?

2. Does this volume control issue have anything to do with the input inpedence of the Aleph series? The Aleph 3 has an input inpedence of around 27 kohm and the Rogue 66 has an output impedence of 650 ohm. Using a 10:1 ratio, I've been told this should not present a problem. Is this true? Does it account for the response to the volume control, or is that more a power issue. The Aleph 5 has a single ended input impedence of 10 kohm. The Rogue 66 still falls under the 10:1 rule of thumb. Can anyone say whether this would cause any problems?

3. The Aleph 5 has both balanced and RCA inputs, which would give me more flexibility with cabling and cable distance. Shouldn't balanced cables be better with longer runs?

4. Peter at Pass Labs says that the Aleph 5 is sonically an improvement over the Aleph 3. I don't think everyone necessarily agrees with that. Has anyone compared the two and formed conclusions?

Thanks All.
peter_s
phild
603 posts
 
I think your volume control issue has to do with the preamp/amp sensitivity, not the amps power. It shouldn't matter if turning the volume to 3 o'clock doesn't add extra preamp noise...I don't see a problem if the pre is quiet at that position. That doesn't mean that the 5 won't sound better in other ways, and yes...balanced could be nice.
quinntheeskimo
20 posts
 
Hello Peter_s,

I have used an Aleph 5 for awhile now, after having an Aleph 3 for awhile on a loan before that. I find that the 5 has more controlled bass, and an overall authority that controls my speakers in a cleaner fashion than the Aleph 3. However, both are pretty similar in their midrange lushness and the very smooth top end. I found both amps to be quite listenable and not fatiguing for extended periods of listening.
I know from chatting with Pass Labs that they do believe that there is a general progression in peformance climbing the ladder. I would hope this to be true, as there's got to be something other than power rating to justify price increases in products? However, the current source and internal components are all quite similar, and therefore, the two models probably are pretty close in a lot of respects. I do not think you'll be unhappy if you get the 5, though.

Cheers!

Quin Greenville
Laramie, WY
subaruguru
1,376 posts
 
Hi.
Remember that the 5 is only 3 dB louder than the 3. Is that enough? What is the lowest impedence dip and phase angle of the Pro_Ac 2.5? And how loudly do you want to listen? Or is it bass dynamics that are wanting?
I had to go to the Aleph 2 monos (they're around for under $3k/pr, vs $1800 for a 5) to get the 160w/ch/4ohms my Parsifal Encores' 4 ohm woofers needed.
Sounds like you should try the 5. If it's dynamic enough during bass whomps and orchestral crescendi without compressing than you're done. If not, then I'd get new speakers before spoiling 2.5s with Aleph 2s! Ha!
unsound
7,329 posts
 
Keep in mind that your volume control acts more like a brake than an accelerator. Many old time audiophiles believe that a volume control works best when set around 2:00.
rsfphil
139 posts
 
The Aleph 3's gain is only 20db. Most amps have a gain of 26db or higher. If the Aleph 5's gain is the same you will need the same amount of gain from the preamp. As long as it can play loud enough and there is no noise problem the 3 o'clock setting is fine. Generally the more wide open the volume control the better off you are.
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