[kyyuan]

Hi all,

I've had the pleasure of hearing Vinnie's 30.2 poweramp, which indeed has a very nice sound.  Now, I'm possibly changing my speakers that have the spec of 89.5 db sensitivity with actually 4/5 ohm impedance, which does not dip below 4 ohm.  Will the 70.2 work on these speakers?  Any feedback is appreciated.  By the way, I listen to all types of music, including large scale orchestral (e.g., Scheherazade).

Thanks,

Ken

[jrebman]

Hi Ken,

While I've not heard the 70.2s, I did have a pair of the original Signature 70s driving a pair of Acoustic Zen Adagios, which are rated at 89dB and 6 ohms.  The 6 ohms will draw even less power from the amps than your speakers will, and given that it looks like your crossover is a fairly easy load, you should be fine.

And yes, I could play the Adagios far beyond what any sane person would listen at and I never heard any compression on loud transients.

Of course what you and I call loud may differ (above I'm talking about a 90-95 dB average level) and your room, etc. will all figure into the equation, but I never felt the Adagios were underpowered with the Signature 70s.

HTH,

Jim

[Srajan Ebaen]

I own the Mark & Daniel Ruby and Maximus Monitors, 4-ohm loads each, 82.5 and 85dB eff respectively. The 30.2 with an active preamp ahead never had any issues whatsoever with either of these speakers, even when the optional OmniHarmonizer was strapped to them. In fact, the bass control was tremendous. Room was about 14 x 20 x 10, i.e. average, not too big, not too small. Loud to me is peaks of 95dB at the ear...

[jwes]

I own the Mark & Daniel Ruby and Maximus Monitors, 4-ohm loads each, 82.5 and 85dB eff respectively. The 30.2 with an active preamp ahead never had any issues whatsoever with either of these speakers, even when the optional OmniHarmonizer was strapped to them. In fact, the bass control was tremendous. Room was about 14 x 20 x 10, i.e. average, not too big, not too small. Loud to me is peaks of 95dB at the ear...

It would seem to make complete sense then that the 70.2's 70 W into 4 ohms (vs. the 30W of the 30.2) would have no trouble with my 88db 4 ohm (min of 3.6 ohm) speakers.  But it's hard not to think that the bigger grunt of the Spectron or the Wyred 4 Sound's would control these better and actually allow for finesse.  My desired sound is not loud so much, but resolution with relaxation but also controlling and driving the bass of my Dali's.  I would think if the 30.2 had no trouble with Srajan's speakers above, then the 70.2's would be o.k., but hard to tell on paper.  Also, maybe there was a high gain preamp in the equation. 

[kyyuan]

Thanks for the input, guys.  My room size is approximately 25x15x8.5, which is not small and not too big.  While I don't listen at a crazy loud SPL level, "ease of sound" is important to me.  As mentioned, I listen to some large scale orchestral music, which requires lots of headroom.  Of course, I realize an in-home trial is the only way to know, but any thoughts are appreciated.

Jim -- are you using something else to drive the Adagios?

Srajan -- your Ruby & Maximus are nice examples.  Again, I think the 70.2 should be fine for normal listening, but I'm not sure about the requisite headroom for orchestral.

[jrebman]

Ken,

My room is roughly the same size as yours -- 30' on one long wall, 26' on the other, 14' wide and 9 foot ceilings.  My guess is that you're going to be ok, because even though the 70s are rated at 70 watts into 4 ohms, that's at .04% total noise and distortion, but they can do 90 or so watts with the distortion going up to .4%, and these amps put out more power at lower impedances, so again, I'm guessing you'll be ok.  You're right though, you really just need to try them.  The Signature amps do have this amazing ability to pump out some real current that belies their power ratings.

I don't have the Adagios any longer and the only other amp I used with them was a Cayin A70T 60 watt PP kt-88 amp, and that too drove them very well.  Keep in mind that I've been talking about the original Signature 70s and not the 70.2s, but in terms of power, there is probably little to no difference.  Based on my experience with the original 70s and the new 30.2, the .2 amps are a huge leap forward in sound quality.

For another point of reference, I'm currently driving a pair of ACI Sapphire XLs 85.5 dB 6 ohms, with the 30.2, and even though with some sources and materials I can crank the amp fully open and still wish for some more volume, the source is a modified squeezebox with a 1.0 v output and no additional buffering, preamp, etc. -- just directly into the amp, and I'm sure a good preamp would give me the extra drive to really make things too loud to stand.  Mind you, this condition is on relatively few albums that were recorded at a low average level -- most from are remasters of 70s and 80s.  With more typical music 2:00 to 3:00  is in the 90-95 dB range at the listening position.

Hope this is of some more help,

Jim

[Afterimage]

I will echo what Srajan said.  I own the Mark and Daniel Ruby, and the 70.2  has no problems driving them.  I can crank them and there is no sign of break up. 

[Srajan Ebaen]

For an added data point: I use the Ruby as an amp destroyer. Not literally of course but because of the forced bass alignment, the speaker's lust for current and the low efficiency coupled to a low-ish impedance, you can readily hear when an amp simply doesn't have the balls to - um, get it up. The bass will become boomy, loose and ill-defined and the speaker will lose overall definition even if the amp can deliver all the SPLs desired. That's why I was personally so surprised that the bloody batteries in the 30.2 apparently are real champs in the current delivery department, doing better Ruby bass than amps which on paper should be superior. So control is not the issue at all. If you need large SPLs because your room is big, you sit far away *and* you like it loud, get an active preamp with 20dB or more gain and you'll be fine. Or, add some gain by way of an appropriate source. My Ancient Audio CDP for example can output 7V max rather than the industry-standard 2V. Gain issues can easily be addressed ahead of the amp 

[Vinnie R.]

Thanks for all your posts!

With 89.5dB, 4-ohm speakers, the 70.2 will have absolutely no trouble delivering the goods!

As good as the 30.2 is, the 70.2s offer even better bass response, sound staging and imaging, and spaciousness.  This is the result of separate SLA power supplies for each unit, complete isolation between the channels (dedicated amplifier boards per channel), and the change in the output stage circuit configuration (paralleled output mode).

Best regards,

Vinnie

[-Richard-]

I originally owned and loved the Signature 30 but upgraded to a Signature 70 on Vinnie's recommendation (Vinnie knows my system very well and what I am trying to achieve sound-wise) and further upgraded to the Signature 70.2... again on Vinnie's recommendation.

The Signature 70 and the Signature 70.2 sound entirely different to me than the Signature 30 in exactly the way Vinnie suggests. Except I think Vinnie is being a bit too modest here. Using a tube preamp that has a 20db gain (as Srajan suggests) I am currently amplifying 2 pairs of drivers hooked up in parallel that create 4 ohms of resistance. The sound is quite extraordinary. It sounds more "spacious", more fully "present", and more tonally rich than any of the marvelously designed SET's I have heard so far. Actually the sound is uncanny... entirely holographic and spills into my listening space with the force and color of exploding fire works... and no SET has this level of micro-interior detail as well. This is the combination of choice for me and Deborah.

The Signature 30.2 is wonderful. With the right tube preamplifier the Signature 70.2 shifts into SingleEndedTriode territory with a more highly saturated musical palette and presence on every level.

With Warmest Regards ~ Richard