Advice needed on choice of Amplifier

[LeontTP]

short answer is yes you should run it on low impedance selector.
Long answer is as the A-S700 measurements shown low impedance selector do limit Voltage so that it can better bare high Amperage, you lose a bit of output power and bit of performance but not much. Revel F35 falls to 3.5 Ohms around 200 Hz with sharp phase rise before that. Better safe than sorry.

So youre saying to run it at "Low" setting? Then I dont know who to trust here.

 

[ZolaIII]

So youre saying to run it at "Low" setting? Then I dont know who to trust here.

Speakers that are hard to drive - fall low on impedance while having sharp phase rise are not only bad on the long run to power amplifier (even if it's very tolerant to low impedance loads which old Yamaha Sanken A-B class isn't) but also to them self (voice coils got hot and trogh time expansion and temperature make them brake). As long as you don't push them hard everything will be OK with both but as we all get urge to from time to time do that (crunch it up), especially after cuple drinks and certainly not in the mood to poke with impedance switch then it's easier to simplify left it in low position.
Edit...
Use it in pure direct mode when you want to listen to close to reference calibration point loudness and when you want to listen on low to moderate volume you can switch it off and engage loudness (equal loudness normalisation) controls to approximate SPL (it goes to - 30 dB).
PDF measurements of A-S700 with impedance switch and loudness.
excelia-hifi.cz
[https://www.google.com/url?sa=t&sou...oQFnoECA0QAQ&usg=AOvVaw2xedP1iIMSrm3Tqkk7YyRp

 

[LeontTP]

Speakers that are hard to drive - fall low on impedance while having sharp phase rise are not only bad on the long run to power amplifier (even if it's very tolerant to low impedance loads which old Yamaha Sanken A-B class isn't) but also to them self (voice coils got hot and trogh time expansion and temperature make them brake). As long as you don't push them hard everything will be OK with both but as we all get urge to from time to time do that (crunch it up), especially after cuple drinks and certainly not in the mood to poke with impedance switch then it's easier to simplify left it in low position.

How loud are we talking here? Because I never drive my speakers over 100db really.

 

[ZolaIII]

How loud are we talking here? Because I never drive my speakers over 100db really.

Enough to put serious pressure to amplifier which depends on speker efficiency and power in W amplifier can provide. As long amplifier is not too hot to touch with a bare hand from above on where power stage is you are good.

 

[Deleted member 48726]

As indicated by the numbers posted by @ZolaIII you should run it at "high" impedance setting to get the most out of the amp.

 

[ZolaIII]

As indicated by the numbers posted by @ZolaIII you should run it at "high" impedance setting to get the most out of the amp.

If you really need all the power it can provide but again better safe than sorry.

It limits voltage rail and you lose output power but it makes that lower voltage more resilient on high Amperage (which 3.5 Ohms @ 200 Hz certainly is), there is less heat and diffusion and it's able to preserve it from overheating, diffusion caused leaking and it's able to preserve voltage stability from collapse (hard clipping) with pedal to the metal gain engaged of course.

 

[LeontTP]

As indicated by the numbers posted by @ZolaIII you should run it at "high" impedance setting to get the most out of the amp.

If you really need all the power it can provide but again better safe than sorry.
View attachment 291355

Sorry but Im just too uneducated about this to evaluate the best decision for myself.

 

[LeontTP]

Would you also have any advice regarding where to plug things in?

I only really play my vinyl and digital through PC. But since I already have a phono stage I can not plug it through there. Does it matter much or at all which other RCA ins I use for Phono and PC DAC signals?
The CD input has the "CD Direct Amp" setting which I assume is just like the "Pure Direct" button right beside it but only for the CD in. Or am I mistaken there?

 

[ZolaIII]

Would you also have any advice regarding where to plug things in?

I only really play my vinyl and digital through PC. But since I already have a phono stage I can not plug it through there. Does it matter much or at all which other RCA ins I use for Phono and PC DAC signals?
The CD input has the "CD Direct Amp" setting which I assume is just like the "Pure Direct" button right beside it but only for the CD in. Or am I mistaken there?

Difference between pure direct and CD direct is also explained in measurement review (difference is input gain adjustment for CD direct in short). For digital input I advise you to try SPDIF/Toslink inputs and all do the old embedded BurrBrown DAC ain't much for today's standard neither is analog input stage (old one in A-S700 whose far better, 6~10 dB better than newer ones in similar range), needless to say it's less important for external phone stage amp. In any case avoid long analog unbalanced cables when you can. Integrated phono stage should be solid.

 

[Deleted member 48726]

Sorry but Im just too uneducated about this to evaluate the best decision for myself.

I'd not worry. Put it in high and if you do not listen at full power for hours on end no problems should arise and you maintain the full power for those dynamics..

 

[LeontTP]

One more thing. Ive noticed that when the amp gets switched On it starts by only playing sound through one channel ( Right typically ). The connections are secure but plugging and unplugging them or playing loud sounds seems to kick the other channel into life again. This keeps happening every startup it seems.
Is this something that should not be happening? Id like to know as this unit was bought used.

 

[Zek]

Is this something that should not be happening?

It shouldn't be happening, surely.

 

[LeontTP]

It shouldn't be happening, surely.

Ill look into it.