AR SP8 mk2 high output volume

Yep, let’s go full circle and get dizzy again, just ditch the AR and use the A30 the way it was meant to be used. And if you don’t like what the source is giving then, change it instead.

Here is another alternative, leave the A30’s volume up full, or again better still take it and the input selector out, and replace it with a 100kohm resistor to ground.

And then get full 6db shaved off the AR preamp’s gain, by a tech to do this.
Parallel R39 (another 39kohm) resistor across R29 (also a 39kohm) resistor, this makes it 19.5kohm, more feedback less gain is the result could sound a bit cleaner also.

AR output stage circuit diagram. https://ibb.co/Chrcx4t

@Georgehifi do not see in any review of the A30 R what you comment as a novelty

https://ibb.co/J7fFmwm

Puresound A30R https://ibb.co/mX2M6CM

Just found this, the newer Puresound A30R model which among other things like 2 power tranies, now also sports a new 4th input call "fixed"
This suggests to me now it can be used as a "proper poweramp" with the volume control and input switching out of circuit when the "fixed input" is used by another preamp or sources with volume control.
https://ibb.co/J7fFmwm

Cheers George

The worst area of rolloff is typically around the middle of the control range

That will be for linear pots, with logarithmic pots it’s more like 1-2 o’clock as we have here with a 100kohm "A" taper pot. If this amp were to used as a poweramp, it would be better for the volume control to be removed and a 100kohm resistor in it’s place to ground, and the gain dropped by 50% by a tech, Then there will be no series resistance causing any HF filtering. And a + could very well be a tighter bass with lower gain/higher feedback, which was it’s only area of question in reviews.

"beautiful sound with minimal distortion, but not too well-controlled bass"  

Cheers George

Whatever, Ralph's told you as well, you can see the forest for the trees, and not worth the effort.

I would like to know your opinion and if you consider its high output volume a problem with this power amp. AR SP 8 mk2 Problem is the volume control is too low, Very sensitive amp. I can’t use much volume control.Does this affect the signal quality.

This is what you asked, you’ve been told, now your making everyone dizzy.

@georgehifi Do you think I’m lying when I say that I like what I hear when I connect the AR?

Not in the least, but you started this thread asking for answers to your high gain problem, you now have them and don’t care to look at what’s said here, and not just by me. Like I said your going round in circles.

Cheers George

@Georgehifi I will not make decisions because they are necessary to respect the Nelson Pass Bible.

I'm saying that the easiest cheapest way out of your high gain predicament, with "gods" recommendation to back it up.
 
Unless you want to have sound quality compromises, by having two volume pots in the siganl path or voltage dividers ( Rothwell attenuators)  at the inputs of the A30 both causing impedance mismatching problems.
 
But seeing this AR pre seems to be some sort of cherished attachment, and your not keen to dump it
Then the A30 needs to be mod'ed properly, input switching and volume potentiometer disconnection, with 100kohm loading resistor to take it's place to ground and a 50% gain lowering, all done by a tech with view on stability still, is the only other way out!!

You can't have your cake and eat it too. So suck it up and do one or the other. because your just going around in circles unless you do.

Cheers George

BTW I do not recommend tampering with the feedback resistor- such things can lead to oscillation

tenoris OP

This is why I say get a tech (not yourself) to disconnect the Alps passive, change the gain with the feedback to half of what it is, as he will scope it and compensate for stability.
And then once that is done you can use your AR preamp which you are so insistent on using, with the volume up around or over 12 o’clock. And this is what you searching for.

Cheers George

This just keeps going around in circles, if you don’t like the sound when it’s used as an integrated, change the source to one you like, instead of coloring it with that premp, and then having your problem of way too much gain.

Just look at the specs of the A30, it’s at FULL POWER already with ONLY 0.5v (500mV) input from a source. Most sources today put out well over 2v!!!

So just use it as is with it’s own passive volume control, and remember Nelson Pass saying to you ("psychological need" to turn it up more) than when the AR pre is in and then sell it.

Nelson Pass,

“We’ve got lots of gain in our electronics. More gain than some of us need or want. At least 10 db more.

Think of it this way: If you are running your volume control down around 9 o’clock, you are actually throwing away signal level so that a subsequent gain stage can make it back up.

Routinely DIYers opt to make themselves a “passive preamp” - just an input selector and a volume control.

What could be better? Hardly any noise or distortion added by these simple passive parts. No feedback, no worrying about what type of capacitors – just musical perfection.

And yet there are guys out there who don’t care for the result. “It sucks the life out of the music”, is a commonly heard refrain (really - I’m being serious here!). Maybe they are reacting psychologically to the need to turn the volume control up compared to an active preamp.”

Cheers George

@georgehifi thank you very much for your advice. If you take it to a technician, you could also complete the operation by reducing the gain at any of the Puresound inputs.As I have already mentioned.

Sorry but no, again introducing series impedance at the A30 inputs is not on, with no thought for impedance ratio matching (min 1:10) between stages.
Best would be to completely take the Blue Alps out of the circuit (not just turn it up or bridge it out) introduce a metal film 100kohm input resistor to ground , and then reduce the gain by 1/2 of the total preamp tube stage with feedback resistance of R14 on imhififan circuit diagram.

Cheers George

tenoris OP
This amp cannot be used as just a poweramp it’s always got the volume control in the signal path, at best it can be said it’s a poweramp with fixed input level controls and source selection.

There is "no rca power amp input" on the back of this amp, as the pic shows, https://ibb.co/fNVJzTb , it only has Tape CD and AUX, aux is also an input for any low level source, but it is not "poweramp input". If it were the passive volume control on the front would not work, and you say it still does.
So once again for the best sound just use it as a Integrated amp which it is, and flick the AR pre.

Or take it to a tech and get the A30's volume control and iput selector fully disconnected then it will be a poweramp, and still use your AR pre, but your going to be back in the same boat with too much gain, with the AR volume down around 9 o'clock.  

Cheers George

There's no power amp input on this, just use it as an integrated and flick the AR.

https://ibb.co/fNVJzTb
Cheers George

tenoris You said it was a poweramp, in your opening post
Ralph is correct the A30 is an integrated!!!
1 o’clock is fine, just use it, it’s probably a passive in front of a poweramp any way, it uses a genuine Alps "Blue Velvet" volume control which is very good.

https://ibb.co/hH8kYpj
.
https://6moons.com/audioreviews/puresound/16.jpg

You are degrading using two preamps, sell the AR pre.


Cheers George

Even better to use the Schiit Sys straight into the amp, if the amps input is 30kohm or higher like the OP's 100kohm A30.

Cheers George

tenoris
Does this affect the signal quality

Yes very much so, as Nelson says below, your throwing away much of the sources output level by turning down the volume of the AR, so the tube gain stage of the AR preamp can make it back up again, which means noise figures are worse, with added distortion.

Perfect reason to go direct if you dac has volume or  just get a good passive.

Nelson Pass,

“We’ve got lots of gain in our electronics. More gain than some of us need or want. At least 10 db more.

Think of it this way: If you are running your volume control down around 9 o’clock, you are actually throwing away signal level so that a subsequent gain stage can make it back up.

Routinely DIYers opt to make themselves a “passive preamp” - just an input selector and a volume control.

What could be better? Hardly any noise or distortion added by these simple passive parts. No feedback, no worrying about what type of capacitors – just musical perfection.

And yet there are guys out there who don’t care for the result. “It sucks the life out of the music”, is a commonly heard refrain (really - I’m being serious here!). Maybe they are reacting psychologically to the need to turn the volume control up compared to an active preamp.”

Cheers George