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Rega Aethos. Missed a trick?

In full agreement Craig B, Paul has been a great addition to the pfm family over the years and his contributions and the Rega (Aethos) have added to my desire to own a Rega product in 2021. ( Once the non related full refund comes through from elsewhere wink ).
 
wow&flutter said:
Hard to tell from the interior Rega pics but here’s one from the web. The pot is mounted below the board but does appear to show two rows of four solder joints similar to an alps (if you zoom in!).

https://hifilounge.co.uk/product/rega-aethos-integrated-amplifier-ex-display/

Here’s one for the technical guys, are Rega using a passive pre in the Aethos like in the Osiris and could this implementation be contributing to the issues mentioned?

Just found this in the Hifilounge description, looks like a ‘blue velvet’ pot.


PRODUCT DETAILS

VOLUME CONTROL AND LINE AMPLIFIER TECHNOLOGY

The Aethos uses a high performance combined feedback and passive volume control plus line amplifier, which was originally developed for the Elex-R. Improvements have been made to the volume control and line amplifier stages in the Aethos with the use of discrete FET input operational amplifiers using the Linear Systems LSK389 FET and the well-respected RK27 ‘Blue Velvet’ potentiometer. The feedback and input levels are varied to set the required volume level. The level and tracking between the two channels is set by the close tolerance parts in the pre-amplifier circuit and less by the actual potentiometer itself, thus keeping the mismatch of channels due to volume control tracking irregularities to a minimum, further improving on the performance of the RK27 potentiometer. As well as keeping tracking irregularities to a minimum, this method also reduces noise and input overload as the control will only ‘use’ the required gain to amplify the signal. This form of volume control is normally only found in professional broadcast environments where accurate low noise control of levels is required.
Click to expand...

Sounds interesting. Hats off to them if they have managed to overcome the channel imbalances and improve the performance of the Alps pot.
 
I believe the Aethos and Osiris both use the ALPS blue velvet pot.

But from what ive read and going from memory [this may be wrong so happy to be corrected] the Osiris uses a full passive preamp , where as the Aethos uses an active pre amp with passive volume control.

Personally the Osiris has the best remote volume control ive ever used. The volume knob has a large useable operating range , going from 7 oclock to approx 11 oclock. But i never have need to use the knob , as its easy to adjust the volume with the remote in small amounts.
 
From Hifi Critic:

Using this volume control is a mixture of good and mildly infuriating: the channel balance does seem to be exceptionally good, even at extremely low levels, but less satisfactory is the enormous change in gain available in less than a quarter of a rotation. Add in a remote motor that doesn't happily make fine adjustments and you have an amp on which it can be tricky to set the correct listening level, particularly with sensitive speakers.
 
I wonder how long some of these reviewer folk hold down their mouse button whilst clicking on 'submit' for the dreck they author?
 
wow&flutter said:
I do remember having my hands on a big Pioneer amp briefly back in the 70’s that had physical clicks in the rotation of the large volume knob and the difference between clicks was substantial. There was though a -20db mute switch which from memory felt like it permitted finer adjustment.
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Are you sure it wasn't a Sansui AU-717 or AU-517?

The 717 sitting in front of me has stepped potentiometer and a -20db muting switch! Though in reality I believe it is just a 4 gang Alps with detents they had custom made.
 
I don't know but there does seem to be a little issue with the volume and remote control that's worth knowing about. No harm pointing it out, and I'd expect Rega will take these comments on board.:)

whoops, boojie beat me to it, I must have been dawdling with me mouse, anyways my remark above was meant to be in reply to Craig's....
 
booja30 said:
Are you sure it wasn't a Sansui AU-717 or AU-517?

The 717 sitting in front of me has stepped potentiometer and a -20db muting switch! Though in reality I believe it is just a 4 gang Alps with detents they had custom made.
Click to expand...
Pioneer integraded amps were the same during most of the 1970s; stepped volume control with a 70dB range in 2dB steps. With such as classic JBL/Altec there was a fine line between 'that's nice, dear' and 'turn that feckin' shite down!'.

The -20dB muting likely saved a few marriages, and/or kept a few of us then young lads from being tossed out of the nest prematurely.
 
Craig B said:
Pioneer integraded amps were the same during most of the 1970s; stepped volume control with a 70dB range in 2dB steps. With such as classic JBL/Altec there was a fine line between 'that's nice, dear' and 'turn that feckin' shite down!'.

The -20dB muting likely saved a few marriages, and/or kept a few of us then young lads from being tossed out of the nest prematurely.
Click to expand...
Interesting. My 717 came with the original manual (and unused rack handles, unused rear bumpers, and even a set of Sansui phono cables). The manual suggests using the -20dB switch when cueing a record, and when tuning the matching tuner. But it does make sense to use it full time with modern sources to get finer volume control. I also noticed since it's not really a stepped attenuator, you can get away with setting it half way between detents.
 
booja30 said:
Are you sure it wasn't a Sansui AU-717 or AU-517?

The 717 sitting in front of me has stepped potentiometer and a -20db muting switch! Though in reality I believe it is just a 4 gang Alps with detents they had custom made.
Click to expand...

I think it was an SA8800 or SA9800, one with the fleuroscan display on it. The knob test guy would have lost his mind if he got his grubby fingers on it!
 
Tryant said:
Is that really asking a lot of an amplifier designer? You would think a £3k amp would have a well-implemented volume control of some sort. Does the Aethos just have an ordinary analogue pot?

On the other hand, I pity poor Paul Darwin having to field all these questions constantly.
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I think the operation of the volume control is explained above in the thread (AIUI, at least, from online sources). I have no idea whether the reported sensitivity is with sources and loudspeakers within a fairly normal range, but yes - there are technical ways to improve handling a large range of uncertainty.

But this comes at an engineering and commercial cost and perhaps a user set-up cost too. The non-technical issues here are well beyond my knowledge so I can't comment. But non-technical constraints are inevitably present in any commercial design. So there will always be some cases where user needs are not going to be met. The art for any kit maker is to make a good enough call on the compromises.
 
For what it is worth, with my pc as source into my LM 502CA DAC, I have a similar problem with high gain making the Dact2 volume control steps a little too big on my preamp when I use output 1. Luckily I had David lessen the gain on output 2 of my AD Audio Satchmo so when I use that output, all is well.
 
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John Phillips said:
I think the operation of the volume control is explained above in the thread (AIUI, at least, from online sources). I have no idea whether the reported sensitivity is with sources and loudspeakers within a fairly normal range, but yes - there are technical ways to improve handling a large range of uncertainty.

But this comes at an engineering and commercial cost and perhaps a user set-up cost too. The non-technical issues here are well beyond my knowledge so I can't comment. But non-technical constraints are inevitably present in any commercial design. So there will always be some cases where user needs are not going to be met. The art for any kit maker is to make a good enough call on the compromises.
Click to expand...

I haven't used this amp either and am just responding to comments made on this thread and a couple of reviews I've seen that mention the issue. I have though used other Rega (and other) amps where the sound level went loud with a quarter turn of the knob with average sensitivity speakers. Isn't this business with the gain the old sleight of hand to make the amp seem more powerful to the unsuspecting?
 
Yeah, hilarious. Craig already made that joke upthread. But hang on, you were suggesting in-line attenuators.:rolleyes:
 
Tryant, using Aethos with cd as we speak and 11.00 is not loud around 13.00 with vinyl. The OP was about speed of remote operation not usable volume.
 
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