advertisement


Rega Amplifiers and “Simulated Class A”?

Tha
No need to measure anything, Rob, mystery solved.

image-asset.jpg
That’s from the Brio. Does anybody know the full text on the io board? All I can read are snippets, it looks like “…mojo, it flies…” and “enough time, it’s an electric…” It could be “through time…” but I can’t tell for sure. I’m basing this on the internal photo of the io on the Rega website.
 
I'd certainly like to understand more about it.
I enjoyed a little IO so much that I just picked up an Elicit-R and judging by the heatsink temps after about 1 hour idling, the bias is definitely cranked up substantially compared to peers.

I usually struggle to differentiate between 'competent' SS amplifiers (Cyrus, Arcam, Naim, Linn, Audiolab, Marantz, bla bla bla) but there is something subtly different about these Rega amplifiers, and in a good way. Super refined and sweet, full bodied even at low listening levels - rather like the promise of Class A.

Whatever Terry is doing, carry on!

PS: I'll measure the mains current draw tomorrow, should be interesting.

Nice one Rob.
Like you after exposure to the IO went for an Aethos as my usual Bryston pre @ power where 30 years old and where definately in need of a recap etc.
So pleased I got the Aethos.It really has this amazing grip even at low levels.Where as some amps you have to turn up to get them to snap into focus.
My Aethos gets hot if I have been playing at 12 oclock but most of the time at 10 oclock its just warm.
The Aethos and as you say the Elicit - R has that very smooth class A sound about it.
Happy listening pleasure with your Elicit - R
 
Nice one Rob.
Like you after exposure to the IO went for an Aethos as my usual Bryston pre @ power where 30 years old and where definately in need of a recap etc.
So pleased I got the Aethos.It really has this amazing grip even at low levels.Where as some amps you have to turn up to get them to snap into focus.
My Aethos gets hot if I have been playing at 12 oclock but most of the time at 10 oclock its just warm.
The Aethos and as you say the Elicit - R has that very smooth class A sound about it.
Happy listening pleasure with your Elicit - R

Thanks:)

Agree entirely on the performance at low listening levels where all of these new-ish Rega designs work especially well.
While I do like to crank the volume sometimes, mostly that's not the case so performance at lower volumes is very important.

Love the look of the Aethos and I was quite tempted, but got the Elicit when I spotted a really good 'open box' deal on one from a dealer. £350 discount not to be sniffed at.

I'm replacing my Cyrus boxes with Rega. Also have the Mk3 Aria phono stage and that's also a peach.
 
I'd certainly like to understand more about it.
I enjoyed a little IO so much that I just picked up an Elicit-R and judging by the heatsink temps after about 1 hour idling, the bias is definitely cranked up substantially compared to peers.

I usually struggle to differentiate between 'competent' SS amplifiers (Cyrus, Arcam, Naim, Linn, Audiolab, Marantz, bla bla bla) but there is something subtly different about these Rega amplifiers, and in a good way. Super refined and sweet, full bodied even at low listening levels - rather like the promise of Class A.

Whatever Terry is doing, carry on!

PS: I'll measure the mains current draw tomorrow, should be interesting.

Interesting!
I wonder how similar the Rega circuit is to the old JLH one? IME this type of circuit (if the Rega is similar) has a quite distinctive sonic signature - I think of it as "harmonic enhancement".
It is (too) apparent in many 1970s Japanese amps and less so in the Ion Obelisk etc.
If Rega have managed to dial in just the right amount of "harmonic enhancement" then I'm not surprised it's nice to listen to.

This approach does have its limitations, but especially for 2nd system type use, the compromise is a good one.
 
Elicit is symmetrical amp seemingly derived from Borbely and Borbely-Lender schematics and brio is a pretty crude op amp input unit similar to the Audio Analogue Puccini.
 
Elicit is symmetrical amp seemingly derived from Borbely and Borbely-Lender schematics and brio is a pretty crude op amp input unit similar to the Audio Analogue Puccini.

Not the newer ones Jez. All from about 2012/13 share the same fundamental topology. Better implementation, power supplies, components etc as you go up the line.
 
Not the newer ones Jez. All from about 2012/13 share the same fundamental topology. Better implementation, power supplies, components etc as you go up the line.

OK will take your word on that:) I only have the schematics which are available on the WWW.
 
I guess the question of Rega having a marketing dept or not comes down to how one views the function of marketing. As they have a spiffy website, do brochures and the provide the press with product, graphics, copy and interact with their customers and retail partners/distros its fair to say there's a marketing function at Rega.

Though I applaud them for never paying for an advert themselves in their home territory.
 
I was poking about inside my Elicit-R recently, as it was running damn hot and cut out a few times. The output stage has +/-54V rails and 0.22R emitter resistors, which in my opinion are too low for good bias stability. I believe the transistors should be biassed for around 80mA idle, i.e. about 35mV across both resistors. Mine were running at least double that. The heatsinks were reaching around 70 deg C near the centre, hot enough to boil a monkey's bum.

I emailed Rega repairs a couple of times just for confirmation on the numbers before I started twiddling pots, but I didn't get a reply; they don't like dealing with the proletariat directly, seemingly.

It's tricky to set the bias - the pot is single turn and the testpoints couldn't be more inaccessible. You need three hands, two of which must be steady. If yours are like the Wako Kid's left then forget it - you've got no chance.
 
If you read the recent IO vs. Brio thread, towards the end I posted about the actual circuit. As best as I can tell based on info from Rega, it's based on the John Lindsley Hood class AB circuit from 1970, as I recall. That circuit attempted (presumably successfully) to emulate class A as far as no crossover distortion viz-a-viz a novel driver circuit

https://startfetch.com/jlh/jlh-1970-ab-amplifier.pdf
That's still an AB, but with high open loop output resistance and a high quiescent current
 
a complementary pair of Darlington output transistors
There's a YouTube video where Michael Fremer tours the Rega factory. I am linking to Roy Gandy talking about Terry Bateman's discovery of what John Curl discovered in the 1970s (at 22:35 in the video).

If I understand correctly (I know almost nothing about electronics), he is saying that Rega used to use transformers to improve sound quality, but they now understand why that worked and are starting to use pairs of FETs in some amplifiers. But he's talking about input stages, not output stages. Does this shed any light on the matter?
 


advertisement


Back
Top