Aries Cerat Protos - class A TriodeFET integrated amplifier in a compact case (can see 2 Ohms load)

[orfeo_monteverdi]

[please forgive my poor English]
Since the thread entitled 'Audio Note vs. Aries Cerat vs. darTZeel' literally became a Protos thread (from post #185) in which valuable information over the Protos were posted, and since there is no dedicated Protos thread yet, I took the initiative to create one, for the sake of clarity.

Before the discussion over the Protos goes on, I will first quote here all the existing posts from the aforementioned thread.

Here is a little TABLE OF CONTENT
1. VoicesInMyHead bought a Protos
2. What are the tubes he uses with the Protos ?
3. Were you able to demo this model before making your commitment, or did you take a giant leap of faith ?
4. Morricab has personally have settled on the E280F tube, but tried other ones
5. with a tube a 6j11p-e tube
6. Protos as a power amp? (+preamplifier)
7. Bias - Bias settings (20? 21? 22?)
8. Bias - Aries Cerat answers (Stavros Danos)
9. tube baking ?
10. Protos soundstage
11. input impedance?
11. E280F tube
12. Morricab answers:

- input impedance​

- bias settings controller​

- E280F & bias​

13. Protos & phono stages compatibility; display


(it took me time to do this. In case of such a previous thread drift, creating a new thread is advisable. Tx)

Single stage, Single Ended, TriodeFet technology.
Single stage amplifier, from input to output posts.
20W @8ohms
TUBES: 2 x 6j11p-e, compatible with: E280F / E282F / E810F / E180F, D3A
61 step Resistor ladder, relay switched volume control technology
DIMENSIONS:
Main unit: 500mm W x 490mm D X 170mm H. 60kg
PSU (transformer unit /soft start) unit: 190mm W x 310mm D x 70mm H. 5kg

 

[orfeo_monteverdi]

POST 1 - VoicesInMyHead bought a Protos

now my Protos has finally arrived and I've been in heaven for a few days with music constantly playing. to say that I'm happy is an understatement, this amplifier is everything I could possibly wish for and more, the sound that comes out of it is simply fabulous! I've gone through some nice integrated amps during the years which has all been good in their own ways and I've appreciated them all very much, but Protos is to me in its own league, no competition! I think it has everything, it has warmth, it sounds natural and organic, it has amazing details and soundstage, depth and height, it has muscles and bass, it brings out engagement and emotions, there's no tendency of listening fatigue or anything sounding harsh or aggressive in my ears. I can play really loud with this thing, and I want to keep that volume coming up! this is a an amazingly fun and addictive amplifier, I simply love it!


it's big and heavy though! it's not very practical in that sense. I thought my Absolare was big and heavy, that was lightweight in comparison. the packaging and padding within the wooden box was impressive and the overall feeling when unpacking was absolutely top quality. I love the remote, the little box containing tubes (and spares) and a nicely looking manual in a hardcover book form. small things maybe, but they absolutely add to the lovely feeling when unboxing and setting it up for the first time.


of all the gear I've bought and heard in my system during the years, this is the best! I've never been as happy and satisfied with anything before. nothing comes even close. so yes, I guess I can recommend it...

 

[orfeo_monteverdi]

POST 2 - What are the tubes he uses with the Protos ?

thanks! about tubes, I can't really tell either name or type from these... looks russian though this is actually the spare ones, the main ones look similar but came in white boxes but due to an "incident" I'm actually running the spare ones now. maybe not what I would have chosen myself, but I have nothing to complain about regarding the sound as for now. any recommendations?

 

[orfeo_monteverdi]

POST 3 - Were you able to demo this model before making your commitment, or did you take a giant leap of faith ?

thanks! I listened at my local dealer with speakers of the same brand as I have at home. it was an instant love affair! I wasn't even supposed to listen to the Aries Cerat, it just happened to stand there craving for my attention, but once it started playing there was no going back. I was actually so sure about what I heard that I didn't bother trying it at home, which I always try to do otherwise.

 

[orfeo_monteverdi]

POST 4 - Morricab has personally have settled on the E280F tube, but tried other ones

I personally have settled on the E280F but I tried these little Russian ones early on and my amp took a long time to fully break in, so I need to given them another shot at some point. I also liked the E810F but need to go back to them again as well to be sure. That said, I have always liked the E280F sound in my Incito and the Genus I had earlier. There is a good reason Stavros uses that tube...it sounds superb!

 

[orfeo_monteverdi]

POST 5 - with a tube a 6j11p-e tube
[/QUOTE]
personally have settled on the E280F but I tried these little Russian ones early on and my amp took a long time to fully break in, so I need to given them another shot at some point. I also liked the E810F but need to go back to them again as well to be sure. That said, I have always liked the E280F sound in my Incito and the Genus I had earlier. There is a good reason Stavros uses that tube...it sounds superb!
[/QUOTE]

 

[orfeo_monteverdi]

POST 6 - Morricab uses an Incito preamp with his Protos and fixed Protos as a power amp

I am using an Incito preamp with my Protos and fixed Protos as a power amp…find that works better with non-AC sources.

 

[orfeo_monteverdi]

POST 7 - Regarding the bias settings (20 ? 21 ?)

I set it to 20 per recommendation from the manual, but I was about to ask about that because it fluctuates quite a lot, and it’s probably not supposed to do that? Maybe I should switch to the “intended” supplied tubes and see if they are more stable?

If these are NOS tubes that have still been used, then it can vary. Put the tubes in the oven for 3 hours at 130-150 degrees, then let them cool down before opening the door. Then try again. It's a tried and tested trick. I do it for every 6c33 tube. I think it works for your tubes too. If it doesn't run stable then new tubes will be needed.
you age the tube with the procedure then usually run more stable.

 

[orfeo_monteverdi]

POST 8 - Bias: Aries Cerat answers (Stavros Danos)

I set it to 20 per recommendation from the manual, but I was about to ask about that because it fluctuates quite a lot, and it’s probably not supposed to do that? Maybe I should switch to the “intended” supplied tubes and see if they are more stable?

Hi
The bias will drift for three reasons
While tubes warm up and settle.6j11 change quite a bit while warm up
While they burn in after new install,takes few days to fully settle.
Also bias drifts while following mains voltage variation within the day.
The bias meter being digital and accurate enough has the downside that make user osc about it when it changes a bit .Do not overly think about it ,let it drift while in the day, as it will track the psu change.
Only change tube if you see big changes downwards during the days.

Do experiment with higher and lower values,as long as you are within operating envelope, try and find you like more.

Cheers
S

thanks! this all seems very reasonable. with the "spare tubes" I had one tube drifting off from 20 almost down to 15 and the other in opposite direction from 20 to 24 which just seemed a bit much to me, but as you say it can maybe be burn in and other reasons. I popped the other tubes back, not sure it makes any difference, but that's how it goes in my head if something is marked as "spare" or "backup"...

my friend who helped me set it up actually said "this is the reason I can't buy this amp, I would not be able to calm down unless those numbers are in sync!", I think I'm a bit more chill about it though...

is it possible to say what happens or what to expect to sound character going up versus down? or does it depend on tubes?

btw, thank you SO much for the instant support the other day, it made all the difference to me!

Hi

Do not overthink about the meters not being in exact on sync. Just for reference, if these were analog meters , you would not even notice movement, but when you have digital meter with 0.X resolution , the accuracy goes against the peace of mind

If you go above sweet spot, the tonality "thickens" a bit and vice versa.
The sweet spot value depends on tube type, tube batch, and system/preferences.
Take your time to learn the amp at ~20 and then try ~16, and then ~30ish values, see what it does to you and your system.
If you get the sonic differences on two bias ends, it gets more intuitive to play around and fine tune.

This type , depending on batch when freshly installed, it will either go significantly down or significantly up.

My pleasure, thank you

With my E280Fs, I have settled on between 20-22. Once fully warmed up they land in this range and fluctuate a bit but not really above or below that range.

 

[orfeo_monteverdi]

POST 9 - tube baking ?

If these are NOS tubes that have still been used, then it can vary. Put the tubes in the oven for 3 hours at 130-150 degrees, then let them cool down before opening the door. Then try again. It's a tried and tested trick. I do it for every 6c33 tube. I think it works for your tubes too. If it doesn't run stable then new tubes will be needed.
you age the tube with the procedure then usually run more stable.

nice! I have never heard of tube baking before, but makes sense!

you heat up cathodes without plate current, no stress for tubes. Unfortunately there are some Russian tube types where there is a lot of waste, sometimes it takes 6-7 pieces before you have 2 perfect ones.

 

[orfeo_monteverdi]

POST 10 - the Protos' soundstage: what about soundstage width and height ?

@VoicesInMyHead Sorry for the slow reply. Missed this one. Congratulations! Sounds incredible. I'm envious Might I ask how the soundstage width and height are? Big step up from what you had previously?​

no worries! I've been away traveling myself, and when I came home the other day I just put on a big smile when I saw the Protos sitting there in my system, and I felt truly happy about it! first attraction getting to know it was great, but a few weeks later I still feel the same about it. absolutely zero regrets for my choice, it makes my heart warm.

regarding soundstage, I don't know, I think it probably sounds bigger and bolder than the Allnic and DartZeel, but I've not really felt that I've been missing much before on the other hand. I think it's closest to the Absolare I had before in that sense, but still it sounds quite different. The Allnic I could loose myself deep into at night, mesmerized by all details, but Aries Cerat simply sounds better in every way, more natural and enjoyable. quite a price difference though.

 

[orfeo_monteverdi]

[Protos as a power amp?]

I am using an Incito preamp with my Protos and fixed Protos as a power amp…find that works better with non-AC sources.

I don't understand, for two reasons:
1. Since the Protos integrated amplifier is a one stage from input to output, it should be super-transparent. So any additional cable and RCA connectors from an external preamp (be it an excellent Incito or something else) should degrade that transparency.
Moreover, the Incito preamplifier uses the same type of volume control as the Protos (relay-latched), not a better type (TVC for instance, that is used by the Incito S).
(and why non-AC sources derogate to this?)
2. I don't see any input at the back of the Protos to use it as a power amp anyway. Did you make some DIY tweak? Or ordered it with such an option?

[Protos as a power amplifier]

 

[morricab]

[Protos as a power amp?]


I don't understand, for two reasons:
1. Since the the Protos integrated amplifier is a one stage from input to output, it should be super-transparent. So any additional cable and RCA connectors from an external preamp (be it an excellent Incito or something else) should degrade that transparency.
Moreover, the Incito preamplifier uses the same type of volume control as the Protos (relay-latched), not a better type (TVC for instance, that is used by the Incito S).
(and why non-AC sources derogate to this?)
2. I don't see any input at the back of the Protos to use it as a power amp anyway. Did you make some DIY tweak? Or ordered it with such an option?

[Protos as a power amplifier]

You can lock the volume control on the Protos at max, effectively taking it out of the circuit. I found that for non-AC sources the low input impedance was not allowing them to give their best…Incito makes a good bridge between source and amp. Also, Incito is only 1 stage as well, meaning just two amplification stages…still not a lot.

 

[VoicesInMyHead]

What are the tubes he uses with the Protos ?

Nice job with starting this thread!

I actually have an update regarding my tubes, I just bought a pair of Valvo E280F red label pinched waist, they are hardly burned in yet but cold out of the box my first impression was a slightly more fleshed out sound but perhaps not as sparkling in the upper regions, but I will give them some time to settle and I think they sound promising.

I'm still very happy with my Protos, but as @morricab mentioned the low input impedance made it challenging to find a suitable phono stage at first (but no big deal), and my Aurender streamer works perfectly.

 

[orfeo_monteverdi]

[please forgive my poor English]

What is exactly the input impedance of the Protos? (not the "usual" 47K or 50K Ohms?). I don't see it mentioned on the Protos spec sheet.
What is the sonic consequence of having to low a ratio between input Ω amp / output Ω source ? (it has never been the case in my system, so I don't know).
As we have: input Ω amp = N * output Ω source, how much is it advised for N ? (50? 100? More?)

Regarding bias setting, @VoicesInMyHead, you said "I set it to 20 per recommendation from the manual":
"20": where is that figure displayed by the Potos? On the front display? (I don't see any digital display inside the Protos, as far as I can see on various pictures).

Display - Is it possible to completely switch off the front display?

Tx

[Back to thread's table of Content]

 

[Argonaut]

I actually have an update regarding my tubes, I just bought a pair of Valvo E280F red label pinched waist, they are hardly burned in yet but cold out of the box my first impression was a slightly more fleshed out sound but perhaps not as sparkling in the upper regions, but I will give them some time to settle and I think they sound promising.

Pretty much marries up with a recommendation from a while back , should one be looking for a slightly bass / midrange centric E280F valve in ones AC electronics :

Kassandra II Ref E280F options

I like to have spares for all my vacuum tubes and the last to source are for the Kassandra Ref II. Stavros, do you have any tips for purchasing E280F spares? Do you supply them? What should I look for when purchasing, measuring and matching? All incoming tubes are tested and traced on my...

www.whatsbestforum.com

And :

Kassandra II Ref E280F options

Yes the above are drop in, you just readjust the bias and you are set. The 810 are not improvement nor downgrading. It is sidestep. In some aspects the E280F has the edge , in some other aspects the E810F is better , what you prefer is a matter of taste and system. Imagine the E810F as more...

www.whatsbestforum.com

The later production white print are a touch more linear and neutral than the earlier production Valvo’s , some nice information referencing them from @DasguteOhr here :

Kassandra II Ref E280F options

Yes the above are drop in, you just readjust the bias and you are set. The 810 are not improvement nor downgrading. It is sidestep. In some aspects the E280F has the edge , in some other aspects the E810F is better , what you prefer is a matter of taste and system. Imagine the E810F as more...

www.whatsbestforum.com

 

[Argonaut]

Nice work on putting this thread together Oliver

 

[morricab]

Not sure exactly but I think it is around 1kohm input impedance. This makes many sources sound a bit dull and weak because they are not designed to drive the low impedance.

 

[morricab]

The bias settings are displayed on the front panel but adjustment is inside.

 

[morricab]

With E280F I run around 20 on the bias.