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Bi amping using Devialet 120 and Cayin A88T MKII (Passive)
#1
Hi, everyone, I'm trying to figure out a plan to bi-amp (horizontal) my system using Devialet Expert 120 (no pre-outs), Cayin A88T MKII (both are integrated amps) and a pair of B & W CM10 S2 (supporting bi wiring and bi amping). For this thread I just want to confine the discussion on passive bi amping. Later I would move on to active bi amping (Orelse too much info in one post). As far as I know there are two ways to do the bi amping depending on if Devialet can be used as amp-only or not (maybe this is too easy but I really cannot figure this out or find the answer online: I know you can make Devialet as preamp only and connect it to other amps through pre-out terminals. But my question is: can Devialet be used as amp only and be connected to another preamp?) But in either case I need to buy something new:

1. Devialet Expert 120 CAN be used as amp-only. Then I need to buy a preamp
 
In this situation the most intuitive way to bi amp (horizontal) is to have the music source (CD+DAC/TT+phono stage) connected to preamp, then preamp to 2 amps respectively (using the preamp to ensure same source and same gain for both amps)
 
2. Devialet Expert 120 CANNOT be used as amp-only. Then I need to buy the optional pre-out board

In this situation I'll connect the system as follows: music source (CD+DAC/TT+phono stage) to Devialet -> Devialet (pre-out) to Cayin (pre-in) -> Devialet to LF terminals of both speakers and Cayin HF terminals.

In this way the audio signals fed to both amps are the same and the gains are matched.

What do you guys think? Any thoughts welcome~ Thank you!
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#2
Hi,
the best solution would be to buy the pre-out for the Devialet. Then you could connect a second amp to the pre-out, you could also use the built-in crossover and remove the passive crossover in the speaker.
You can also use the Devialet as power-amp, you can set the initial volume to a high level (e.g. 0) and the default input to a line input. But for me this seems not to be a good idea...
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#3
(22-Oct-2018, 14:14)Vivialet Wrote: Hi,
the best solution would be to buy the pre-out for the Devialet. Then you could connect a second amp to the pre-out, you could also use the built-in crossover and remove the passive crossover in the speaker.
You can also use the Devialet as power-amp, you can set the initial volume to a high level (e.g. 0) and the default input to a line input. But for me this seems not to be a good idea...

Hi thank you for your input~ Three questions remain lol:

In this case, is the connection "music source (CD+DAC/TT+phono stage) to Devialet -> Devialet (pre-out) to Cayin (pre-in) -> Devialet to LF terminals of both speakers and Cayin HF terminals." bi-amping?

To use the Devialet as power-amp only, besides setting the default input into line-input, do I need to tick pass-though in the special mode? And why you think it may not be a good idea? Would like to know some potential hazards if any

Last but least, for active bi-amping: the two crossover frequencies of my speakers are 350Hz and 4kHz. If I want to use Devialet to power bass and Cayin midrange/treble, how do I set the frequencies below 350Hz to Devialet and above to Cayin? I need to configure the cut-off frequencies both in the speakers' configuration and pre-outs' configuration, right? As for the frequencies above 350Hz, can I further set that frequencies above 4kHz to tweeter and those in-between 350Hz and 4kHz to the midrange ?

Thank you~
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#4
pass through should also work, I never used it.
For a 3-way active crossover you need either 3 Devialets or 2 Devialets and one power amp.
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#5
My first question will be: Why?

Let's say theoretically you get it right by using a dedicated pre-amp and you manage to only use the Devialet and the Cayin as power amps; the pre-amp only attenuates the signal. Each "power amp" will have potentially wildly different output levels. You will have to level match the 2 power amps by using additional in-line attenuators.

You will also be getting potentially two very different sounding amps powering your speakers.

Both these "issues" are true for both your option 1 and 2.

Devialet 440PRO CI/ Mola Mola Tambaqui + Kalugas / Vivid Audio Giya G2
Cape Town, South Africa
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#6
(22-Oct-2018, 16:10)Vivialet Wrote: pass through should also work, I never used it.
For a 3-way active crossover you need either 3 Devialets or 2 Devialets and one power amp.

Hi, thank you. In this case, it would be tr-amping haha

However I still kinda confused:

1. Can I use Devialet and two stereo amps + a preamp to do this?

If so I may consider this because I'm considering the two options for my desktop hi-fi system: active speakers vs stereo amp+passive speakers. The former now seems more attractive for the sake of active crossovers but if I end up with the latter option, I'll have another amp to try the tri-amping.

2. Even if I can, is it true active bi-amping by inserting DSP between preamp and amps?

I doubt because:  for one thing, the passive crossover boards are still there in the speakers. Sure the crossover will be done in DSP rather than the passive crossover boards, but will there will be an audible or even huge improvement in SQ? For another: there are only HL and FL posts on the speakers. Signal below 350Hz will pass through the LF ones and above LF ones in the bi-amping setting. However, the signals above 350Hz will be separately fed into the tweeter (above 4kHz) and the mid-range woofer (between 350Hz and 4kHz) by the built-in passive crossover. To me, this nullifies the settings of DSP.

Seems that to do tri-amping on 3-way speakers, the speakers have to be equipped with HF, MF and LF posts; and the built-in passive crossover boards need to be removed. Correct?
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#7
(22-Oct-2018, 16:10)Vivialet Wrote: pass through should also work, I never used it.
For a 3-way active crossover you need either 3 Devialets or 2 Devialets and one power amp.

Thank you @Drifter for your input! Good question, yeah, why?

In short, curiosity and availability lol. I just bought a new TT, phono stage and the Cayin integrated Amp so I would like to try the bi-amping for the possible improvement of SQ (I know, controversial here). Besides, I learnt that both my Oppo 103D and Marantz HD DAC1 can be used as preamplifiers. In this case, I think I'll just try method one without buying the optional pre-out board for Devialet 120.

OK. Let drift a bit: I'm always tempted to buy the optional pre-out board coz I want to use my Devialet as a headphone amp (never thought about preamp coz I thought the same as Devialet puts on its FAQ session: using Devialet as preamp only is like owning a Ferrari but only driving in the first gear). I don't need to connect a subwoofer coz my listening room is quite small (L*W*H=4m*2.9m*2.4m) and I've already had too many bass problems and adding a subwoofer would make it worse (I read somewhere adding a subwoofer would make it  better but that was denied by a guy who came and did acoustic analysis for me). But later I learnt that pre-out uses the WM8740 which is not as good as MagicWire DAC which is used in the main board. Considering this (especially there are ways to connect headphones to speaker-outs by some adaptors) and the fact that Method 1 is feasible now. I'll postpone the purchase of the optional pre-out board (which costs USD $400) and how things go with the current bi-amping set-up

On most questions towards hifi, you never expect to get unanimous answers from audiophiles. Such is the case with bi-wiring, bi-amping and jumper cables...Most of the audiophiles are sceptical of bi-wiring these days but in the manual of my speakers it specifically mentioned  that bi-wiring will improve SQ; as for jumper cables, some say they are purely snake oils and the difference is not audible at all and the gold plated thin copper jumper will do the job; some say the metal jumpers are the weakest links in the speakers and have to be replaced by something; Some say this something can be a short bare speaker cables connecting the HF and LF posts (super cheap solutions!); some say you cannot do that and have to buy coated/terminated jumper cables

The same applies to bi-amping. The general consensus (if there's any) is that it's more effective than bi-wiring but how effective will depends on how you do it: passive or active. There's a video on bi-wiring and bi-amping discussed by Gene and Hugo in YouTube channel Audioholics which is quite good. Contrary to the claim that passive bi-amping is utterly useless, they claim that by caring matching up the system, it can still do a nice job. But course, active bi-amping is a better way to do.

Drift bank: people do bi-amping for various reasons: maybe the amp is not powerful enough to power three drivers at the same time for optimal performance (as in my case, Devialet is OK I guess but Cayin obviously has difficulties powering the bass and low-midrange); maybe they want the warm, laid-back tube sound in treble and midrange but punchy bass powered by an SS amp. I'm sort of in the latter case. Regarding active vs passive bi-amping, I'll try passive first and then see how things go.

Here I'll address @Drifter's point:

The attenuating problem you mentioned seems only applying to Method 2 but I think Method 1 should be scrutinized under the same lenses too: does Method 1 overcome this attenuating problem by connecting pre-out on Devialet to pre-in on Cayin?

I learnt that the key condition to do bi-amping is to match the gains of two amps (is it the attenuation problem we're addressing here?). But how to do this? How to find the gains of two amps (I cannot find it in the manual of Devialet and Cayin). Or I should just match the output powers (Devialet 120W; Cayin 45w/25w)?

OK, this question may seem stupid but, with two integrated amps, why cannot I just connect the same audio source to the two integrated amps using RCA splitter cables and then two integrated amps to HF and LF posts of speakers? In this way can I address the gain mismatch or attenuation problem by adjusting the volume controls on two integrated amps respectively until a perfect match of bass and midrange/treble is achieved?

Thank you~
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#8
(23-Oct-2018, 05:09)mjledme Wrote:
(22-Oct-2018, 16:10)Vivialet Wrote: pass through should also work, I never used it.
For a 3-way active crossover you need either 3 Devialets or 2 Devialets and one power amp.


Here I'll address @Drifter's point:

The attenuating problem you mentioned seems only applying to Method 2 but I think Method 1 should be scrutinized under the same lenses too: does Method 1 overcome this attenuating problem by connecting pre-out on Devialet to pre-in on Cayin?

I learnt that the key condition to do bi-amping is to match the gains of two amps (is it the attenuation problem we're addressing here?). But how to do this? How to find the gains of two amps (I cannot find it in the manual of Devialet and Cayin). Or I should just match the output powers (Devialet 120W; Cayin 45w/25w)?

OK, this question may seem stupid but, with two integrated amps, why cannot I just connect the same audio source to the two integrated amps using RCA splitter cables and then two integrated amps to HF and LF posts of speakers? In this way can I address the gain mismatch or attenuation problem by adjusting the volume controls on two integrated amps respectively until a perfect match of bass and midrange/treble is achieved?


Thank you~

You will have the same issue (level matching the 2 amps) for both option 1 and option 2. It is not just the very different power outputs that plays a part (120W versus 45W) but also  many other factors that will cause big difference in volume between two amps. You may get 2 power amps from different manufacturers with exactly the same same power output rating, through they result in different volume levels when driving the same set of speakers at the same volume knob setting on the pre-amp. 

You will have to attenuate the Devialet down (assuming that its higher output power will result in more volume than the Cayin at the same volume dial setting) and you will have to measure the levels with some or other db meter to ensure they are exactly equal. Otherwise you will get louder mid and highs than bass when playing a track.

Your next plan (in green) is an issue as you will have 2 integrated amps with 2 volume knobs. If you want to increase the volume, you will have to turn both amps up. How will you know how much to increase each to still have the exact same volume level from both amps?

Devialet 440PRO CI/ Mola Mola Tambaqui + Kalugas / Vivid Audio Giya G2
Cape Town, South Africa
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#9
mjledme, this plan just seems like a huge pain for very little gain.....
Personally id just have two systems or sell one.

>>> 1st Place Award: Devialet, last decades most disappointing technology purchase.  <<<

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#10
Hi everyone, thank you for your inputs. I have almost made up my mind to give it up. It’s really beyond my ability and may not worth it in the end. I’ll save the time enjoying more music lol
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