What's a Balance Preamplifier Should Be Like?

[LTig]

What it means?

Tilt tone control, see description here.

 

[Sokel]

Considering that a nice (obviously analog) high pass filter with variable frequency,slopes,level,etc as it should be to integrate nicely will be no less than 50-100 euro for components (even more for top quality),nice non-scratchy pots (and that's without top of the notch opamps,count about 8 of them at least for all the above) I don't see that happening for the low cost device we see here.

 

[Mnyb]

Considering that a nice (obviously analog) high pass filter with variable frequency,slopes,level,etc as it should be to integrate nicely will be no less than 50-100 euro for components (even more for top quality),nice non-scratchy pots (and that's without top of the notch opamps,count about 8 of them at least for all the above) I don't see that happening for the low cost device we see here.

I figured all EQ , room correction and sub xover and volume should be digital in a modern preamp with built in DAC , you just add an ADC for the analog sources you still have left ? It should simply have an DSP ?

Sub integration the analog ways seems bit archaic since you need to complement the sub’s with some kind of room eq anyway for successful integration, just having xover is not enough ?

 

[Sokel]

I figured all EQ , room correction and sub xover and volume should be digital in a modern preamp with built in DAC , you just add an ADC for the analog sources you still have left ? It should simply have an DSP ?

Sub integration the analog ways seems bit archaic since you need to complement the sub’s with some kind of room eq anyway for successful integration, just having xover is not enough ?

What's the point of been on a device with limited (always will be) available PEQ ,double convertion,etc?
All of this can be done then a thousand times better on the PC and all it need is a couple extra outputs (different channels) to route the low's.

The useful would be to be completely standalone and include every source where it can mix and match everything,bal to unbal,unbal to bal,etc.

There's already miniDSP for the above,a preamp as a center of a system must be as versatible,stable and standalone as possible as the immediate link to power amps where security is the number one factor.

 

[Joey]

I have go at this, my list to santa :

Can we please have

* Room EQ (Dirac or similar)

* Loudness contour , variable possibly to tune against level ( like RME does it ).

* Subwoofer outputs , with crossover

* One more balanced analog input

* USB input

* ARC or EARC

* Tone controls or EQ for a quick fix adjusting for taste regarding recordings ( the room and speaker EQ are set and forget )

* Balance control

* Mono button

* Mute button

* Tape loop

(* Optionally a phono stage )

(* Optionally a built in streamer )

subwoofer is mean active？

 

[Joey]

Serve what everyone is looking for and nobody wants to dare. Sub output with high pass filter for the speaker outputs, possibly with adjustable frequency. we all want to manage the subwoofer by splitting the frequencies, but nobody seems to care

Limit the subwoofer output frequency to within 60Hz or there is a knob to adjust the frequency between 20Hz to 20kHz. which you need

 

[Joey]

My 2 cents - add a SUB OUT that is controlled by the volume knob (in every product possible, not just this one). And then, consider removing coaxial and optical and add USB and Bluetooth instead. If you will, you can do a poll (or a kind of research of your own) regarding having optical + coaxial vs USB + Bluetooth; I'll be curious to see the results.

Would you prefer the subwoofer output to be active or passive？

 

[Mnyb]

What's the point of been on a device with limited (always will be) available PEQ ,double convertion,etc?
All of this can be done then a thousand times better on the PC and all it need is a couple extra outputs (different channels) to route the low's.

The useful would be to be completely standalone and include every source where it can mix and match everything,bal to unbal,unbal to bal,etc.

There's already miniDSP for the above,a preamp as a center of a system must be as versatible,stable and standalone as possible as the immediate link to power amps where security is the number one factor.

There is double conversion only for analog inputs? Look at the OP the suggested design from Fosi comes with built in DAC in the preamp . So built in DAC for digital sources this would be as straight as it can get , and thus all signal manipulation thereafter should be done in digital domain , for bets performance .
An ADC would be completely transparent to your analog sources such as a phono stage or tuner or whatnot .

Oh more digital inputs are needed .

A mini DSP can also be a digital preamp , that’s a device I’m contemplating to buy actually .

And yes completely stand alone no PC involved for peq or room eq or crossover .

Doing everything in the digital domain makes sense to me , volume control is for example better done digital, you get perfect channel balance all the time .
Tone controls are better done digitaly or any EQ or crossover .
Traditional analog tone controls did come with some performance penalties, with a digital implementation you can have your cake and eat it at the same time imo and an ADC is a small cost for making room EQ aviable to analog sources to or subwoofer integration for best bass management

Using an external DAC to a preamp with in inbuilt DAC should be pointless anyway, the included DAC should be good enough otherwise it’s not good .

You could go in the other direction and make a completely analog preamp instead and remove the onboard DAC that’s another suggestion for Fosi remove the DAC if the product does not include a complete digital solution it’s rather half done this way .

Imo a traditional analog approach breaks down as soon as you have a subwoofer to integrate .

 

[GXAlan]

What would it cost to do something like a Classe Delta Pre but at low costs? That has tilt, peq, crossovers, RIAA, etc.

 

[Joe Smith]

IMO this is all getting pretty Pie in the Sky...the collective feature set that's been raised here is daunting, to say the least.

I think keeping it in the range of a Schiit Saga preamp type unit, with a really good volume control, basic remote, 4-5 RCA inputs, and some form of RCA SW output would be manageable for them... Maybe offer a balanced version as well...? (Something that would pair well down the road with monoblocks with no VC and no SW out...)

 

[TonyJZX]

yeah this

we always will come back to what is deliverable from this fine company

like to me a remote is MANDATORY... there's not much to discuss there... a preamp from 10yrs ago should have that

i'm not expecting displays or dsp or room correction etc etc

i'd love some way to have analog trim knobs to control the cutoffs of the main and s/w but even that could be in the too hard basket

i believe Parasound did that in their high buck preamps

 

[Sokel]

There is double conversion only for analog inputs? Look at the OP the suggested design from Fosi comes with built in DAC in the preamp . So built in DAC for digital sources this would be as straight as it can get , and thus all signal manipulation thereafter should be done in digital domain , for bets performance .
An ADC would be completely transparent to your analog sources such as a phono stage or tuner or whatnot .

Oh more digital inputs are needed .

A mini DSP can also be a digital preamp , that’s a device I’m contemplating to buy actually .

And yes completely stand alone no PC involved for peq or room eq or crossover .

Doing everything in the digital domain makes sense to me , volume control is for example better done digital, you get perfect channel balance all the time .
Tone controls are better done digitaly or any EQ or crossover .
Traditional analog tone controls did come with some performance penalties, with a digital implementation you can have your cake and eat it at the same time imo and an ADC is a small cost for making room EQ aviable to analog sources to or subwoofer integration for best bass management

Using an external DAC to a preamp with in inbuilt DAC should be pointless anyway, the included DAC should be good enough otherwise it’s not good .

You could go in the other direction and make a completely analog preamp instead and remove the onboard DAC that’s another suggestion for Fosi remove the DAC if the product does not include a complete digital solution it’s rather half done this way .

Imo a traditional analog approach breaks down as soon as you have a subwoofer to integrate .

Agree on most but one (for me):No digital VC will ever be before my power amps,that's an absolute no-go to me.

Any penalty taken by an analog VC (as long as is inaubible and keeps a rock solid balance,no cheap but absolutely doable) is a fair trade to me for peace of mind,I 've been around long enough to know that a digital VC without draconian protection measures is an accident waiting to happen.

 

[Mnyb]

Agree on most but one (for me):No digital VC will ever be before my power amps,that's an absolute no-go to me.

Any penalty taken by an analog VC (as long as is inaubible and keeps a rock solid balance,no cheap but absolutely doable) is a fair trade to me for peace of mind,I 've been around long enough to know that a digital VC without draconian protection measures is an accident waiting to happen.

I know , almost filled my underpants on some occasions

it's gets hard to do analog when you have more than 2 channels for example 4 with dual subs or almost impossible with full blown HT with >7 channels .
And get them all to track properly .

If you have active speakers you can set their volume so that full output from the preamp is about as loud as you want to go , that's good disaster prevention too .

With power amps it gets tricky , nowadays i would not buy anything without gain adjustments so i can have a nice gain structure .
Reasonable gain helps some , but does not cure the problem completely , you get loud output but not full clipping .


Software volume ?

Some manufacturers are better than others , I've had my Meridian pre/pro reset to default volume , which is not full volume btw , but its loud enough .

Never had an AVR flunking on this possible when they get old and loose thier settings ? but again the default is usually not full volume .

I'm waiting for my Topping DAC to blow my head off at my headphone setup .. it has been a few such cases , tried to replicate with mine but could not make it fail ...

You possible have to use a startup routine and check stuff before the power amps goes on if you use a software volume .


But it's also possible to have the volume knob turned to full by mistake too ( house cleaning , kids, pets, drunken friends , drunk you ? ) so you have an old fashioned analog disaster ! the veils are blown away literally .

 

[Sokel]

kids,

Two Scanspeak 26W/8861T00,I still remember the model
I don't know which of the two of us got the most scare (we were playing around with music and it was the second I loosened my guard),fact is he never touched the pot again.

 

[Mnyb]

You can get worst of two worlds in pre-amps if the designer is not aware the analog volume can be software controlled !

 

[antcollinet]

Balanced interconnect systems are great. All balance internal circuits are an expensive engineering challenge.

It isn't really - maybe one or two additional op amp chips needed:

https://www.diyaudio.com/archive/blogs/alexcp/attachments/1926d1460406090-bruno-putzeys-micropre-g-word.pdf

 

[antcollinet]

It looks good to me.

I would second the requirement for fully balanced through from input to output, and from any dac output immediately to balanced across the circuit board. (See Bruno's link I posted above)

If not already suggested (I've not read the whole thread) I would want to see dedicated input buttons (direct input select) both on the device and on the remote. Cycling inputs is a pain in the neck.

Having sadi that - I am not in the market for this device. My preaamp is also my DSP (MiniDSP Flex). If you fancied including DSP, then you'd be in a really interesting place. I suspect that is not part of your product brief though.

 

[Sokel]

It looks good to me.

I would second the requirement for fully balanced through from input to output, and from any dac output immediately to balanced across the circuit board. (See Bruno's link I posted above)

Denafrips Athena is like this and I think is a must.
In fact a cut-cornered version of it would not be the worst idea in the world.

 

[JeremyFife]

Kudos to @Fosi Audio for openness here, but good luck getting manageable requirements out of this

Seriously, it is brilliant that manufacturers are also on this site; open to comment and (inevitably) criticism - hopefully constructive.

 

[Joe Smith]

I keep waiting for Schiit to incorporate a optional phono pre (slot) in one of their preamps. That's the main thing stopping me from buying one, really. Maybe that's harder to do than I think because of the amount of space needed on a phono board with specs similar to their Mani.