More Disruptive Schiit (Vidar)

[rando]

I hit send before looking at the product page.

[thyname]

This is what the "Nick" guy from Schiit just wrote me:

 

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Yes, 400W total into one channel in one Vidar. Two Vidars means 2 channels at 400W into 8Ohm.

 

Nick T
Schiit Tech

 

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Now I am even more confused...

 

[Speed Racer]

Why are you confused? Regardless of how the electronics work, Vidar, when used as a monoblock, generates 400 watts at 8 ohms. There is no lying or false advertising going on.

[thyname]

3 minutes ago, Speed Racer said:

Why are you confused? Regardless of how the electronics work, Vidar, when used as a monoblock, generates 400 watts at 8 ohms. There is no lying or false advertising going on.

 

400 watts PER CHANNEL? 

[firedog]

16 minutes ago, thyname said:

So it's not 400 per channel?! If so, totally false advertising...

No. Apparently you don't understand, this is per amp:

 

Stereo, 8 Ohms: 100W RMS per channel

Stereo, 4 Ohms: 200W RMS per channel

Mono, 8 ohms: 400W RMS 

 

That is totally typical of how amps are rated, and it also makes sense. When you run a 200W per channel stereo amp as mono, you get one channel of 400 W. In mono it is rated to be used as an 8 ohm amp. Absolutely nothing deceptive here. 

[thyname]

Just now, firedog said:

No. Apparently you don't understand, this is per amp:

 

Stereo, 8 Ohms: 100W RMS per channel

Stereo, 4 Ohms: 200W RMS per channel

Mono, 8 ohms: 400W RMS 

 

That is totally typical of how amps are rated, and it also makes sense. When you run a 200W per channel stereo amp as mono, you get 400 W. In mono it is rated to be used as an 8 ohm amp. Absolutely nothing deceptive here. 

 

'Maybe I don't understand. Not familiar with Mono Blocks. Enlighten me!

[firedog]

2 minutes ago, thyname said:

 

'Maybe I don't understand. Not familiar with Mono Blocks. Enlighten me!

Just what the name says. Each box has one channel, ergo a "mono" block. You need one for each channel, 2 for a stereo setup.

 

A lot of amps are designed so that they can run with two channels in stereo, or have the 2 channels merged (usually called "bridged") into one channel for mono operation. But then you need 2 of them for stereo. 

[thyname]

Just now, firedog said:

Just what the name says. Each box has one channel, ergo a "mono" block. You need one for each channel, 2 for a stereo setup.

 

A lot of amps are designed so that they can run with two channels in stereo, or have the 2 channels merged (usually called "bridged") into one channel for mono operation. But then you need 2 of them for stereo. 

 

I appreciate you taking the time to explain to me. In all honesty.

 

To be clear, you are saying that one Vidar would produce 400 watts feeding one  speaker, and the second would do 400 to the other speaker, for a total of 800 watts, or 400 watts per channel?

[firedog]

12 minutes ago, thyname said:

 

I appreciate you taking the time to explain to me. In all honesty.

 

To be clear, you are saying that one Vidar would produce 400 watts feeding one  speaker, and the second would do 400 to the other speaker, for a total of 800 watts, or 400 watts per channel?

Yes. 

Again, rated for 8 ohms when running in mono mode.  

Meaning that you might have an issue (overheating, protection circuit kicking in to shut amps down) using them with a speaker rated for 4 or 2 or ohms, at least if run very loudly for a long time.

Chris said he would test this with his 4 ohm speakers for his Vidar review (to see if it is just a theoretical problem, or an actual problem in use).

Also note the mono input is XLR, stereo input is pair of RCA (Just want to make sure you understand what it is you might be buying). 

[thyname]

6 minutes ago, firedog said:

Yes. 

Again, rated for 8 ohms when running in mono mode.  

Meaning that you might have an issue (overheating, protection circuit kicking in to shut amps down) using them with a speaker rated for 4 or 2 or ohms, at least if run very loudly for a long time.

Chris said he would test this with his 4 ohm speakers for his Vidar review (to see if it is just a theoretical problem, or an actual problem in use).

Also note the mono input is XLR, stereo input is pair of RCA (Just want to make sure you understand what it is you might be buying). 

 

Yep! I should be fine with the preamp. I have the Rotel RC-1590, which has XLR outputs, and (I believe) fully balanced design.

 

8 Ohms not an issue. I have B&W CM10s, which are rated 8 Ohms.

 

I look forward to @The Computer Audiophile Review (as well as others').

 

thanks again for helping me!

[firedog]

1 minute ago, thyname said:

 

Yep! I should be fine with the preamp. I have the Rotel RC-1590, which has XLR outputs, and (I believe) fully balanced design.

 

8 Ohms not an issue. I have B&W CM10s, which are rated 8 Ohms.

 

I look forward to @The Computer Audiophile Review (as well as others').

 

thanks again for helping me!

I'm guessing if you hook a Vidar up to each of those speakers you are going to be astounded at the result.

What is your present power amp? Also Rotel?

[thyname]

2 minutes ago, firedog said:

I'm guessing if you hook a Vidar up to each of those speakers you are going to be astounded at the result.

What is your present power amp? Also Rotel?

 

That is right: Rotel RB-1582 MKII.

 

Not a slouch, don't take me wrong. But I a think a bit of more power would really open up my CM10s more. I have been eying the RB-1590, but too expensive 

[dean70]

5 hours ago, thyname said:

 

'Maybe I don't understand. Not familiar with Mono Blocks. Enlighten me!

When running bridged mode each "half" of the amplifier sees half the speaker impedance (4ohms), so you get the 4ohm rated power x 2. Not sure though how it would cope with a load impedance that dips below 8ohms at that level.

[fas42]

The number of watts is pretty irrelevant - it's the quality of those watts that count. A totally competent 20W amplifier feeding reasonably sensible speakers will annihilate a monster amp claiming 100s and 100s of raw watts of grunt, in the SQ stakes, if the latter is poorly done. How do I know this? Because I've been here many times - listening to "mega" amplifiers doing a terrible job of getting the sound right ...

[Ralf11]

I believe in the credo: One driver, One amp.

 

 

[Ralf11]

31 minutes ago, fas42 said:

The number of watts is pretty irrelevant - it's the quality of those watts that count. 

 

How do you measure the Quality of those Schitt watts?

[fas42]

1 hour ago, Ralf11 said:

 

How do you measure the Quality of those Schitt watts?

 

By listening to a system that was using that Schitt amplifier, and seeing how it behaved as the volume requirements were steadily upped. If it could go right to clipping for the particular speakers with no noticeable change in quality then I would give it a big tick - extremely few amplifiers are capable of this, most start 'compressing', or begin to make a mess of the treble.

[Ralf11]

what's quality mean in terms of looking at the waveform on a scope?

[esldude]

Oh no! Such confusion. 

 

Bridging amps.  Let's use some hypothetical examples.

 

100 wpc into 8 ohms in a stereo amp.  28 volts and 3.5 amps (please allow me to drop extra decimals).

200 wpc into 4 ohms in a stereo amp.  28 volts and 7 amps. 

 

Now if we bridge the amps the way is being done with the Vidar our two channel amp becomes mono.

400 wpc into 8 ohms.  56 volts and 7 amps.

 

How did we get 56 volts?  Because each channel is being run in opposite phase so you really have +28 volts and -28 volts for a 56 volt difference.  You will need twice the amps and it results in 4 times the power.   You don't gain any increase in amperage this way because one channel is feeding 7 amps in one direction and the other must take it in the opposite direction.  If 7 amps is the most your amps can put out then it has become a limiting factor.

 

So you'll get a mono bridged rating of 400 watts into 8 ohms.  Into 4 ohms what will you get?  As 4 ohms will require more amperage than can be supplied at 56 volts the power output will not be able to double. 

 

Does that mean 4 ohms is verboten and can't be used?  No.  The amp has become current limited and into 4 ohms would manage 7 amps which would give only 200 watts.  So obviously bridging the amp for 4 ohm speakers doesn't gain you anything versus just using a stereo amp for the same load and output power.  Though if you did use a mono amp with 4 ohm speakers requiring no more than 200 watts it would work fine.  Bridging does increase the output impedance so damping of the bass might be negatively effected.  Reactive aspects of speaker loading also might require amperage not available and alter the sound in some ways too. 

 

BTW, bridging like this for electrostats is often a very good thing.  ESL's don't often need extreme current.  What they need is higher voltage. 

 

There are other ways to combine two channels that increase current capability without increasing voltage.  Usually not done with SS amps.  When you bridge some transformer coupled tubes amps that is usually what you are doing.

[Speed Racer]

Vidar is not bridged when acting as a monoblock amp.

[fas42]

21 minutes ago, Ralf11 said:

what's quality mean in terms of looking at the waveform on a scope?

 

A way of doing it on the scope would be to feed an input signal consisting of a very high level bass frequency, combined with a pair of treble frequencies dramatically lower in level - and just see how those treble components fare as the volume was raised, into a dummy load perhaps. A dodgy amp would likely start injecting all sorts of IM from the treble input waveforms, at points along the bass frequency waveform

[esldude]

2 hours ago, Speed Racer said:

Vidar is not bridged when acting as a monoblock amp.

I am pretty sure it is.

 

If you feed only single ended inputs for stereo, guess what happens if you have balanced XLR input for mono.  The two channels are out of phase.  You connect up the two positive posts and voila' you have a bridged amp.

 

From the owner's manual:

 

 

When using Vidar as a mono amp, connect your speaker to the two

top red terminals only. Right is “+”, and left is “-”.

 

Please note both of these are active outputs—do

not ground one of them!

 

XLR Input.

Connect a balanced source (usually

a preamp) using a high-quality XLR cable. It’s

important that the preamp is truly balanced for

maximum power output.

 

 

The following is from Schiit's FAQ:

 

 

Wait. How does the monoblock mode work?

It’s not a mode. It’s just the natural result of driving each channel with one half of a truly balanced signal. That’s why you need a preamp with balanced outputs. And that means REAL balanced outputs, not just XLR connectors.

 

There’s a difference between XLR and balanced?

There can be. If you aren’t using Freya, ask your preamp manufacturer if it has true balanced, differential outputs. If it does, you can easily run two Vidars as monoblocks. Or more, if you want to use them for home theater or something. 

 

Same for 4 ohms when running monoblocks?

Yes. Again, Vidar will probably work fine at sane volumes, but at higher output, you may trigger the protection. 

 

So what’s a Vidar?

Vidar, in Norse Mythology, is said to be the strongest of the gods after Thor. And no, this isn’t a hint that there’s an even more powerful “Thor” amp coming—we just don’t want the copyright battle on that one. Vidar is one of the newer generation of gods that survive Ragnarok. Yep. I know. We’re here all day.

[Speed Racer]

I am sure it is not!

 

Here is a quote from Jason Stoddard, the designer, from another forum:

 

"Sorry to disagree, but it is not [bridged]."

 

"Bridging is the process of using the output of one side of the amp to drive the inverting input (feedback point) of the other side of the amp, in a typical Lin-topology amp. This is technically "in series" and can have sonic consequences that are not ideal."

 

"Vidar is not a Lin topology. When used as a monoblock, it is simply amplifying a differential signal. It is not bridged."
 

 

 

[esldude]

15 minutes ago, Speed Racer said:

I am sure it is not!

 

Here is a quote from Jason Stoddard, the designer, from another forum:

 

"Sorry to disagree, but it is not [bridged]."

 

"Bridging is the process of using the output of one side of the amp to drive the inverting input (feedback point) of the other side of the amp, in a typical Lin-topology amp. This is technically "in series" and can have sonic consequences that are not ideal."

 

"Vidar is not a Lin topology. When used as a monoblock, it is simply amplifying a differential signal. It is not bridged."
 

 

 

You give a tremendous example of why I dislike Jason's approach to promoting his products.  Why I asked in this thread why this amp was disruptive when nothing about it is other than the PR.   Here they are pretending to be doing something different when it amounts to a tiny point of difference about how some others do bridging.  Some do the same exact thing Schiit does.  It can be done both ways, and it amounts to the same difference.   The other way is one needed if you only have single ended inputs.   The Schiit way is also the cheapest way to do it with RCA or XLR, but not both.  Nothing wrong with that in a bang for buck amp like the Vidar. Its smart.  It isn't revolutionary or disruptive.

 

A bridged amp has opposite phase in the two channels.  You tap the positive side outputs only and the differential voltage is doubled.  Current capabilities halved.  Power output quadruples.  Exactly what Schiit is doing.

 

You can invert one channel to feed the other which some people do.  You can simply used balanced input which can be switched from feeding one channel to feeding two and ignore the other input (usually with a switch to swap connections), or you can feed a transformer which can be switched for the different inputs needed.  There are other ways, but those are most common.   You could call it a differential amp instead of bridged as he does.  The way it works for current and voltage and power is all the same.  Just like a Sumo Andromeda from the 1980's. 

 

 

[Speed Racer]

This "no it all" type of response is what turns me off to this site. Do you really think you know more about what is and isn't a bridged amp than Jason does?

 

How many amps have you designed and successfully sold? What are your credentials that allow you to admonish Jason like this?