Stereo Amp recommendations with...

[TheloniousEllington]

I'm planning on getting a Schiit Kara preamp running in passive mode. Since I'll be spending money, I've been learning about matching certain specs of the Kara, though I know no matching is always perfect. It has an output of 4v and input impedance of at least 10k. I'm hoping to find a balanced stereo amp (class D hopefully) that has an input voltage closer to 4v and the input impedance over 30k ohms. I know specs can work in lower levels like 2.5v for input voltage from 4v and even 12k ohm input impedance is doable, but matching closer to the preamp's specs will work more synergistically. That's more or less what I'm after, if possible.

I spoke to Warren at VTV and he said the 1ET-400A is balanced, has an input impedance at 47k, but still has the 2.5v input voltage. Any recommendations besides this amp? I know it might be splitting hairs to some, but I'd like to know different options, opinions, and even logic behind differential voltage input/output levels and their affects on signal and distortion.

As always, I'm here to learn, because it's interesting. Thanks for your input and help.

 

[TLS Guy]

I'm planning on getting a Schiit Kara preamp running in passive mode. Since I'll be spending money, I've been learning about matching certain specs of the Kara, though I know no matching is always perfect. It has an output of 4v and input impedance of at least 10k. I'm hoping to find a balanced stereo amp (class D hopefully) that has an input voltage closer to 4v and the input impedance over 30k ohms. I know specs can work in lower levels like 2.5v for input voltage from 4v and even 12k ohm input impedance is doable, but matching closer to the preamp's specs will work more synergistically. That's more or less what I'm after, if possible.

I spoke to Warren at VTV and he said the 1ET-400A is balanced, has an input impedance at 47k, but still has the 2.5v input voltage. Any recommendations besides this amp? I know it might be splitting hairs to some, but I'd like to know different options, opinions, and even logic behind differential voltage input/output levels and their affects on signal and distortion.

As always, I'm here to learn, because it's interesting. Thanks for your input and help.

First off, using a preamp in passive mode is a really bad idea. That is out on the loony spectrum, and has no body of engineering suggesting that is remotely sensible. If you use it in passive mode you will be spending over $600.00 to use components that could be bought for about $30.00.

The next issue is that preamp is analog only and has no bass management. In this day and age it won't be very useful. Heck if you are into analog, you can't even connect a turntable to it, unless it has a built in phono preamp, and those turntables are generally down to the bottom end of the spectrum.

I would like to know which lunatic, audiophhool guru was recommending this as a reasonable purchase and using it in passive mode.

These sort of nutters are all over the internet, and the clueless blindly follow. We seem to have a rising epidemic of this nonsense of late, and it pointing people in wasteful and harmful directions.

 

[PENG]

I'm planning on getting a Schiit Kara preamp running in passive mode. Since I'll be spending money, I've been learning about matching certain specs of the Kara, though I know no matching is always perfect. It has an output of 4v and input impedance of at least 10k. I'm hoping to find a balanced stereo amp (class D hopefully) that has an input voltage closer to 4v and the input impedance over 30k ohms. I know specs can work in lower levels like 2.5v for input voltage from 4v and even 12k ohm input impedance is doable, but matching closer to the preamp's specs will work more synergistically. That's more or less what I'm after, if possible.

I spoke to Warren at VTV and he said the 1ET-400A is balanced, has an input impedance at 47k, but still has the 2.5v input voltage. Any recommendations besides this amp? I know it might be splitting hairs to some, but I'd like to know different options, opinions, and even logic behind differential voltage input/output levels and their affects on signal and distortion.

As always, I'm here to learn, because it's interesting. Thanks for your input and help.

I thought I had explained what input sensitivity is in your other thread but may be not.
Anyway, if Warren told you the 1ET-400A's input sensitivity is 2.5 V, it means the power amp needs 2.5 V at the input, to drive it to output it's rated level.

For example, if the 1ET-400A amp is rated 225 W 8 ohms, the preamp you use to drive it will have to output 2.5 V.

So I don't understand what you meant by "I'm hoping to find a balanced stereo amp (class D hopefully) that has an input voltage closer to 4v". You will not find any such power amp to have an input voltage closer to 4 V, or any V, because its input voltage will have to come from the output of a preamp!! Without that, the power amp's input voltage will be 0 V, naturally.

Passive preamp does not amplify the signal, but attenuates it, so I don't think it is a good match to that VTV amp that has gain of about 25 dB, that's not very high at all.

You need preamps such as Denon or Marantz's AVRs or AVPs that can output at least 2 V cleanly and up to about 4 V at or near their clipping point. That is if you do want the power amp to be able to output up to about 200 W 8 ohms cleanly. If you only need to drive it to say 90 W, just an example, then 1.5 V will do it.

 

[TheloniousEllington]

I thought I had explained what input sensitivity is in your other thread but may be not.
Anyway, if Warren told you the 1ET-400A's input sensitivity is 2.5 V, it means the power amp needs 2.5 V at the input, to drive it to output it's rated level.

For example, if the 1ET-400A amp is rated 225 W 8 ohms, the preamp you use to drive it will have to output 2.5 V.

So I don't understand what you meant by "I'm hoping to find a balanced stereo amp (class D hopefully) that has an input voltage closer to 4v". You will not find any such power amp to have an input voltage closer to 4 V, or any V, because its input voltage will have to come from the output of a preamp!! Without that, the power amp's input voltage will be 0 V, naturally.

Passive preamp does not amplify the signal, but attenuates it, so I don't think it is a good match to that VTV amp that has gain of about 25 dB, that's not very high at all.

You need preamps such as Denon or Marantz's AVRs or AVPs that can output at least 2 V cleanly and up to about 4 V at or near their clipping point. That is if you do want the power amp to be able to output up to about 200 W 8 ohms cleanly. If you only need to drive it to say 90 W, just an example, then 1.5 V will do it.

Thanks Peng, this makes much more sense. It also helps that I've been researching more to understand better.

I decided not to go with the Kara because of the clicking noises of the relays.

I found a musical fidelity M6s preamp that looks like it would fit my preferences, except the phono pre that I don't need. Would you happen to know if this preamp would match my EVAL-1 Eigentakt amp?

Thanks again for all your time and help, Peng. I've been learning alot through your comments and I appreciate it.

 

[TLS Guy]

Thanks Peng, this makes much more sense. It also helps that I've been researching more to understand better.

I decided not to go with the Kara because of the clicking noises of the relays.

I found a musical fidelity M6s preamp that looks like it would fit my preferences, except the phono pre that I don't need. Would you happen to know if this preamp would match my EVAL-1 Eigentakt amp?

Thanks again for all your time and help, Peng. I've been learning alot through your comments and I appreciate it.

I tried to warn you before. Entirely analog units are yesterday's products. My analog units, and I have a lot, are in my museum sections of my system. But the fact is, that analog sources just can't compete with digital sources, and not even streamed sources now.

It is just plain idiocy to try and put together a system that does not have the ability to deal with state of the art digital sources. Sure you can use DACs with analog outputs, but that involves additional conversions.

There is just a boat load of wrong information all over the place. For reasons that remain unclear to me, people seem to suck it up like a sponge to the detriment of what they could achieve.

The next thing I would say, is that systems should be analog only if it is just for background music in an office, or if you are blind. The fact is that video with high quality audio, is a huge advance. Both complement each other. So putting a state of the art audio only system together is yesterday's technology. All my systems have the ability to combine video and audio. That is my two, three and 11 channel systems. They all have bass management. An audio system without bass management is just not state of the art.

This nonsense promulgated that only straight analog systems get you to audio nirvana is just that: absolute unadulterated nonsense.

 

[PENG]

Thanks Peng, this makes much more sense. It also helps that I've been researching more to understand better.

I decided not to go with the Kara because of the clicking noises of the relays.

I found a musical fidelity M6s preamp that looks like it would fit my preferences, except the phono pre that I don't need. Would you happen to know if this preamp would match my EVAL-1 Eigentakt amp?

Thanks again for all your time and help, Peng. I've been learning alot through your comments and I appreciate it.

The Kara preamp has much better specifications than the M6S, and has been verified by Amir's bench test that it met or exceeded the specifications.

The M6S is capable of higher output but if you only need 2.5 V, it does not matter than the M6S can output higher.

Relay clicking is not a bad thing, it only clicks when it has to anyway and it won't click when you are listening to music. If you really want to have a pure analog preamp, the Kara amp seems to be the best at the below $1,000 price point and based on its verified audio specs, it should be totally transparent, to humans, including the self proclaimed golden ears.

Schiit Kara:

Balanced to Balanced

Gain: 1 (0dB)
Frequency Response: 20Hz-20Khz, -0.1db, 3Hz-500KHz, -3dB
THD: <0.0002%, 20Hz-20KHz, at 4V RMS
IMD: <0.0002%, CCIR
SNR: >129db, A-weighted, referenced to 4V RMS

Gain: 4 (12dB)
Frequency Response: 20Hz-20Khz, -0.1db, 3Hz-300KHz, -3dB
THD: <0.0004%, 20Hz-20KHz, at 4V RMS
IMD: <0.0004%, CCIR
SNR: >123db, A-weighted, referenced to 4V RMS

M6s PRE - Specifications
Pre-Amplifier

• THD(+ noise) - single ended: <0.005%
• THD(+ noise) - XLR Balanced: <0.004%
• Signal to Noise Ratio: >96dB ‘A’-weighted
• Frequency Response: +0, –1dB, 10Hz to 80 kHz

 

[PENG]

I'm planning on getting a Schiit Kara preamp running in passive mode. Since I'll be spending money, I've been learning about matching certain specs of the Kara, though I know no matching is always perfect. It has an output of 4v and input impedance of at least 10k. I'm hoping to find a balanced stereo amp (class D hopefully) that has an input voltage closer to 4v and the input impedance over 30k ohms. I know specs can work in lower levels like 2.5v for input voltage from 4v and even 12k ohm input impedance is doable, but matching closer to the preamp's specs will work more synergistically. That's more or less what I'm after, if possible.

I spoke to Warren at VTV and he said the 1ET-400A is balanced, has an input impedance at 47k, but still has the 2.5v input voltage. Any recommendations besides this amp? I know it might be splitting hairs to some, but I'd like to know different options, opinions, and even logic behind differential voltage input/output levels and their affects on signal and distortion.

As always, I'm here to learn, because it's interesting. Thanks for your input and help.

Did you check into the Apollon amp?

It costs a little more than the VTV amp I assume, but I am impressed with their build quality and test results.

Purifi 1ET400A ST Stereo Amplifier (apollonaudio.com)

(1) Apollon NCx500ST Stereo Amplifier Review | Audio Science Review (ASR) Forum

 

[TheloniousEllington]

The Kara preamp has much better specifications than the M6S, and has been verified by Amir's bench test that it met or exceeded the specifications.

The M6S is capable of higher output but if you only need 2.5 V, it does not matter than the M6S can output higher.

Relay clicking is not a bad thing, it only clicks when it has to anyway and it won't click when you are listening to music. If you really want to have a pure analog preamp, the Kara amp seems to be the best at the below $1,000 price point and based on its verified audio specs, it should be totally transparent, to humans, including the self proclaimed golden ears.

Schiit Kara:

Balanced to Balanced

Gain: 1 (0dB)
Frequency Response: 20Hz-20Khz, -0.1db, 3Hz-500KHz, -3dB
THD: <0.0002%, 20Hz-20KHz, at 4V RMS
IMD: <0.0002%, CCIR
SNR: >129db, A-weighted, referenced to 4V RMS

Gain: 4 (12dB)
Frequency Response: 20Hz-20Khz, -0.1db, 3Hz-300KHz, -3dB
THD: <0.0004%, 20Hz-20KHz, at 4V RMS
IMD: <0.0004%, CCIR
SNR: >123db, A-weighted, referenced to 4V RMS

M6s PRE - Specifications
Pre-Amplifier

• THD(+ noise) - single ended: <0.005%
• THD(+ noise) - XLR Balanced: <0.004%
• Signal to Noise Ratio: >96dB ‘A’-weighted
• Frequency Response: +0, –1dB, 10Hz to 80 kHz

Thanks again for the specs and advice. Schiit told me that the Kara will have audible relay clicks nearfield and I usually adjust volume every other song or so. Unfortunately, I'll have to pass because of that.

At this point of researching, I'm hopefully looking for:

-Solid State
-Balanced Outputs
-Hopefully 3 RCA inputs
-Transparent/Clean
-Minimal to no extras included (maybe a DAC, but doesn't matter)
-$700-2k

 

[dolynick]

Thanks again for the specs and advice. Schiit told me that the Kara will have audible relay clicks nearfield and I usually adjust volume every other song or so. Unfortunately, I'll have to pass because of that.

A little clicking as the knob turns is a complete deal breaker for you? That seems a little overly fussy.

I went back and re-read their site info on the Kara and, to my comprehension, they're just telling you that unlike most smooth turning knobs, the Kara's has a fixed 128 steps and there's a click as it shifts to each notch while adjusted. Once you're done, there shouldn't be any more clicking.

 

[TheloniousEllington]

A little clicking as the knob turns is a complete deal breaker for you? That seems a little overly fussy.

I went back and re-read their site info on the Kara and, to my comprehension, they're just telling you that unlike most smooth turning knobs, the Kara's has a fixed 128 steps and there's a click as it shifts to each notch while adjusted. Once you're done, there shouldn't be any more clicking.

I emailed them and said I listen about 10 feet away and usually adjust my volume every other song or so and asked if it's loud enough to hear as I adjust. They said minute adjustments have one click, but major adjustments will be several clicks and will be audible during it. For jazz, blues and classical, this would be a bit annoying during low volume passages. Sure, I understand it sounds fussy, but that's how I feel for what I want to spend.

 

[dolynick]

I emailed them and said I listen about 10 feet away and usually adjust my volume every other song or so and asked if it's loud enough to hear as I adjust. They said minute adjustments have one click, but major adjustments will be several clicks and will be audible during it. For jazz, blues and classical, this would be a bit annoying during low volume passages. Sure, I understand it sounds fussy, but that's how I feel for what I want to spend.

Right. It will click as you turn the knob and it moves from one step to another. It stops as soon as you stop adjusting the volume knob. They're just telling you that the knob has an audible feedback, along with the physical notch movement.

Unless you're constantly standing there changing the volume in the middle of playing a song, it seems like a non-issue to me.

I mean, if a knob that makes noise while turning is a deal breaker for you, so be it. To each their own. I get the impression that you might be misunderstanding what they're telling you concerning when and how it makes its clicking noise. It would be a shame to rule out a pre-amp you seemed quite positive on over something that may not actually be an issue though.

 

[lovinthehd]

Interested to know which way this piece of gear goes, audible electrical relays or just the detents on the knob....or both?

 

[PENG]

Thanks again for the specs and advice. Schiit told me that the Kara will have audible relay clicks nearfield and I usually adjust volume every other song or so. Unfortunately, I'll have to pass because of that.

At this point of researching, I'm hopefully looking for:

-Solid State
-Balanced Outputs
-Hopefully 3 RCA inputs
-Transparent/Clean
-Minimal to no extras included (maybe a DAC, but doesn't matter)
-$700-2k

It only clicks when you the knob is being turn, once your fingers off of it, there should be no click, otherwise they will never sell a single unit.

Based on your need, the best measured preamp on ASR, or anywhere so far, is one that is made in China. If that's not a factor then it is one that will meet your requirements except instead of 3 RCA inputs, you only get 2 (you said hopefully 3, but you also get 4 XLR inputs, especially in terms of transparency.

Topping Pre90 Review (preamplifier) | Audio Science Review (ASR) Forum

I have never seen any such old fashion all analog pre amp measured better anywhere.

The total distortions+noise starts in the 5th decimal place, that is, 0.00097%, or -120 dB. Such low level means well below the threshold of audibility so it will have no sound signature, and that may not be for everyone, some people may turn to Nelson Pass's harmonics generator for help.

 

[tparm]

Interesting to catch up on a few of these threads. Not buying a piece of gear because of relay clicks seems short sighted. My Mola Mola Kula clicked away and I loved it. the Kula also didn't have bass management so some would say it was a terrible piece. It wasn't. Some also analog integrated amps are outdated. They aren't. Seeking input is what these forums are for, just take away what applies to you and your preferences and don't take what anyone says as total gospel. Except may @PENG he's usually right.