Schiit KARA Preamp and Headphone Amp Review

[MorningsideMan]

I used Kara rca in to balanced out. Worked well. I also tried the various modes including passive and it worked. Just be mindful that the Kara is 10 kOhm input and the volume relay is a ladder type. I have Benchmark AHB2 with 50 kOhm input and it was fine. With my powered monitors, the passive stuggled a bit due to the lower input 10 kOhm input impedance.

The Kara would output into a Boxem Arthur 4216/E2 which has an input impedance of 94k so I assume I'd be ok in passive mode. I could also try the buffered 1X gain stage. How does the relay-switched attenuator ("ladder type") relate to input impedance?

 

[Dougey_Jones]

I was warded off by minidsp's advice on that option, but given it's a relatively cheap experiment I could try it out. What max output voltage from the Flex can I expect in this scenario?

Warded off why? I'm using a Schiit Mani --> Mini DSP Flex Balanced and it literally acts exactly like any other source, I didn't have to fiddle with anything, it just works, and is dead silent.

EDIT: Oh, I see now.

"WARNING: This adaptor(TRS to RCA) is ONLY to be used for the Flex OUTPUTS. We've noticed a performance drop (15dB SINAD drop) when using such adaptor for INPUTS of the FLEX. For that reason, we do not recommend customers to use an unbalanced to balanced cable on the "input" side of the Flex. If you want to have unbalanced in/out for both inputs and outputs, it's strongly recommended that you just use the miniDSP Flex unbalanced version. The miniDSP Flex was engineered with best performance in mind and it's therefore our intention to stay consistent on making sure best audio quality is kept for this platform!

Once again to clarify, there isn't any performance drop for OUTPUTS. i.e. TRS to RCA cable for an unbalanced amplifier or subwoofer if perfectly fine. This limitation is for INPUTS only. i.e. RCA source to TRS input of the Flex."

Ok.. But as a thought experiment, if the ADC in the Flex Balanced performed at -107db in Amir's testing, and the theoretical max SINAD of Vinyl as a medium is -78db, is -92db SINAD really problematic? It surely hasn't been in my experience..

 

[MorningsideMan]

@Dougey_Jones thank you for sharing your positive experience. The only unbalanced to balanced connection I would have a use case for is from my phono stage (same as you) and you make a good point that the loss in performance shouldn't matter. At least worth testing. I'll start there. I could even shift to an ADC like the minidsp ADept if the RCA to TRS connection causes me issues. I will still consider the Kara for the option of a full analog train from my turntable, which I understand is based on nothing but sentiment and nostalgia. It's even irrational when I'm spinning a digital recording and yet it is a capability I like to have available. However, I wouldn't mind also having the opportunity to try my turntable through Dirac!

 

[nagster]

Cable A is for the TRS output of the Flex listed on the miniDSP website and is likely to cause problems if used with the TRS input. -input is open.

For TRS inputs you would normally use cable B or cable C.

However, there was at least one balance input device that performed disastrously with unbalance sources. It's also possible that this is related to some feature of the 2i2, but the cause doesn't seem to be identified.
Focusrite Scarlett 2i2 (4th Gen). The sleeve and ring should be grounded in these measurements, but the cable details are unknown.

Focusrite Scarlett 2i2 (4th Gen) Interface Review

@amirm the ADC section is lacking the comparison chart, just wanted to make sure it's included :) Problem is that it would not be relevant since XLR rear connectors are for Microphone. Front are for line input. This is the difference, with 1.7Vrms input as Amir did with XLR rear connectors...

www.audiosciencereview.com

Focusrite Scarlett 2i2 (4th Gen) Interface Review

They might even use a otg rpi with camilla dsp and UAC2 USB audio gadget linux setup so the PC dont need a setup for both cards, just the rpi usb in/out stream

www.audiosciencereview.com

To know the results in a particular environment, try it in that environment.
With TRS input, cable A may cause unexpected problems, so we do not recommend it.
Cables B and C will not cause any major accidents, so listen to them and use whichever you like best.
If you want numerical evidence to back up whether there is a difference or the extent of the difference, try measuring it in your environment using REW, Multitone, ARTA, etc.

 

[MorningsideMan]

@nagster What's the difference between cable A and B? They look like a transpose of each other. What makes the cable directional?

 

[40th Anniversary]

This has been my experience also but a good buffer between your passive and your amp will fix this.

I currently just received a Hattor tube line stage buffer. Another nice gem of a product (dead quiet).

 

[nagster]

What's the difference between cable A and B? They look like a transpose of each other.

Cable A has the RCA sleeve connected to the TRS sleeve. The TRS ring is open.
Cable B has the RCA sleeve connected to the TRS ring.

What makes the cable directional?

When converting from balanced to unbalanced using cables/plugs, you must select a wiring method that is appropriate for each.
In experience, it is often not possible to use the same cables.
(There are also some devices that prohibit balanced to unbalanced conversion using cables/plugs.)

By the way, in most cases when converting from unbalanced to balanced, cable C is used.

 

[Stoutblock]

I currently just received a Hattor tube line stage buffer. Another nice gem of a product (dead quiet).

I use the balanced version of the Modwright Analog Bridge with exceptional results.

 

[MorningsideMan]

TLDR: I do not understand the relationship between the volume control on my digital source and the Kara F, depending on which of the three gain settings is chosen.

I am trying to understand the different gain options that the Kara F provides. Note that my questions come from a general lack of understanding, but since the Kara F has 3 different options available, it seems like a good case study. For context, my upstream devices are a balanced minidsp Flex and a Rega MM MK5 phono stage. I have been using an integrated amplifier for quite some time so I haven't worked through these concepts, but, now I'm on a journey to learn.

1. Passive. My understanding is that if I set the Flex to 0 dB the output is ~4 Vrms. If I set the Kara F to max volume, 4 Vrms will be output to my amp. If I turn the volume down on the Kara, the input from the Flex would be attenuated and the output from the Kara will be lower than 4 Vrms respective of 128 steps all the way down to 0 Vrms output. Given the 200 ohms output impedance of the Flex, what is the input and output impedance of the Kara in passive mode?

2. Gain 1 (0 dB). I think this can also be called unity gain? When I look up what unity gain is, it appears the output gain will be equal to the input gain. So in this case what role does the volume control on the Kara play? Again, if the output on the Flex is set to 0 dB, ~4 Vrms, and the Kara is set to max volume, I assume 4 Vrms is output, but what happens as I turn the volume knob? Is the volume knob on the Kara F rendered inactive and now I use the Flex volume knob to control output which is passed through the Kara with no gain? What about impedance? I'm struggling with the difference between passive and this option, both functionally and in terms of specifications.

3. Gain 4 (12 dB). For anyone who got this far, you can tell I am thoroughly confused. Intuitively I would assume that this option will increase the input by 12 dB. But again I have the same questions as to the function/relation of the Kara volume control to the Flex volume control when set to this mode.

My examples were within the context of the minidsp Flex as input, but I assume the only option that would make sense for my phono stage is the 12 dB gain option if I input it directly into the Kara instead of running it through the Flex. Rega specs.

 

[MorningsideMan]

Warded off why? I'm using a Schiit Mani --> Mini DSP Flex Balanced and it literally acts exactly like any other source, I didn't have to fiddle with anything, it just works, and is dead silent.

EDIT: Oh, I see now.

"WARNING: This adaptor(TRS to RCA) is ONLY to be used for the Flex OUTPUTS. We've noticed a performance drop (15dB SINAD drop) when using such adaptor for INPUTS of the FLEX. For that reason, we do not recommend customers to use an unbalanced to balanced cable on the "input" side of the Flex. If you want to have unbalanced in/out for both inputs and outputs, it's strongly recommended that you just use the miniDSP Flex unbalanced version. The miniDSP Flex was engineered with best performance in mind and it's therefore our intention to stay consistent on making sure best audio quality is kept for this platform!

Once again to clarify, there isn't any performance drop for OUTPUTS. i.e. TRS to RCA cable for an unbalanced amplifier or subwoofer if perfectly fine. This limitation is for INPUTS only. i.e. RCA source to TRS input of the Flex."

Ok.. But as a thought experiment, if the ADC in the Flex Balanced performed at -107db in Amir's testing, and the theoretical max SINAD of Vinyl as a medium is -78db, is -92db SINAD really problematic? It surely hasn't been in my experience

@Dougey_Jones I'm curious as to what the sensitivity of the amp you are inputting the Flex into is? As well, seeing that the max output of the Schitt Mani is 300mV, what max voltage will the balanced Flex output?

 

[wwjokerk]

TLDR: I do not understand the relationship between the volume control on my digital source and the Kara F, depending on which of the three gain settings is chosen.

I am trying to understand the different gain options that the Kara F provides. Note that my questions come from a general lack of understanding, but since the Kara F has 3 different options available, it seems like a good case study. For context, my upstream devices are a balanced minidsp Flex and a Rega MM MK5 phono stage. I have been using an integrated amplifier for quite some time so I haven't worked through these concepts, but, now I'm on a journey to learn.

1. Passive. My understanding is that if I set the Flex to 0 dB the output is ~4 Vrms. If I set the Kara F to max volume, 4 Vrms will be output to my amp. If I turn the volume down on the Kara, the input from the Flex would be attenuated and the output from the Kara will be lower than 4 Vrms respective of 128 steps all the way down to 0 Vrms output. Given the 200 ohms output impedance of the Flex, what is the input and output impedance of the Kara in passive mode?

2. Gain 1 (0 dB). I think this can also be called unity gain? When I look up what unity gain is, it appears the output gain will be equal to the input gain. So in this case what role does the volume control on the Kara play? Again, if the output on the Flex is set to 0 dB, ~4 Vrms, and the Kara is set to max volume, I assume 4 Vrms is output, but what happens as I turn the volume knob? Is the volume knob on the Kara F rendered inactive and now I use the Flex volume knob to control output which is passed through the Kara with no gain? What about impedance? I'm struggling with the difference between passive and this option, both functionally and in terms of specifications.

3. Gain 4 (12 dB). For anyone who got this far, you can tell I am thoroughly confused. Intuitively I would assume that this option will increase the input by 12 dB. But again I have the same questions as to the function/relation of the Kara volume control to the Flex volume control when set to this mode.

My examples were within the context of the minidsp Flex as input, but I assume the only option that would make sense for my phono stage is the 12 dB gain option if I input it directly into the Kara instead of running it through the Flex. Rega specs.

Hello to the experts,

I went through the whole thread to understand more about Kara and how it works.

Those questions above are exactly the one I have as well.

My scenario:
I am using an Eversolo DMP-A8 as Streamer with Tidal, currently directly connected via XLR to Fosi V3 mono amps (those little guys are really awesome).
Unfortunately, the volume levels of the A8 are a bit loud to really rock the house. Also the case with my former Audiophonics MPA-S250NC amp.
When using an Atoll MS120 Streamer before, I could easily burn down the house with the Audiophonics amp.

Thus other users in the Eversolo Forum and also in some reviews recommended to use a proper preamp.

Here Kara comes into the game.
Can I use x4 gain (+12 dB) to increase the volume level of the Eversolo?

I try to understand the impedance story as well:
All numbers for xlr connection
Eversolo DMP-A8 output 4.2 V with 102Ohm impedance
Kara 10 kOhm Input and 600 Ohm output
Fosi V3 mono amps 5k Ohm input.

As far as I understand step 1 DMP-A8 to Kara is more than fine.
Step 2 Kara to Fosis is at the lower end of the 1:10 rule.

Is that correct?

Again what is the difference between passive mode and gain X1 (0 dB)?

Thanks
Kurt

 

[solderdude]

Step 2 Kara to Fosis is at the lower end of the 1:10 rule.

There is no 1:10 rule in interlinks.
a 5k load to 600ohm output will work fine.

The difference between passive and X1 is the output resistance (in x1 the volume control is buffered) and can't convert SE to balanced.
In active mode the output resistance will be constant.
In active mode an (inaudible) small amount of distortion and noise is added compared to passive mode (as does all active electronics).
Of course in active mode there are also gain options available.
In passive mode you will still need to have the Kara powered and 'on' for the volume control to work.

Kara is a great and versatile choice.

 

[wwjokerk]

Okay thanks. Thus Kara could not only be superior to the Preamp of the DMP-A8 in sound quality, but could also help to increase volume levels, at least at x4 gain.

What I read and heard in reviews is that the x4 setting also has more punch and the sound is more 'into your face'. I will give Kara a chance, once it is available again at the European Schiit store.

Thanks for clarification

 

[wwjokerk]

One more question:
The Kara has no auto on or trigger in.

Can I keep it permanently on and use one of those trigger adapters to turn it on with the Eversolo in one rush?
Audiophonics Trigger Adapter

Thanks
Kurt