Schiit Buf: tube buffer + gain

[typericey]

Yeah, an APx test chart was also posted on the 1st page (source of the chart wasn't mentioned tho). Shows the most prominent harmonics around -45dB if I read correctly.

Please correct me if I'm mistaken but isn't it around the limit of human perception (of harmonic distortion), and even more difficult to detect with complex music?

 

[solderdude]

The source is the APx555 test report from Schiit.

https://www.schiit.com/public/upload/PDF/Schiit%20APx%20Test%20Suite_%20Buf.pdf

It was at 1V though where most DACs have 2V so distortion will be higher.
IM distortion CCIF was 3dB higher going from 1V to 2V.

Below THD @ 1kHz for different input voltages up to 8V.

Here we can see that 100mV (-26dB opposite 2V) has -63dB THD distortion which is inaudible with music.
This means that when the Buf is used between pre-amp and power amp (or headphone amp) the effect will be less profound.

People hearing 'a distinct tube sound' using this device are likely to have tested this sighted.

 

[john61ct]

Remember there are many (hundreds?) of different tube types that fit Buf, and adapters readily available

I doubt if many of the choices will be as "subtle" as the default

 

[solderdude]

Yes, there will be ones that aren't well suited and could have an audible noise floor, channel imbalance and/or are on their way out and maybe even some that roll-off in the treble or even lows which can certainly be audible.

Other than those faulty or non suited ones the 'tube effect' will be in a very similar order but certainly will have different amounts of measured distortion for sure.

 

[Bob from Florida]

Remember there are many (hundreds?) of different tube types that fit Buf, and adapters readily available

I doubt if many of the choices will be as "subtle" as the default

You will need an adapter for certain to use anything other than the 6922/6DJ8 tubes and their Russian named versions. We used to sub 12AY7’s for 12AX7’s in guitar amps to reduce gain and change tonality in the input circuits- without changing any component values or power supply voltages. This would “sound” different. But the circuits were significantly higher gain than this “low gain/buffer selectable” product.

Several folks - on this thread - that purchased one have noted that it “pops” when you power it on or off. This is a common occurrence with audio equipment if you fail to put a muting relay on the output that mutes for an appropriate number of seconds upon power on and immediately upon power off. Schiit made a decision not to include this to keep the pricing at 2 digits instead of 3 digits. Version 2 will cost $10 more and include this essential feature. I’d hate to be the guy that blows his $3000 headphones because of forgetting to unplug them or turn the amp off first before powering the buffer off……

 

[Joe Smith]

I hadn’t tried it inserted between a source and the preamp. Would that have any effect on audible thd versus placement between preamp/amp?

 

[Bob from Florida]

I hadn’t tried it inserted between a source and the preamp. Would that have any effect on audible thd versus placement between preamp/amp?

Likely be a “wash”. Putting it before the preamp gives more gain, but you attenuate it anyway to get the same volume at your listening position. Putting it on top of a subwoofer with a nice microphonic Sylvania 6922 in it will likely get you some distortion….

 

[fpitas]

I'd wager that the other harmonics are exactly the "tube juice" it's designers were after

I've been a little puzzled just what "tube sound" designers are going for, by way of distortion. It seems to vary depending on who you ask. But, as long as people are having fun...

 

[john61ct]

Yes, this is just a cheaper way to get into "playing around" see if you like that sort of distortion.

Becomes a huge part of the hobby for some, end up spending thousands on their tube collections.

Also helps to keep the room warm in winter

 

[Joe Smith]

I found a decent way to use the Buf for now. I’ve got a down and dirty garage system going for morning tunes while I have coffee in the porch. Currently had some gifted Bose 201 V speakers, Aiyima A04 amp with a 32v brick, WiiM Mini. The Buf at high gain really boosts the signal for the little A04. Don’t know how much “tube warmth” I’m actually getting this way, but it sounds good for now.

Overall, I can’t say the Buf was worth $100, but it’s essentially a cute little gain stage to plug in for situations where one does not need a full-featured preamp.

Just be careful about order of device startup, shutdown, etc due to the pop issue.

 

[jdjung]

Voltage gain. 12 db gain equals 3.981 times the input voltage. Voltage gain in db =20log(voltage out/voltage in) - it’s math.
Most of the time you won’t use the 12 db gain stage. It would be useful if you had a very low gain amplifier, not sure why they included it unless just for marketing.

A lot of McIntosh amps have 8 volt inputs including the headphone amp MHA200. At 12db you get right under 8 volts with a standard 2 volt line output which is amazing. The only other device I know that gets that high other then McIntosh amps was the RME DAC, forgot which model. This is a definite buy for me because of the high gain as I have some McIntosh devices that I can now use with standard 2 volt line output devices.

 

[LostMyMind]

Hi everyone. Long time lurker, first time caller.

It looks like you all have been occupying the same tube buffer, mental realm that I've been stuck in for the last few weeks. Due to the endless purgatory I've decided I want to insert a Schiit Buf and a Schiit Saga 2 into the fixed hardware Processor Loop of my Peachtree Nova 150. My goal is to use the Saga 2 as a set-and-forget limiter, ideally letting me toggle the Buf between 0dB and +12dB to see if the overdrive mode is a marketing gimmick or sleeping Goliath.

I plan to max out the Saga 2's volume knob (Active Class-A for +12dB, Passive for 0dB) and handle daily volume from the Peachtree.

But before buying cables, I have a few quick questions:

1. Input Overload: Does hitting the Saga 2 input with an 8.0V RMS signal from the overdriven Buf risk input clipping or severe SNR penalties?

2. Impedance: Are there any glaring impedance mismatches when the signal leaves the Saga 2 and returns to the Peachtree's loop input?

3. Interaction: Am I miscalculating this layout, or does using the Saga 2 as a fixed voltage gate right after the Buf make electrical sense?

I would appreciate any technical feedback to ensure I'm not missing anything. Thanks!

 

[Joe Smith]

Hi everyone. Long time lurker, first time caller.

It looks like you all have been occupying the same tube buffer, mental realm that I've been stuck in for the last few weeks. Due to the endless purgatory I've decided I want to insert a Schiit Buf and a Schiit Saga 2 into the fixed hardware Processor Loop of my Peachtree Nova 150. My goal is to use the Saga 2 as a set-and-forget limiter, ideally letting me toggle the Buf between 0dB and +12dB to see if the overdrive mode is a marketing gimmick or sleeping Goliath.

I plan to max out the Saga 2's volume knob (Active Class-A for +12dB, Passive for 0dB) and handle daily volume from the Peachtree.

But before buying cables, I have a few quick questions:

1. Input Overload: Does hitting the Saga 2 input with an 8.0V RMS signal from the overdriven Buf risk input clipping or severe SNR penalties?

2. Impedance: Are there any glaring impedance mismatches when the signal leaves the Saga 2 and returns to the Peachtree's loop input?

3. Interaction: Am I miscalculating this layout, or does using the Saga 2 as a fixed voltage gate right after the Buf make electrical sense?

I would appreciate any technical feedback to ensure I'm not missing anything. Thanks!

As to "toggling" with the Buf between high and low, you will have to shut down the amp to change the gain, or you will get a very nasty pop.

I previously ran a Buf at both low and high gain between a Saga 2 and a Gjallarhorn amp without clipping problems. You might have issues though if using the Buf on high gain between a source and the Saga.

I am currently using the Buf between various sources (streaming, DAP, cd) and a low-power Aiyima amp in my garage system. Running the Buf in high gain provides good sound and allows me to run the amp at a lower volume level.

 

[john61ct]

Like asking vegetarians about BBQ?

Try also copy pasta to here, lots more Schitty expert tube aphiles hang out there

Headphone Reviews and Discussion - Head-Fi.org

www.head-fi.org

 

[LostMyMind]

Like asking vegetarians about BBQ?

Try also copy pasta to here, lots more Schitty expert tube aphiles hang out there

Headphone Reviews and Discussion - Head-Fi.org

www.head-fi.org

I didn't mean to bring up overly cooked meats in a place like this!

But as a "vegetarian" who originally built a purely detailed and transparent system, I'm slowly gaining interest in how to correctly mix the seasonings without blowing the voice coils on my Revel performa M22's. So, to be honest, I really wanted your two-channel perspective, and I'm willing to get roasted a bit more to hear it.

 

[john61ct]

I just meant you'll likely get a higher count of knowledgeable folk with relevant experience there

Saga 2 does excellent attenuation, so I would use it.

Maybe not for Ad Hoc user level control

but to experientially wrangle the gain from BUF as / if needed to prevent (the wrong sort of) distortion.

 

[path4play]

I don't "need" the gain, but it i think it adds a diff sound (beyond volume of course). I did choose the "low noise/microphonics" & "balanced triodes" upon checkout from tubedepot.

I guess I'll find out soon enough. Am hoping to capture some of that "..very lush presentation with a 3 dimensional soundstage."

My too! I'm waiting on my Schiit Buf to arrive Thursday. I have been running a crazy system that may be getting crazier. WiiM Airplay 2 to Fosi ZD3 DAC w/MUSES02 to Rolls SX45 crossover to (FX-Audio Tube 03J+ w/OPA1656, to Fosi ZA3 amp to Dali Oberon 3s) and to (Cambridge Audio Mini X201) w/Flyinsky Ultra-Low Noise Linear Power Supply. Now, I like this sound and have tailored it to tastes with tweaking. BUT I can't help wondering, what if the tubes were full "serious 100V on the tube plates"? This "little Schiit" would seem to answer that question for me.. so have one on way with a Balanced Amperex Bugle Boy 6DJ8 D Getter. Now, what will I hear? Will the upstream MUSES02 now add too much richness? Will putting this "little Schiit" between the Rolls and FX Tube, running two tube buffer/pre-amps in a row make a difference or just dumb? Do I have too much Schiit? I want to hear a full tube sound and see if I can get more airy 3d holographic sense out of this. Any predictions?

 

[Bob from Florida]

My too! I'm waiting on my Schiit Buf to arrive Thursday. I have been running a crazy system that may be getting crazier. WiiM Airplay 2 to Fosi ZD3 DAC w/MUSES02 to Rolls SX45 crossover to (FX-Audio Tube 03J+ w/OPA1656, to Fosi ZA3 amp to Dali Oberon 3s) and to (Cambridge Audio Mini X201) w/Flyinsky Ultra-Low Noise Linear Power Supply. Now, I like this sound and have tailored it to tastes with tweaking. BUT I can't help wondering, what if the tubes were full "serious 100V on the tube plates"? This "little Schiit" would seem to answer that question for me.. so have one on way with a Balanced Amperex Bugle Boy 6DJ8 D Getter. Now, what will I hear? Will the upstream MUSES02 now add too much richness? Will putting this "little Schiit" between the Rolls and FX Tube, running two tube buffer/pre-amps in a row make a difference or just dumb? Do I have too much Schiit? I want to hear a full tube sound and see if I can get more airy 3d holographic sense out of this. Any predictions?

There is a lot of talk about “tube sound”. The closest thing I would associate with the “tube sound” is a tube power amplifier where the output transformer compresses the output before going into hard clipping. Tube preamps don’t exhibit this effect. You can overdrive a tube preamp as an effect pedal for electric guitar, but for audio - we don’t want that. Harmonic distortion will get lost in the music, so - hard to say if you’ll notice.

 

[Joe Smith]

I think frankly, the best way to think of the Buf is that it's a fairly low cost +12 dB gain stage - if one needs that. "Tube sound" is quite minimal, at least with the stock tube.

 

[antcollinet]

My too! I'm waiting on my Schiit Buf to arrive Thursday. I have been running a crazy system that may be getting crazier. WiiM Airplay 2 to Fosi ZD3 DAC w/MUSES02 to Rolls SX45 crossover to (FX-Audio Tube 03J+ w/OPA1656, to Fosi ZA3 amp to Dali Oberon 3s) and to (Cambridge Audio Mini X201) w/Flyinsky Ultra-Low Noise Linear Power Supply. Now, I like this sound and have tailored it to tastes with tweaking. BUT I can't help wondering, what if the tubes were full "serious 100V on the tube plates"? This "little Schiit" would seem to answer that question for me.. so have one on way with a Balanced Amperex Bugle Boy 6DJ8 D Getter. Now, what will I hear? Will the upstream MUSES02 now add too much richness? Will putting this "little Schiit" between the Rolls and FX Tube, running two tube buffer/pre-amps in a row make a difference or just dumb? Do I have too much Schiit? I want to hear a full tube sound and see if I can get more airy 3d holographic sense out of this. Any predictions?

Can't tell if this is parody or not. If it is, then you need emoji's because you've been poed.