If "Tube Sound" Is a Myth, Why Tubes?

[rwortman]

Nelson Pass quoted someone saying to him about audio, “it’s entertainment not dialysis”. If everything that’s competently designed is essentially transparent where is the consumer choice? Why isn’t everyone here running the same cheapest transparent things? Are we only to buy by the spec sheet? We are music and equipment fans. We buy for all kinds of reasons. Tubes can sound different or not. People that like them like them. I ran a tube full function preamp for many years. I am currently listening to my new Crown XLS1500 as a middle finger to high end audio jewelry. It is being fed by a Saga preamp because it is a simpler signal path than using my AVR in stereo mode. Maybe it sounds different, maybe not. The Saga output buffer is a triode tube and a transistor opposite each other in a push pull unity gain amplifier. There is no engineering reason to do this. Jason just did it for fun and because people like preamps with tubes sticking out the top. I wanted a low distortion preamp without spending much. This fits the bill.

There are people going on about “tube rolling” in their Saga’s. I pointed out that any audible difference would mean that they had essentially broken their preamp to no avail.

 

[Daverz]

The high today is only in the low 80s Fahrenheit, so I decided to try my BAT 3iX tube pre-amp and Rogue M-180 tube monoblock amps with the Buchardt S400s I'm auditioning. (Otherwise I'm going straight from the Vega DAC into a Bryston 3B-SST amp).

As I sat there sweltering in my listening room, the heat making me a bit sleepy, I started contemplating how to get this sound without running dual space heaters. What if I measured the impulse response from the tube amp outputs with the speakers hooked up to provide a load, then measured again with the all solid-state equipment. I should then be able to create a filter to get the sound of the tube gear, at least the part that can be modeled with a FIR filter.

I think it should be safe to hook a Behringer UMC202HD in parallel to the amp outputs if I keep the output voltage well under 1V.

 

[SIY]

The high today is only in the low 80s Fahrenheit, so I decided to try my BAT 3iX tube pre-amp and Rogue M-180 tube monoblock amps with the Buchardt S400s I'm auditioning. (Otherwise I'm going straight from the Vega DAC into a Bryston 3B-SST amp).

As I sat there sweltering in my listening room, the heat making me a bit sleepy, I started contemplating how to get this sound without running dual space heaters. What if I measured the impulse response from the tube amp outputs with the speakers hooked up to provide a load, then measured again with the all solid-state equipment. I should then be able to create a filter to get the sound of the tube gear, at least the part that can be modeled with a FIR filter.

I think it should be safe to hook a Behringer UMC202HD in parallel to the amp outputs if I keep the output voltage well under 1V.

108° here, so it's a Class D day.

Yes, you can either get the frequency response by Fourier transform of the impulse or by a swept frequency measurement, then EQ, and that'll get you the sound. There's still the extra TING! of the microphonics of direct heated triodes, but that also shows up in the frequency response as long as you take it at normal listening levels.

 

[audimus]

With the ambient room temperature hitting the 80s inside, the AC Infinity AIRCOM on top of my all-solid-state gear is kicking in continuously.

I am concerned that the altered air patterns from the cooler are nullifying the earlier Dirac RC calibration that made my gear sound more tube-like and the gear is sounding more solid-state-like on hot days.

Should I run my DRC calibration again and have a different correction profile on hand for hot days?

 

[DonH56]

Here's the one I always remember: http://www.rfcafe.com/miscellany/cool-products/wj-g1-catalog-page.htm

Pretty sure I still have that catalog in the black hole masquerading as storage in the basement.

 

[Julf]

As I sat there sweltering in my listening room, the heat making me a bit sleepy, I started contemplating how to get this sound without running dual space heaters. What if I measured the impulse response from the tube amp outputs with the speakers hooked up to provide a load, then measured again with the all solid-state equipment. I should then be able to create a filter to get the sound of the tube gear, at least the part that can be modeled with a FIR filter..

Vintage tube simulator plugin

 

[MattHooper]

I have nothing objective to offer this thread. But simply opining as a user of tube amps, I love 'em! I've had my Conrad Johnson Premier 12 monoblocks for over 20 years, and my Eico HF-81 for around 6 years, and can't ever see getting rid of them. I certainly may be under the "mystique" of tube amps to some degree, but I enjoy them as cool audio gear, and the sound strikes me as more enjoyable than any SS amp I've owned (e.g. Bryston, Harman Kardon, and others).

My CJ amps only had to go in to the shop once in 20 years...not bad I think for tube amps. I think it was a fuse.

But both during that time, and one other time when I got too lazy to change tubes, I stopped using the CJ amps and inserted a solid state amp. For whatever reason both times my listening to my system dwindled to less and less interest. And both times it was revived when I got my tube amps running again. In fact one time when the CJ amp was down and I had replaced them with a SS amp, over the following 6 months or so I found myself less and less compelled to actually sit and listen to the system. I figured I'd simply become uninterested in the whole music/high-end 2 channel thing, and prepared to sell some of my gear including the CJ amps. But I had to have them fixed in order to sell them. Got them fixed, put them in the system just to double-check before listing them and...bam...my system seemed to have "that sound" again, a sort of rich, organic quality that I crave, and where I would put on a song and walk away to listen from another room previously, I found myself locked to my sofa listening. Day after day. Couldn't sell them and have been listening with pleasure ever since. (I had the same experience with the Eico as well).

Now, of course not one shred of that is any compelling objective evidence that the tube amps even sound different than the SS amps I used. I'm well aware of the power of bias (pun intended). BUT...in this case even if there were no sonic differences, I'm happily availing myself of that bias effect, because it's awfully strong and seems to work wonders for my interest in listening to music on my system

 

[watchnerd]

In order:

1. Fun. It's enjoyable for some (like me) to use old technologies and see what performance can be scraped out of them. Think of someone restoring a 1959 Avanti. I also take advantage of the high available voltage swings for things like mike and phono preamps as well as electrostatic direct drive.

Oh, like vinyl....getting performance out of old tech can be fun. I can relate.

3. The whole point of making a good tube amp is to get a low output impedance, sufficient current/voltage swing for the intended load, and anything else that defines a good amp, irrespective of active devices.

4. Yes. There may even be advantages for a guitar amp given the voltage sag under load. For audio reproduction, tube rectifiers are at best benign and at worst a severe performance degradation.

5. All of them, but most of all, output transformers are the key to getting rid of the amp's effect on sound.

To those points, I was looking at the specs for this amp:

http://quicksilveraudio.com/products/headphone-amplifier/

It seems to have a respectably low output impedance for a tube headphone amp (2.2 ohms), a big honking output transformer, and no tube rectifiers.

I haven't heard it, nor seen it, but it seems to be off to a better start than the Woo designs.

 

[watchnerd]

I can imagine this making it into hifi before too long so people can choose it easily if they wish.

It already exists in hifi. The Parks Audio Puffin, originally intended as a DSP based phono stage, can also accept line level input and you can apply 'tube' or 'tape' effects to the inputs.

 

[scott wurcer]

It already exists in hifi. The Parks Audio Puffin, originally intended as a DSP based phono stage, can also accept line level input and you can apply 'tube' or 'tape' effects to the inputs.

The op-amps in the front end are a little marginal, possibly JR and SY can put me in the loop for a look at it.

 

[watchnerd]

The op-amps in the front end are a little marginal, possibly JR and SY can put me in the loop for a look at it.

I have no dog in this fight (I don't own or use one), but marginal in what way and why?

It's intended main use case is as a phono stage.

 

[scott wurcer]

I have no dog in this fight (I don't own or use one), but marginal in what way and why?

It's intended main use case is as a phono stage.

+-1 V common mode range, 60dB CMRR/PSRR min, meh slew rate and BW compared to what is available, noise is just OK for MC while bias current is high.

 

[SIY]

+-1 V common mode range, 60dB CMRR/PSRR min, meh slew rate and BW compared to what is available, noise is just OK for MC while bias current is high.

Save me the search, which ones are they?

I have a Pro-Ject on hand that @BDWoody sent me. It uses OP2134 for the MM part and LT1028 for MC. One major issue, but I'll have review and measurements up shortly.

 

[scott wurcer]

Save me the search, which ones are they?

I have a Pro-Ject on hand that @BDWoody sent me. It uses OP2134 for the MM part and LT1028 for MC. One major issue, but I'll have review and measurements up shortly.

NJM2122

Just noticed some scary stuff...

( note )Between 30 to 50dB voltage gain is recommended. In case of voltage gain less than 30dB,phase compensation by external circuit is required. The voltage follower circuit must not be used. DMPpackage should be used in operating voltage less than ±7V,because of thePD limitation.

 

[Blake Klondike]

In that case why not just put VUs and non-functioning tubes (just a heater element, no audio circuit) as a facade on a class D amp?

I am sure that would work! In the late sixties, Fender made a portable Hammond B3 organ for bands to take on the road. There were complaints that it was so light that it couldn't be high quality or sound good, so they started putting cinder blocks in the cases-- no kidding.

 

[Blake Klondike]

I should add.

Tube sound is not a myth when it comes to guitar amps and stuff like SET power amps but their goal is not to be indistinguishable from SS but rather to change the sound deliberately.

The fact that SS can emulate tube sound should be enough.

I too have fooled people by using a tube amp which secretly was all SS on the inside and only heaters connected. It works. Placebo is a powerful thing in the world of audio.

This was my first thought, as well-- tube guitar amps are designed to sound like tube amps, rather than SS amps. Isn't the case for tube stereo gear identical? A tube stereo amp can take advantage of the distortion qualities of a slightly over-driven tube? It seems like the problem begins is when people claim that tube sound is more accurate, or inherently superior. I have no EE training at all, so I could be totally full of it.

 

[Blake Klondike]

I can say that I auditioned a Prima Luna tube amp and couldn't hear any discernible difference between it and a comparable NAD SS. That just told me that the Prima Luna was simply designed to sound good and I didn't need to buy it because the NAD already sounded good.

 

[watchnerd]

In any case, people who want tube sound or believe in it, could use low powered tube amps like preamps feeding them into clean SS amps to have their cake and eat it too. I've even had in mind making a preamp with the right character. Using 12AT7s in push pull circuits able to deliver a watt or so, transformer coupled and loaded by resistors on the output to be like a mini push-pull triode amp. You could even switch in a few elements to simulate loudspeaker loading. Probably should have done it years ago without saying what I was doing. Come up with some marketing story to sell.

Have you seen the new 'budget priced' ($6500 for the 200 watt version) McIntosh integrateds?

"Hybrid design: vacuum tube preamp and solid state power amp"

"An all analog design, the MA352 has a vacuum tube preamplifier section that is powered by a pair of 12AX7A and a pair of 12AT7 vacuum tubes; its output stage is a direct coupled solid state amplifier that outputs 200 Watts per channel into 8 Ohm speakers or 320 Watts per channel into 4 Ohm speakers"

https://www.mcintoshlabs.com/products/integrated-amplifiers/MA352

If it weren't for the green LEDs, I'd almost be tempted.

 

[Julf]

If it weren't for the green LEDs, I'd almost be tempted.

This is when I realized McIntosh had become a brand marketing exercise: https://www.mcintoshlabs.com/products/merchandise/LB100

 

[SIY]

This is when I realized McIntosh had become a brand marketing exercise: https://www.mcintoshlabs.com/products/merchandise/LB100

$1500! Fifteen. Hundred. Dollars.