Any other SS amps with output transformers out there except Hellborg?

[agedhorse]

To the original question:
Bryston 3B and 4B.

To the hijack:
Scientific data is essential as a baseline for understanding how a piece of audio equipment functions. But the quality of that data is limited to the quality and intent of the measuring equipment so lets not mistake it for an accurate representation of what a particular individual may or may not be hearing. The auditory cortex is the most complex brain system. The mechanical system of the ear differs in functionality from person to person. Basing an argument on the premise that everyone's ears and auditory cortex work the same seems incredibly sophomoric.

Right, so if somebody's hearing is deficient in high frequencies, they might find an overly bright amp more "accurate" compared with somebody with less damaged hearing. This is where subjectivity comes in, but it would be incorrect to claim that the overly bright amp is better for everyone (which clearly it would not be).

A designer needs to quantify their target audience, their target baseline response curves, their target functionality goals and design products that are baseline acceptable to most players, but provide enough adjustment (within reason) to accommodate those who fall on either extreme of the bell curve. This is much more difficult in practice than it might appear.

 

[blr2]

It's mostly myth

At "saturation" it's saturated - sound isn't getting through - it's terrible distortion.
As it approaches saturation bandwidth becomes limited.

Ultimate HiFi amps are output transformer less (OTL) and that is natural for SS amps.

If the hellborg had some kind of high voltage output that needed to be converted to lower voltage then maybe it'd be useful. Instead it's just a 1:1 type output transformer. a Gimmick, a Placebo

Don't know what you mean. My point was that transformers can introduce coloration to the sound. Nothing gimmicky or placebo about that.
Don't know what you mean by "ultimate HiFi" amps either, but the majority of HiFi tube amps use output transformers.
Rupert Neve uses discreet opamps driven at much higher voltages than IC opamps (up to 70 V!). This is the reason for using OT in his amps.

 

[rufus.K]

To the original question:
Bryston 3B and 4B.

To the hijack:
Scientific data is essential as a baseline for understanding how a piece of audio equipment functions. But the quality of that data is limited to the quality and intent of the measuring equipment so lets not mistake it for an accurate representation of what a particular individual may or may not be hearing. The auditory cortex is the most complex brain system. The mechanical system of the ear differs in functionality from person to person. Basing an argument on the premise that everyone's ears and auditory cortex work the same seems incredibly sophomoric.

Were the Brystons rack mount multichannel amps?

 

[Jeff Bonny]

Were the Brystons rack mount multichannel amps?

Yes. 2 channel bridgeable rack mountable. Unfortunately their reputation in the audiophile world has kept the used price in the stratosphere.

 

[seamonkey]

To the original question:
Bryston 3B and 4B.

To the hijack:
Scientific data is essential as a baseline for understanding how a piece of audio equipment functions. But the quality of that data is limited to the quality and intent of the measuring equipment so lets not mistake it for an accurate representation of what a particular individual may or may not be hearing. The auditory cortex is the most complex brain system. The mechanical system of the ear differs in functionality from person to person. Basing an argument on the premise that everyone's ears and auditory cortex work the same seems incredibly sophomoric.

I absolutely believe people hear things that aren't there, and they don't hear things that are there. Sometimes I say "What?", "Excuse me?", "Come again", hearing just isn't perfect. Sometimes what they hear depends on what they see, smell, or taste. And some people see colors when they hear certain sounds. There's still a bell curve, but the discussions always seems to focus on the edge cases. Edge cases are rare.

 

[seamonkey]

Don't know what you mean. My point was that transformers can introduce coloration to the sound. Nothing gimmicky or placebo about that.
Don't know what you mean by "ultimate HiFi" amps either, but the majority of HiFi tube amps use output transformers.
Rupert Neve uses discreet opamps driven at much higher voltages than IC opamps (up to 70 V!). This is the reason for using OT in his amps.

'cuse me The question was on output transformers, but small signal transformers somehow creeped in. Voltage doesn't seem to mean much, a low voltage transformer can also approach saturation. Walter Jung points out the lows distort soon with a weak transformer design, but transformers can be designed to perform better. Better being no coloration or distortion.

In some circles the ultimate hifi is transformerless. Others are the more transformers the merrier. Simple parts of circuits that could be transformer coupled usually end up be a cap. Missed opportunity? or as long it's the big output transformer - that makes up for it all I guess.

In anycase, shoving an OT on a SS amp that doesn't need it is a gimmick. It's not being used for isolation and barely for impedance matching. Much of what it's doing is being "seen" in case, and on the sales ads.

 

[agedhorse]

There's opinion and there's fact... let's keep the differences separate.

 

[Jeff Bonny]

I absolutely believe people hear things that aren't there, and they don't hear things that are there. Sometimes I say "What?", "Excuse me?", "Come again", hearing just isn't perfect. Sometimes what they hear depends on what they see, smell, or taste. And some people see colors when they hear certain sounds. There's still a bell curve, but the discussions always seems to focus on the edge cases. Edge cases are rare.

I'd think that those "edge cases" would be less rare amongst musicians who over years and decades have honed the ability to hear minute subtleties of tone and pitch.

 

[KF2B]

To the original question:
Bryston 3B and 4B.

To the hijack:
Scientific data is essential as a baseline for understanding how a piece of audio equipment functions. But the quality of that data is limited to the quality and intent of the measuring equipment so lets not mistake it for an accurate representation of what a particular individual may or may not be hearing. The auditory cortex is the most complex brain system. The mechanical system of the ear differs in functionality from person to person. Basing an argument on the premise that everyone's ears and auditory cortex work the same seems incredibly sophomoric.

Thank you Sir!

 

[beans-on-toast]

For example, here is an old Vox output section (note transistors on secondary side):

I remember that VOX really had issues with their first transistorized amp, the T60, with burning up output transistors due to oscillations. They took that model off the market as a result. It never sounded that good. They went back to tubes in the power amp. Later they tried again but this time used large heatsinks to dissipate heat. They also had a thermal shutdown sensor. They didn't want to get burnt again like they did with the T60.

The schematic that you posted is interesting. The interstage transformer is acting as a phase inverter. This works very well and goes back to the early days of tubes when interstage transformers were more common. An added advantage of the transformer is that it also helps protect the power transistors from potentially damaging spikes. This added another layer of protection for the output transistors.

 

[Mark Reccord]

Unfortunately, their description is not how transformers work. They are neglecting the reflected impedance of the load, which by nature is reactive. A transformer can help mitigate SOME of the effects of capacitive load but not all of it.

Also, their comments about not needing DC protection circuits because DC can not get through is incorrect... unless you are ok with DC across the transformer primary saturating the core and probably taking at least something out in the process (maybe the transformer itself, a VERY expensive "fuse")

I wish marketing guys weren't allowed to write ad copy without an engineer (a real engineer) reviewing it for accuracy. A LOT of ad copy would disappear overnight

Yeah, that's the first thing I thought too. And fully agreed on the ad copy.

To the original question:
Bryston 3B and 4B.

To the hijack:
Scientific data is essential as a baseline for understanding how a piece of audio equipment functions. But the quality of that data is limited to the quality and intent of the measuring equipment so lets not mistake it for an accurate representation of what a particular individual may or may not be hearing. The auditory cortex is the most complex brain system. The mechanical system of the ear differs in functionality from person to person. Basing an argument on the premise that everyone's ears and auditory cortex work the same seems incredibly sophomoric.

I'm intimately familiar with Bryston's amplifiers and I can say with certainty that 3B and 4B do not have and have never had output transformers. They do have two transformers inside the chassis but they are both power transformers. Each channel has its own independent transformer and power supply so they are true dual monaural amplifiers. Great power amps for sure. I have a box full of populated 2B power amp PCBs sitting in my basement, that I inherited when the hifi manufacturer I used to work for folded. I should shove some of them into a chassis some day.

On your point about measurement: While audio is subjective, the limits of the human auditory system are well known as are the vagaries of the human brain. Measurement equipment is capable of perceiving things well beyond the realm of human perception. I routinely measure stuff in the GHz range and I have access to equipment that can accurately detect phase differences in the picosecond range. I do think that anything in audio that we can perceive can be measured with current measurement gear. I think the disconnect many people have between measurements and the listening experience is largely due two things: Not being provided with proper or adequate measurement data and the inability to interpret the audible effects of certain measurements. As an example, two pieces of equipment with exactly the same static frequency response can sound quite different and if that's the only data you're given it's easy to say that the differences aren't measurable, when in fact frequency response alone isn't adequate to fully characterize a piece of audio equipment. But if we add in all of the other stuff like THD, IMD, noise, dynamic and overload behaviour, distribution of distortion harmonics etc. we quickly get into a complex set of measurements that most people wouldn't know how to interpret. I always say that if you can't measure something that can be heard you're not measuring the right things.

 

[wcriley]

Carvin used a transformer as a PI in their early 70s SS bass amps.

 

[beans-on-toast]

I always liked Bryston products. They also offer a 20 year warranty on their amps and speakers.

 

[Jeff Bonny]

I'm intimately familiar with Bryston's amplifiers and I can say with certainty that 3B and 4B do not have and have never had output transformers. They do have two transformers inside the chassis but they are both power transformers. Each channel has its own independent transformer and power supply so they are true dual monaural amplifiers. Great power amps for sure.

You're right, I dunno what the **** I was thinking.....talkin' when I shoulda been listening I guess.

 

[brianrost]

It's a gimmick

It's not a gimmick, it's a design choice. There are many very early transistor audio amp designs with output transformers. Early 70s Univox solid state heads had a transformer and an impedance switch.

Also you can read this about McIntosh solid state amps.

The flip side of that coin is that it won't put more power into a lower impedance load than it will into 8 ohms.

If the transformer loads the output transistors at the optimum impedance, then you get full power out of the amp. As the article linked above points out, in theory you can just reduce load impedance and get more power. The issue is current and heat dissipation. Few amps show ideal power increases as impedance drops for this very reason. You should get 2x the power at 4 ohms compared to 8 ohms, but relatively few amplifiers can in fact do this. Wouldn't it be great to take an amp rated at 100 watts at 8 ohms, drive a 0.8 ohm load instead and get 1000 watts?

 

[beans-on-toast]

While audio is subjective, the limits of the human auditory system are well known as are the vagaries of the human brain. Measurement equipment is capable of perceiving things well beyond the realm of human perception. I routinely measure stuff in the GHz range and I have access to equipment that can accurately detect phase differences in the picosecond range. I do think that anything in audio that we can perceive can be measured with current measurement gear. I think the disconnect many people have between measurements and the listening experience is largely due two things: Not being provided with proper or adequate measurement data and the inability to interpret the audible effects of certain measurements. As an example, two pieces of equipment with exactly the same static frequency response can sound quite different and if that's the only data you're given it's easy to say that the differences aren't measurable, when in fact frequency response alone isn't adequate to fully characterize a piece of audio equipment. But if we add in all of the other stuff like THD, IMD, noise, dynamic and overload behaviour, distribution of distortion harmonics etc. we quickly get into a complex set of measurements that most people wouldn't know how to interpret. I always say that if you can't measure something that can be heard you're not measuring the right things.

It's scary how little we know about how the brain works. We can design a circuit. We can measure it's performance. We can reproduce it in the factory. We don't fully understand how the brain processes auditory signals to make us feel good when we listen. That part of the measurement system has a long way to go.

So we design circuits. We try to understand them. But instruments alone can't be used as the only design tool. So we listen and refine the design. Then we get more people to come in and listen and refine the design some more based on the wider sample. Computers can't design an amp. The human factor is important. Perhaps at some point we'll have a better understanding of brain function based on being able to measure the entire system, the human and the electronic circuit.

 

[agedhorse]

Hill audio used transformer based phase inverter's in their large solid state PA amps. DX series.

 

[JimmyM]

I wish marketing guys weren't allowed to write ad copy without an engineer (a real engineer) reviewing it for accuracy. A LOT of ad copy would disappear overnight

Wow, hope the marketing guys don't jack you on your coffee break

 

[Mark Reccord]

I always liked Bryston products. They also offer a 20 year warranty on their amps and speakers.

Great Canadian company. I've been to their factory in Peterborough and have had a couple of good chats with Chris Russell about power amps over the years.

You're right, I dunno what the **** I was thinking.....talkin' when I shoulda been listening I guess.

No worries, happens to all of us. Especially me according to my wife.

You're up early!

Hill audio used transformer based phase inverter's in their large solid state PA amps. DX series.

Man, that's a name I haven't heard in a while. I seem to recall using a Hill console with a 6 band fixed eq on it or something odd like that.

It's scary how little we know about how the brain works. We can design a circuit. We can measure it's performance. We can reproduce it in the factory. We don't fully understand how the brain processes auditory signals to make us feel good when we listen. That part of the measurement system has a long way to go.

So we design circuits. We try to understand them. But instruments alone can't be used as the only design tool. So we listen and refine the design. Then we get more people to come in and listen and refine the design some more based on the wider sample. Computers can't design an amp. The human factor is important. Perhaps at some point we'll have a better understanding of brain function based on being able to measure the entire system, the human and the electronic circuit.

I'm certainly not advocating designing audio gear without listening to it and I'm sure you don't think I am advocating that. Listening is important and there have been lots of cases where a technically "better" piece of audio equipment didn't sound as good as a technically "worse" one but I don't think for a second that this is inherently beyond measurability. With the right metrics and a good understanding of how they relate to sonic performance I think it's possible to get a very good picture of how something behaves in the real world. That said, it's usually easier to listen to it than to take and interpret a complex suite of measurements.

 

[BadExample]

I absolutely believe people hear things that aren't there, and they don't hear things that are there. Sometimes I say "What?", "Excuse me?", "Come again", hearing just isn't perfect. Sometimes what they hear depends on what they see, smell, or taste. And some people see colors when they hear certain sounds. There's still a bell curve, but the discussions always seems to focus on the edge cases. Edge cases are rare.

Actually, your brain stem is suppoed to filter your sensory perception of normal stuff it deems unimportant as well as what it determines is not real. It is not perfect and people do hear things not there. If it fails you get to take lithium or the people in your basement will start talking and make you paranoid.