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Amp Effects + Distortion - Page 2

post #16 of 26
Quote:
Originally Posted by OJNeg View Post

Do push-pull tube amps have lower harmonics (compared to single-ended) in general? How come?

Push pull amps generally cancel out some distortion, relative to SE tube amps.
They predominantly cancel out even order harmonics, leaving the odd order harmonics, and at a lower level than SE amps.
post #17 of 26
Quote:
Originally Posted by jcx View Post

details of the Carver-Stereophile challenge were deliberately obscured - I think somewhere it is mentioned that Caver may have made ~ minor change to the feedback - in addition to the added output parts

 

the tube amp wasn't identified to spare the manufacturer's reputation - but could have been push-pull to get the power rating - so may have had very little 2nd harmonic to begin with

 

we can build SS or Tube amps that do have "sound" effects - it is easier, cheaper to build "transparent" SS amps than with Tubes

I thought it was Conrad Johnson.

post #18 of 26
Quote:
Originally Posted by Chris J View Post


Push pull amps generally cancel out some distortion, relative to SE tube amps.
They predominantly cancel out even order harmonics, leaving the odd order harmonics, and at a lower level than SE amps.

Are you talking about push-pull in SS amp? SE amp I assumed you're talking about a class A amp. I am trying to understand what is the harmonic cancellation that you're talking about. Is it some sort of negative feedback?

post #19 of 26
Quote:
Originally Posted by bigshot View Post


Solid state amps all sound the same. Tube amps are all over the place. It's possible to hobble a solid state amp in just the right way and get it to perform like a tube amp, but there isn't much call for that. The amps you buy are calibrated for flat response with minimal distortion. That guarantees they'll sound the same.

Carver sold a line of amp that mimic tube amp in the 70s/80s. The x-t series; t means tube sound. I have a computer program that has two canned recipes of converting SS sound to tube sound by tuning your ripped music file. Now you can have your tube sound on IPOD. To me it does not change the enjoyment of music, but it's a lot of fun.

post #20 of 26
Quote:
Originally Posted by dvw View Post

Are you talking about push-pull in SS amp? SE amp I assumed you're talking about a class A amp. I am trying to understand what is the harmonic cancellation that you're talking about. Is it some sort of negative feedback?

Push-pull can be SE?

post #21 of 26
Quote:
Originally Posted by dvw View Post

I thought it was Conrad Johnson.

It was

post #22 of 26

some terms get reused, need to be interpreted in context - sort of like programming language operator overloading

 

Single-Ended can mean slightly different things when used with "push-pull" vs "bridged/balanced", as a amplifier circuit description vs a load driving description

 

push-pull vs SE tube amp http://www.aikenamps.com/SingleEnded.htm

 

the output winding doesn't have to be gnded anywhere in particular so the output can be "SE" (gnd one end) or "balanced" (gnd center tap)

 

a confusion is SS complementary transistor output stages can be described as "push-pull" but can optionally, or not, be bridged or sometime called "balanced"

 

so engineers may talk about Push-Pull output amplifier circuits driving a load Singe-Ended


Edited by jcx - 8/19/12 at 6:17pm
post #23 of 26
Quote:
Originally Posted by jcx View Post

some terms get reused, need to be interpreted in context - sort of like programming language operator overloading

 

Single-Ended can mean slightly different things when used with "push-pull" vs "bridged/balanced", as a amplifier circuit description vs a load driving description

 

push-pull vs SE tube amp http://www.aikenamps.com/SingleEnded.htm

 

the output winding doesn't have to be gnded anywhere in particular so the output can be "SE" (gnd one end) or "balanced" (gnd center tap)

 

a confusion is SS complementary transistor output stages can be described as "push-pull" but can optionally, or not, be bridged or sometime called "balanced"

 

so engineers may talk about Push-Pull output amplifier circuits driving a load Singe-Ended

This was helpful. I was thinking of bridged.

post #24 of 26
Quote:
Originally Posted by dvw View Post

Carver sold a line of amp that mimic tube amp in the 70s/80s. The x-t series; t means tube sound. I have a computer program that has two canned recipes of converting SS sound to tube sound by tuning your ripped music file. Now you can have your tube sound on IPOD. To me it does not change the enjoyment of music, but it's a lot of fun.

 Carver also sold a TFM series of amps that were based on the sound of the Silver Seven tube amp he built. TFM stands for Transfer Function Modified. The TFM series amps were nulled to the Silver Seven tube amp during the modification & adjustment phase.

post #25 of 26
Quote:
Originally Posted by jcx View Post

some terms get reused, need to be interpreted in context - sort of like programming language operator overloading

 

Single-Ended can mean slightly different things when used with "push-pull" vs "bridged/balanced", as a amplifier circuit description vs a load driving description

 

push-pull vs SE tube amp http://www.aikenamps.com/SingleEnded.htm

 

the output winding doesn't have to be gnded anywhere in particular so the output can be "SE" (gnd one end) or "balanced" (gnd center tap)

 

a confusion is SS complementary transistor output stages can be described as "push-pull" but can optionally, or not, be bridged or sometime called "balanced"

 

so engineers may talk about Push-Pull output amplifier circuits driving a load Singe-Ended

 

I like the amplifier vs. load driving description.

With the correct Output Transformer (i.e. a differential drive (balanced output)) a push pull amp or an SE amp can drive a load in a balanced configuration.

 

In a solid state amp, as they do not use output transformers, you need two complementary output stages to create a balanced output stage.

Therefore one complementary output stage would create a SE load drive,

 

Note: there are a few SS amps out there using transformers in the output stage (e.g. McIntosh), but they are not very common.

 

Quote:
Originally Posted by dvw View Post

Are you talking about push-pull in SS amp? SE amp I assumed you're talking about a class A amp. I am trying to understand what is the harmonic cancellation that you're talking about. Is it some sort of negative feedback?View Post

 

I was thinking about Push Pull in tube amps because your question referred to tube amps.
Vacuum Tube SE amps are class A as there is only one output device (a power triode or a power pentode) to provide output current, hence, unlike a push pull amp, you don't have two output devices to share current, i.e.  in Push Pull: one to output current for the positve half of the waveform, and a second output device to provide output current for the negative half of the waveform.

 

Yes, it is a form of negative feedback within the output stage itself. 

 

JCX's link does a great job of explaining this.


Edited by Chris J - 8/20/12 at 4:19am
post #26 of 26
Quote:
Originally Posted by Chris J View Post

 

Note: there are a few SS amps out there using transformers in the output stage (e.g. McIntosh), but they are not very common.

 

 

I was thinking about Push Pull in tube amps because your question referred to tube amps.
Vacuum Tube SE amps are class A as there is only one output device (a power triode or a power pentode) to provide output current, hence, unlike a push pull amp, you don't have two output devices to share current, i.e.  in Push Pull: one to output current for the positve half of the waveform, and a second output device to provide output current for the negative half of the waveform.

 

Yes, it is a form of negative feedback within the output stage itself. 

 

JCX's link does a great job of explaining this.

 

Just to pick a nit, the McIntosh solid state amps used autoformers rather than transformers.

 

se

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