Class A vs AB impact on bus compressors and use of neve cards in output buffer

[Nickerz]

So Stam last year came out with their "neve mod" which is supposedly a B283 wired to the output buffer in class A\B. Now I am pretty new to this, but as I understand it, a compressor that has the output buffer wired in A\B will not behave differently depending on how hard it is loaded. That is to say that THD should be linear, that compression will be ratio dependent. So as I understand it then, the neve output card isn't going to be "loaded down" and therefor there's no difference if I insert the card on the output buffer, or if was run inline down the chain.

The reason why I ask is I really liked the way it sounded. But if it doesn't make a difference if I put it down the chain, then I would do that. If it however plays a part in the dynamics of the sound (that is to say that being wired to the output buffer sounds different than in line later in the chain), then I would like to work on a compressor with this built in.

It is my understanding that if I want the dynamics to impact that output buffer that it would need to be wired in class-a.

 

[Nickerz]

Bump!

 

[ruffrecords]

I am not sure where you got your information but it makes little sense to me. If you are talking about the BA283 class A card, the one with the 2N3055 output transistor, then this has to be run in class A, end of story, because it is a single ended output stage. If you are talking about the BA440 and friends then they are push pull output can can be run in class A/B.

I can find no info on the Stam Audio website about a B283 running in A/B.

Cheers

Ian

 

[Nickerz]

Posted by Stam himself on Facebook. My question is still theoretical though, so it doesn't matter which is true. I'm just trying to assertain if I need to DIY this into the output buffer or if running the cards inline after it accomplishes the same goal. I really like the sound that it adds, but if it's proportional to the amount of compression being used, then I do not think running it in line will accomplish the same thing.

I'm still very new, so as I understand it, if it was class a\b, then it wouldn't distort at any different of a ratio based on any difference of settings, just strictly as a matter of how much signal is hitting it, which would mean I could run it inline afterwords. Also as I understand it, if I were to DIY it into class-a, it would be output dependent and would add to the dynamics doing it that way.

 

[ruffrecords]

I don't have Facebook so I cannot access your link. Can you cut an paste the actual text where he talks about class A/B please.

Cheers

Ian

 

[abbey road d enfer]

I'm still very new, so as I understand it, if it was class a\b, then it wouldn't distort at any different of a ratio based on any difference of settings, just strictly as a matter of how much signal is hitting it, which would mean I could run it inline afterwords. Also as I understand it, if I were to DIY it into class-a, it would be output dependent and would add to the dynamics doing it that way.

I agree with Ian here, this doesn't make sense really. The difference between class A and class AB circuits is very well documented, and it's an almost extinct debate (except for audiophools) because the performance of class AB circuits is almost flawless today.
Now you have to know that most of the sonic signature (including how distortion behaves vs. level) is in the side-chain and variable gain element, not in the input/output circuitry.

 

[gyraf]

..iow, you shouldn't take the SA hype too serious..

 

[abbey road d enfer]

I know the guy who "designs" most of the Stam products. He himself admits that the owner is technically ignorant.

 

[Nickerz]

I don't have Facebook so I cannot access your link. Can you cut an paste the actual text where he talks about class A/B please.

Cheers

Ian

Stam claims the output buffer is wired class A\B on the SA4000 mkii with the "neve mod" (neve output card)

 

[Nickerz]

I agree with Ian here, this doesn't make sense really. The difference between class A and class AB circuits is very well documented, and it's an almost extinct debate (except for audiophools) because the performance of class AB circuits is almost flawless today.
Now you have to know that most of the sonic signature (including how distortion behaves vs. level) is in the side-chain and variable gain element, not in the input/output circuitry.

That's what I'm trying to clarify. Would either circuit type behave differently if there was a neve output card wired to the output buffer VS running the neve card AFTER the compressor. If it behaves differently BECAUSE it is wired to the output buffer, then it is its own thing. If not, it's a gimmick.

 

[Nickerz]

..iow, you shouldn't take the SA hype too serious..

I'm not which is why I'm asking these questions rather than waiting 2 years to get one. I want to know if having the neve output card wired to the output buffer on the compressor will behave differently than running a neve output card after the compressor instead.

 

[Nickerz]

I know the guy who "designs" most of the Stam products. He himself admits that the owner is technically ignorant.

PM me, I'd like to ask the guy a question or even establish business a relationship with him. Stam's business model is atrocious.

 

[abbey road d enfer]

I want to know if having the neve output card wired to the output buffer on the compressor will behave differently than running a neve output card after the compressor instead.

This does not make much sense to me. I may be thick. A schemo would help understanding your dilemma.

 

[iampoor1]

I know the guy who "designs" most of the Stam products. He himself admits that the owner is technically ignorant.

I officially serviced their units in the US for about 6 months as there us tech. My "official" diagnosis resource from stam was "look at the schematic on the website and figure it out". I'm sure that's no surprise to anyone here tho

 

[Nickerz]

This does not make much sense to me. I may be thick. A schemo would help understanding your dilemma.

I don't have one. The SA4000 MK II is a Gyraf derived SSL clone that has a Neve B283 wired as an output buffer supposedly in class A\B, and I've been asking whether anyone thinks that it is playing any part of the dynamics, or if it is coloring the signal in a static way. This is just the statement of the seller, I do not have a sample or a schemo.

 

[ruffrecords]

I don't have one. The SA4000 MK II is a Gyraf derived SSL clone that has a Neve B283 wired as an output buffer supposedly in class A\B, and I've been asking whether anyone thinks that it is playing any part of the dynamics, or if it is coloring the signal in a static way. This is just the statement of the seller, I do not have a sample or a schemo.

I wall say it again, please cut and paste where Stam says the B283 is working in class A/B. The Neve BA283 is a single ended class A amplifier. I cannot be operated in class A/B. The only thing I can find on their web site is this qquoate:

"The “British” mod adds two BV283 cards (the output section of the 1073MP preamp) as a Class A output buffer with 2 Carnhill transformers to the signal making it the perfect way to add low end and effortlessly warm up a mix." No mention of class A/B.

Cheers

Ian

 

[abbey road d enfer]

"The “British” mod adds two BV283 cards (the output section of the 1073MP preamp) as a Class A output buffer with 2 Carnhill transformers to the signal making it the perfect way to add low end and effortlessly warm up a mix." No mention of class A/B.

Which does not make sense to me. Two cards? Are there two outputs?

 

[Nickerz]

I wall say it again, please cut and paste where Stam says the B283 is working in class A/B. The Neve BA283 is a single ended class A amplifier. I cannot be operated in class A/B. The only thing I can find on their web site is this qquoate:

"The “British” mod adds two BV283 cards (the output section of the 1073MP preamp) as a Class A output buffer with 2 Carnhill transformers to the signal making it the perfect way to add low end and effortlessly warm up a mix." No mention of class A/B.

Cheers

Ian

I already told you this, someone literally asked him and he said it was wired "class a/b." Its a literal discussion on facebook that involves no context necessary at all.

It doesn't make it true (Stam does not design his hardware) and my question is IN THEORY. I am not buying a compressor from STAM, so I am asking people who proport to know. Does anyone know the answer to my question or does everyone here just copy schematics and know exactly the same amount as Stam?

I am coming to you as a person who has no knowledge, asking people who claim to have some, or even a lot of knowledge... whether A vs A\B has any impact on the DYNAMICs of the neve card, if it were wired to the output buffer of a compressor, or if it is static. Whether it would behave just the same run after the compressor (inline).

I am asking if there is any benefit to wire this into a compressor at all, whether class makes a difference in how it behaves in this instance. Because I would like to purchase a regular off the rack SSL clone and then wire these after if they would behave the same.

In the absense of anyone able to answer the question I have to buy a compressor from Stam, which I don't want to do.

 

[Nickerz]

Which does not make sense to me. Two cards? Are there two outputs?

Well yeah it's a stereo bus compressor. So linked stereo. Otherwise it'd have to be summed mono.

 

[JohnRoberts]

class A vs class ab makes a difference in power amplifiers.

JR