Super cheap opamp used in Transporter Analog Stage

[chesebert]

I don't know how you feel about opamp in analog out, but using 'jelly bean' opamp is another matter all together

I am scratching my head looking at the photo and going back and forth with Stereophile review. Elcheapo NE5534 ($0.96 on digikey) sounds as good as Ayre's C5XE with its discrete 0 feedback output?

Pic

 

[dw8083]

At least there's tons of room to add a discrete I/V and powersupply. I bet the Pass Labs D1 I/V would sound great here.

Thanks for finding the internal photos, this was VERY helpful.

-David

 

[Jon L]

Even though I have a problem with Transporter's pricing, using NE5534 is not necessarily a bad thing at all. This family of op-amps tends to have a warm, forgiving sound that serves digital equipment well. The studio recording/mastering equipment is chock-full of NE5534 op-amps, which are pretty much industry-standard, so any given CD you may have has probably been made with hundreds of NE5534's in the chain by the time you get it.

It would be interesting to see what brand of NE5534's are used in the transporter and how they're implemented. There may be simple mods that can really improve things, i.e. biasing NE5534 into class A or dropping in SE5534/SA5534 by ON Semi.

 

[chesebert]

Quote:

Originally Posted by Jon L /img/forum/go_quote.gif Even though I have a problem with Transporter's pricing, using NE5534 is not necessarily a bad thing at all. This family of op-amps tends to have a warm, forgiving sound that serves digital equipment well. The studio recording/mastering equipment is chock-full of NE5534 op-amps, which are pretty much industry-standard, so any given CD you may have has probably been made with hundreds of NE5534's in the chain by the time you get it. It would be interesting to see what brand of NE5534's are used in the transporter and how they're implemented. There may be simple mods that can really improve things, i.e. biasing NE5534 into class A or dropping in SE5534/SA5534 by ON Semi.

I think I saw JRC on the opamp and with probably what I guess to be, negative feedback with the resistors next to them. The caps I am not sure could be output caps, which would be quite bad for sound quality.

The point is I just don't understand how stereophile could find Transporter equal to one of the best CDP with all those audiophile 'no no's in their circuit design.

 

[Konig]

sorry for my noob question but do i have to worry abt opamps when im not using their analog out?

 

[Jon L]

Quote:

Originally Posted by chesebert /img/forum/go_quote.gif I think I saw JRC on the opamp and with probably what I guess to be, negative feedback with the resistors next to them. The caps I am not sure could be output caps, which would be quite bad for sound quality. The point is I just don't understand how stereophile could find Transporter equal to one of the best CDP with all those audiophile 'no no's in their circuit design.

Do you have one to listen to? I know what you're saying about "audiophile no no's," but in the end, what counts is how it sounds, which I haven't listened to.

Plenty of equipment sounds great with dirt-cheap NE5534 with heavy negative feedback even though it "shouldn't."

However, I hate that JRC NE5534, and I would immediately order some ON Semi replacements and figure out a way to bias them into class A.

 

[Herandu]

It looks like a symmetrical analogue stage after the DAC chip. An additional analogue stage is then used after that in what seems to be an unbalanced output.

I am not sure why the use of a feedback loop is a bad thing. I would love to see an opamp amplification stage that doesn't use feedback. An internet link to such a schematic would be most welcome.

I have mentioned before that cost of components do not mean an inferior sound quality. The 5532 and 5534 were expensive when they first came out, but they are now widely available from several manufacturers, who make them under license from Philips. So prices have dropped. That has nothing to do with the quality of the 5532/5534. Using the world's most expensive opamp doesn't guarantee the world's best sound quality.

 

[morphsci]

Quote:

Originally Posted by chesebert /img/forum/go_quote.gif The point is I just don't understand how stereophile could find Transporter equal to one of the best CDP with all those audiophile 'no no's in their circuit design.

Umm .... maybe because they listened to it rather than just looking at images of its internals? Just a guess. Hope this helps.

 

[audioengr]

Quote:

Originally Posted by Jon L /img/forum/go_quote.gif Even though I have a problem with Transporter's pricing, using NE5534 is not necessarily a bad thing at all. This family of op-amps tends to have a warm, forgiving sound that serves digital equipment well. The studio recording/mastering equipment is chock-full of NE5534 op-amps, which are pretty much industry-standard, so any given CD you may have has probably been made with hundreds of NE5534's in the chain by the time you get it. It would be interesting to see what brand of NE5534's are used in the transporter and how they're implemented. There may be simple mods that can really improve things, i.e. biasing NE5534 into class A or dropping in SE5534/SA5534 by ON Semi.

I would normally consider this a bad choice, but it is probably the N5534 from TI. Now this is an entirely different chip from the original Philips op-amp. Very nice indeed. There are better dual and singles of course, but the top end of this chip is very pristine and clear, and the power delivery to it is simple, so they tend not to screw this up.

 

[audioengr]

Quote:

Originally Posted by chesebert /img/forum/go_quote.gif I think I saw JRC on the opamp and with probably what I guess to be, negative feedback with the resistors next to them. The caps I am not sure could be output caps, which would be quite bad for sound quality. The point is I just don't understand how stereophile could find Transporter equal to one of the best CDP with all those audiophile 'no no's in their circuit design.

I dont find it so difficult to believe. Every reviewers system is at a different level of perfection, and most of them are not as good as what I have in my own living room IMO. Not even close.

 

[audioengr]

Quote:

Originally Posted by Herandu /img/forum/go_quote.gif It looks like a symmetrical analogue stage after the DAC chip. An additional analogue stage is then used after that in what seems to be an unbalanced output. I am not sure why the use of a feedback loop is a bad thing. I would love to see an opamp amplification stage that doesn't use feedback. An internet link to such a schematic would be most welcome. I have mentioned before that cost of components do not mean an inferior sound quality. The 5532 and 5534 were expensive when they first came out, but they are now widely available from several manufacturers, who make them under license from Philips. So prices have dropped. That has nothing to do with the quality of the 5532/5534. Using the world's most expensive opamp doesn't guarantee the world's best sound quality.

Good points, however the wrong parts choices means that no matter how good the board design and cap choices, it will never sound world-class.

I imagine that they just copied the circuit recommended by AKM. Most manufacturers do this. I have the evaluation board from AKM and the schematic. The JRC NJM5534 is the op-amp that comes in the evaluation board. Sounds like they just copied everything, including the same op-amps in the eval. board.

If anyone wants the schematic for the demo board, just email me. I cannot attach it because it is 293 kBytes.

Steve N.