[regal]

Quote:

Originally Posted by Parafeed /img/forum/go_quote.gif I'll preface by saying that I'm not trying to be argumentative, but how many balanced headphone circuits have you built and listened to? (Balanced == differential, not balanced == bridged.) Without getting bogged down into what sounds good on paper - perfect AC balance from a LTP, K&K's differential headphone amp design, (the circuit used for the Moon Audio amp if I remember correctly), is a good starting point. (I've built this with paralleled 6H30 output tubes as well.) In terms of dynamics, this will leave the 6EW7 direct coupled amp you proposed building in the other thread, crying in a corner.

Still a 2 channel amp, with a transformer/phase splitting, no advantage of balanced vs unbalanced inputs. Signal is combined at the driver stage and split again at the output transformer. Probably 3rd harmonic dominant. Why compare this to an SET amp, thats apples and oranges?

 

[luvdunhill]

Quote:

Originally Posted by regal /img/forum/go_quote.gif Still a 2 channel amp, with a transformer/phase splitting, no advantage of balanced vs unbalanced inputs

one thing to point out. I'd argue that there is definitely is still an advantage of the balanced inputs in this case.

You'll have to think outside of the box and take the system as a whole, something few people do .. but.. ready?

The benefit is in the fact that the output stage of the source is balanced.

That alone is a huge advantage.

So, if you A/B this amp with SE input and balanced inputs being used, do you think they would sound different? I bet they will!

 

[regal]

Quote:

Originally Posted by luvdunhill /img/forum/go_quote.gif The benefit is in the fact that the output stage of the source is balanced. That alone is a huge advantage.

My experience has been that sources measure better when the differential outputs of the DAC are transformed to unbalanced, this is how we get the CMRR that the DAC chips are rated for, in other words measure the differential output of a 24 bit DAC and they have a 16 bit S/N ratio. Now this might be achieved at the headphones after your amp.

 

[luvdunhill]

Quote:

Originally Posted by regal /img/forum/go_quote.gif My experience has been that sources measure better when the differential outputs of the DAC are transformed to unbalanced

then why build a balanced amp?

transformers can transform quite well in fact...

 

[Parafeed]

Quote:

Originally Posted by luvdunhill /img/forum/go_quote.gif I'd argue that there is definitely is still an advantage of the balanced inputs in this case.

There are several advantages of this circuit design, even down to isolating SE input ground via the transformer.

But as per usual, regal dismisses what he does not understand and then goes on to talk about CMRR in a later post. LOL. It's a lost cause.

 

[Parafeed]

Quote:

Originally Posted by pabbi1 /img/forum/go_quote.gif Heh, this Raven design (with 6h30 and 6n23) has left me crying in the corner... and pity I used all that pretty Lundahl iron.

I don't know the history..... You had a problem with building it?

 

[sachu]

FWIW,

In my experience balanced makes little to no difference. This was again vindicated at the recent Portland meet where the Exstata+SR404 run out of the Meridian G08 source made no difference if it was being driven in balanced or unbalanced output mode. Albeit this was under meet conditions so perhaps there was some micro detail that we couldn't pick up or something, but off the cuff to two of us who listened to balanced v/s SE couldn't pick out any difference at all.

 

[regal]

Quote:

Originally Posted by Parafeed /img/forum/go_quote.gif There are several advantages of this circuit design, even down to isolating SE input ground via the transformer. But as per usual, regal dismisses what he does not understand and then goes on to talk about CMRR in a later post. LOL. It's a lost cause.

Not dismissing it, just don't think its worth a 3rd order dominant P-P type amp to say "I'm balanced." Again is it worth the cost over a simple SET amp?

If we're back to personal attacks, Parafeed are there any amps you haven't built? You seem to have built them all ! lol,

Again maybe you should start contibuting to these forums instead of blasting and boasting of how rich and powerful you are. You've been here since 2005 and contributed how many DIY designs? zero. Stick to your opinions and stop making personal attacks, we all appreciate you sharing your knowledge/experiences but it doesn't have to be mixed with pompous personal attacks. We are here to learn, are you?

 

[dsavitsk]

Quote:

Originally Posted by regal /img/forum/go_quote.gif Not dismissing it, just don't think its worth a 3rd order dominant P-P type amp to say "I'm balanced."

I think you miss the point of balanced vs single ended vis-à-vis distortion numbers. If balanced added 3rd harmonic distortion while reducing 2nd, then there would be something to your argument. But, it doesn't. It simply cancels the 2nd, making the stage lower distortion overall. So, a differential amp may be "3rd order dominant", but this is a misnomer as there isn't any more 3rd order distortion than in a single ended stage. Moreover, it isn't like the single ended's 2nd order distortion hides the 3rd order harmonic distortion -- you still get both. A differential amp is simply lower in distortion in some places, and equivalent in others.

At any rate, there is a popular canard on the internet that says that tubes sound better than solid state because they add 2nd harmonic distortion and this sort of distortion is pleasant sounding. But, this simply isn't true. Tubes sound good because they are more linear devices than transistors. This is despite the added 2nd harmonics, and they sound even better of you can get rid of it.

Quote:

Originally Posted by regal /img/forum/go_quote.gif Again is it worth the cost over a simple SET amp?

Something often forgotten in this sort of argument is that, for the most part, a differential design will have good PSRR relieving one of the cost of a power supply. A "simple" single ended amp generally won't, so you have to spend more money on the power supply. Pick your poison.

 

[nikongod]

Quote:

Originally Posted by regal /img/forum/go_quote.gif maybe you should start contibuting to these forums instead of blasting and boasting of how rich and powerful you are. You've been here since 2005 and contributed how many DIY designs? zero. Stick to your opinions and stop making personal attacks, we all appreciate you sharing your knowledge/experiences but it doesn't have to be mixed with pompous personal attacks. We are here to learn, are you?

He has shared valuable information in several places in this thread. he had a schematic free to the taker up in another thread you posted I think it came down when it became obvious that thread was almost as worthless as this one.

On that note, why should anyone really feel compelled to post a schematic or design?
Quote:

Originally Posted by regal /img/forum/go_quote.gif DIY is about sharing schematics/designs, having fun building an amp that competes with anything on the market, not trying to prove how clever you are.

Why cant DIY be about sharing ideas as well as schematics & designs? Many people get more from DIY for hearing about something new they can work into what they already have than just "here is another schematic most people who can point-to-point could have drawn up from a quick description"

Many people would consider posting a schematic of an amp they could pull from any tube textbook a thinly veiled attempt to prove how clever one is.

The bit about "competes with anything on the market" is nice & ironic. I guess DIY designs should be included despite being the "wrong" topology (what does right/wrong mean?). Anything includes quite a lot of things after all. Indeed, it could be said that its impossible to design/build an amp that "competes with anything on the market" and as such it is irresponsible to post schematics that are clearly sub-optimal (whatever optimal means).

From another post of his, I agree that once you get to a certain point you learn more by taking a rough idea and figuring out how to make it work and tune it to your own preferences yourself.

Quote:

Originally Posted by sachu /img/forum/go_quote.gif FWIW, In my experience balanced makes little to no difference. This was again vindicated at the recent Portland meet where the Exstata+SR404 run out of the Meridian G08 source made no difference if it was being driven in balanced or unbalanced output mode.

The first stage of the exstata is a differential pair phase splitter. The amp is balanced regardless of what signal you put in.

Unless the designer screwed something up (unlikely, the last versions of the schematic I saw looked quite nice) there should be little difference between the 2 inputs.

FWIW, from my previous experiments with it, I preferred the balanced inputs on my STAX gear, using a transformer to convert a SE signal to balanced rather than the input differntial pair. I dont know what changed so it may not be worth much.

Welcome back

 

[Parafeed]

Quote:

Originally Posted by regal /img/forum/go_quote.gif Not dismissing it

You dismissed it as "Still a 2 channel amp". That was the beginning of your reply. It's too frustrating trying to have a conversation with you.

Quote:

Originally Posted by regal /img/forum/go_quote.gif are there any amps you haven't built?

Of course. Are there any topologies I've not built, probably not.

Quote:

Originally Posted by regal /img/forum/go_quote.gif blasting and boasting of how rich and powerful you are.

Rich and powerful..... I don't have a clue what you are talking about.

Quote:

Originally Posted by regal /img/forum/go_quote.gif You've been here since 2005 and contributed how many DIY designs? zero.

Eh? I spend most of my time communicating via PM and email, not in public. Twice I've been asked for circuit diagrams, unsolicited, from people I don't know on Head-Fi. Twice I've provided them, with the proviso that they are not published so that a) I don't have to support them, and b) I don't need to explain them to nitwits who look at a fully balanced, (not bridged), differential design and then comment that "the signal is combined at the driver stage and split again at the output transformer".

 

[TimJo]

Quote:

Originally Posted by nikongod /img/forum/go_quote.gif From another post of his, I agree that once you get to a certain point you learn more by taking a rough idea and figuring out how to make it work and tune it to your own preferences yourself.

This is my goal. But as I'm finding, it requires a lot of reading. The more studying I do though, the easier it's becoming to filter the good advice from the pool of information that is posted on this here interweb, which is a good thing.

 

[regal]

Quote:

Originally Posted by Parafeed /img/forum/go_quote.gif b) I don't need to explain them to nitwits who look at a fully balanced, (not bridged), differential design and then comment that "the signal is combined at the driver stage and split again at the output transformer".

I didn't see that the schematic had the bottom tubes flipped 180*, but see thats your problem you call people nitwits and boast yourself up instead of sharing ideas and thoughts. A simple "no look the tubes are 180* turned" instead you get off on by putting people down and trying to make yourself look good.


And since there are so many nitwits out there you don't want to deal with explain how the amp is fully balanced when the two phases of the input are bridged at the primary of the input transformer ?

 

[nikongod]

Does it matter that the tubes are drawn upside down? Is it a normally accepted convention? I draw my own schematics whichever way the symbols fit on the paper best. I guess some convention makes sense as it makes for a fun time when revision one is drawn horizontally and rev2 is vertically (and when you file them as rev one and rev 2 on the topic of conventions). Is there any formally accepted convention for drawing tubes in a differential configuration? SS circuits are always drawn with both complementary devices next to each other facing the same way.... I have seen tube schematics drawn both ways. GRRR.

Quote:

Originally Posted by regal /img/forum/go_quote.gif I didn't see that the schematic had the bottom tubes flipped 180*, but see thats your problem you call people nitwits and boast yourself up instead of sharing ideas and thoughts. A simple "no look the tubes are 180* turned" instead you get off on by putting people down and trying to make yourself look good.

Quote:

Originally Posted by regal /img/forum/go_quote.gif Still a 2 channel amp, with a transformer/phase splitting... Probably 3rd harmonic dominant. Why compare this to an SET amp, thats apples and oranges?

If you knew it was not a SET amp, and you knew it had a transformer as a phase splitter, what else could it be? Does it matter how the symbols are drawn at that point?

You are backpedaling after writing off a solid design.

 

[regal]

Quote:

Originally Posted by nikongod /img/forum/go_quote.gif Does it matter that the tubes are drawn upside down? Is it a normally accepted convention? I draw my own schematics whichever way the symbols fit on the paper best. I guess some convention makes sense as it makes for a fun time when revision one is drawn horizontally and rev2 is vertically (and when you file them as rev one and rev 2 on the topic of conventions). Is there any formally accepted convention for drawing tubes in a differential configuration? SS circuits are always drawn with both complementary devices next to each other facing the same way.... I have seen tube schematics drawn both ways. GRRR. If you knew it was not a SET amp, and you knew it had a transformer as a phase splitter, what else could it be? Does it matter how the symbols are drawn at that point? You are backpedaling after writing off a solid design.

I'm not writing it off, the topic of the thread is "Best Tube Amp to DIY". This amp has expensive iron a lot of tubes, not the greatest output impedance. And I still question with the single input transformer and the two separate phases connected at the input if it is the Best AMP to DIY. Its surely a fine a fine amp, I just always point out the negatives I see as discussion points, Parafeed takes offense to this but this is how engineering design teams work. The idea is to prove the questioner wrong, defend the design.

One thing I wanted to throw out there for this thread is I see a lot of respected members like Zanth, HeadphoneAddict, etc say that the old Melos SHA-Gold was one of the finest amps, some even say better than a ZD for Grados. The company is defunct, the schematics out there. Do you think this would be a good Best Tube amp to DIY candidate ?