AB comparison

[carlosfm]

Raka,

Just a little hint:
Could you try to repeat the A/B test with other speaker cable?
On the two amps.
Is it possible for you?
It's that the TNT-based Cat.5 construction, while a very good cable, it's not ideal for a GC, as it has high capacitance.
You could have different results even with cheap cable.
Let's say, Supra 2.5 classic.
Or, just for testing, use cheap "figure-of-8" cable.

 

[Raka]

I haven't had time to fit and check the 2228, but I'll try very soon.

I took care about the speaker cable, and used a 8 euro meter cable, and the TNT for both amps.
At first my GC did a PLOPLO sound with the TNT, but now is fixed and TNT sounds very good. Maybe a little thin, but clearer that the other one.

BTW, it's clear which hemisphere are we, isn't it? Peter, Carlos and I live at day, and the others at night.

Carlos, could you AB your GC?

 

[Raka]

Carlos,

I forgot to ask, you used a BUF634, didn't you? Any hint?

 

[carlosfm]

Carlos,

I forgot to ask, you used a BUF634, didn't you? Any hint?

Veeeery good.
Use it inside the feedback loop of a good op-amp (as OPA627) and you won't regret.
You'll find an example on the BUF634 datasheet (a headphone amp).
Are you planing on making a preamp?

As for the OPA2228, you don't use sockets?
It's just two seconds to change the op-amp.
I'm curious about your impressions.

 

[carlosfm]

Carlos, could you AB your GC?

For me it's very difficult to make pure A/B tests of two amps.
My Kimber speaker cable is expensive, and long runs.
Anyway, as I already said, I compared my GC to my Nad, connecting one and disconnecting the other and the difference is so marked I don't have doubts.
GC is better.
I can tell you I have "difficult" speakers (86~87db) and the GC gives much more deffinition in the bass, it really kicks.
Not to talk about the other parts of the spectrum...
Treble is more extended, without ever aggressing, and the midband is oh so natural...
And believe me, I know my Nad very well.
I have it for 12 years, it's tweaked by me, and it sounds very good.

 

[Raka]

Well, isn't so easy because I made a mistake with the mirror and the pcb, and the chips are upside down and I have to dismount the pcb and change them. I have a wedding this weekend , and after that so it has to wait until next monday
Have you commented your BUF634 thing in a thread? If not, could you start a new one and give some info, please? I would be interested in building a pre, for a compact GC all chip (nor better, nor worse than a Denon)

 

[carlosfm]

Have you commented your BUF634 thing in a thread? If not, could you start a new one and give some info, please? I would be interested in building a pre, for a compact GC all chip (nor better, nor worse than a Denon)

I have made some comments about my pre in some threads, but I can't remember right now.
Yes, I'm waiting to finish the film on my analogue camera to start a new thread, with some pictures.
It's not finished yet, right now the boards are laying on the floor and playing some nice tunes.
I'm still waiting for the box , they said 2 weeks , deam, it seams they buy them from a dealer in Mars .
If TI and others send me some chips in 3 days and it almost travels around the world, why does a box take two weeks to arrive?

Anyway Raka, I didn't understand very well what you mean with "compact GC all chip".
If it's a standalone pre, very well.
But if you're planning to make an integrated GC amp (all in one box), you don't need a pre, just a selector switch and a volume pot.
And Raka, IT HAS TO BE BETTER THAN YOUR DENON!

 

[carlosfm]

I have a wedding this weekend , and after that so it has to wait until next monday

Take your pre, the op-amps and the soldering iron with you.
You'll have plenty of time to change the op-amps in the wedding.

 

[Raka]

I'm thinking about a pre because my phono stage don't have enough gain to break the walls, and with classical music (that is not compressed to death- music) you need plenty of power or gain. I really don't understand why they say "this low power could be enough for folk or classical, but no way for rock". This automatically dis-qualifies any comment by them. Well, I forgive them (by now)

I'll try with some other cables, but why don't you AB your GC with some cheap cables, too? C'mon Carlos, aren't you brave enough to test your beast ? I'll pay you a beer, I'm dying to hear about an AB in a GC!!

 

[carlosfm]

I'm thinking about a pre because my phono stage don't have enough gain to break the walls, and with classical music (that is not compressed to death- music) you need plenty of power or gain. I really don't understand why they say "this low power could be enough for folk or classical, but no way for rock". This automatically dis-qualifies any comment by them. Well, I forgive them (by now)

I'll try with some other cables, but why don't you AB your GC with some cheap cables, too? C'mon Carlos, aren't you brave enough to test your beast ? I'll pay you a beer, I'm dying to hear about an AB in a GC!!

Raka, I'm also thinking in giving a try to the ESP phono pre you did.
It's so simple...
If you want more gain out of it, just change the 100k resistor on the feedback loop of the second stage op-amps to 180k.
With this, you may have an output similar to your CD player.
Anyway, if it's an integrated GC amp you have in mind, you may change the 220k resistor of the feedback loop for 300k, and you won't need a separate preamp.
But if, like me, you like to keep things separate, go ahead and make a good preamp.
That way you may change your power amps without problems and your good preamp will always be the same.

As for the A/B test, come around, I need help.
Then we'll drink the beer.
I'm really needing that, it's 40ºC in Lisbon.

Anyway, as I don't have difficulty in distinguishing the sound of the two amps, in the end I would get to the same conclusion: GC is better.

 

[pedroskova]

Build a tubed phonostage with a simple 6SN7 linestage. That will make you forget about all of this A/B tomfoolery.

 

[carlosfm]

Oh, Raka, I forgot to say:
When I compared my GC with my Nad, I was using the preamp seccion of the Nad.
So I was comparing the power amps.
You couldn't whant better than this.

 

[carlosfm]

Build a tubed phonostage with a simple 6SN7 linestage. That will make you forget about all of this A/B tomfoolery.

I have doubts that would be better than an OPA627/637.
And more silent, no way.
But then... it may be a question of taste.

 

[Raka]

When I compared my GC with my Nad, I was using the preamp seccion of the Nad.
So I was comparing the power amps.
You couldn't whant better than this.

Well, you connected the pre-out to the GC, and the speaker output of the Nad to a speaker cable, and then simply swapped speaker cables, didn't you? But, did you checked the gain of both?
This was the great mistake in my first test.

Pedroskova,

Any scheme you had built? How much was it? What does tomfoolery mean?

I can listen the differences between the DAC of the denon and the DAC of the DVD, but I can't distinguish between Denon and GC, what's wrong with me?

 

[carlosfm]

Well, you connected the pre-out to the GC, and the speaker output of the Nad to a speaker cable, and then simply swapped speaker cables, didn't you? But, did you checked the gain of both?
This was the great mistake in my first test.

The gain is valid and important on a pure A/B test.
I played with the volume, low, high...
I can assure you that even with very low volumes my GC has a dynamics I thought impossible with my little (but very good) Epos speakers.

I can listen the differences between the DAC of the denon and the DAC of the DVD, but I can't distinguish between Denon and GC, what's wrong with me?

It's not you...

 

[pedroskova]

Pedroskova,

Any scheme you had built? How much was it? What does tomfoolery mean?

tons of schematics on the web

I've only finished the linestage - 6SN7 direct-coupled to 6SN7 cathode follower (cost?...$100US?, not including chassis). I've been collecting the parts for the phonostage and for converting the line to a 76 -> 6J5 but, unfortunately, my B&K st202 amp died last month and forced me to build an inverted GC in its place(actually, in its chassis )

The GC is so much better than the amp it replaced, that I think the other must have been "out of tune", i.e., its bias was way off...or something like that.


"tomfoolery" n., from ME "Thome fole"(Tom the fool)...a silly act or silly behavior.

 

[mothman]

Hi Raka,

My Gainclone has very good Dact attenuators and easily beats my brothers Denon 3803.
With all due respect I think the pre-amp section of your 1801 is the limiting factor in your comparison.
Borrow a good preamp and make your comparison again.
My system includes Sony SCD-1,Dynaudio Contour 1.1 and all very high quality,sensible,silver cabling that I made myself.
Very fine solid state amps I've owned recently include several McCormack original DNA 1 and 0.5,Audio Research 100.2,Krell 300il and more from
Classe,Bryston,Bel Canto,Edge,Muse and excellent pre-amps from many of the above.
As I said in my previous post my well built Gainclone with premium parts is as musically satisfying to me as any of the above.
I think it's meaningless to debate what BEATS what as taste are as varied as opinions,and you know what they say about opinions.
So in the end it's completely up to you which musical device you prefer and don't be afraid to trust your own ears.

 

[Peter Daniel]

I wouldn't be getting involved with GC for almost a year, if it wasn't good

 

[carlosfm]

I wouldn't be getting involved with GC for almost a year, if it wasn't good

Now you said it!
Short and clear.
It's good when someone comes with clear and objective ideas.
It's THAT simple.

 

[carlosfm]

Raka,

I need to know some things about your A/B test procedure to see if I can detect what's wrong:

1 - How do you connect your DVD player at the two amps, at the same time? Can you give exact details?

2 - Are you comparing the two amps completely or are you using the preamp seccion of your Denon? Does your GC have an input pot, or you use it as a power amp?