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Old 21st August 2013, 10:32 PM   #741
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Kolby,

I agree, no controversy at all. You obviously have experience with components that are new to me and I'm learning, so please keep sharing. Those Rhopoint resistors look interesting. I used to be negative about wirewound resistors until I tried some Mills wirewound that sound quite nice in a different project.

Dario,

I see that R101, R201 are specified at 1/2 watt in the BOM, but the Caddock are rated at 15 watts. Is the 1/2 watt enough for the circuit?

Jac
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Old 21st August 2013, 11:05 PM   #742
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Talking AMTRANS 1nF @ PCX

I just got word from Stephanie at Parts ConneXion that the AMTRANS 1nF or 1000 pF AMCH capacitors are back in stock. This makes me particularly happy as I like using that cap both as C30 and as a bypass for C13:-)
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Old 22nd August 2013, 07:32 AM   #743
koldby is offline koldby  Denmark
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Dario,
The Rhopoint resistors I use are the ones I linked to: the 8G16D types , radial 0,1% 0,33W wirewound. The ones in your pic. are GG102 radial types and beside this:
Each resistor undergoes multiple tests during manufacture including accelerated ageing and thermal shock procedure.
they are essentially the same, as far as I know.

lehmanhill,
The R101/102 has 1,25V across (lm317 makes sure this is the case) so with 50 Ohms the power loss in these resistors are 1,25X1,25/50 = 0,03125Watts.

Well, I am an old fart and I have been in the high end business for many many years and even though I completely agree with what Harry Pearson (founder of The Absolut Sound) said in 1973: There is one objective goal for all audiophiles, Tha Absolute Sound, eg. the sound of the unamplified music, meaning if we had perfect source material, perfect playback devices and were listening to perfect loudspeakers in perfect rooms, we would all agree witch amplifire was the perfect one...
This not being the case, there is a big difference between the compromisses each of us prefer, depending on, as example, what speakers/room we have and what kind of music we listen to.
A person that listen in a small room close to relatively small speakers or even headphones, tend to have other preferences than a person listening in a large room a relatively long distance from big loudspeakers. And if the preffered music is small scale jazz or folk the preferences are different from a person listening foremost to big orchestral work.
It seamed to me, after reading a lot of the threads concerning this My-Ref amp., that there is sort of a consensus of what to listen for, that I did not want to disturb or question, therefore my remarks on controversy.


Koldby
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Old 22nd August 2013, 09:10 AM   #744
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Quote:
Originally Posted by lehmanhill View Post
I see that R101, R201 are specified at 1/2 watt in the BOM, but the Caddock are rated at 15 watts. Is the 1/2 watt enough for the circuit?
Sure, as Koldby already calculated for you.

Quote:
Originally Posted by koldby View Post
The Rhopoint resistors I use are the ones I linked to: the 8G16D types , radial 0,1% 0,33W wirewound.
Fine, I can eventually order them from Distrelec, on the contrary I didn't find a source for GG102s.

They're not cheap, though... over 2X Vs the already costly Caddocks!

Quote:
Originally Posted by koldby View Post
they are essentially the same, as far as I know.
I would not be so sure about it... But since you heard an improvement using the 8G16Ds this is not the point...

Quote:
Originally Posted by koldby View Post
It seamed to me, after reading a lot of the threads concerning this My-Ref amp., that there is sort of a consensus of what to listen for, that I did not want to disturb or question, therefore my remarks on controversy.
Absolutely not, again, every contribution is appreciated and welcome
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Old 22nd August 2013, 10:35 AM   #745
koldby is offline koldby  Denmark
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Ok let me try to give a couple of examples on what I hear, with or without the SAL caps.
Linn records Barb. Jung: Grain of sand,I´ll be your baby tonight:
With SAL:
More room more focus less sibiliance on her voice (SSS) and easier to hear the echo machine on the sss´s.
Without SAL:
More blurred image, less room maybe a little more bass.

Atterberg Symph. for cello and orchestra Truls Mørk BIS records.
With SAL:
Extremely big and well defined room. Good separation of instruments.
Without:
A softer presentation with less defined room and ambience. Darker tonal character.

Charles Ives: Symf 1&4 Chicago Symf.and chorus Tilson Thomas SONY:Nearer my god to thee.
With:
Organ clearly backstage. Good separtion of members i choir. Deep bass better(!) defined.

Without:
Forshortened depth, less separation in choir a little "hole in the middle effect".

Liszt Piano concert. Byron Janis Mercury living presence: Falla: El Sombrerode tre Picos.

With:
Very dynamic and involving. Easy to hear the single notes.
Without:
Broader piano, some of the notes seams to come from a higher plane than others. The blurring effect actually in the cresendos overpowers my ears. Will cause earfatique in the long run.

All this is of cause my view and other can have other preferences. If anybody wants, you can listen to the examples and hear if you hear the same things.

Koldby

The tonal charater of the piano is almost identical a little softer (blurring?) maybe.
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Old 23rd August 2013, 10:42 AM   #746
bcmbob is offline bcmbob  United States
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That's great stuff Koldby. Those subjective and personal reports hopefully will encourage others to take the time to "tune-in" their builds to get the most from any specific combination of system components. It's been my experience that various music styles almost require more that a single system. Finding the configuration that covers the most bases for each individual is clearly a challenge - but well worth the time and cost. Builders should be encouraged to buy and install a few of those sockets to hear differences for themselves.
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Old 23rd August 2013, 12:50 PM   #747
koldby is offline koldby  Denmark
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bcmbob
Thanks for the comment.
And thak you for your "freindly challenge" in "the very best amplifier I have ever heard" thread!
That is the reason, why I now enjoy this extrodinary amplifier. There are still areas where the GM clone beats My_Ref, but the gab is closing and My_ref betters the GM in some very crusial areas IMHO.
I have been too busy playing around with the My_ref to do the same trick with socets and component optimization in the GM.
Interesting race between those two!

Koldby
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Old 23rd August 2013, 01:56 PM   #748
bcmbob is offline bcmbob  United States
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Here is a little more on my take on "The Best Amp" and "Tuning. As a musician I learned I was gifted with something called "relative pitch". Essentially, that means I can perceive and/or recreate accurate tonal matching. If someone plays middle C on a piano I can sing the octaves accurately and tell if all the other notes on the keyboard are in tune. Those with "Absolute/Perfect Pitch" can naturally create exact frequencies without the need of a reference. I think my pitch abilities are still mostly intact, but at my age I have found my ability to hear much above 15,000 MHz is lessening. I have a friend who has some gaps around 800 and 1200. (That's what he gets for listen to all the Rock )

For many years I had a job that required a lot of driving. I have never been a big fan of constant AC and more often than not kept the driver's side window cracked open when the temps were not at extremes. The obvious cost of that was a slight permanent imbalance in the sensitivity in my left ear - not much, but at times I need to compensate.

When I listen today I don't perceive any loss or compression, but I suspect the combination of caps, resistors, wires - everything that sounds accurate to me - might sound overly bright and top heavy to different and younger ears.

Dario and others have done marvelous things in the technical/scientific development of modern amps. I stand in awe and appreciation of their efforts and where we are now. It's obvious I feel the FE can outperform a wide selection of both commercial and DIY designs. I'm simply suggesting and encouraging that given the fact that we are "building" these little gems, we take the time to do some experimentation beyond general assembly. Only then can we be not so concerned with "The Best" and discover what sounds the best in each builders system, setting and listening abilities.
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Last edited by bcmbob; 23rd August 2013 at 01:58 PM.
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Old 25th August 2013, 06:31 PM   #749
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Finally got one FE built, playing right now. Worked perfectly at first power on, with no noise of any kind. Offset was initially 58mV, down to 31mV after a couple hours of play. That concerns me somewhat, as my RevC amp measures 1.4mV.

I don't understand why an amp that uses the same active devices has far more offset than a similar design. Is it the dual rectifiers? If so, can one be disconnected, and at what sonic penalty?

Right now, comparing the FE to the RevC, I hear more detail, clarity of individual instruments. Hard to tell about depth and image with unequal channels. Tonality of FE might be a bit sharper, but not really bright as far as I can tell. Will play it for a few hours and report again.

Using True Copper at C13, BG Std at C9, most TH caps are styrene or silver mica, R12 is naked Vishay Z-foil TH soldered to SMD pads, R10 is Shinkoh tant. Balance of parts is mostly configured to premium BOM.

Peace,
Tom E
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Old 25th August 2013, 07:12 PM   #750
koldby is offline koldby  Denmark
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Quote:
Originally Posted by madisonears View Post

I don't understand why an amp that uses the same active devices has far more offset than a similar design. Is it the dual rectifiers?



Peace,
Tom E
The short answer is component tolerances and no.
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