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Old 14th March 2012, 04:44 AM   #3401
Previously: Kuei Yang Wang
 
Join Date: Nov 2002
Hi,

Quote:
Originally Posted by a.wayne View Post
OK some graphs looking at amplifiers, ones that knee buckles below 8 ohms and the ones that don't ...

Electrocompaniet, Goldmund, Plinus Class-a mode...
Alas, I do not see a SINGLE Amplifier in this quartett which precisely doubles it's output power from 8R to 4R for 0.1% THD.

So based on your evidence so far there is no Amp that "doubles down" under the conditions under which the Citation XX is specified.

Basically another case where the vendor with the honest specs gets beaten up over them while the BullS...t merchants are lauded as paragons of performance due to their less transparent specs...

I guess if HK had rated it at 250W8R/500W4R @ <0.5% THD (which they could likely have done) all would be well...

Ciao T
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Old 14th March 2012, 04:46 AM   #3402
Previously: Kuei Yang Wang
 
Join Date: Nov 2002
Hi,

Quote:
Originally Posted by bcarso View Post
When Harvey Rubens and I sat in the audience at a local AES talk about grounding issues with pro equipment, the speaker started his talk with "Hi. I'm George P. Maggilicuddy*, and I have a Pin 1 Problem". Harvey and I spontaneously erupted:

HI GEORGE!!!

Not that many people in the audience found this amusing, whether because they were recovering alcoholics or just uninformed or possessed of a minimal sense of humor, we never knew.
George may have been Bill (Withlock).

Given that it's the AES (and who it's leading lights are) I though proof of a double humorectomy was required before they let you in? How did you two sneak in...

Ciao T
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Old 14th March 2012, 04:53 AM   #3403
a.wayne is offline a.wayne  United States
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Yes, true , then there is 2 ohm ....

Look at the graphs again T, all 3 tell a different tale, the goldmund and the electro really fall apart after 8 ohms , unlike the plinus and I'm not surprised I found the Plinus the best sounding ...

anyway put a bid in on the XX...........
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Old 14th March 2012, 04:56 AM   #3404
Previously: Kuei Yang Wang
 
Join Date: Nov 2002
Hi,

Quote:
Originally Posted by tvrgeek View Post
I am totally blank on what the H parameter charts are trying to tell me. When I see the Cob-Vcb chart, this is showing me the Early effect? What do I do with this?
All of this shows you how a devices parasitics change if voltage cross or current through the device change.

They allow you to derive the various parasitic resistance (early effect induced limited collector impedance, Beta changes, Changes of the internal emitter and base impedance as well as the parasitic capacitances), so they allow to tell you what goes wrong and where if you change voltages and/or currents (which you will as a transistor that works only static is not useful in an amplifier)...

Of course you can just blissfully ignore all the non-linear parasitics and throw a ton of looped feedback around the Amp instead...

Quote:
Originally Posted by tvrgeek View Post
Side note, The On-Semi datasheet for the 2N5401 is identical to the Motorola, right down to the defects in font.
That could be related to the fact that Motorola Semiconductors was spun off and is now called "On-Semi", just as Philips Semiconductors is now NXP and Hitatchi Semiconductors is now Renesas...

Ciao T
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Old 14th March 2012, 05:00 AM   #3405
Previously: Kuei Yang Wang
 
Join Date: Nov 2002
Hi,

Quote:
Originally Posted by a.wayne View Post
Look at the graphs again T, all 3 tell a different tale, the goldmund and the electro really fall apart after 8 ohms , unlike the plinus and I'm not surprised I found the Plinus the best sounding ...
Your comments make me think you need a lot of power.

In this case the Plinius looks like it has the most distortion of all of them.

Maybe you just like distortion?

Ciao T
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Old 14th March 2012, 05:03 AM   #3406
a.wayne is offline a.wayne  United States
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So distortion measurements matters ...........
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Old 14th March 2012, 05:04 AM   #3407
bcarso is offline bcarso  United States
diyAudio Member
 
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Location: Canoga Park, California
Quote:
Originally Posted by ThorstenL View Post
Hi,



George may have been Bill (Withlock).

Given that it's the AES (and who it's leading lights are) I though proof of a double humorectomy was required before they let you in? How did you two sneak in...

Ciao T
No, I know Bill. And this was no Bill
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Old 14th March 2012, 05:07 AM   #3408
bcarso is offline bcarso  United States
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Join Date: May 2005
Location: Canoga Park, California
Quote:
Originally Posted by jcx View Post
no, say it aint so...

at least don't try to support the criticism with "conventional engineering", Bode Sensitivy analysis, build dedicated hardware like Cordell...
Langford-Smith 4th ed., Supplement section at the end, following the index. 1952 and prior cites. Obviously not as detailed as Otala, but the gist is there about feedback going "wrong".
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Old 14th March 2012, 05:12 AM   #3409
Previously: Kuei Yang Wang
 
Join Date: Nov 2002
Hi,

Quote:
Originally Posted by a.wayne View Post
So distortion measurements matters ...........
No, this was "on line audio discussion standard reply # 1" when someone posts they preferred a Tube (High Distortion) Amp over a Solid State (Low Distortion) Amp...

Ciao T
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Old 14th March 2012, 06:40 AM   #3410
godfrey is offline godfrey  South Africa
diyAudio Member
 
Join Date: Nov 2009
Location: Cape Town
Quote:
Originally Posted by tvrgeek View Post
I still don't know why someone would put two 4148's in parallel with a red led...
I've seen that in another circuit, with a footnote explaining that it's optional to use either the two diodes or the LED. Maybe that's the idea here too.
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