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Old 7th October 2012, 12:27 PM   #7511
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σας ευχαριστούμε

I like you dude you dig the Knakered on sofa and soul part exactley

Thing is my cheap and nasty build of Simplistic and Riccardo exuisit version give us both the same impression of space.

So there must be same special ingredient for it.

Aple and pears not one is better just different. (and me think) you being to modest about Simplistic

As you say Vinyl is not an exact medium (I am posting records catalogue numbers to try to remove one variable, still how old was the press master remains) apart from that the remaining component chain is the same including the room.
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Old 7th October 2012, 12:31 PM   #7512
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Quote:
Originally Posted by RCruz View Post
This puts an end to the topic...Nice as ever Salas.
Sorry Riccardo posting as same time so I missed the bit when you decided to end this part of the discussion

Sorry again if you get mentioned in my last post

My question still remain

How to corect small difference in gains between Left and Right Boards on Paradise ?
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Old 7th October 2012, 12:43 PM   #7513
pdul is offline pdul  Denmark
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A big crude and dusty trimpot at the output
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Old 7th October 2012, 01:03 PM   #7514
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Yes but it wuld spoil sound and ad signature where there is none (Paradise is to good for it
I am shure you can do better than that.

I am Just a "mechanic" and strugle to understand how things work altrought I got in front of me Page 89 of The Art of Eletronics (no need to name names as is also known as the "Bible").

Quote (maybe I shuld ask for permission first )

Figure 2.47. Improved current mirror.
One solution, if a better current source
is needed (it often isn't), is the circuit
shown in Figure 2.47. The emitter resistors
are chosen to have at least a few tenths
of a volt drop; .....

end quote

So maybe there is a non intrusive way to alter gain there, maybe by doing so is also possible to tweack the Off set, if there is same, by acting on small imbalances between "NPN & PNP" mirrors?

Or looking at the emmiter resistors on the 4 PNP&NPN Inputs. (input dc offset to cart.)

Returning to staging
Another side of the problem may lay with my set up and is caused by feed back from the speakers to the TT at low frequency <30Hz

Last edited by Bksabath; 7th October 2012 at 01:17 PM.
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Old 7th October 2012, 01:09 PM   #7515
pdul is offline pdul  Denmark
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I guess you need to ask Joachim which resistors to adjust to alter gain
The other post was a joke
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Old 7th October 2012, 01:19 PM   #7516
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Quote:
Originally Posted by pdul View Post
The other post was a joke
I know very well did I not say you could do better?
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Old 7th October 2012, 01:27 PM   #7517
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How high is the gain difference in dB ?
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Old 7th October 2012, 01:33 PM   #7518
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Tiny Litle bit
certanly less than audible 3dB

Maybe ball park figure 1dB even less as I am talking about left and right ballance.

Altrought a general way to tweack gain due to different cartridges may suit the General Population.

Or refering to Hessener Guide
voltages at the emiter resistors are 0.68 and - 0.69 Maybe the 10 mV difference is nothing and I am looking at the wrong place

Last edited by Bksabath; 7th October 2012 at 01:39 PM.
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Old 7th October 2012, 01:46 PM   #7519
Salas is offline Salas  Greece
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Quote:
Originally Posted by Bksabath View Post
σας ευχαριστούμε
Παρακαλώ (you are welcome).
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Old 7th October 2012, 02:18 PM   #7520
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The gain in the Paradise comes from the Gm of the input stage degenerated by the RIAA.
Provided that the RIAA components in both channels are the same and assuming that the
current mirrors are just high impedance polarity shifters the gain difference can only come from not so well matched input transistors from left to right. A ball park number of 1dB does not tell me anything. I need the EXACT value and when you are not able to make reliable measurements in the under 1dB range then it may be the limited resolution of your measurement system.
A naive reader may interpret " there is a gain difference " as a design flaw. That is the reason i am so strict here. The DC readings at the emitters you made have nothing to do with the gain.
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