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Old 28th March 2013, 07:44 PM   #3041
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At least one thing to don't worry about
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Old 28th March 2013, 07:45 PM   #3042
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Quote:
Originally Posted by Vinylsavor View Post
Hi Felipe,

as I wrote you can connect the secondary either way depending if you want the stage to be inverting or non inverting. Some transformers have different high frequency performance depending on the polarity. Not the Lundahls. So you can choose.

Best regards

Thomas
Thanks again for your kind support Thomas
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Old 29th March 2013, 10:32 AM   #3043
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Quote:
Originally Posted by vgeorge View Post
No, use a resistor the value of the input impedance of your power amp as dummy load.
Quote:
Originally Posted by merlin el mago View Post
I ask Erno Borbely.
My power amps have an input impedance in unbalanced mode of 100K, how to calculate de RC filter?
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Old 29th March 2013, 01:19 PM   #3044
mthoi is offline mthoi  Malaysia
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I finally had the 26 boxed and tested. Hum free and driving my 845 tube amp. After 20+ hours, I think it would be the mainstay to replace my 76 tube preamp.

Click the image to open in full size.
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Old 29th March 2013, 01:42 PM   #3045
vgeorge is offline vgeorge  Greece
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Quote:
Originally Posted by merlin el mago View Post
My power amps have an input impedance in unbalanced mode of 100K, how to calculate de RC filter?
I would start with a 2.2nF to 3.3nF cap and a 20K trimmer and watch squares and the resonance on the scope.
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Old 29th March 2013, 01:47 PM   #3046
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Like the pic?
Attached Images
File Type: png 26 RC filter.png (12.2 KB, 183 views)
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Old 29th March 2013, 01:49 PM   #3047
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Hi!

Quote:
Originally Posted by merlin el mago View Post
10KHz no load
Don't get too worried about square wave response. If you want good square wave response, a transformer coupled line stage will not get that.

Listen to the thing.

Then you can still experiment with loading and RC filters, but I doubt you'll really need it

Best regards

Thomas
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Old 29th March 2013, 01:53 PM   #3048
iko is offline iko  Canada
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Quote:
Originally Posted by mthoi View Post
I finally had the 26 boxed and tested. Hum free and driving my 845 tube amp. After 20+ hours, I think it would be the mainstay to replace my 76 tube preamp.
Looks great! Thanks for sharing!
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Old 29th March 2013, 01:58 PM   #3049
vgeorge is offline vgeorge  Greece
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Quote:
Originally Posted by merlin el mago View Post
Like the pic?
No, RC in series parallel to the load.
Agree with Thomas, like I said before. Listen first without and then decide.
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Old 29th March 2013, 02:12 PM   #3050
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OK guys a will listen before to decide.
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