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Old 8th March 2014, 08:32 PM   #1
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Default Passive Preamplifier builder req

I'm looking for an experienced builder thats capable of building a mini passive pre-amp as good or close to the spec of a Townshend Allegri preamp does anyone here have that kind of experience and knowlege of passive pre amps at a budget ?? Must have knowlege and experience of working with Autotransformers !!

Allegri Preamplifier | www.townshendaudio.com

Review http://www.tnt-audio.com/ampli/townshend_allegri_e.html

Target Spec:

Frequency response: 8Hz-100kHz +/- 0.1dB
Maximum signal level: 4V RMS 8Hz; 10V RMS 20Hz
Maximum DC offset : 5mV. (For undistorted 8Hz)
Distortion: Less than 0.01% at 400Hz, 10V (2nd and 3rd harmonic only)
Input impedance is dependent upon the load impedance and gain setting. So, with a power amplifier having 20kohm input impedance (typical)
Impedance: At 0dB, input impedance is 20kohm
At -10dB (normal listening) input impedance is 200k
Inputs: 3x pairs RCA phono sockets (gold plated)
Outputs: 1x pair RCA phono sockets (gold plated) + Subwoofer : 1x pair RCA phono sockets (gold plated)
Dimensions: Size : 150mm/185mm (D) x 92mm (W) x 43mm (H) Approx

Autotransformer has a Four position input selector, a mute switch and a 24 position volume control with intervals chosen to cover a wide range of volume levels in different systems. Autotransformers are wound with Audio Fractal-Wire and laminated with ultra-thin metal laminations for the highest possible resolution.Volume 24 discrete steps, ranging from +4dB to -60 dB.

Well something along these lines ??

Click the image to open in full size.

Last edited by laughingbuddha; 9th March 2014 at 01:36 AM.
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Old 15th March 2014, 12:16 PM   #2
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How exactly would your like this to work? What other constraints do you have? Parts selection, looks, cost, time, ?

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Old 15th March 2014, 06:51 PM   #3
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Better to PM me I think ?
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