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Hifi: XTC PRE-1 preamp

I bought this second hand and found myself distinctly underwhelmed with the sound quality.

I decided to take a look inside, and reverse engineer it.

Imagine my disappointment when I discovered that the claims of "Uni-junction FET Preamplifier - Single ended class A" on the rear were untrue.

It transpired that the only FET device in the unit was the Op amp for the DC servo.

Update Sept. 2017: I found this XTC PRE1 / POW1 thread on the Pinkfish media forum, and the preamp illustrated here does indeed have the FET outputs, along with the heatsinks (missing in my preamp).

Interestingly, both preamps have the same "PRE1MB" and "ISSUE4" PCB.

Additionally, the silver PRE1 in my gallery (pictures were from Ebay) also show the same ISSUE4 board without the heatsinks.

This must surely mean there were running changes to the design at the factory at some stage - my guess is these were later releases?

If anyone has any information on this, please email me and let me know!

I have copied the pictures from Pinkfish media and added them to the gallery below for reference.

HiFi: XTC PRE-1 preamp - schematic
HiFi: XTC PRE-1 preamp - schematic
HiFi: XTC PRE-1 preamp - front view
HiFi: XTC PRE-1 preamp - front view
HiFi: XTC PRE-1 preamp - front view
HiFi: XTC PRE-1 preamp - front view
HiFi: XTC PRE-1 preamp - rear view
HiFi: XTC PRE-1 preamp - rear view
HiFi: XTC PRE-1 preamp - remote control
HiFi: XTC PRE-1 preamp - remote control
HiFi: XTC PRE-1 preamp - close up of input relays
HiFi: XTC PRE-1 preamp - close up of input relays
HiFi: XTC PRE-1 preamp - input sockets and relays
HiFi: XTC PRE-1 preamp - input sockets and relays
HiFi: XTC PRE-1 preamp - protection and mute circuits
HiFi: XTC PRE-1 preamp - protection and mute circuits
HiFi: XTC PRE-1 preamp - muting and protection alternate view
HiFi: XTC PRE-1 preamp - muting and protection alternate view
HiFi: XTC PRE-1 preamp - drivers / current sources
HiFi: XTC PRE-1 preamp - drivers / current sources
HiFi: XTC PRE-1 preamp - main preamp section
HiFi: XTC PRE-1 preamp - main preamp section
HiFi: XTC PRE-1 preamp - another view of the main preamp
HiFi: XTC PRE-1 preamp - another view of the main preamp
HiFi: XTC PRE-1 preamp - main preamp section - different revision
HiFi: XTC PRE-1 preamp - main preamp section - different revision
HiFi: XTC PRE-1 preamp - overall view
HiFi: XTC PRE-1 preamp - overall view
HiFi: XTC PRE-1 preamp - overall view - different revision
HiFi: XTC PRE-1 preamp - overall view - different revision
HiFi: XTC PRE-1 preamp - PSU and motorised pot
HiFi: XTC PRE-1 preamp - PSU and motorised pot
HiFi: XTC PRE-1 preamp - close up of main section
HiFi: XTC PRE-1 preamp - close up of main section
HiFi: XTC PRE-1 preamp - power supply
HiFi: XTC PRE-1 preamp - power supply
HiFi: XTC PRE-1 preamp - alternate PSU revision
HiFi: XTC PRE-1 preamp - alternate PSU revision
HiFi: XTC PRE-1 preamp - Aerovox caps
HiFi: XTC PRE-1 preamp - Aerovox caps
HiFi: XTC PRE-1 preamp - close up
HiFi: XTC PRE-1 preamp - close up

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