I am clearing some more test equipment out. I bought this HP239A a while back and it works great. Its in reasonable cosmetic condition and has the HP folding feet. All of the internal shields/covers are in place as well. I modified this unit with the 339A oscillator mods, it is now using an LT1468 & LME49710 in the oscillator circuit and a lot of the unnecessary compensation parts have been removed.
I included a picture showing the 1kHz THD+N measurement on my Amber 3501 after the mods, the picture is showing -104dB with the 400Hz HP & 30kHz LP filters active. This is about a 5dB improvement in performance from before the parts change. Switching the 400Hz filter off results in a rise to about -100.5dB. I never cleaned the attenuator pot so there may be a bit more performance to be had out of this unit.
My asking price is what I paid for this 239A not including the parts I put into it so I’m firm on this price. It’ll move to the big auction site if nobody is interested in it at this price. I’m fairly confident it’ll sell for more money if it’s moved but I wanted to give someone at diyaudio a chance to pick it up first.
Asking $150 + actual shipping + Paypal or use paypal.me
I included a picture showing the 1kHz THD+N measurement on my Amber 3501 after the mods, the picture is showing -104dB with the 400Hz HP & 30kHz LP filters active. This is about a 5dB improvement in performance from before the parts change. Switching the 400Hz filter off results in a rise to about -100.5dB. I never cleaned the attenuator pot so there may be a bit more performance to be had out of this unit.
My asking price is what I paid for this 239A not including the parts I put into it so I’m firm on this price. It’ll move to the big auction site if nobody is interested in it at this price. I’m fairly confident it’ll sell for more money if it’s moved but I wanted to give someone at diyaudio a chance to pick it up first.
Asking $150 + actual shipping + Paypal or use paypal.me
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