Kit Ryan mod for Adcom GFA-555

Status
Not open for further replies.
Hi All:

I was going through some old Audio Amateur magazines and came across a detailed article by Kit Ryan on building a Power Supply regulator for the Adcom GFA-555. According to the article, with this modification, "the transient response of the amplifier is dramatically improved, bringing increased resolution, imaging and sound stage definition with it. The best part is that these qualities are maintained from low volume levels right up to when the green 'overload' LEDs on the front panel light up".

This looks very attractive and I would like to start this project and modify my GFA-555.

2 questions - has anyone on the forum built this? Are the results of the modification really as described?

Thanks in advance
Mayank
 
Hi Mayank,
I'm not sure about that one. Regulating some of the parts in the voltage amp section should do it.

Adcom had an option for this, but I've never seen one installed. Try it, but make sure you can back out as well.

-Chris
 
" I was wondering if you still have that article and might could send it to me???"

You need the errata that was detailed in a letter later on.

"Regulating some of the parts in the voltage amp section should do it."

A much better solution.

I sold a friend a higher power, higher voltage Hafler DH500 transformer to replace the Adcom transformer, which he then ran into the Ryan regulator.

It would have been simpler to regulate the front-end voltage, that's what does the most good.
 
Status
Not open for further replies.