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Gear / Technical Help => Battery Boxes, Preamps, Mixers, ADCs, and Processors => Topic started by: Wiesel on September 20, 2009, 07:57:07 AM

Title: UA-5 preamp mod
Post by: Wiesel on September 20, 2009, 07:57:07 AM

There's this thread (http://taperssection.com/index.php/topic,62680.0.html) in the archive where it says:

Quote from: poorlyconditioned

/begin{geek speak}
- digimod (described elsewhere)
- replace four i4580 chips with AD8620 or AD712.  (I used AD712 for the mic pres, AD8620 for the ADC drivers).
- replace eight 1uF/50V aluminum caps with four 0.47uF poly caps.  (Note: you replace two series 1uF caps with a single 0.5uF cap, which is equal, but you disable the TRS inputs in the process.)
- replace two 22uF aluminum caps near ADC with higher quality electrolytic bypassed with 0.1uF poly or film cap
/end{geek speak}

I've got a few questions about the mod and hope that someone can help:

1. My UA-5 contains i4570 chips, not i4580. I guess they're basically the same, but I count 9 of them on the pcb - can I replace all of them or are only those 4 at the XLR inputs important for better performance?
2. Is it essential (technically mandatory) to replace the caps when replacing the chips, or is it optional (for better performance)? (idea is to keep the TRS input intact)
3. Since the instructions are 3 years old - are there already better chips existing that I should favor over the AD8620/AD712?

Thanks!

Title: Re: UA-5 preamp mod
Post by: Chuck on September 20, 2009, 01:22:37 PM

Richard elaborates a bit in this thread:

http://taperssection.com/index.php/topic,126940.0.html

Title: Re: UA-5 preamp mod
Post by: Wiesel on September 21, 2009, 07:03:09 AM

Interesting thread, thanks. Like always, things aren't as simple as they seem... I think I'll pass on the mod...  :o

Title: Re: UA-5 preamp mod
Post by: bdasilva on September 21, 2009, 02:31:14 PM

As one who has fucked up mods on this very unit    I have two words... BussMan  Mod