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Author Topic: UA-5 preamp mod  (Read 1803 times)

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Offline Wiesel

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UA-5 preamp mod
« on: September 20, 2009, 07:57:07 AM »
There's this thread 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?


Offline Chuck

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Re: UA-5 preamp mod
« Reply #1 on: September 20, 2009, 01:22:37 PM »
Richard elaborates a bit in this thread:,126940.0.html
Reality is merely an illusion, albeit a very persistent one.

Microphones: Microtech Gefell M300, AKG C 480 B comb-ULS/ CK 61/ CK 63, Sennheiser MKE 2 elements, CAD GXL1200 (cardioid and mod-cardioid capsule & electronics mod), Audix M1290-o, Micro capsule active cables w/ Naiant PFA's, Naiant MSH-1O, Naiant AKG Active cables, Church CA-11 (cardioid), (1) Nady SCM-1000 (mod)
Pre-amps: Naiant littlebox, Naiant littlekit v2.0, BM2p+ Edirol UA-5, Church STC-9000
Recorders: Sound Devices MixPre-6, Tascam DR-680, iRiver iHP-120 (Rockboxed & RTC mod)

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Offline Wiesel

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Re: UA-5 preamp mod
« Reply #2 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

Offline bdasilva

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Re: UA-5 preamp mod
« Reply #3 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
Cad E300S set.. AT822  AKG C 414 B-XLS/ST  
Dorsey-Mod MK-012 w/ O, C, H and RED L/D Caps
Superlux S502 ORTF   LSD2
Silverpath  Cables> 
Tascam DR-680MKii    DR- 680 (X2)   Tascam DR-40     Sound Devices USBPre    SONY  PMD-M10   Zoom F8

"Buy a Taper a Drink... Prime the Pumps of live Music"

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