|
|
Post by vitruvian on Jul 5, 2012 22:51:02 GMT -5
A while ago I was asked to post a list of mods made to my UPA-1s. So here it is....
- New rectifier bridge (800V 35A)
- Re-capping of the main PSU - replaced the PCB caps with Panasonic TS-UP 15KuF and added two 10KuF outside the PCB. This makes capacitance of 25kuF per voltage rail or 50KuF in total.
- Replaced all small electrolytic caps with Panasonic FC, Elna Silmic and Nichicon Muse.
- Replaced 1.5K resistors on the main board with Panasonic 3W MoX ones.
- Replaced the binding posts and input RCA with Vampire Wire ones
- All signal and PSU wiring replaced with MIL Spec silver plated wire in teflon
- Input signal wiring pure silver in teflon
Mod cost is about $250 AUD/ each monoblock (including labour)
Pics to follow....
|
|
|
|
Post by vitruvian on Jul 5, 2012 22:52:40 GMT -5
Can anyone post me a link that will guide through the process of uploading pics. All my attempts have been unsuccessful.
Thanks
|
|
|
|
Post by lar on Jul 5, 2012 23:00:23 GMT -5
Any improvement in sound?
|
|
|
|
Post by vitruvian on Jul 5, 2012 23:03:42 GMT -5
Cleaner and better bass response. Also there is better retrival of micro-dynamics.
|
|
|
|
Post by lar on Jul 5, 2012 23:06:49 GMT -5
Interesting, very interesting.  Worth the hassle then? |
|
|
|
Post by vitruvian on Jul 5, 2012 23:11:56 GMT -5
I am happy. That said, the choke point for these amps is the transformer. They will never sound like a pair of XPA-1s. But, even with cost of mods they are about half the price.
I have bought and modded three to run my Paradigm S2s and C1. I will see how they go. If I still crave more then I will get the big 'uns.
As funds allow I intend on moving to monos for my HT to keep speaker cable runs as short as possible anyway...
|
|
|
|
Post by vitruvian on Jul 5, 2012 23:19:22 GMT -5
Hopefully there is a picture below... Attachments:
|
|
hemster
Global Moderator 
Particle Manufacturer
...still listening... still watching
Posts: 51,951
|
Post by hemster on Jul 5, 2012 23:20:40 GMT -5
|
|
|
|
Post by vitruvian on Jul 5, 2012 23:21:26 GMT -5
And another... Attachments:
|
|
|
|
Post by vitruvian on Jul 5, 2012 23:22:30 GMT -5
And another... Attachments:
|
|
|
|
Post by vitruvian on Jul 5, 2012 23:23:17 GMT -5
And still another, a few more yet... Attachments:
|
|
|
|
Post by vitruvian on Jul 5, 2012 23:24:01 GMT -5
And still a few more... Attachments:
|
|
|
|
Post by vitruvian on Jul 5, 2012 23:24:44 GMT -5
Second last one... Attachments:
|
|
|
|
Post by vitruvian on Jul 5, 2012 23:25:29 GMT -5
Last one.  Attachments:
|
|
|
|
Post by vitruvian on Jul 5, 2012 23:30:17 GMT -5
Thank you Is it worth it? Well, to me I think 'yes'. There is an audible difference. The UPA-1s are wonderful amps that are built to a price. My modder knows his stuff (i.e. builds gear from scratch), and we spoke/ listened at length about the best way to go with these amps. He was impressed with the price/ performance ratio of these amps. But, they are built to a price, nevertheless. |
|
|
|
Post by wizardofoz on Jul 6, 2012 7:51:57 GMT -5
I have 3 upa-1's..might consider doing one of them so it can hopefully keep up as a centre channel with 2 xpa-1's for l/r. Then I have the other 2 to do a/b comparisons. Thus having a fully monoblocked 5.1 setup.. The 7.1 option would include a upa-2 for the rearr or perhaps a mini-x. This is my listening room...hence the 2.0 xpa-1 setup, but also has the means to run for ht and more importantly multichannel sacd.
My other ht room is using xpa-5 in 5.1 for now, but can go 7.1 with a mini-x too.
Interested to know if you did any a/b comparison of the modded and non modded upa-1's in the process of getting all 3 upgraded.
|
|
|
|
Post by wizardofoz on Jul 6, 2012 7:59:57 GMT -5
For the powersupply I might have suggested a dual bridge rectifier and cabling the transformer direct to the bridge/s rather than the pcb, but that just me. A beefier transformer is not out of the ballpark cost wise at least for me here in Singapore.
|
|
|
|
Post by Jim on Jul 6, 2012 8:48:33 GMT -5
What would you say was the most significant improvement? Re-capping? Or that and the new rectifier bridge?
I can't imagine that changing the wiring or binding posts would really be audible.
Some kind of measurements before/after modifications would be interesting.
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Jul 6, 2012 10:34:17 GMT -5
While I applaud the OP's diligence in getting the project done, unless he kept at least one of the amps stock, there is *no* way he can tell if the mods really did improve the sound. Expectation bias is a *powerful* drug, and after dropping $250 on each amp, most anyone would hear an improvement.
Me? I'd probably just buy better amps to start with, or invest the $750 in upgraded spkrs., room treatments, and/or better source matl. No monkeying around with "microdynamics", whatever those are. But that's just me...
-RW-
|
|
DYohn
Emo VIPs 
Posts: 18,489
|
Post by DYohn on Jul 6, 2012 10:37:12 GMT -5
Modding is fun. At least I like slinging my soldering iron when I can. Nice work on the amp, whether it makes any audible difference or not. |
|
Worth the hassle then?
