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EQUIPMENT FORUMS >> MINI TORII >> Mini Torii UL-tra
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Message started by erik2a3 on 12/31/18 at 17:13:44

Title: Mini Torii UL-tra
Post by erik2a3 on 12/31/18 at 17:13:44

News Year's Greetings!

Thought I would share my own Mini Torii modification (though please let it be known that I adored the original version when it was factory-fresh from Decware a few years ago).

This modification started with a failed power transformer in the right channel -- a straightforward repair, and obviously nothing that could be termed a modification. I replaced inter-stage coupling caps with orange drops long before this, because, over the years, they are what I have come to prefer to use on virtually every project I've done -- and I've tried very expensive capacitors (a topic I'm extremely weary of discussing...)

So, I kept looking at the screens in the output stage, and thought, "Why not?!?" And so began my search for a suitable output transformer that had the taps I would need to realize this idea. And found them! They are considerably larger than stock OPTs, but still fit the chassis top-plate perfectly (with some very minor milling needed of the wooden edge on which the chassis plate rests.

The big regulator valves were also removed in the process, and their former position on the chassis is now occupied by larger filter caps.

The Mini Torii is also home to a fair number of switches (for all sorts of things), and my wife told me simply gets confused by what is what when she wants to listen to music. So, there is now only a single power switch near the front, and the treble attenuation circuit will soon be occupied by a 3-position input selector switch (when an additional RCA jack is added at the back of the chassis). I tend to like a hotter midrange and HF response, and never really used that feature anyway. Feedback from the output to input stage was also removed. I experimented first by switching it in and out of the circuit, and really prefer the decidedly more raw or immediate (and yes, less-damped) sound without it.

This is what it looks like:

Title: Re: Mini Torii UL-tra
Post by Lon on 12/31/18 at 17:24:54

Great work! Nice personalizing it to your tastes--which are pretty much the opposite of mine (I like laid back and mellow!) You know what you are doing and have done it well.

Title: Re: Mini Torii UL-tra
Post by erik2a3 on 12/31/18 at 23:30:42

Thank you Lon, for your feedback and compliment. I'm trying to post a better image and having trouble with it.

Title: Re: Mini Torii UL-tra
Post by Lon on 01/01/19 at 00:00:15

The one you have posted looks great.

Title: Re: Mini Torii UL-tra
Post by erik2a3 on 01/01/19 at 02:56:40

Ok, thanks. I'll leave it at then! :) I have too many other audio projects to work on, anyway, so I'll leave this as it is!

I still need to reconfigure the 3-input selector switch instead of dual mono, which makes it easier for the other audiophile in the house (my wife!) to use the system.

Happy New Year!

Title: Re: Mini Torii UL-tra
Post by Brian on 09/30/19 at 00:12:26

Hello Erik,
Can you characterize the difference between Ultra Linear and Pentode sound? Particularly on this amp.

Thank you,
Brian