Anybody checked out the Italian mods here?

http://www.autocostruire.com/catalog/index.php?cPath=42

I was mulling over the idea of getting one myself.  Currently I'm using to two unmodded SI 5066's to run my biampable speakers.  Using an amp per channel really improves the imaging as well as using one channel per driver increases dynamic impact.

I've used the air core inductors from that company replacing the toroids on several amp3's and I really liked the results.  It was a pleasant surprise to find that the air cores imparted more heft to the presentation by enhancing the amp3's bass and mid-bass.  At about $30/set, they are a bit pricey, but worth it to me and the trans-Atlantic shipping is quick.

Also, don't overlook trying some nice paper in oil input caps if you have some hiding in a forgotten corner.  I found that Sprague 2.0uF's result in addictive midrange, although Auricaps have the edge on bass.

It seems crazy to throw high dollar parts into a $25 kit, but the results are equally insane.

Larry,

Keep us updated as you try out these different input caps.

I've only tried a Hovland in this position so I cannot make any comparisons. I'd be interested, however, to hear your opinion of the Vit Q. I have a bunch of them and tried them once as coupling caps in my SE amp. While the sound was warm and fluid, I found that it was way too muddy, syrupy, and detail-obscuring to my ears. It also threw a heavy blanket over the pacing and propulsiveness of the sound and glossed over the dynamics and attack of the leading edge of notes. I didn't enjoy it.

I also had a Cary Audio SLP-94 preamp that used Audio 1 caps for coupling. These looked very similar to the Vit Q type vintage sealed metal-cased oilers. They deadened the sound in a very similar way. I couldn't stand to listen to music on it because it sounded too restrained and the sense of timing was off. I changed them out to VTV Ultratones and that transformed the pre into something I really enjoyed.

In some of the reviews I've read, there seems to be a slight lack of harmonic richness in the upper midrange on these T-amps. Perhaps the right input cap would help out a bit? How about the Audio Note coppers or Jupiter beeswax?

Also, I've seen a site that recommends the Blackgate C caps for the input cap. These must be a recent addition to the Blackgate line - I never recalled seeing a C cap before (the Cs are specified for coupling applications).

Best,
KT

I've had this running for about an hour so far. My first impression was the huge soundstage it throws. It images way better than my modded SI. It has more bass authority, also. Top end is still a bit dodgy, but that's typical until several hundred hours. Detail is as good or better than the SI. Better dynamics.
     So far it's stock, unhoused. I'll be making changes after getting some hours on it.

Regards,
Larry Welsh

Barry:
       Yup, 12v SLA. Additionally, I put a bank of 3 1800 uf Panasonic FC's across the battery posts (observing proper polarity, of course). I've found it to have a positive effect on dynamics (especially DAC's) even though it shouldn't.
       BTW, I changed the power rail caps to Panny 2200 uf. FC's. Noticeable improvement.


Regards,
Larry Welsh

O:
     The Autocostruire has addressed most of the problems with the SI and corrected them: good air-core inductors, proper-sized input caps, impedence matching, location of the caps on the rails, quality of the parts, 2020 chip instead of the 2024. The sound is a big improvement over my modded T-Amp. I had the T-Amp back in my system for an hour while I changed some things on the 2020 and the experience was painful.
      I'm waiting for one of Yeo's Diyparadise 2020's. Maybe I'll try one of the 41hz through-hole 2020 kits. I need a couple of amps for bi-amping anyway.
   
Regards,
Larry Welsh

Hi
Just registered so if Ive repeated anything please forgive.

Ive been a user of the the bigger Tripaths for years and just love them. Ive moded them just like the smaller versions. One extra thing I found was critical,  the  +5V supply had to be very very clean.
A friend  gave me an SI to mod for him and  the previous posts have been most useful, thanks but the +5V area doesnt seem to have been mentioned. The TA202x chips look interesting in that they have separate +5v digital and analogue supply pins which are supplied on the SI chip at least from an on board regulator in turn supplied from the main power rails. I want to try to separately regulate the +5V analogue supply with something like an LT1763 supplied from its own battery. Anyone heard of this?
Geoff

Hi Paul

Thanks for the encouraging reply. I guess the hard part comes now. I think I will have to lift the +5V analogue pin off the board as I think the connecting track goes under the board as far as I can see on the SI.

Initially I was just going to try separately regulating the analogue supply
with the intent of keeping any noise from the +5V digital out. If it is succesful I will probably try a separate reg for the digital +5V

I have some little boards for the LT1763 left over from another project
which will do nicely. I used a 1uf/16V oscon on the reg i/p and 10uf/16V oscon on the o/p which seems to work well. Ill let you know how it turns out.

All:
     I feel like I'm hogging this thread, but if your're bothering to read my blather, it may be because you'd like to build one.
     I discovered how critical matching speaker impedence is. I've listened with two values before today. It figures that the third is the charm in my system and the difference is not subtle. It's HUGE. If I were to build another, I'd substitute some posts in the four cap positions and experiment with .22 and .33 on the posts. It would then be possible to parallel both on  ...

hi larry, the autocostruire website mentions the ability to match speaker impedence for 4-6-8 ohms.  do you know if it's possible to match for higher ohms, like 14 or 16?

thanks,

doug s.