I finished up building a Twisted Pear (
www.twistedpearaudio.com) TXO-2 amp for a good friend last week and have to say this is one really nice amp. When I first got it up and running it was OK but nothing special but he'd asked me to put Black Gate's in and they tend to take some time to start sounding good.
After about 3 days the amp was sounding very nice and I was really enjoying it. I put it into the system in place of my R.E. Designs LNPA 150's driving the mids/tweeters of my speakers. The system is actively bi-amped so they are running from 275Hz and up.
These amps are fully balanced from input to output and use a TI chip that incorporates the Pass Labs Super Symmetrical technology and are a very interesting design. They actually use the LM3886 amp chip, which is used in many gain clones though in this implementation they are used more as a current pump (at least that's how I read it). I can say this doesn't sound anything like a gain clone. Anyway, since these are fully balanced and my active XO (Marchand XM44) is capable of balanced operation I took the Marchand down to the bench yesterday and added some XLR jacks and wired up the balanced outputs.
Connected everything back up, still in single ended mode between the XO and the amp. Sounded the same, very good but not a major change from the LNPA's. This is good as the LNPA's are IMO very good amplifiers. I then pulled out the single ended IC's and put in the balanced set and adjusted the XO gain accordingly.
Holy shit! I was stunned and shocked. It was literally like someone swapped in a different amp. It's hard to describe just how much better the system sounded. Literally everything was better. Midrange had more body and a richer tone with supreme clarity. Highs were crystal clear and exceptionally detailed but at the same time very sweet with no grain to be found. The spaciousness and imaging were greatly expanded and even the sense of height was improved. I've switched things from SE to balanced before and sometimes it's better and sometimes not. With the TXO amp the difference was not subtle and I am hearing things I've never heard in any system before. It's really going to be hard to give the amp to it's owner.
I will have no choice except to build one for myself. The owner came by yesterday and I switched it back to SE before he arrived and once he was happy with the sound I switched it over to balanced mode. He was as shocked as I was. Fortunately I get to keep it for another week or two so I can add 4 more output modules. This will allow it to drive 4 ohm loads at nearly 300WPC. I almost forgot, the dynamics are really good as is the tone. Strings, piano and woodwinds just sound so right. Acoustic guitar is mesmerizing.
If you're a DIY type and have a balanced source you might consider building one of the Twisted Pear amps. It has an SE to balanced converter in the amp so I didn't expect much change, maybe a little quieter but the change is quite amazing. The cool part is that it only has about 100 hours on it and will likely keep improving.
Here are some photos of the amp. I used a chassis from DIYEnclosures.com, a pair of 400VA transformers and some heat sinks from an old Carver amp. It's dual mono after the IEC/Fuses and power switch.
Mike
