The only hafler amps that have the Diablo and Diamond circuits are the Transnova 9505 and the Transnova 9303. The Transnova 9500 and 9300 are very similar to these two amplifers, except for these two circuits.
Because of these circuits, the 9505 and 9303 are better than the 9500 and 9300, but all 4 of these amps are very good sounding amps. They were well worth their retail price in the 1990s when they were made, and since they were made well, they hold up very well - even in 2010. Because of their age, and because many do not know how good they truly are, they can be found very inexpensively on Audiogon and eBay.
In the late 1990's, my brother was blowing woofers regularly in his Celestion SL-700SE Speakers. These were some of the best monitors ever made - about $4,000 a pair in the late 1980's - but they had a very low sensitivity, around 80db. For some reason, his ADCOM 565 Mono Amps could not drive them, so he kept blowing woofers. After blowing his third woofer, I recommended he sell his Adcom amps and buy a Hafler Transnova 9300. He did and heard a huge improvement in sound quality. 11 years later, he still has not blown any other woofers and loves his Hafler amp. Interestingly, the retail price of the ADCOM Mono Amps was more than the Hafler!
These 4 transnova amps were specifically designed by David Hafler and Jim Strickland (of Acoustat) to sound great while driving demanding all speakers, even low impedance speakers. Jim joined David to design these transnova amplifiers because he needed a powerful, good sounding amp that was capable of driving his low impedance elecrostatic speakers. Without an amp like the transnova, he really couldn't sell his speakers to anyone, as there was a market for them without an amp like the transnova. Their design worked very well and received excellent reviews. It was rated Class B and $$$ by Stereophile, meaning they sounded very good and were an excellent value for the dollar. The retail price for the 9300 was $1395.00, the 9500 was $2595.00, and the 9303 and 9505 were a couple fo hundred dollars more than the 9300 and the 9500, respectively. Good luck!
Because of these circuits, the 9505 and 9303 are better than the 9500 and 9300, but all 4 of these amps are very good sounding amps. They were well worth their retail price in the 1990s when they were made, and since they were made well, they hold up very well - even in 2010. Because of their age, and because many do not know how good they truly are, they can be found very inexpensively on Audiogon and eBay.
In the late 1990's, my brother was blowing woofers regularly in his Celestion SL-700SE Speakers. These were some of the best monitors ever made - about $4,000 a pair in the late 1980's - but they had a very low sensitivity, around 80db. For some reason, his ADCOM 565 Mono Amps could not drive them, so he kept blowing woofers. After blowing his third woofer, I recommended he sell his Adcom amps and buy a Hafler Transnova 9300. He did and heard a huge improvement in sound quality. 11 years later, he still has not blown any other woofers and loves his Hafler amp. Interestingly, the retail price of the ADCOM Mono Amps was more than the Hafler!
These 4 transnova amps were specifically designed by David Hafler and Jim Strickland (of Acoustat) to sound great while driving demanding all speakers, even low impedance speakers. Jim joined David to design these transnova amplifiers because he needed a powerful, good sounding amp that was capable of driving his low impedance elecrostatic speakers. Without an amp like the transnova, he really couldn't sell his speakers to anyone, as there was a market for them without an amp like the transnova. Their design worked very well and received excellent reviews. It was rated Class B and $$$ by Stereophile, meaning they sounded very good and were an excellent value for the dollar. The retail price for the 9300 was $1395.00, the 9500 was $2595.00, and the 9303 and 9505 were a couple fo hundred dollars more than the 9300 and the 9500, respectively. Good luck!