Post by SteveC on Nov 5, 2021 14:03:23 GMT
I have recently been on the hunt for a replacement power amp for my system. I currently use a Conrad Johnson Premier 350SA (solid state) to power my current-hungry TAD CR1 MKII speakers, which are 86db efficient and a nominal 4 Ohm load! The CJ power amp is good for 600 watts into 4 Ohms and has always been happy driving the TAD's.
I have owned the CJ 350 since 2004 and although it still works perfectly, I decided that I would treat myself to a new power amp for my 65th birthday (yesterday)!
Little did I realise how fussy the TAD CR1's would be of a partnering amplifier and an added complication was my Conrad Johnson GAT 2 preamp, which operates in single-ended only, so any balanced power amp with XLR only input, would have to be ruled out on the grounds of complexity in matching and integration. I believe that it can be done with the insertion of a transformer-based gizmo converting the single-ended signal at -10db to a balanced XLR output at +4db, allowing a balanced XLR set of interconnects to connect to the power amp inputs. However, I am convinced that this would be a compromised way of doing things!
Having auditioned a few contenders, I settled on the purchase of a TAD M2500 MKII power amp, which will accept balanced and single-ended connections, with a switch on the rear panel to select the appropriate input. The amp is beautifully built (as are all TAD components) and is hewn from a 90 Kg solid aluminium block, to combat vibration! The finished amp weighs 43 Kg and is constructed as a true dual-mono chassis, with 2 X 1 Kva transformers for the analogue input stage and a Class D output! It delivers 500 watts into a 4 Ohm load and this output doubles as the impedance is halved, indicating a very healthy power supply. The amp runs cool and consumes 250 watts in operation and a measly .5 watt in standby, due to Class D operation!
As a single stereo power amp, it works very well in my system, providing a convincing grip of the TAD speakers and delivering a smooth, highly detailed and dynamic sound with a deep and broad soundstage. The bass is very deep and powerful!
Having the opportunity to borrow a second, identical TAD M2500 MKII power amp, I set about, removing the bi-wire links from the speaker terminals and with another set of stereo RCA phono interconnects from the second set of preamp main output terminals on my GAT 2 preamp and a set of Tellurium Q Ultra Black II speaker cables, I configured my system for passive horizontal bi-amping, with a kilowatt of power available for each channel (I also utilise two REL Gibraltar G2 subs, crossed over at 32 Hz to underpin the sound and enhance imagery and soundstage)!
First track on was "Unfinished Symphony" by Massive Attack and I was relieved to hear that all the faffing around was well worth the effort. The bi-amped mode produced a smooth, totally unforced sound delivery from the speakers, with enhanced separation and headroom. The soundstage was highly detailed and depth/width of image was increased, compared to use in a conventional stereo setup.
I have no doubt, that tweaking further with speaker and interconnect cabling would bring further improvements to the sound.
I have a couple more days to enjoy the bi-amped system, before returning the second loan power amp, but I am glad that I carried out the exercise to see what bi-amplification could do for a decent system.
For those of you with a keen eye who noticed that phase is reversed at the speaker terminals - this is because my CJ GAT 2 preamp inverts phase, which has to be corrected at the speaker terminals!
I have owned the CJ 350 since 2004 and although it still works perfectly, I decided that I would treat myself to a new power amp for my 65th birthday (yesterday)!
Little did I realise how fussy the TAD CR1's would be of a partnering amplifier and an added complication was my Conrad Johnson GAT 2 preamp, which operates in single-ended only, so any balanced power amp with XLR only input, would have to be ruled out on the grounds of complexity in matching and integration. I believe that it can be done with the insertion of a transformer-based gizmo converting the single-ended signal at -10db to a balanced XLR output at +4db, allowing a balanced XLR set of interconnects to connect to the power amp inputs. However, I am convinced that this would be a compromised way of doing things!
Having auditioned a few contenders, I settled on the purchase of a TAD M2500 MKII power amp, which will accept balanced and single-ended connections, with a switch on the rear panel to select the appropriate input. The amp is beautifully built (as are all TAD components) and is hewn from a 90 Kg solid aluminium block, to combat vibration! The finished amp weighs 43 Kg and is constructed as a true dual-mono chassis, with 2 X 1 Kva transformers for the analogue input stage and a Class D output! It delivers 500 watts into a 4 Ohm load and this output doubles as the impedance is halved, indicating a very healthy power supply. The amp runs cool and consumes 250 watts in operation and a measly .5 watt in standby, due to Class D operation!
As a single stereo power amp, it works very well in my system, providing a convincing grip of the TAD speakers and delivering a smooth, highly detailed and dynamic sound with a deep and broad soundstage. The bass is very deep and powerful!
Having the opportunity to borrow a second, identical TAD M2500 MKII power amp, I set about, removing the bi-wire links from the speaker terminals and with another set of stereo RCA phono interconnects from the second set of preamp main output terminals on my GAT 2 preamp and a set of Tellurium Q Ultra Black II speaker cables, I configured my system for passive horizontal bi-amping, with a kilowatt of power available for each channel (I also utilise two REL Gibraltar G2 subs, crossed over at 32 Hz to underpin the sound and enhance imagery and soundstage)!
First track on was "Unfinished Symphony" by Massive Attack and I was relieved to hear that all the faffing around was well worth the effort. The bi-amped mode produced a smooth, totally unforced sound delivery from the speakers, with enhanced separation and headroom. The soundstage was highly detailed and depth/width of image was increased, compared to use in a conventional stereo setup.
I have no doubt, that tweaking further with speaker and interconnect cabling would bring further improvements to the sound.
I have a couple more days to enjoy the bi-amped system, before returning the second loan power amp, but I am glad that I carried out the exercise to see what bi-amplification could do for a decent system.
For those of you with a keen eye who noticed that phase is reversed at the speaker terminals - this is because my CJ GAT 2 preamp inverts phase, which has to be corrected at the speaker terminals!
