Thuneau
New Head-Fier
- Joined
- Aug 14, 2004
- Posts
- 16
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Just wanted to share this with those who own or consider buying the AKG K-1000 head speakers.
I work for a large AVL (audio video lighting) systems integrations company. I get notifications of pretty much all new pro audio products. Last year Rane came out with a high-end, class-D, 4-channel amplifier for the installations market- the MA-4. Nothing extraordinary in itself, but to acommodate the 70V (so called constant voltage) loudspeakers they came up with matching high fidelity step up transformers. The primary looks like an 8 Ohm load to the amp, the secondary has two taps: 70V and 100V, corresponding to approximately 50 Ohm and 100 Ohm load. When I saw it I noticed its specs right away: 40Hz-20kHz response (+0,-1dB) up to 100W. I thought it would match the 130 Ohm load of the K-1000 perfectly, so I got a pair of them. At first I tried them with a Sonic Impact amp and didn't care for the results, so I set the transformers aside and didn't come back to them until now. Recently, I decided to give them one more shot, this time with my 6-channel B&K amp. I'm happy to report that I find the results almost in the "spectacular" category. Apparently the Tripath chip doesn't like the inductive load of the transformer, but a basic solid state output deals with it just fine.
The sound of the K-1000 with the Rane transformer in line exhibit none of the HF zing that I get with them hooked up directly to the output of the amp, plus the sensitivity is at least 6dB higher (it's a step up transformer- that's to be expected). Now the amp works in its low power mode ( the "magical" first Watt, class A bias) and has a lot of control and authority. The low end is well defined down to mid/upper 30's Hz ( I used a function generator to check it) and the high end is smooth and not brittle at all.
I notice a bit of blurring of HF, noisey sounds, such as loud splash cymbals, but nothing that would be really objectionable. When I switch to my JBL near field monitors (LSR-25) the HF and upper mids are still much clearer on the K-1000. I would say the transformer is definitely not "transparent", but it compliments the K-1000 well. The sound is just like with very good loudspeakers at 6 ft., less the room coloration.
For all interested, the spec is here:
http://rane.com/pdf/mt4dat.pdf
The transformers can be had from any Rane dealer for about $60.00-$70.00 each. The rack mount enclosure is another $70.00 or so, but the thansformers come with mounting hardware, so you can use just about any box.
With the TF-4's in line, any low-power, high-fidelity amplifier will drive the K-1000 to satisfying levels (be careful with anything over 10W/ch @ 8 Ohm) as you might blow the K1k up- their high impedance is no longer a limiting factor.
My B&K amp is rated at 60W @ 8 Ohm, but my preamp with the volume set to appr 8 o-clock drives the combo perfectly- just like my JBL monitors. Not too loud, not too soft.
I should note that I use a sub with my K1k's, but even without it, the sound is very good, even if lacking some authority in the first two octaves.
Stay tuned for more info as I have some other cool mods on the bench.
I work for a large AVL (audio video lighting) systems integrations company. I get notifications of pretty much all new pro audio products. Last year Rane came out with a high-end, class-D, 4-channel amplifier for the installations market- the MA-4. Nothing extraordinary in itself, but to acommodate the 70V (so called constant voltage) loudspeakers they came up with matching high fidelity step up transformers. The primary looks like an 8 Ohm load to the amp, the secondary has two taps: 70V and 100V, corresponding to approximately 50 Ohm and 100 Ohm load. When I saw it I noticed its specs right away: 40Hz-20kHz response (+0,-1dB) up to 100W. I thought it would match the 130 Ohm load of the K-1000 perfectly, so I got a pair of them. At first I tried them with a Sonic Impact amp and didn't care for the results, so I set the transformers aside and didn't come back to them until now. Recently, I decided to give them one more shot, this time with my 6-channel B&K amp. I'm happy to report that I find the results almost in the "spectacular" category. Apparently the Tripath chip doesn't like the inductive load of the transformer, but a basic solid state output deals with it just fine.
The sound of the K-1000 with the Rane transformer in line exhibit none of the HF zing that I get with them hooked up directly to the output of the amp, plus the sensitivity is at least 6dB higher (it's a step up transformer- that's to be expected). Now the amp works in its low power mode ( the "magical" first Watt, class A bias) and has a lot of control and authority. The low end is well defined down to mid/upper 30's Hz ( I used a function generator to check it) and the high end is smooth and not brittle at all.
I notice a bit of blurring of HF, noisey sounds, such as loud splash cymbals, but nothing that would be really objectionable. When I switch to my JBL near field monitors (LSR-25) the HF and upper mids are still much clearer on the K-1000. I would say the transformer is definitely not "transparent", but it compliments the K-1000 well. The sound is just like with very good loudspeakers at 6 ft., less the room coloration.
For all interested, the spec is here:
http://rane.com/pdf/mt4dat.pdf
The transformers can be had from any Rane dealer for about $60.00-$70.00 each. The rack mount enclosure is another $70.00 or so, but the thansformers come with mounting hardware, so you can use just about any box.
With the TF-4's in line, any low-power, high-fidelity amplifier will drive the K-1000 to satisfying levels (be careful with anything over 10W/ch @ 8 Ohm) as you might blow the K1k up- their high impedance is no longer a limiting factor.
My B&K amp is rated at 60W @ 8 Ohm, but my preamp with the volume set to appr 8 o-clock drives the combo perfectly- just like my JBL monitors. Not too loud, not too soft.
I should note that I use a sub with my K1k's, but even without it, the sound is very good, even if lacking some authority in the first two octaves.
Stay tuned for more info as I have some other cool mods on the bench.
