Want to add that using the fixed outs of the M1clic with less sensitive speakers sounds great . King Sound electrostats and Magnepam MMG . Using both speakers the sweet spot for the volume is around 50 out of the 100 on the digital display for the BAT . Can go louder as well without distortion . So in a nutshell is the high sensitivity speakers the cause ? and is there a solution besides using a different pre ? Possibly different amps with the triangles ?
DAC to preamp technical question
Curious as to what is happening in this situation : Using a Musical Fidelity M1 Clic as a DAC (has a volume control as well). Using the fixed rca outputs into a Balanced Audio Technology vk51 preamp into a pair of Hypex Nc400 monoblocks ,into a pair of Triangle celius 202 speakers . The issue is the volume gets loud very quickly and distorts at a lesser volume than i would like . When i use the rca variable volume outs and use the M1's remote at about half volume there is a much greater range on the bat and sounds better . This is my first dac into the newly aquired BAT pre . I have three more dacs coming next week as well . Is the issue the volt output from the fixed outs on the M1 clic ?
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Your better of driving your Hypex Nc400 direct from the variable output of the M1. As it’s output stage has better low output impedance drivability than the Bat has, you’ll also loose some of that excess gain doing so as well, and gain more transparency. Musical Fidelity M1 Measured: The impedance from the variable jacks was 47 ohms at high and middle frequencies, rising to 76 ohms at 20Hz. Bat VK51 Measured Test: Output impedance was twice that specified, at 410 ohms over most of the audioband. This is low, though it did rise to a high 4.7k ohms at 20Hz, due to the size of the output coupling capacitors.This will not be an issue with components having high input impedances, such as BAT’s own power amplifiers, but it does mean prematurely rolled-off low frequencies with low load impedances. Cheers George |
I found this when reading the specs of the M1:After looking at both the website description of the M1CliC and the manual, apparently what this means is that if an analog input is selected (the unit provides both analog and digital inputs), the level of the fixed output will be the same as the level of that input. Unfortunately, though, the level of the fixed output when a digital input is selected is not specified. In any event, after looking at the relevant specs for all of the components that were mentioned, consistent with George's comments it appears to me that the root cause of the problem is the high gain of the BAT preamp (18.34 db per John Atkinson's measurements of the SE version, as published in Stereophile), coupled with the fact that nearly all digital sources having non-adjustable unbalanced fixed outputs provide "full scale" (maximum) output levels of at least 2 volts, and often more. That would certainly explain the limited range of the volume control that can be used when the fixed outputs are boosted by 18.34 db and then applied to a 200W/8 ohm amp having 25.8 db of gain powering the 92 db/1W/1m/8 ohm Triangle speakers. I'm not sure, though, how to explain the distortion that was mentioned, which occurs with the Triangle speakers but not with the other lower efficiency speakers. Also, in most cases I would second George's suggestion of trying the system with the preamp removed altogether, but after looking at section 7.3 of the NC400 datasheet I'm not certain that would work, given that the M1CliC provides only unbalanced outputs, and depending on how the power amp is configured externally to the NC400 module. I'll mention also, BTW, that the BAT's output impedance rise he cited is not an issue in this case, as the NC400 has very high input impedance. Finally, it appears that the BAT only provides balanced inputs, while as I mentioned the M1CliC only provides unbalanced outputs. Which leads me to wonder how well the BAT may be performing when provided with unbalanced inputs. If you are using adapters or adapter cables to connect the two, you may want to consider using a Jensen transformer instead (~$275), which would provide the BAT with a true balanced pair of signals. To reduce the signal level, you might then also want to try a pair of Rothwell attenuators, in their balanced version, inserted into the input jacks of the BAT. Or, alternatively, just use the M1's variable outputs into the BAT, as you have done, and be happy. :-) Regards, -- Al |
"but after looking at section 7.3 of the NC400 datasheet " Yeah, looks like your right Al, what a pain, not being able to connect normal RCA’s, as it’s ground floats at this point and this is where the shield (ground potential) on external equipment has to connect. I don’t understand why they would design it that way, how would they sink any RF to ground when using XLR anyway, suppose they had their reasons, not good for sales though in my opinion. Cheers George |
Thanks for the responses fellas . A new twist in my journey . I had just purchased the BAT used from a hifi dealer in town last week . I inquired if they knew the tube life on the tubes . They did not know . So yesterday after about an hour of listening the left channel just went dead and gone . No warning signs what so ever .Shut her down , left and came back an hour later and started up again . This time it only took ten minutes for the same thing to happen again . I am assuming the tubes are in need of replacement . Might have some correlation as to why the BAT sounded worse with the higher sensitivity speakers ? Goerge , you really need to get over your obsession with putting down Hypex . LOL |
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