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In Reply to: RE: Mundorf M-Lytic HC+ 4-Pole 250V 22,000uF storage caps posted by Cousin Billy on September 02, 2014 at 15:20:28
This first picture shows the output from a speaker I am working on. The yellow line is the Mundorf modded amp, with the green line from the original.
I use my MP-1 as the signal generator, and I tested at an elevated volume level. I also disconnected the active woofer.
The slight rise in output below 1200Hz, gave a more fleshed out sound to my speakers. Female voice had a bit more body.
There is also a slight rise above 4K Hz.
What's interesting to me is the distortion measurements.
If you go back and forth between the two pictures, you will see the Mundorf modded amp has slightly lower distortion starting at 200Hz. There are a few small spikes in the original amp (namely at 430Hz). This lower distortion was easy to enjoy from day one, and I might go so far as to say it's getting better.
Over the last two weeks I have listened to a fair bit of music. One of my favorite albums is Dead Can Dance, Into the Labrynth. I have to say, the better the album, the more noticeable the improvements.
Time to listen to more music.
Follow Ups:
Just for clarity (my own), you are here comparing the output(s) from speakers driven, respectively, by one amp that was modified with the Mundorf substitution and the other amp, unmodified. Is that correct? if not, what? Thanks.
Output from the speaker increased with the new 4-pole caps.
As you can see, this output increase was from 1200Hz and lower, and in the upper treble.
Do you have as a control the "before" data for the same amplifier/speaker combination that has been modified? There are so many variables here as regards the measurements that I would think such controls are necessary for interpretation of your data attempting to compare one amp/speaker to the other amp/speaker. That said, I am perfectly willing to believe that the modified amplifier is subjectively improved by installation of the Mundorf capacitors.
Hey Lew
I measured the speaker output with the original amplifier.
I left everything as is, except the MA-1's. I replaced the stock caps with the Mundorf's, reconnected the amps, let them warm up for an hour, and remeasured.
The only change in the measuring process was the replacement of the caps.
My own experience with making sound measurements with an SPL meter is that it is rather hard to get accurate and repeatable results. The tiniest of movements of the meter, the speaker, or even nearby objects, can change the measurements significantly. Did you, by chance, make analogous plots to those you posted, but measuring the output signal on the speaker wires rather than the acoustic signal?
Also, I am interested in your distortion curves. I am only familiar with FFT plots where one looks at the amplitudes of the various harmonics vs the amplitude of the fundamental. Do I understand correctly that your measuring device and software is calculating the THD level for each source frequency, as that frequency is swept through the audio spectrum? That seems pretty neat, and I'd like to know more about doing that.
Also, are those distortion plots measured on the electrical output of the amplifier, or on the acoustic output of the loudspeaker? (I would assume the former, but I'd just like to be sure.)
Chris
It is a pleasure to see actual measurements being posted, rather than the purely subjective "listening reports" that one commonly sees presented!
I'm curious about one thing. When you say "This first picture shows the output from a speaker I am working on. The yellow line is the Mundorf modded amp, with the green line from the original", do you mean literally the audio output from the speaker (picked up by a microphone), or do you mean the electrical audio signal going into the speaker? Your wording suggests the former, but I'd just like to be sure.
Thanks,
Chris
Hey Chris
The graphs are what the speaker is outputting, and the microphone picking up. The microphone was about 1 meter away.
Hi Billy,
Very interesting ! What amp are you installing the Mundorf's in ?
Thanx,
Jack
Hello Jack
I have the MA-1 Silver edition.
Ralph has brought it up to the latest version.
I have done a few minor upgrades myself. Increased the High Voltage power supply's total capacitance, and changed the full wave bridge rectifiers to IXYS high current (32 amp I believe).
The 4-Pole caps are pretty simple to install. The FWBR supply power to the input +ve and -ve, with the signal wires connected to the output +ve and -ve.
I have my smoothing caps on the signal terminal portion.
This evening I decided to remove my smoothing caps on the Mundorf 4-poles.
The Mundorf's now have no caps attached.
Maybe I was in a good mood this evening, but I would swear it's getting even better. I believe a type of distortion is gone.
Tomorrow I will try a 1.2uF Clarity cap in place of the Duelund CAST PIO's that where installed (15uF).
Question; do the caps installed across the +ve and -ve poles of a storage cap typically introduce intermodulation distortion?.
Maybe- if they were able to resonate somehow. Did you measure IM?
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