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PostPosted: July 6th, 2018, 4:28 pm 
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TubeDriver wrote:
I have tried using the Corcom type filters in the past but I did not like the effect on the sound. Cleaner perhaps but also less perceived dynamics and just plain sucked the life out of music. Virtually every passive AC conditioner (probably heard a couple dozen different manufacturers units over the years) has done this. Sort of like placing a couple ferrites on your line level interconnects, makes things sound boring. The big (15A or 20A) balanced power conditioners are least objectionable IMHO. I admittedly don't have a lot of experience with the regenerator types such as the ones from PS Audio, and seeing how the new 15A-20A ones cost $8k to $10k, I probably will not get the chance. Maybe I just like noise?


If you want to try the equivalent of the PS Audio conditioner, I have a Crown Studio Reference that in bridged mode can swing over 200 volts RMS. In the past when I needed a very clean AC line I used it being driven from a low distortion signal generator and used the output level control of the generator to get whatever voltage I needed. That way you can test the performance of the equipment under conditions of low, normal, and high AC input voltages. Obviously you have to use caution when straying from nominal voltage, especially on the high side.

The output of the amp is impervious to any changes in the input line as everything is rectified to DC and then regenerated by the amp. It is the cleanest power I have ever seen. As far as output capabilities I have run my large shop vacuum off of it with no sag at all in the output. For tests of equipment power supplies I also created a noise generator that I can put in series with the signal generator to give a known and repeatable noise level on the AC power. I can then determine which power supply is better at rejecting the noise. If you would like to try that please let me know.


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PostPosted: July 6th, 2018, 4:59 pm 
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tomp wrote:
Interesting observation. The better Corcom or similar filters have very low impedance at power line frequencies and minimal effect on power transfer. I wonder what the physical effect is that causes what you hear. That would be a tough thing to track down.


My experience having tried the Corcoms on power amplifiers duplicates his. For some reason the filters get the job done with line level components with much improved sound, but power amps do not like the restriction and tend to get "dark" and slow.

I even tried a big-ass isolation transformer dedicated to the power amps. with the same result. Go figure.

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PostPosted: July 6th, 2018, 6:52 pm 
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Thanks Tom but my current setup is satisfactory. I am in the process of completing a long delayed ne plus ultra buildup of an early TD124 to replace older setups I have.


tomp wrote:
TubeDriver wrote:
I have tried using the Corcom type filters in the past but I did not like the effect on the sound. Cleaner perhaps but also less perceived dynamics and just plain sucked the life out of music. Virtually every passive AC conditioner (probably heard a couple dozen different manufacturers units over the years) has done this. Sort of like placing a couple ferrites on your line level interconnects, makes things sound boring. The big (15A or 20A) balanced power conditioners are least objectionable IMHO. I admittedly don't have a lot of experience with the regenerator types such as the ones from PS Audio, and seeing how the new 15A-20A ones cost $8k to $10k, I probably will not get the chance. Maybe I just like noise?


If you want to try the equivalent of the PS Audio conditioner, I have a Crown Studio Reference that in bridged mode can swing over 200 volts RMS. In the past when I needed a very clean AC line I used it being driven from a low distortion signal generator and used the output level control of the generator to get whatever voltage I needed. That way you can test the performance of the equipment under conditions of low, normal, and high AC input voltages. Obviously you have to use caution when straying from nominal voltage, especially on the high side.

The output of the amp is impervious to any changes in the input line as everything is rectified to DC and then regenerated by the amp. It is the cleanest power I have ever seen. As far as output capabilities I have run my large shop vacuum off of it with no sag at all in the output. For tests of equipment power supplies I also created a noise generator that I can put in series with the signal generator to give a known and repeatable noise level on the AC power. I can then determine which power supply is better at rejecting the noise. If you would like to try that please let me know.


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PostPosted: July 7th, 2018, 8:20 pm 
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Location: Baltimore MD
I built The Felix filter 10 years ago for all my low level stuff except digital(DAC and what not has a different filter) from Audiocircle
https://www.audiocircle.com/index.php?topic=50284.0
I feel this is a pretty good noise filter
If I was to add a iso tranny would it go before or after the felix


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PostPosted: July 7th, 2018, 9:31 pm 
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Pelliott321 wrote:
I built The Felix filter 10 years ago for all my low level stuff except digital(DAC and what not has a different filter) from Audiocircle
https://www.audiocircle.com/index.php?topic=50284.0
I feel this is a pretty good noise filter
If I was to add a iso tranny would it go before or after the felix


Before. AC receptacle -- then any other filters -- then enjoy!

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PostPosted: July 7th, 2018, 9:37 pm 
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SoundMods wrote:
Before. AC receptacle -- then any other filters -- then enjoy!

Walt,
What's the thought process behind your recommendation? I'm asking because I've done it the other way around with good results. In other words I've used a Felix-like filter (Cap/CMC/Cap) followed by a big isolation transformer and it worked really well. I especially liked that combination to isolate noise from digital class D amps.
---Gary
p.s. the Felix link from Pelliot is to my thread over on Audiocircle, where I go by my initials, GBB.


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PostPosted: July 8th, 2018, 8:47 am 
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I'm curious also, and does it really matter. With Felix first, it will keep trash out of the xformer. With Felix second the xformer will keep trash out of the filter. This will be fun to play with


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PostPosted: July 8th, 2018, 10:39 am 
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GaryB wrote:
SoundMods wrote:
Before. AC receptacle -- then any other filters -- then enjoy!

Walt,
What's the thought process behind your recommendation? I'm asking because I've done it the other way around with good results. In other words I've used a Felix-like filter (Cap/CMC/Cap) followed by a big isolation transformer and it worked really well. I especially liked that combination to isolate noise from digital class D amps.
---Gary
p.s. the Felix link from Pelliot is to my thread over on Audiocircle, where I go by my initials, GBB.



Well for the most part with an isolation transformer having multiple receptacles you can isolate all of your line level goodies as a group and then individually filter them.

Then there is the issue of inter-product interaction. RFI/EMI noise is not directional. Devices like CD transports and DACs especially generate their own trash that can find its way to to other components without individual filters. Same goes for devices with switch-mode power supplies. Those with tube eqipment would think that since tubes are natural RF amplifiers there would not be a problem. There still is. Even though solid-state devices, especially I.C. op-amps, can easily get into trouble, tube amplifiers will still enable subtle overlay of RFI/EMI contamination to effect the audio signal in negative ways. Paul Miller of Hi-Fi News & Record Review performed a study that I passed on to all of you that showed how the noise hitches a ride on the audio signal with the end result being deteriorated sound quality.

The audio signal is a delicate flower that can easily be messed up. I even use ferrite filters on interconnects with the same predictable results. Those that have visited here have heard the end result.

Even video systems benefit from aggressive isolation and filtering resulting in better resolution of detail and color saturation.

Then there is the trash that's generated inside the home. The utility is not the only culprit. Refrigerator and HVAC fan and compressor motors and controls, light dimmers, Wi-Fi, Bluetooth, LED lighting fixtures (these can be really nasty), and whatever other crap one has in their home that radiates RFI/EMI noise.

It's everywhere!!

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PostPosted: July 8th, 2018, 11:10 am 
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I use the Felix on my analog devices and have a special filter for digital devices that blocs trash both ways.
I plan to use the iso tranny I got and build another box that will incorporate both filters, two zone as it were one for digital and another for analog
not putting anything on power amps.
Im no wondering about the Quad 67 power supplies, what to put on them


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PostPosted: July 8th, 2018, 1:09 pm 
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Again, be careful if you are relying on filters or isolation transformers only as I found out with my laptop feeding schmutz out to the ground line from an internal filter. Just isolating and filtering the power feed did not solve the problem as it was traveling down the ground line and since I was using an amp with an unbalanced input it snuck into the signal circuit via the outer shell of the RCA jack which was grounded. To paraphrase Walt, noise sucks.


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