fewtch
Headphoneus Supremus
- Joined
- Jul 23, 2003
- Posts
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Received my Elpac 24v 330mA linear regulated wall wart today (WM080-1950-760), plugged it into the Creek OBH-11 amp (non-SE) and did some testing. The male jack on the Elpac wall wart is center positive and of the correct size, and so the wall wart is a direct swap-out replacement for the Creek OBH-1 (note -- the Elpac has a 3-prong grounded plug).
First, a note on my philosophy: I feel that ears + measurements are often better than ears or measurements by themselves. Ears always come first, but measurements can be good pointers or indicators toward problem areas, and how they're likely to affect sound quality. In areas where they apply, they can also serve as a sort of objective verification of audible improvements, so there's less chance that we're imagining them or even missing a potential improvement somewhere.
Output is from the Creek's headphone jack to the analog line-ins of my M-Audio Audiophile 24/96 soundcard. Volume was set at minimum to test residual noise only, with nothing connected to the RCA input jacks of the Creek -- however, I did mess with the volume control to verify that nothing much changed at maximum volume either (negligible hiss or general noise floor increase).
Measurements were taken using Cool Edit Pro v1.2a software and its Analyze/Statistics function on a 10-second recorded sample of the Creek's residual noise (I'm not much of a RMAA fan, and prefer doing things my own way). The values below are not absolute, as the sound card has a noise floor itself and also adds a little low-level hiss called dither, which is normal and required in digital recording. However, the values are excellent for comparative purposes since the level of dither doesn't change.
Here are the results (interpretation below):
---------------------
Using Creek OBH-1 PSU:
Left / Right
Peak Amplitude:-60.94 dB-61.21 dB
DC Offset:-.001 -.001
Minimum RMS Power:-94.92 dB-95.12 dB
Maximum RMS Power:-61.76 dB-61.93 dB
Average RMS Power:-81.1 dB-81.2 dB
Total RMS Power:-77.1 dB-77.25 dB
Using Elpac 24v Linear Regulated PS:
Left / Right
Peak Amplitude:-80.61 dB-81.01 dB
DC Offset:0 0
Minimum RMS Power:-95.74 dB-95.5 dB
Maximum RMS Power:-91.93 dB-92.91 dB
Average RMS Power:-94.84 dB-94.62 dB
Total RMS Power:-94.82 dB-94.61 dB
---------------------
Interpreting the results:
Look at the following when comparing:
(1) Peak Amplitude -- this delineates the loudest the Creek's noise floor got during the time measurement was taking place. As these are in negative dB values, a higher number is better. The Elpac bettered the OBH-1 by nearly 20dB! This is a huge improvement that should translate directly to better sound.
(2) Total RMS power -- this measures average levels over time (in this case 10 seconds), rather than the highest residual noise peak that occurred. The Elpac bettered the OBH-1 by nearly 18dB, again a very large improvement.
(3) Minimum and Maximum RMS power -- look at the difference between the two values with each power supply, rather than comparing one PS to the other. This shows fluctuations and instability in the noise floor (often due to EMI and/or RFI as well as flaky power). With the OBH-1 it's bouncing all over the place like a kangaroo on crack -- confirmed visually using Cool Edit Pro's digital VU meters. With the Elpac it's quite steady (also confirmed visually).
The differences are stunning, and far greater than I'd expected. The test results show that the standard Creek OBH-11 is more sensitive to bad power and more responsive to improvement using a clean power source than is commonly believed, and that the OBH-1 is a horrible power source that adds a great deal of low-level noise and noise floor instability when used with the OBH-11. The grounding with the Elpac wall wart probably helps as well.
Preliminary Sonic Impressions: As I suspected (from previous experience with delivering cleaner power to amplification equipment), treble has improved greatly (biggest improvement) and there is a general unveiling, firming up and improved clarity throughout the entire sonic spectrum. Soundstaging has improved. Even bass seems to have lost some of the 'loose' character it had using the OBH-1 supply. I like the sound well enough now that I'm not going to attempt a capacitor upgrade and risk damaging the unit.
Final Impression: The Creek sounds like a completely different and much better amp. Get rid of that OBH-1 as soon as you can and get the Elpac (much cheaper) or an OBH-2.
Update (30 Aug 03): I realized this morning with some dismay that I had performed these tests with the wall warts plugged into my PC's surge protector! After banging my head on the wall, I quickly repeated the tests with the OBH-1 plugged into two different wall outlets, and with both the wall wart and the amp itself located well away from any computer gear. Thankfully I can report that the results didn't vary significantly. It did make me realize that your mileage may vary a little on the amount of improvement you see -- you may get less (or even more) than I did depending on how clean your wall power is in the first place, and what's located nearby the OBH-11.
First, a note on my philosophy: I feel that ears + measurements are often better than ears or measurements by themselves. Ears always come first, but measurements can be good pointers or indicators toward problem areas, and how they're likely to affect sound quality. In areas where they apply, they can also serve as a sort of objective verification of audible improvements, so there's less chance that we're imagining them or even missing a potential improvement somewhere.
Output is from the Creek's headphone jack to the analog line-ins of my M-Audio Audiophile 24/96 soundcard. Volume was set at minimum to test residual noise only, with nothing connected to the RCA input jacks of the Creek -- however, I did mess with the volume control to verify that nothing much changed at maximum volume either (negligible hiss or general noise floor increase).
Measurements were taken using Cool Edit Pro v1.2a software and its Analyze/Statistics function on a 10-second recorded sample of the Creek's residual noise (I'm not much of a RMAA fan, and prefer doing things my own way). The values below are not absolute, as the sound card has a noise floor itself and also adds a little low-level hiss called dither, which is normal and required in digital recording. However, the values are excellent for comparative purposes since the level of dither doesn't change.
Here are the results (interpretation below):
---------------------
Using Creek OBH-1 PSU:
Left / Right
Peak Amplitude:-60.94 dB-61.21 dB
DC Offset:-.001 -.001
Minimum RMS Power:-94.92 dB-95.12 dB
Maximum RMS Power:-61.76 dB-61.93 dB
Average RMS Power:-81.1 dB-81.2 dB
Total RMS Power:-77.1 dB-77.25 dB
Using Elpac 24v Linear Regulated PS:
Left / Right
Peak Amplitude:-80.61 dB-81.01 dB
DC Offset:0 0
Minimum RMS Power:-95.74 dB-95.5 dB
Maximum RMS Power:-91.93 dB-92.91 dB
Average RMS Power:-94.84 dB-94.62 dB
Total RMS Power:-94.82 dB-94.61 dB
---------------------
Interpreting the results:
Look at the following when comparing:
(1) Peak Amplitude -- this delineates the loudest the Creek's noise floor got during the time measurement was taking place. As these are in negative dB values, a higher number is better. The Elpac bettered the OBH-1 by nearly 20dB! This is a huge improvement that should translate directly to better sound.
(2) Total RMS power -- this measures average levels over time (in this case 10 seconds), rather than the highest residual noise peak that occurred. The Elpac bettered the OBH-1 by nearly 18dB, again a very large improvement.
(3) Minimum and Maximum RMS power -- look at the difference between the two values with each power supply, rather than comparing one PS to the other. This shows fluctuations and instability in the noise floor (often due to EMI and/or RFI as well as flaky power). With the OBH-1 it's bouncing all over the place like a kangaroo on crack -- confirmed visually using Cool Edit Pro's digital VU meters. With the Elpac it's quite steady (also confirmed visually).
The differences are stunning, and far greater than I'd expected. The test results show that the standard Creek OBH-11 is more sensitive to bad power and more responsive to improvement using a clean power source than is commonly believed, and that the OBH-1 is a horrible power source that adds a great deal of low-level noise and noise floor instability when used with the OBH-11. The grounding with the Elpac wall wart probably helps as well.
Preliminary Sonic Impressions: As I suspected (from previous experience with delivering cleaner power to amplification equipment), treble has improved greatly (biggest improvement) and there is a general unveiling, firming up and improved clarity throughout the entire sonic spectrum. Soundstaging has improved. Even bass seems to have lost some of the 'loose' character it had using the OBH-1 supply. I like the sound well enough now that I'm not going to attempt a capacitor upgrade and risk damaging the unit.
Final Impression: The Creek sounds like a completely different and much better amp. Get rid of that OBH-1 as soon as you can and get the Elpac (much cheaper) or an OBH-2.
Update (30 Aug 03): I realized this morning with some dismay that I had performed these tests with the wall warts plugged into my PC's surge protector! After banging my head on the wall, I quickly repeated the tests with the OBH-1 plugged into two different wall outlets, and with both the wall wart and the amp itself located well away from any computer gear. Thankfully I can report that the results didn't vary significantly. It did make me realize that your mileage may vary a little on the amount of improvement you see -- you may get less (or even more) than I did depending on how clean your wall power is in the first place, and what's located nearby the OBH-11.
