Yes, and a willingness to apologise. Even I say really stupid things ...... sometimes. Never hurts to say sorry, does it? My Paco Osuna CD arrived yesterday, and I'm really excited about hearing his music later on - that was a genuine non sequitur, by the way. Goodnight everybody. ToS
I agree, but, wait, it is a relatively high power emitter. Nothing to compare with the levels of RFI inside a DAC, don't you think ?
This said, I'm not at all qualified to talk about DAC engineering and radio frequencies. Just trying to understand.
Last edited:
You might have never first hand worked with wet film processes. Dust is a major issue. No negative has an ultrasonic dust shaker, just to mention one thing.
Sorry Max this is torture for me, fully occupied spectrum like 256 QUAM just pop noise. None of these sound any different than the others.
Thanks for pointing that out, fun review to read, cures one from even considering to buy the book.
You're right. The output of high powered intentional radiator like that can be rectified by basically anything. That's part of the reason why everything is canned in a cell phone. CTIA test labs have told me that most common radiated emissions failure for devices with cellular radios are 2nd and 3rd harmonic of the carrier.
Mark is right though about the LME497xx op-amps, there are a number of people that have noticed that, for whatever reason, they are more susceptible than even an undegenerated input like AD797.
Not unexpected to see the clock and out-of-band noise on the output of a DS converter. Do you know what kind of output filter this thing has? Maybe it's just not sufficient.
The Benchmark has a datasheet-like 3rd order filter I think, and it looks like they have ferrite beads over the outputs to the connectors.
What we don't know is how much is a problem. Are levels below what would fail compliance testing still too much? We would like to see none, of course.
I dont know if the "bad" output one is in or out of compliance. The issue I am more concerned with is having this much HF going to the audio IC opamp and then out to a power amp. Not many audio amps can handle such HF cleanly and amplify it another 30dB or so.
Its amazing to me that so many designers dont seem to notice this or think it is just fine to send it/HF thru. Its only -55db down +30 db PA gain ..... !
THx-RNMarsh
Its amazing to me that so many designers dont seem to notice this or think it is just fine to send it/HF thru. Its only -55db down +30 db PA gain ..... !
THx-RNMarsh
Last edited:
There’s garbage all over the place in the average modern home. Another bad one is the power line based network extenders, let’s not even talk about CFL. I have a Dell laptop PSU that cannot be used while I am doing audio measurements it’s that bad (but a much older laptop is fine).
Yeah, I would be interested in how other well-designed equipment performs, like the RME interfaces and RTX analyzer.
I am not educated in electronics and I don’t know what are the tradeoffs for designing with large overload margins. What I have experienced is that depending on the cartridge sensitivity (I have met MM cartridges ranging from 2.5 to 11 mV/5cm/sec) and the Vdc of the preamp PS plus elevated subsonic signal from the cart/arm/rumble, there is a real risk of preamp overloading.
A lot of hot MM cartridges have got a bad name as harsh, only due to overloading of the RIAA pre (music signal rides over subsonic signal).
I have got the habit to measure the RIAA preamps that I copy and build together with the cartridge I intend to use.
Congratulations Dimitri! Is it the ML 585.5 ?
George
Attachments
The subsonic overload is also discussed in the Holman paper - seems it is often a bigger issue than at first meets the eye. A subsonic filter can remove the problem from downstream electronics and prevent speaker cone flapping, but will not prevent the front end overloading in severe cases, and especially with a hot cart or recording.
In all active equalizers, one trick is to run a resistor from the output of the opamp back to the top of the DC blocking capacitor where it connects with the lower arm of the gain setting resistor. If you select the resistor correctly, you get c 12 dB gain reduction vs 20 Hz at 6-8 Hz. The LT1115 data sheet RIAA has an example.
In all active equalizers, one trick is to run a resistor from the output of the opamp back to the top of the DC blocking capacitor where it connects with the lower arm of the gain setting resistor. If you select the resistor correctly, you get c 12 dB gain reduction vs 20 Hz at 6-8 Hz. The LT1115 data sheet RIAA has an example.
I rather enjoy Dreamth's posts, he seems quite knowledgeable and well studied as well. Were did it go wrong? Can't blame him for reacting with some humor on your broadsides.
Last edited:
I was talking of durst making stain on the photo, as you we have on near each one with captors if we are used to change lenses.
I had less problems of durst with "ultrasonic" (Olympus like) than with my Canon and Sony, but it is always a boring problem.
I don't had so many problem with durst in my little lab at that time. Film is easy to clean in the lab, and, in 35mm, the cartridge is durst free. it can affect one photo, not all of them, like in digital.
Hi Scott.
Sorry that the Jump recording is not to your taste....this Jump version is a recent live recording that I have to hand that I have processed for my sister who is the female vocalist, she indicates strong preference for one particular loopback recording.
I have Dropbox posted Test Dept - Two Flames which has tons of LR and time spatial information, and a Benny Goodman 1938 live recording which is of course two channel mono with performance and spoken word.
The tracks numbered 02 - GS (or TS) are loopback recordings and you ought to be able to find differences wrt the 01 - Original files.
If you are unable to discriminate differences between Original and any of the Loopback recordings there is no point in proceeding to discriminating the further differences embedded into the M1 and M2 files.
The loopback recordings are performed using a 2003 era Roland US-122 USB audio interface, an early prosumer level 24 bit interface.
RMAA reports essentially zero loopback distortion but not SOTA noise figures......-80dB channel noise level.
It could be said that such performance ought to not seriously damage audio throughput, in practice I find that the combination of this interface and my custom GoopCable© does indeed substantially alter throughput and these changes are able to be captured and later auditioned.
The fact that you report no differences between any of the four Jump files indicates problem/causes concern.
If this null result is because of your disdain at the choice of programme material then we can move on to different programme.
If this is not the case and the Jump programme choice is of no consequence, then question is raised of your system performance, and/or your hearing acuity and your listening skills.
The three YouTube 'industrial' tracks you linked are strongly compressed and are not full bandwidth.....I can process any wav/flac file that you send to me if that is preferable.
I can still process your YouTube versions and this should demonstrate differences.....I didn't do so because of the source file quality limitations, but more recent experience with 320k MP3 files indicates subjective 'restoration' of missing information, very interestingly.
Over to you Scott and others,
Dan.
@Scottjoplin, you mentioned the Benny Goodman 1938 concert, I found the Columbia Legacy version, you ought to hear differences.
Mark,
That's the one. The spread in value on the DC blocking caps means you have to select them or adjust the resistor accordingly if you have concerns about LF response. My values are a bit different (my DC blocker cap is 470uF) and the resistor values were optimized on LTSpice. This solution works very well (measured).
That's the one. The spread in value on the DC blocking caps means you have to select them or adjust the resistor accordingly if you have concerns about LF response. My values are a bit different (my DC blocker cap is 470uF) and the resistor values were optimized on LTSpice. This solution works very well (measured).
470uF gives a MC low frequency corner of about 15Hz (slightly lower due to the cartridge few ohms impedance). I wonder how you kept the 20Hz RIAA with this single LF pole, the error at 20Hz is about -2.5dB.
- Status
- Not open for further replies.