Jump to content

doctorcilantro

Regulars
 View Profile  See their activity

  • Posts

    463

  • Joined

  • Last visited

 Content Type 

Posts posted by doctorcilantro

    Speaker calibration with RS SPL meter

    in 2-Channel Home Audio

    Posted

    I have never tried active compensation for freq. response.

    I was thinking of generating
    all the test tones at the listed frequencies (at the link below), and
    calibrating them to 83db SPL using Replay Gain (-20db for 0dbfs).


    Measure each sine wave with Rat Shack SPL meter, and use the given error correction values.


    Then use a parametric EQ to adjust for error found in each speaker.

    I'll
    use a directx 10-band parametric EQ, but not sure how to cover
    (average) the 30+ measurements/adjustments that may need to be made.

    http://home.comcast.net/~audio-worx/page3Electrical%20RoomTx.html

    Any ideas?

    DC

    Digital RIAA sample

    in 2-Channel Home Audio

    Posted

    The file
    was record at 32bit-float/96kHz and saved with Wavelab 5 as 24/44. A Grado
    Reference Statment (.4mv) on an MG-1 tonearm (Bix turntable) was
    connected to an AEA Big Ribbon flat mic pre which fed a Lavry AD-10.
    the AD-10 integrated with the PC via a Van Den Hul Optcoupler and EMU
    1212M S/PDIF input. In Samplitude, digital RIAA was applied in realtime
    along with a rumble filter during recording & monitoring. No
    crackle removal or other restoration was done on the audio file.

    The digital RIAA filter is an EQ plugin which means we can do the most accurate possible RIAA possible, in the digital domain instead of the analog domain of the recording chain.

    The benefits of this are touted in white paper by Orban who I believeoffers "Pure Vinyl" for MAc users. Diamond Cut 7 also offers a built "virtual phono pramp" to do what I'm doing via VST plugin in Sampitude.

    I'd like ot hear suggestions for more test samples. I have a lot of nice classical. Any composer or movement or particualar recording that others may have a copy of and be familiar with?

    White paper

    Purevinyl features

    I don't use Pure Vinyl but I've talked to software engineer who is very knowledgable in EE and he said this top is the best of the best. My setup sounds good and the desinger claims specs as good as Orban's.

    DC

    Digital RIAA sample

    in 2-Channel Home Audio

    Posted

    Finally got around to making a sample, well I have made many, but some final issueswere ironed out. I still need to run through final cartridge setup and this motorfall out of step too quickly, but give a listen. It will stream, but feel free to download to critically listen on the system/player of your choice.

    http://digitanalogue.blogspot.com/2008/10/ive-made-few-minor-improvements-on.html

    I recorded some Beethoven and Mozart; I'll put those up in a bit.

    best,

    Jon

    Amperex 6922 fakes? ("H" "A" or "X")

    in 2-Channel Home Audio

    Posted

    Tubemonger(.com) tolfd me the symbol under the tube has nothing to do with the production company/facotry. I'd still like to know how these fir into the scheme of things though. The etchings seem like they could be easily forged as well as the labels, which was alreayd discussed; it wouldn't be hard for grey vendors to produce labels that sratch off easily or mimic valid etchings...for that matter they could also copy the symbol under the tube.

    DC

    Amperex 6922 fakes? ("H" "A" or "X")

    in 2-Channel Home Audio

    Posted

    Trying to figure out if I have fake Amperex 6922s.

    I have found the best way to look at it is with a magnifying glass, holding the tube upside down in good light. If you look at an angle the glass allows you to clearly see the letter (acts as a lens); otherwise it is hard to see when looking straight down from above the tube.

    I have (4) USN-CEP Amperex with date codes etched on the side which appear valid, but the letter underneath is "X" and not "A".

    I have (3) Amperex PQ white label and two of them have an "A" where as one (whose label happens to be rathered rubbed off) has an "X".

    I thought they should have "A" or "H" for America or Holland, respectively.

    many thanks
    Jonathan

    Dean still working on crossovers?

    in 2-Channel Home Audio

    Posted

    Huh? ; )

    "In
    spite of being a great speaker right out of box, the RF-7 has some
    ringing from both the underdamped cones, as well as in the treble
    response from the horn's resonant peak. The combination of the better
    parts and a small value adjustment to a single resistor in the notch
    circuit in the HF section reduces the ringing to an inaudible level.

    What I do:

    I
    desolder the parts, remove all of the old solder with braid, clean the
    boards with denatured alcohol, and then replace the capacitors and
    resistors. I use Kimber capacitors in the HF section, and Solen or
    Dayton Audio in the HF notch circuit and LF section. The junk resistors
    are replaced with Mills non-inductives.





    Those who listen with the RF-7, and who are on a tight budget -- might
    find the most cost effective improvement by simply tacking on a 10 ohm
    resistor to the existing resistor in the notch circuit. You won't get
    all of the benefits of the full package, but it would probably prevent
    the tweeter from going shrill during some musical passages. At any
    rate, I wouldn't hesitate for a second to buy a set of RF-7s and listen
    to them just as they are. The mod is sweet, but it doesn't make or
    break the speaker by any stretch of the imagination."
    DeanG
    DC - found what I needed...knew I had it somewhere!

    Dean still working on crossovers?

    in 2-Channel Home Audio

    Posted

    Too bad. I should have done it when I had the chance.Would you divulge the resistore change so I could have it perfomred by someone else? Strictyl for personal use.....?

    "The combination of the better
    parts and a small value adjustment to a single resistor in the notch
    circuit in the HF section reduces the ringing to an inaudible level."

    DC

    Heresy vs. RF7

    in 2-Channel Home Audio

    Posted

    I'm down here in Tampa Florida wishing I could demo a pair of Heresy IIIs.

    Maybe there's a store over in St. Pete, not sure.

    I know the Heresy doesn't dig as low as the RF-7 but it has the midrange horn, correct?

    What are the major differences between the two? Is this a good example of Heritage vs. Reference? Or would I need to compare the RF-7 to Belle or LaScala.

    DC

    Transducer Grooming: Maintaining Your Speakers

    in 2-Channel Home Audio

    Posted

    I've been staring at LaScalas and Belles online lately, but I have to face the reality that is...I'm not going to be able to convince my lovely wifethatI need an upgrade (given that I just sold my pre and amps for new pair of monoblocks).

    So, I've been seriously considering finally purchasing the DeanG crossover upgrade for my RF-7s.

    Is there anything else I can do to these to improve the fidelity? Thoughts and ideas:

    1. They came from a smoking home, a party house, and I feel like cleaning behind the tweeter screen or cleaning the screen itself. Is this possible? How should I go about it? Does this matter? A light rub of alcohol on the screen with Q-tip? IIRC, the screens seemed a little dirty.

    2. Currently, they are sitting on spikes on a raised wood floor which sits on steel beams.

    3. One of the midrange woofers has a small indent. Not on the center dome but the radial part (my cat knocked a PC mouse off the top and it fell down behind the screen).

    4. The DeanG upgrade.

    Anythingelse? Comments appreciated.

    DC

    ATTN: Fenderbender, Don Richard: Theatre Organ Download

    in 2-Channel Home Audio

    Posted

    I downloaded (4) 24/96 FLAC albums from HDtracks last night. One of which was the Crown Imperial.

    "From the shriek of piccolo to the thunder of the organ's awesome 32
    foot-pedal stops, this will give the best stereo system a workout. .
    .hold on to your subwoofer and when organist Mary Preston cuts loose,
    don't be surprised if neighbors complain about their furniture sliding
    across the floor."
    - Scott Cantrell, The Dallas Morning New"

    http://www.hdtracks.com/index.php?file=9624albums

    No amps until later this week so I haven't heard yet.

    DC

    Deciding on new monoblocks (SET? VRDS?)

    in 2-Channel Home Audio

    Posted

    I do like to crank it now and then; I listen to jazz, blues, rock, classical, jamaican (i.e.ska, rock steady,reggae), soul, funk, etc. ...the gamut.

    One thing I don't know is the for the rated input sensitivity, is that full power? So at 1v the Mites are doing 25w? I don't think I could ever get that loud with 98db/w RF7s and not blow my ears off. The Mites store 100 joules of energy and put out some serious juice for the RF-7s. Maybe VRDs ARE the way to go; I would run them in Triode I think. Has anyone compared the Sixpacs to the VRDs? I really like Craig; he's a stand up guy and knows his valves.

    I also assume since Craig uses LaScalas that his amps mesh well with them or RF-7s. I have a dream....to someday own LaScala IIs : )

    DC

×
×
  • Create New...