Jump to content
Electronics-Lab.com Community

D0T-C0M

Members
 View Profile  See their activity

  • Posts

    53

  • Joined

  • Last visited

    Never

 Content Type 

Posts posted by D0T-C0M

  3. Speaker help please

    in Electronics chit chat

    Posted

    Ok so are these tweeters here going to do me justice?

    Pioneer Tune-Up Tweeter

        * 7/8" PPTA (P-Phenylene Terephthal Amide) Hard Dome
        * Strontium Magnet with Magnetic Fluid Cooling
        * Built-in Crossover (6 dB/Octave)
        * Surface or Flush Mounting Capabilities
        * Overall Housing Diameter: 1 7/8"
        * Flush Mounting Depth: 3/4"

        * Tweeter Type: PPTA Hard Dome
        * Size: 7/8 inch
        * Crossover Included: yes
        * Sensitivity: 90 dB
        * Frequency Response: 2,500-30,000 Hz
        * Recommended RMS Power: 40W
        * Peak Power Handling: 120W

  5. Speaker help please

    in Electronics chit chat

    Posted

    Hi audioguru

    Yes its here's the link for the specs. It does say 4 x 50 W S-MOSFET power output but its probably peak watts.

    http://www.sonystyle.ca/commerce/servlet/ProductDetailDisplay?storeId=10001&langId=-1&catalogId=10001&productId=1003305&navigationPath=n32150n32153

    At what frequency should I crossover my tweeters at? I have the choice from the supplier. Also what brands are considered good brands when it comes to tweeters?

    I would really love to install new speakers but I am really limited to in the choice of speakers I can use due to the limited space I have in my truck.

  6. Speaker help please

    in Electronics chit chat

    Posted

    I have a sony CDX-GT310 in my toyota pickup. It puts out 4x55w in 4 ohms.  I have just have cheap 2-way speakers installed in the front and back. I got 6"round 120W in the back and 4" round 2-way 90W in the front under the dash almost.

    I know its a cheap system but it sounds ok except I find the higher freq sound is muffled in the front but sounds ok in the rear.  I would like to obtain more treble sounds from the front to try to equalize the sound a bit.  I was thinking of adding a tweeter in each door by paralleling the front speakers but I'm concerned with the impedance.

    I guess the question i have is if I disconnect the existing tweeter in my front 2-way speakers, will that allow me to connect my door tweeters in parallel with the front speakers and return the impedance back to the original value?  Also at what frequency do you recommend I crossover at?

    What other methods could I use that doesn't cost an arm and a leg. I'm looking to spend no more than $100 to try to equalize the higher mid range and tremble frequencies.

    thanks in advance.

  7. Can someone suggest a good 50 to 75Ohm impedance matching transformer?

    in Electronics chit chat

    Posted

    Ok I was told the the impedance of the stereo antenna in my truck was 75 Ohms, so I thought maybe I should match the impedances because initially I thought the signal loss would be roughly 2/3 of full power but I read up on the net while awaiting your response and I guess the signal loss from the impedance mismatch varies with the length of the wire. The wire in my truck is very short so I guess I won't need a matching transformer like you suggested as the signal loss will be mimimale.

    Audioguru, Thanks very much for replying.

    D0T-C0M

  8. Can someone suggest a good 50 to 75Ohm impedance matching transformer?

    in Electronics chit chat

    Posted

    I use a FM transmitter in my truck and would like to use a normal FM antenna to transmit the signal. I think I will need a RF impedance matching transformer that will match the 50ohm impedance of my transmitter to the 75ohm impedance of the FM antenna. Can someone please suggest a good one that I can buy or if it isn't too difficult I would consider making one.

    Am I correct in assuming I would lose about 1/3 of my radiating signal if I directly connected the 50ohm FM transmitter output to the FM antenna?

    Does it make a difference where in the circuit I put the matching transformer? Should I connect it as close as possible to the FM transmitter and run 75ohm cable to the antenna OR should I place the matching transformer as close to the antenna as possible and run 50 ohm cable to my transmitter? Or does it make a difference?

    Should I be concerned about the change in temperature in regards to the matching transformer which I understand is temperature sensitive to some extent?

    Thanks as usaul for all your help.

  9. fm transmitter scematic required

    in Electronic Projects Design/Ideas

    Posted

    I researched the Ramsey model but they are about $60 more for a kit and about $100+ assembled. Second is the fact that EDM is also microprocessor controlled and has digital LED readout. If I can quote from their site

    This is the only Compact, Multi-Channel, Digital-Display, Fully-Synthesized, Microprocessor-Controlled, Stereo FM Transmitter kit that we know of for under $100 (including S/H)!!


    I found all the feedback I read on all the independant website was all positive. I was hard pressed to find anything negative about them. I also liked that EDM posted alot of their graphs and tests online. As a customer I felt re-assured that they were very open and honest by posting their specs online. This tell me that they have nothing to hide and not afraid to post their results publically.

    Full Band operation: (87.7 - 107.9MHz) in 0.2MHz increments, on LED display
    Frequency Stability: < 0.0005% of set frequency
    Frequency Accuracy: < 0.001% error from set frequency
    10mW (+10dBm) into a 50 Ohm load
    100mW (+20dBm) unit also available
    RF output is reduced 20dB while tuning with PLL un-locked
    VSWR: Withstand 20:1 without damage (both models)
    Low phase-noise
    -90dBc/Hz @ 10kHz
    -94dBc/Hz @ 20kHz
    -104dBc/Hz @ 100kHz
    Low spurious output: < - 50dBc
    Low Residual FM: < 25Hz rms (Measured in a 300-3kHz Bandwidth)
    Incidental AM: < 0.2%
    Frequency Response: 20Hz - 15kHz
    Level: Line level input via RCA type sockets (level adjustment on module)
    Max Audio I/P sensitivity: < 100mVp-p (integrated limiter)
    Distortion (THD): 0.2% with 1kHz tone at 75kHz deviation level (mainly 2nd, 4th)
    Signal to Noise Ratio (SNR): > 60dB
    Stereo Separation: Typical about 40dB

  10. fm transmitter scematic required

    in Electronic Projects Design/Ideas

    Posted

    using the stock whip antenna I did some preliminary range tests. The Tx was installed in the cab of my truck with the antenna running up and down the mirror which isn't the best placement for it but nevertheless I was very happy with the range I received.  using a fairly good quality FM headset I walked down the road and the sound was crystal clear up to about 300 feet after that I started getting some static and the occasional blank spots. On high setting I got crystal clear sound up to 500-600 and after that a bit of static and the occasional blank spot. Keep in mind that the Tx was in the cab of my truck with alot of metal around it.  I have made a custom 50Ohm coax and made a 1/4wave ground plane antenna and I expect the range to be better when I mount this antenna outside the cab of my truck.  I've read that on high setting I can get about 1/8mile.

  11. fm transmitter scematic required

    in Electronic Projects Design/Ideas

    Posted


    Was wondering if you could give us a report when you receive this transmitter?


    I recieved my EDM transmitter last Wednesday.  It is an awesome little unit. I am so impressed with the sound quality. It really sounds awesome especially when I connect my cd player to it. Sirius Sat Radio sounds alot better too. Seems to have a really great pre-emphasis stage in the input. The treble sounds better and the base sounds better too. What I like the most is it's separate L-R input level POTs so you can fine tune your inputs for better stereo balance and you can adjust MPX value manually so you are capable of using all the the 75Khz deviation band of the FM signal. Anyone who gets this Tx will not be disappointed. The workmanship is excellent and support so far has been really good. fast email responses. You can purchase them through paypal. Once you purchase a unit from EDM they give you access to a private yahoo group which has lots of great info on such as homemade attenuators, antennas etc...

    Anyone who wants more info , dont hesistate to contact me.

  14. Got a couple questions regarding this fm transmitter

    in Electronic Projects Design/Ideas

    Posted

    hehe geez your fast I re-posted my last post after re-reading your post. I thought because you said that Canada/US had to much pre-emphasis that maybe I should go with the 50uS. Now I understand that I have to go with 75uS so that the sound won't be muffled in my canadian reciever. Sorry I am still quite new, while I understand basic electronics, this FM stuff is real new to me. I've been reading alot of material lately and trying to understand all the details of it. I really apprecaite your time.

  19. fm transmitter scematic required

    in Electronic Projects Design/Ideas

    Posted

    yeah but I was thinking that because the 1W amp needed 100mW to drive 1W out that with the 10mW or so that the micromitter has (without the attenuator) that I might be able to drive 100-200mW. Anyway i decided to return the micromitter kit and bought the EDM kit the is switchable between 10mW and 100mW which should be more than enough for what I need. From what I've read the signal quality is pretty decent.

  23. Got a couple questions regarding this fm transmitter

    in Electronic Projects Design/Ideas

    Posted

    I bought it from jaycarelectronics.com which I would imagine ships out of Australia. It was pretty cheap at $36CAN plus $10 shipping. 

    I just cancelled my micromitter order because I really like the 10mw/100mW selector mode of the EDM transmitter. the 10mW would be great when I am driving about but when I want the extra range, all I have to do is flick a switch.  I really dont have the expertise to fabricate a circuit to suit my application so I don't mind paying $120 for an advanced system as this. The kit is pretty much assembled. here are the steps to follow to assembly

      1.  Remove pre-programmed microprocessor from protective foil and plug into socket holder on PCB
      2. Plug digital displays into respective sockets on PCB
      3. Connect the power wires to a suitable 12VDC source.
      4. With the EP versions, install the supplied power connector and fasten with screws
      5. Solder the power wires, Red and Black to power terminals on the mounted power connector
      6. For versions without enclosures, you may construct your own enclosure or purchase from another supplier
      7. For versions without power units, you may construct your own or purchase from another supplier
      8. Follow operating instructions supplied for specific model series in manual




    My only concern was it uses the bh1415 chip but from what I read its has the same specs as the bh1417 only the frenquency is PIC controlled.

    this is from there site

    Frequency Response: 20Hz - 15kHz
    Level: Line level input via RCA type sockets (level adjustment on module)
    Max Audio I/P sensitivity: < 100mVp-p (integrated limiter)
    Distortion (THD): 0.2% with 1kHz tone at 75kHz deviation level (mainly 2nd, 4th)

    I emailed them to see what the +/- db is.

  25. Got a couple questions regarding this fm transmitter

    in Electronic Projects Design/Ideas

    Posted

    ok thanks Audioguru for your very quick responses.  I've read so many different forums and you seem to be on all of them and you seem to be so knowledgable. Thanks for taking the time to answer my questions.

    I've been searching for 4 days now on the internet for some site that has a decent 100Mhz amplifier. Why is it so rare to find??  If you don't have any amp circuits maybe you could tell me what exactly I should look for when choosing a good high quality amp circuit? How much power would I need to push a clear signal to at least 500ft?

×
×
  • Create New...