Connect with us

Guitar Amp Modification

Discussion in 'General Electronics Discussion' started by N_Hound, Jun 5, 2017.

Scroll to continue with content
  1. N_Hound

    N_Hound

    2
    0
    Jun 5, 2017
    Hey guys,

    I have an 'Orange Micro Crush', and I had fun with it, but it seems the speaker blew. So, I was looking online to possibly place the speaker for a better one as a project. The amplifier runs off a 9v battery, and the speaker has an impedance of 8 ohms and it states the 'Power' is 2 Watts RMS. That's about all I know. I came across a few 3-4 inch speakers that seem to be an improvement. I was just curious if it would work since most the other speakers I found have a 20-30 Watt RMS. I'm not sure if that's too much of a power demand for the 9v battery. If I could get any insight on this, it would be really appreciated.
     

    Attached Files:

  2. davenn

    davenn Moderator

    13,866
    1,958
    Sep 5, 2009
    the power rating of the speaker is kinda irrelevant
    it will still work, the 2 W amp will just give it 2 watts
    there is no power demand going on :)

    Dave
     
  3. hevans1944

    hevans1944 Hop - AC8NS

    4,615
    2,154
    Jun 21, 2012
    The image you uploaded shows the device runs from a 9V to 12 V "wall wart" power supply capable of supplying up to 500 mA, and that the amplifier provides up to 3 watts RMS output power over the stated range of input voltages. That current and voltage works out to 4.5 watts for 9 V input, and 6 watts for 12 V input.

    Either way, 500 mA is waaay beyond the capacity of a typical "9 V battery." See this Google result page. Use a wall wart to power up this puppy. Note the center post is negative while the barrel shell is positive. Check wall-wart polarity before you plug it in and apply power to your micro Crush guitar amplifier.

    The speaker "power rating" is what a speaker can safely handle without damage. If the replacement speaker has the same 8 ohm impedance as the original, then the power applied to it by the guitar amplifier will be the same. The maximum power sent to your speaker will be limited by the power output capability of the guitar amplifier, NOT the power handling capability of whatever 8 ohm speaker you connect to it. However, a speaker rated for a maximum power of 20-30 watts RMS may not be as efficient in converting electrical power to audible sound. Try to match a replacement speaker to the maximum power capability of the original speaker, about 3 - 4 watts.
     
  4. N_Hound

    N_Hound

    2
    0
    Jun 5, 2017
    I know it can use a wall power supply, but i'd like to use a 9 volt battery so it can be mobile. So, if I use the speaker with a 20 watt RMS, it might not be as loud. If I use a speaker with a 4 ohm impedance, how would that affect the sound/volume?
    Thanks for all of the help!
     
  5. hevans1944

    hevans1944 Hop - AC8NS

    4,615
    2,154
    Jun 21, 2012
    If you want to "be mobile" consider using a 12 V sealed lead-acid battery. These are popular for use in emergency exit lights. It should run for at least an hour before requiring a re-charge, depending on battery size. Of course you will need a lead-acid battery charger, so I don't know how that affects mobility. You could also consider wiring six or eight D-size alkaline cells in series, but that gets pretty expensive.

    The amplifier is designed to drive the 8 ohm speaker shown in your image. It may not provide full output power when driving a lower impedance, such a 4 ohm speaker, but it probably won't hurt it either. Battery life is going to be very poor if you consistently drive this guitar amplifier to its full rated output. Consider switching to an acoustic guitar and ditching the amplifier. This will force your audience to be quieter and to pay close attention to your playing.
     
  6. davenn

    davenn Moderator

    13,866
    1,958
    Sep 5, 2009
    s
    the small 9V batteries are only for very small loads. you would be lucky to get 5 minutes out of it
    they just don't have the current capacity

    hevan1944 said a 12V battery :) just to expand on that......
    get yourself a 7.2Ah 12V sealed lead acid battery and use a buck converter to drop the 12V to 9V
    with the minimum of loss
    there's a zillion DC-DC buck converters on ebay for a few $$ each
     
  7. hevans1944

    hevans1944 Hop - AC8NS

    4,615
    2,154
    Jun 21, 2012
    A 12 V SLA will work "as is" since the guitar amp has a supply voltage range of 9 V to 12 V according to OP's image.
     
    davenn likes this.
  8. davenn

    davenn Moderator

    13,866
    1,958
    Sep 5, 2009
    I didn't look too close at the image haha
    was going by his 9V requirement comment
     
  9. Audioguru

    Audioguru

    3,389
    732
    Sep 24, 2016
    An ordinary single-ended amplifier powered from 12V produces an output of about 1.5W into 8 ohms at fairly low distortion.
    If the volume is turned up too high then the horribly distorted squarewaves produce 3W. The cheap little 2W speaker was doomed. A 3" or 4" cheap little speaker is used in a cheap clock radio. My computer speakers use high quality 3" speakers rated at 5W.

    Powered with a new 9V battery the output of your amplifier is about 0.88W and is 0.3W when the battery voltage has dropped to 6V.
     
Ask a Question
Want to reply to this thread or ask your own question?
You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Electronics Point Logo
Continue to site
Quote of the day

-