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Comment by Murdoc_420 on June 17, 2016 at 9:38am

 Can't really get any closer images, phone pics.

 I think it has to be the amp, everything else has been tested.

 Well, not the speaker, but the clock radio speaker was working before I pulled it.

 The LED shows that I'm getting power. So battery works. My cables and active and passive bass both work.

 I bought a male>male 1/8 to try and test the ipod with, but I think I'm going to return it rather than waste that money. The amp was only $3 (I just had to wait a month for it :(  )

Comment by Paul Craig on June 17, 2016 at 8:56am

Some close up pics might help.

Comment by Paul Craig on June 17, 2016 at 8:40am

You have a schematic of that amp Murdoc?

Comment by Murdoc_420 on June 17, 2016 at 8:36am

Was thinking I had the red going to the wrong connection on the 1/4 jack (there are two+ the ground). Swapped, burnt my finger and nothing.

 So I plugged my cable into a 1/4 to 1/8 into the amp (forgot I had that adapter- it was part of the original plan.) and nothing.

 Could be either the speaker (I got it cheap -$10 with shipping- seems new) or the amp I guess.

 Guess my best choice now is trying to find another speaker to test. If not then an amp.

------

 Found a cheap clock radio with working speaker at Salvation army. Plugged that speaker in and it seems like the LED is brighter. But still no sound :(

 I don't like the 1/8 jack thing but I didn't want to build an amp from scratch.

Comment by Murdoc_420 on June 16, 2016 at 5:17pm

 Thanks Wayfinder.

 The wires from the speaker are in the jacks (+/-) correctly. and I tried both sides (it has speaker on other side where the red arrow is too). I'll try and reverse them anyway.

 The 1/8 jack is a headphone so I believe stereo. I think they were from a phone I had a long time ago but never used them.

 I may have soldered them wrong (just went with red being the live and green being the ground).

 The jack mount on the amp is soldered on. I was a little hesitant on getting that amp because of that. Going to try everything else before I try and remove it.

 I did test the volume in both extremes, etc ;)

--------

 I'll pick up a male/male 1/8 tomorrow and check it with my ipod.

Comment by Murdoc_420 on June 16, 2016 at 1:06pm

 I had all my amp parts ordered in a post somewhere, can't find it now...

 So here is my amp all soldered up, broke the control panel yesterday so need to make a new one.

 One problem, no sound :(

 The toggle works and the led lights up when I connect the battery and flip the switch.

 The problem MAY be ... I used the jack from an old pair of headphones. Wires are real skinny. One has a red/one has green 'insulator' wire with it.

 I soldered the red insulated side to the positive on the 1/4 jack.

 Active/passive basses connected = no sound from speaker. Tried both sides of speaker connections from the amp.

 Any ideas what's wrong?

 My next step is to buy a 1/8-1/8 male jack and try my ipod through it.

Comment by Scott aka Farmer Ted on April 7, 2016 at 2:05am

Way,

I spent some time this morning researching this issue. As I understand it, using the 6 ohm speaker with the 8 ohm amp module will be okay at any volume. But the overall effect would be less tone and volume. This is because of the mismatched impedance. 

Think of it this way: the amp is a garden hose, and you want to send the water flow (amplified guitar signal) across the yard (through the amp). Turn on the valve, and the water (voltage/pressure) flows through the hose. If there is no nozzle (speaker) to restrict the water flow (voltage/pressure), the water streams out unobstructed (no ohms). Add a nozzle (speaker impedance) and open it partly...the water comes out under pressure (voltage) and emits further than without the nozzle...but not quite across the yard. Adjust the nozzle to the optimum setting, the water shoots out to the desired point across the yard.

Effectively, using a 6 ohm speaker on the 8 ohm module will make the output section of the amp draw more current, resulting in more heat dissipation in the components, especially if there is a transistor.

I was unable to find any info about adding components (resistors, etc) to the speaker leads to effectively change/match the impedance.

However, you will likely have no trouble simply using the speaker as-is.

Comment by Scott aka Farmer Ted on April 6, 2016 at 12:58pm

Whoa, my head just exploded.

Comment by Scott aka Farmer Ted on April 6, 2016 at 12:57pm

Wayfinder,

One might assume that simply adding a 2 ohm resistor between the amplifier and the 6 ohm speaker would make a total of 8 ohms. But the speaker is valued in "impedance". And while impedance and resistance are calculated in similar fashion, impedance is relative to alternating current, resistance is relative to direct current.

The guitar signal input to the amp and the output to the speaker is alternating current. The power inside the amplifier is direct current. Both AC and DC power can co-exist within the same wire/circuit line. But DC cannot pass through a capacitor.

Comment by Mickey Ray Parker on March 29, 2016 at 4:33am

Right on. Thanks!

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