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Author Topic: Champion Amp Kit help needed.  (Read 2371 times)

mickeyj4j

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Champion Amp Kit help needed.
« on: October 14, 2020, 10:35:05 PM »
Ok so after at least a year or more, I have taken out my Champion Amp Kit. It has been sitting in my draw for over a year now. While I was still a bit confused, my brain said look up on YouTube. This its what I found
YouTube video
So finally I am going to try attempt to build it.
I worked out how to test all the resisters etc to check the values etc. Soldered them in place and its been so much fun.

I have tried the following speakers
3"/76mm 8ohm 1W
100mm 8ohm 3W
6"/150mm un-labled speaker from my Line 6 Micro Spider amp.
Sony SS-H991 8ohm Stereo speaker
10" Speaker From powered Car Subwoofer.

Plugging in my acoustic guitar and even electric Strat style. Apart from the Subwoofer and Sony stereo speakers, all the other ones tend to distort from too much volume. Powered from 12v or 9v batteries. This amp is supposed to be rated to run with small speakers.
I was surprised that the speaker from the Line 6 Amp seemed to work better when in its original amp cabinet when taken out it distorted a bit too much.
So I am looking for the best option. I want to make a range of smaller amps in some cool looking tins I have. So need a smaller speaker that wont distort similar to a mini 9v battery amp like the Marshall MS4.
I also want to make a few bigger amps with Bigger speakers to put in old suitcases for that cool retro look.

What I am thinking is that I may need to put something to limit the volume output with smaller speakers. Maybe just adding it to the input jack or speaker output to limit the signal so not to max the speaker. Any ideas on speakers that may work well for these needs. thanks.

Jazz P Bass

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Re: Champion Amp Kit help needed.
« Reply #1 on: October 15, 2020, 11:58:21 AM »
You need to figure out where the distortion is coming from.
From the datasheet the power amplifier has an input sensitivity of 125 mv at a rail voltage of 9-12Vdc.
That is o/k for a typical guitar signal.
The preamp is a different animal.
Input sensitivity is rated at 5 mv @ 9-12Vdc power supply.
A guitar signal will overload that input.
I would go with the datasheet suggestion of adding a 10K control to limit the input signal.

"Features:
• Operating voltage range: 4 - 13.5VDC
• Music power: 3W @ 9 - 12V
• Frequency Response: -2.5dB @ 20Hz, -0.2dB @ 20kHz
• Gain: 34dB for Amplifier, up to 58dB with pre-amplifier
• Input Sensitivity for Amplifier only: 52mV RMS @ 5V, 125mV RMS @ 9 - 12V
• Input Sensitivity for Amplifier & Pre-amplifier: 2mV RMS @ 5V, 5mV RMS @ 9 - 12V
• Quiescent current: 2mA (Pre-amplifier) + 30-60mA (Amplifier)
• Standby current: 2mA (Pre-amplifier) + 1-10uA (Amplifier)

Note: Optional 10kohm potentiometer for external volume control use RP-7610"

mickeyj4j

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Re: Champion Amp Kit help needed.
« Reply #2 on: October 18, 2020, 05:25:37 AM »
You need to figure out where the distortion is coming from.
From the datasheet the power amplifier has an input sensitivity of 125 mv at a rail voltage of 9-12Vdc.
That is o/k for a typical guitar signal.
Great
The preamp is a different animal.
Input sensitivity is rated at 5 mv @ 9-12Vdc power supply.
A guitar signal will overload that input.
I would go with the datasheet suggestion of adding a 10K control to limit the input signal.
In the manual it says the  full amp+preamp is designed for guitar

"Features:
• Operating voltage range: 4 - 13.5VDC
• Music power: 3W @ 9 - 12V
• Frequency Response: -2.5dB @ 20Hz, -0.2dB @ 20kHz
• Gain: 34dB for Amplifier, up to 58dB with pre-amplifier
• Input Sensitivity for Amplifier only: 52mV RMS @ 5V, 125mV RMS @ 9 - 12V
• Input Sensitivity for Amplifier & Pre-amplifier: 2mV RMS @ 5V, 5mV RMS @ 9 - 12V
• Quiescent current: 2mA (Pre-amplifier) + 30-60mA (Amplifier)
• Standby current: 2mA (Pre-amplifier) + 1-10uA (Amplifier)
Note: Optional 10kohm potentiometer for external volume control use RP-7610"
Yes but that does not say if it is a A10k or B10k pot.
See attached full kit instructions

willpirkle

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Re: Champion Amp Kit help needed.
« Reply #3 on: October 18, 2020, 08:17:16 AM »
Figure 6 shows the external volume pot as 10k-log for line-level sources.

mickeyj4j

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Re: Champion Amp Kit help needed.
« Reply #4 on: October 18, 2020, 11:33:58 AM »
Figure 6 shows the external volume pot as 10k-log for line-level sources.
Volume pots are sold labled as A10k, B10k, C10k.

phatt

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Re: Champion Amp Kit help needed.
« Reply #5 on: October 19, 2020, 07:10:00 AM »
I assume you are asking which one?
 A is log/audio pot.     B is linear.   IIRC, C is reverse log.
Log and Audio pots are very close to the same curve and are mostly interchangeable.
Note;
Be aware if you use hi gain PU's  this little amp will distort real fast :-X Such little amps just don't have enough headroom so they distort very early on the dial.
Phil.

mickeyj4j

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Re: Champion Amp Kit help needed.
« Reply #6 on: October 19, 2020, 07:38:30 AM »
I assume you are asking which one?
 A is log/audio pot.     B is linear.   IIRC, C is reverse log.
Log and Audio pots are very close to the same curve and are mostly interchangeable.
So its an A10k pot cool.

Quote
Note;
Be aware if you use hi gain PU's  this little amp will distort real fast :-X Such little amps just don't have enough headroom so they distort very early on the dial.
Phil.
Well this amp does state it is built for guitars.

phatt

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Re: Champion Amp Kit help needed.
« Reply #7 on: October 19, 2020, 09:56:24 AM »
A 50cc Moped and a Rolls Royce are both built for travel one will do that better than the other.
Your $30 kit is a far cry from a real Guitar amp circuit. 8|

Regard this;
"I was surprised that the speaker from the Line 6 Amp seemed to work better when in its original amp cabinet when taken out it distorted a bit too much."

Yes often the case, speakers need to be in a box or at least mounted on a baffle.

Don't use woofers for guitar they are a completely different design.
If you pay close attention to the design you will note that woofers are long travel cones and the cone moves a long way in/out, they are high compliance drivers and need to be in a well designed box. they are for hifi.
Easy to pick them as they often have a big rubber surround on the edge of cone.
While a musical instrument speaker is low compliance, they don't require a strict sealed box. You can use then open back or closed back. easy to tell as the cone has little travel and the cone edge usually has a tight ripple spider.
hope that helps,, Phil.

mickeyj4j

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Re: Champion Amp Kit help needed.
« Reply #8 on: October 19, 2020, 03:33:47 PM »
A 50cc Moped and a Rolls Royce are both built for travel one will do that better than the other.
Your $30 kit is a far cry from a real Guitar amp circuit. 8|
I trust this is a guitar amp designed for instrument and microphone, as it says in manual. Even one of the mini 9v battery amps, like Marshall Ms2, Danelectro Honeytone, Pignose etc. Are not going to stand up to being in a band situation, they tend to distort easily at higher volumes and have limitations. They are still guitar amps like this Champion amp kit.
Quote
Regard this;
"I was surprised that the speaker from the Line 6 Amp seemed to work better when in its original amp cabinet when taken out it distorted a bit too much."

Yes often the case, speakers need to be in a box or at least mounted on a baffle.
I am starting to understand this
Quote
Don't use woofers for guitar they are a completely different design.
If you pay close attention to the design you will note that woofers are long travel cones and the cone moves a long way in/out, they are high compliance drivers and need to be in a well designed box. they are for hifi.
Easy to pick them as they often have a big rubber surround on the edge of cone.
While a musical instrument speaker is low compliance, they don't require a strict sealed box. You can use then open back or closed back. easy to tell as the cone has little travel and the cone edge usually has a tight ripple spider.
Yes i do understand the difference and reasons for different speaker types. I also go on sound, from testing and the amp I built from a subwoofer has a setting for full range (I assume this bypasses the built in subwoofer preamp inside). It gives the speaker judt that more full mid range but lacks higher frequencies so by adding a tweater or stereo speaker off the main speaker it gives it great high end frequencies. I have used this setup as
1. a mini PA with a small 4 channel mixer.
2. As an amp for Acoustic and electric guitar, ukulele with a guitar preamp,
3. As a amp for bass guitar, using a bass preamp 
Quote

hope that helps,, Phil.
Yes thanks I understand your points totally. Great information much respect thanks.