Hey!
Got my A07 last week ...connected it to a Yamaha MG10 mixer (using xlr to rca adapters) to the amp then to some Neumi BS5 speakers ... seemed to work great.
My wife is using it as a practice unit for a chorus she directs.
Now after a week, I notice when my level meters on the mixer go to 0 (when talking into a microphone), the amplifier cuts out (meters are -20 to +20)!
It will sometimes come back ... sometimes I need to power it down then turn it back on.
I have the amazon version that came with 32 v 5A power supply.
I have the volume about 3/4 up.
Do I have a bad amp?
I am not an electronics guy (just know enough to be dangerous) ... my assumption was that if I played the amp at high volumes for long periods, it could over heat and shut down but I didn't think overloading the inputs (I don't think I am ... the meters say I am not) would cause it to shut down.
Seems to be getting worse.
Any idea what is happening and why?
Mike
Got my A07 last week ...connected it to a Yamaha MG10 mixer (using xlr to rca adapters) to the amp then to some Neumi BS5 speakers ... seemed to work great.
My wife is using it as a practice unit for a chorus she directs.
Now after a week, I notice when my level meters on the mixer go to 0 (when talking into a microphone), the amplifier cuts out (meters are -20 to +20)!
It will sometimes come back ... sometimes I need to power it down then turn it back on.
I have the amazon version that came with 32 v 5A power supply.
I have the volume about 3/4 up.
Do I have a bad amp?
I am not an electronics guy (just know enough to be dangerous) ... my assumption was that if I played the amp at high volumes for long periods, it could over heat and shut down but I didn't think overloading the inputs (I don't think I am ... the meters say I am not) would cause it to shut down.
Seems to be getting worse.
Any idea what is happening and why?
Mike
If possible activate the high pass filter on the microphone input (subsonic filter). I suspect too much low frequency power being generated by the mic input. We must not forget that it remains a living room amplifier, not suitable in my opinion for the sound system.
I agree ... this is just a stop gap measure till I can get a few more $'s for a "real" amp.
I was playing again this morning and noticed that when I use the compensation control (I had never touched it before) I can almost eliminate it cutting out.
Just so I understand .... am I overloading the input and it is shutting down (it has some kind of protection circuitry)?
Thanks ... Mike
PS ... I am a machinist by trade and just dabble in electronics ... I only know enough to be dangerous. The chorus my wife directs doesn't have any real money so as I said, this is a bit of a stop gap measure ... I can reused the mixer and maybe use the amp later just as a monitor output. Right now they are only using it for practice sessions.
Vermont's Freedom and Unity Chorus
A microphone will easily reproduce low frequencies at the subsonic level which saturates the amplifier. Just touching the microphone with these fingers causes these bass peaks, hence the interest of activating the subsonic filter on the microphone input. The A07 can push around 58w per channel based on Amir's measurements. Changing the PSU to a higher voltage will not provide more power and this is due to poor ventilation and a somewhat small heatsink. An IRS2092 based amplifier would have been a much better choice than the 07, I understand the budget issue.
Yes, has to be infrasonics or some other problem. The +4dBu level of the mixer and 21.5dB gain of the amp should put the output power well below 58W into his 6Ω speakers.
Had the same symptoms on one of my my A04´s. Amp was quiet and red LED (front) was blinking at exactly 3/4 volume pot.
Funny thing, this even happened without load and I think also input signal.
Got good service from Aiyima and in the end they changed the amp for a new one.
The amps are quite good for the money. PCB layout most probably isn´t 100% and the thermal solution rather simple
so it can´t provide 100W continuously but they can put out pretty big peaks without breaking a sweat at low THD.
Might be true but there will be a precise reason for this and I´m pretty sure its more down to the applicant rather than the chip designer.
The various protection mechanisms are clearly laid out in the datasheet.
There are enough TPA-designs out there that work flawlessly. (XRK´s etc.)
Good luck looking to the future whilst I enjoy my TPA3251´s ;-)
WOW .... thanks so very much for all the information!!!!!!!!
Since I am not a sound or electrical guy, this is a lot of "learning on the fly".
When I read the reviews of the amp, one thing I noted was the heat generated by it. With my little knowledge of electronics, I know heat = failure
To this end, I bought a small USB powered fan. about 4" square ... very quite.
I am planning to pull off the cover and drill a bunch of holes in it, then mount the fan on top.
I am not trying to push out 1000W but I do think keeping it cool can not hurt no matter what.
This is just a stop gap measure .... if I can come up with a few $'s then maybe by next season I can come up with a "real" amp and speakers for the group.
I took a look at the IRS2092 ... very nice ... but as you said, just outside the budget right now.
Thanks again so very much for all the info !!!!!!!!!!!!!
Mike
Since I am not a sound or electrical guy, this is a lot of "learning on the fly".
When I read the reviews of the amp, one thing I noted was the heat generated by it. With my little knowledge of electronics, I know heat = failure
To this end, I bought a small USB powered fan. about 4" square ... very quite.
I am planning to pull off the cover and drill a bunch of holes in it, then mount the fan on top.
I am not trying to push out 1000W but I do think keeping it cool can not hurt no matter what.
This is just a stop gap measure .... if I can come up with a few $'s then maybe by next season I can come up with a "real" amp and speakers for the group.
I took a look at the IRS2092 ... very nice ... but as you said, just outside the budget right now.
Thanks again so very much for all the info !!!!!!!!!!!!!
Mike
Just an update ...
With the stock 32 v power supply, I kept having the amplifier shut down when the input reached a certain level. I figured it had to be either a protection on the input or on the output. The meters on the mixer were no where near the red.
I got a 0-48 volt supply (10A ... $35 on Amazon).
I set it to 40 volts ... no more shut down!
I "guess" is the caps (or ??) simply ran out of power and drew it down to a level that shut down the amp for a few seconds till it sensed the voltage was above some minimum.
I may even try a bit lower voltage ... my speakers are only rated at 100W ... right now I just leave the amp about 3/4 volume.
I was still worried about the heat.
I got a small USB powered fan ... bent some 1/4 inch welded wire into a cover and put the fan on that.
Seems to work great!
Also, the mixer was a balanced (XLR) output. I used a Pyle PDC22 in reverse of what most people do (balanced to unbalanced) to match the input / output.
Thanks for all the help ....
Mike
With the stock 32 v power supply, I kept having the amplifier shut down when the input reached a certain level. I figured it had to be either a protection on the input or on the output. The meters on the mixer were no where near the red.
I got a 0-48 volt supply (10A ... $35 on Amazon).
I set it to 40 volts ... no more shut down!
I "guess" is the caps (or ??) simply ran out of power and drew it down to a level that shut down the amp for a few seconds till it sensed the voltage was above some minimum.
I may even try a bit lower voltage ... my speakers are only rated at 100W ... right now I just leave the amp about 3/4 volume.
I was still worried about the heat.
I got a small USB powered fan ... bent some 1/4 inch welded wire into a cover and put the fan on that.
Seems to work great!
Also, the mixer was a balanced (XLR) output. I used a Pyle PDC22 in reverse of what most people do (balanced to unbalanced) to match the input / output.
Thanks for all the help ....
Mike
You are correct, but it is worth keeping in mind that MI/PA speakers are much more efficient than Hi-fi speakers. Generally in the 95-100dB efficiency range. However, I would agree that a High Pass Filter is vital on Vocals. Most mixers have a low cut switch on each channel for this.