Hi,
Are there anybody in here that has expirence in doing service on Advance Acoustic hifi products, i have a pair of Advance Acoustic X-A220 monoblocks, and the VU meter responds are uneven on the two amps, with the same mono signal input
Anybody in here that has expirence in these products?
Are there anybody in here that has expirence in doing service on Advance Acoustic hifi products, i have a pair of Advance Acoustic X-A220 monoblocks, and the VU meter responds are uneven on the two amps, with the same mono signal input
Anybody in here that has expirence in these products?
Meter circuit
Hi MT 🙂
Check this meter circuit. I know it´s from a MAA-406, but I can´t imagine, that they would have changed this much.
The main thing is, that there´s a trimpot on the meter circuit. This is used to adjust the meter sensitivity/output for the incoming signal. You have to rig up a test circuit, if you want it to be accurate. If it´s only a question of "the looks", just adjust one to match the other.
If it´s too troublesome, take some photo´s and PM me on H4A 😎
Hi MT 🙂
Check this meter circuit. I know it´s from a MAA-406, but I can´t imagine, that they would have changed this much.
The main thing is, that there´s a trimpot on the meter circuit. This is used to adjust the meter sensitivity/output for the incoming signal. You have to rig up a test circuit, if you want it to be accurate. If it´s only a question of "the looks", just adjust one to match the other.
If it´s too troublesome, take some photo´s and PM me on H4A 😎
Woww, thanks Boydk, well, i am in contact with the Danish rep and they have promished to help, but it just take too long time for a impaitient guy like me....🙂)
I would prefer not to open the amps myself, not to violate the warrenty, but it may be necessary.....in the meantime, thank you very much for the info.
I already have a description of the problem, and did some smale videos that i send to the danish rep, i think i will give them a little more room to solve the problem....
br
Martin
I would prefer not to open the amps myself, not to violate the warrenty, but it may be necessary.....in the meantime, thank you very much for the info.
I already have a description of the problem, and did some smale videos that i send to the danish rep, i think i will give them a little more room to solve the problem....
br
Martin
A-x220 monoblocks meter adjustment
Hi there
I was hoping you could explain in more detail , of where exactly the trimpot is situated,
Many thanks joppie
Hi there
I was hoping you could explain in more detail , of where exactly the trimpot is situated,
Many thanks joppie
Hi Martin,
Well, it is only the meter indication for starters, and in music the two channels are almost never equal. I agree the meters should read the same, but it just isn't worth voiding warranty to chase such a trivial thing like this.
Meters are set using a constant, low distortion tone. Normally 1 KHz and the set point is typically "0 Vu", but that could differ between manufacturers. Understand that these are not test instruments and they may not be linear. While correctly adjusted, at low levels the reading may differ. You can't really do anything about that, and the purpose of power meters is to give you some idea when you are approaching maximum power so you can avoid clipping. That and they look cool bouncing around.
I'm an old audio technician with 45+ years in the business and did administer warranty for 16 years of that time. Please, do not go into your amplifier which may (probably) void your warranty, just in case you do experience a problem later on. Besides, you stand zero chance of setting them correctly yourself. This just isn't worth it.
If the distributor will accept the amplifiers for warranty service to correct the problem - let them. If there is a charge and it really bugs you, pay it so at least it is done properly and you don't void your warranty.
Now, if you are out of warranty, have them do it anyway. From what I see of service out in the wild, you could have your amplifier destroyed by a hack. Think I'm kidding? I recently got a McIntosh MC2505 completed and back to the customer. The original fault was one meter not working properly. The hack rewired the power supplies (incorrectly), replaced the outputs, stripped every transistor socket and replaced the output transformer! I kid you not! He also mis-wired the meter switch and circuit.
-Chris
Well, it is only the meter indication for starters, and in music the two channels are almost never equal. I agree the meters should read the same, but it just isn't worth voiding warranty to chase such a trivial thing like this.
Meters are set using a constant, low distortion tone. Normally 1 KHz and the set point is typically "0 Vu", but that could differ between manufacturers. Understand that these are not test instruments and they may not be linear. While correctly adjusted, at low levels the reading may differ. You can't really do anything about that, and the purpose of power meters is to give you some idea when you are approaching maximum power so you can avoid clipping. That and they look cool bouncing around.
I'm an old audio technician with 45+ years in the business and did administer warranty for 16 years of that time. Please, do not go into your amplifier which may (probably) void your warranty, just in case you do experience a problem later on. Besides, you stand zero chance of setting them correctly yourself. This just isn't worth it.
If the distributor will accept the amplifiers for warranty service to correct the problem - let them. If there is a charge and it really bugs you, pay it so at least it is done properly and you don't void your warranty.
Now, if you are out of warranty, have them do it anyway. From what I see of service out in the wild, you could have your amplifier destroyed by a hack. Think I'm kidding? I recently got a McIntosh MC2505 completed and back to the customer. The original fault was one meter not working properly. The hack rewired the power supplies (incorrectly), replaced the outputs, stripped every transistor socket and replaced the output transformer! I kid you not! He also mis-wired the meter switch and circuit.
-Chris
Morning chris
My amps are well out of warranty is out of date
And there is nothing wrong with my meters really,
I would just like to make them more sensitive at low
Volume,
Cheers Pete
My amps are well out of warranty is out of date
And there is nothing wrong with my meters really,
I would just like to make them more sensitive at low
Volume,
Cheers Pete
I did some repairs to a pair of these (without schematics). If I remember correctly, the circuit for the meter is in the front 'box'. If you remove the front plexi-glass with the meter, it should be on the right side. I think I remember seeing a potentiometer there.. Try it if you feel like experimenting..
Morning
I removed the glass front of the amp , but no joy there are not any pedometers in there ~ the only ones I can see is at the back of the amp , there are 2 but impossible to know if they control the meter
I removed the glass front of the amp , but no joy there are not any pedometers in there ~ the only ones I can see is at the back of the amp , there are 2 but impossible to know if they control the meter
Hi Boydk,
old post but could not find trimpot circuit on maa 406. Can you help? Thanks
Attachments
Well, to increase sensitivity you are really just changing the gain of the meter circuit or attenuation of the sampling point. Simple in concept, but you need then to protect the parts from excessive voltage when in high sensitivity mode, also not hard to do. You'll probably want to use a switch unless you go for more complexity to make it auto-ranging. The othe roption is to use a TA7318P type log meter amp IC where it will cover the entire range. Look at something like a Luxman M-02 for an idea of that circuit.
-Chris
-Chris
If tthat is the original schematic, you´re right. No trimpots.
Sorry, this is so long ago now, that I can´t find the images. Will post them if I find them.
Seems that the only trimpots related to the meters are these (photo is from MAA-405):
Attachments
Brute force approach, but it works I guess. We used to see that in meters that sampled the amplifier output without any active electronics.
If you would like to reduce or increase sensitivity by factor of 10 then what resistor should be modified - if the intetntion would be to do it in the regulating circuitry? Just put a voltage divider on the input?
Yes, you would have to attenuate the input, or change the circuit as what exists would clip at higher input levels to reduce sensitivity (but it is set to lower sensitivity now). To increase sensitivity you would look at R55 and R56 I think (then it will clip at higher levels probably). U03A is just a buffer and U05A seems to provide modified feedback. I didn't get right into the circuit deeply. But if you want to have a set and forget display, a log meter amp like the TA7318P might be the way to go. Otherwise you are dealing with a switch, or automatic ranging solution for what is really juts an output activity monitor really. Of course the meter face would have to indicate a log reading, so there is pain as well.
What I see happening is to modify the R55 and R56 values, then a switched attenuator on the input. I say this because I don't know if the circuit would be unstable with wires running from the existing input attenuator or not. You just never know even though it should be stable if you want to try that first.
-Chris
What I see happening is to modify the R55 and R56 values, then a switched attenuator on the input. I say this because I don't know if the circuit would be unstable with wires running from the existing input attenuator or not. You just never know even though it should be stable if you want to try that first.
-Chris
I do aythorised service for advance acoustics
how may i help ?
Chris its been very long time since we talked glad to see you my very best !!!
how may i help ?
Chris its been very long time since we talked glad to see you my very best !!!
Yes Chris its the wrong place to do anything ....Only the sun and the beach remains fine
still shop is doing grate we managed arround 3500 audio machines the latest year so yes all is fine for me
its a huge number for such a small shop and such a small country
so im fine no matter what
I hope you are doing well
any time you feel like drop me a mail very nice to hear from you !!!!