100W Ultimate Fidelity Amplifier

[stuartmp]

I'll adjusted to about 23.5 mV DC reading voltage drop in one of the emmiter resistors

re' = Vt / Ic
re' = 26mV / Ic
re' = 26mV / RE
Vt = The thermal voltage 26mV
This makes the re' of the output transistor equal to the resistance of its associated emitter resistor RE.
In this case 26mv / 0.33 ohms = 79mA Ic

So basically 26mV accross RE is optimum no matter the value of RE.

 

[Gurpreet Turna]

I'll adjusted to about 23.5 mV DC reading voltage drop in one of the emmiter resistors

re' = Vt / Ic
re' = 26mV / Ic
re' = 26mV / RE
Vt = The thermal voltage 26mV
This makes the re' of the output transistor equal to the resistance of its associated emitter resistor RE.
In this case 26mv / 0.33 ohms = 79mA Ic

So basically 26mV accross RE is optimum no matter the value of RE.

Hello Guys, its about ax14.1?
Regards

 

[44250]

all - about, yes.

 

[Sunny22g]

Happy Diwali

 

[kandimba]

Here, Apex Bootstrap Amplifier, with prot. detection, On, Signal and Clip. Not tested yet.

 

[apexaudio]

Here, Apex Bootstrap Amplifier, with prot. detection, On, Signal and Clip. Not tested yet.

Nice work,
Regards

 

[PPetrovic]

Hi sir Apex, and everyone. Can you tell me for FX12 amplifier how much is the power and with 2 pair of sk1058/2sj162 which is the maximum rail voltage, and power.
Regards

 

[ivanlukic]

With two pairs max is 65VDC, but the safe voltage is 56VDC (40V-0-40V transformer). Power is around 100W.

 

[bigaudioscotto]

Apex FH9 gerber help?

Hey guys is there anyone who can import the Apex FH9
Gerber file from ver 1.05 and fix it to have thru hole plating
And solder pads for both sides?
Right now the gerber link has no thru hole plating or pads top side.

https://www.diyaudio.com/forums/att...te-fidelity-amplifier-fh9-ver-1-05-gerber-zip

Regards
Scott

 

[macd]

AX20P Question....

Good Day....

Thanks to Sir Apex for the AX20 circuit and a Big thanks to Kandimba for the PCB Layout....

Completed AX20P....see pics attached....

Thanks Sir Apex and Kandimba.....

One question....how much bias current for this circuit???? How do I adjust the bias current??? Here is what I am doing....

I measure with DVM across 0.33R resistor. I use ohms law...V=IR...6.6mV=20mA x 0.33....Is this correct????

Regards,
macd.....

Good Day Sir Apex and Kandimba....

I have completed my second channel of my AX20P amp. Second channel is working, adjust bias current to 20mA. Sound is great...

When I measure the offset voltage on output, the first one is 15mV and I get a 0mV reading on my second amp. Is this normal/OK ????

Second Question.... When I play my first amp at full power, clip LED goes ON but amp is still playing sound. When I play my second channel at full power, when the clip LED comes on, the relay disconnects the second speaker and only one channel is playing. What can be the problem? At first I thought it is the thermal cut out, but the amp is still cold when this happens ....

I am not sure if the one channel is faulty, maybe overload protection is not working or if the second channel's overload protection is to sensitive???

Thanks in advance...

Regards,
macd

 

[kandimba]

Good Day Sir Apex and Kandimba....

I have completed my second channel of my AX20P amp. Second channel is working, adjust bias current to 20mA. Sound is great...

When I measure the offset voltage on output, the first one is 15mV and I get a 0mV reading on my second amp. Is this normal/OK ????

Second Question.... When I play my first amp at full power, clip LED goes ON but amp is still playing sound. When I play my second channel at full power, when the clip LED comes on, the relay disconnects the second speaker and only one channel is playing. What can be the problem? At first I thought it is the thermal cut out, but the amp is still cold when this happens ....

I am not sure if the one channel is faulty, maybe overload protection is not working or if the second channel's overload protection is to sensitive???

Thanks in advance...

Regards,
macd

I MACD, about DC offset is OK. The first channel is ok, because when clip led goes on, amp should stay playing. You should see what you have done in second one, and compare with first one. Maybe you have put components in wrong places

 

[macd]

RE AX20P Question...

I MACD, about DC offset is OK. The first channel is ok, because when clip led goes on, amp should stay playing. You should see what you have done in second one, and compare with first one. Maybe you have put components in wrong places

Hello Kandimba...

I will double check everything again tonight and give feedback...

Regards..
MACD

 

[Bangla H]

FH9 Pads

Apex FH9 gerber help?
Hey guys is there anyone who can import the Apex FH9
Gerber file from ver 1.05 and fix it to have thru hole plating
And solder pads for both sides?
Right now the gerber link has no thru hole plating or pads top side.

Hi Scott


may this new routed Board will work for your need.
It is mostly followed by Sonal traces, but added above traces.
Have fun.
I place my orders to KiKiPCB, like vargasmongo.


Regards.

 

[bigaudioscotto]

Thank you for the Gerber.

Regards
Scott

Hi Scott


may this new routed Board will work for your need.
It is mostly followed by Sonal traces, but added above traces.
Have fun.
I place my orders to KiKiPCB, like vargasmongo.


Regards.

 

[macd]

AX14P and AX20P problem....

Good Day Sir Apex,

I've build 2 AX14P amp modules. When both channels is playing, the one channel goes into protect while the other channel is still playing. I have the same problem with my 2 AX20P amp modules, one channel is playing while the other channel the relay is clicking open and close the whole time.

I do suspect that I have the same problem on both AX14P and AX20P amp modules. What resistors do I need to change or double check??? How can I change the sensitivity of the DC protection circuit???

Do you have a schematic with voltages that I can check???

Thanks in advance...

Regards,
macd

 

[apexaudio]

Good Day Sir Apex,

I've build 2 AX14P amp modules. When both channels is playing, the one channel goes into protect while the other channel is still playing. I have the same problem with my 2 AX20P amp modules, one channel is playing while the other channel the relay is clicking open and close the whole time.

I do suspect that I have the same problem on both AX14P and AX20P amp modules. What resistors do I need to change or double check??? How can I change the sensitivity of the DC protection circuit???

Do you have a schematic with voltages that I can check???

Thanks in advance...

Regards,
macd

AX14P use 680R/2W resistor in series with 24V relay coil to get voltage drop from 50V DC rail... change 680R/2W resistor value to get 24V on relay coil.

 

[kandimba]

Good Day Sir Apex,

I've build 2 AX14P amp modules. When both channels is playing, the one channel goes into protect while the other channel is still playing. I have the same problem with my 2 AX20P amp modules, one channel is playing while the other channel the relay is clicking open and close the whole time.

I do suspect that I have the same problem on both AX14P and AX20P amp modules. What resistors do I need to change or double check??? How can I change the sensitivity of the DC protection circuit???

Do you have a schematic with voltages that I can check???

Thanks in advance...

Regards,
macd

I MACD you should have some problems with wrong components or with pcb shunt some where. You should compare mesures between good ones and bad ones. AX14P are diferente from AX20 with detected protection, AX20 protection has NTC and IC555, as you can see in the attachments. All of theme with me, are working perfectly.

 

[kandimba]

I MACD you should have some problems with wrong components or with pcb shunt some where. You should compare mesures between good ones and bad ones. AX14P are diferente from AX20 with detected protection, AX20 protection has NTC and IC555, as you can see in the attachments. All of theme with me, are working perfectly.

Sorry attachments no.

 

[macd]

AX14P working....

I MACD you should have some problems with wrong components or with pcb shunt some where. You should compare mesures between good ones and bad ones. AX14P are diferente from AX20 with detected protection, AX20 protection has NTC and IC555, as you can see in the attachments. All of theme with me, are working perfectly.

Good Day Sir Apex and Kandimba....

I am happy to report that my second channel is working now as advertise. Sound is clear and crisp....I have stereo setup now waiting to be installed in case. I just have to check my PSU today, then I am ready.

Thanks Sir Apex for circuit and Thanks Kandimba for PCB.

I made a new board as the one I was using, under microscope, tracks had holes and board was just bad made. Both channels work now as advertise. see pics....

I set my bias current at 30mA. Is this fine?

Thanks a lot for your help.

Regards,
macd

 

[vargasmongo3435]

bias go with 26mV DC reading across a emiter resistor that is the optimus performance there Mr. Stuart's tips