The Breeze Audio is completely different and much simplified. It is a clone of the HA5000 in name only.
The ZeroZone kit and fully assembly box are much more expensive, the later is close to $400. Both ZeroZone and the Shanling have similar layout and are more faithful the the Audio Technica HA5000.
Aliexpress.com : Buy GZLOZONE Finished Clone AT HA5000 Class A Headphone Amplifier from Reliable class a headphone amplifier suppliers on sep_store
Impression of Zero Zone HA-5000 clone
Hi, Ricotjuh, any update on your Zero Zone kit adventure yet?
Hi, Ricotjuh, any update on your Zero Zone kit adventure yet?
I bought the kit. When I received it, I will share my experience
Just found some extra information:
Hello Keilau,
I have some problems with the components. It starts with the 2SK330GR Fet. It wasn't possible to adjust it with the potentiometer so there was 0,7V on the 620 ohm resistor. I did some measurments on this FET, and what I think there can be 2 things. 1 both FETS are broken. Or 2, I have fake ones. After that I orderd new ones en I received it last week. But I haven't got time to test.
To be continued...
Sorry to hear the mis-adventure. When you are done, please, share how you correct the FET problem, including the source of a good supplier. Best wishes.
I have changed the 2SK330GR for 2SK246GR. Now i can adjust 0.7V on the 620 ohm resistor.
I was able to arrange one channel well on a bias of 200mA. The voltage is then 44mV across the emitter resistor (because I have 0.22 ohm resistors instead of 0.1 ohms).
However, the other channel does not get much higher than about 25mV. I have no idea where the problem is. Resistors are measured. These seem okay. Voltage measured at various points. These also seem to correspond to both channels. So I have to figure this out.
The protection ciruit also does not function yet. The relays do not want income yet. I also have to check this again. But firstly ensure that the bias can be set up properly.
I was able to arrange one channel well on a bias of 200mA. The voltage is then 44mV across the emitter resistor (because I have 0.22 ohm resistors instead of 0.1 ohms).
However, the other channel does not get much higher than about 25mV. I have no idea where the problem is. Resistors are measured. These seem okay. Voltage measured at various points. These also seem to correspond to both channels. So I have to figure this out.
The protection ciruit also does not function yet. The relays do not want income yet. I also have to check this again. But firstly ensure that the bias can be set up properly.
I have just done some measurements. The values of the channel in green are what regulate themselves well. In red, the channel where I do not set the rest current to 44mV. As can be seen, all values are correct up to the end transistors. I then soldered the output transistors and exchanged the channel. Now one channel can be arranged well but the other is not.
So the problem seems to be in the end transistors. But with a component tester, I do not measure deviations on the transistors.
So the problem seems to be in the end transistors. But with a component tester, I do not measure deviations on the transistors.
Here the measurements of the MOSFETS. I see no deviations between the 2 types here. That is strange in itself.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
yes but if the mosfets don't work then it seems likely the tester is inaccurate?
Where did you get the mosfets from? I had a look around the web and they seem unavailable.
Where did you get the mosfets from? I had a look around the web and they seem unavailable.
Yes I am also looking for new types. But that is not easy to come by. On Aliexpress I see there but there are the J554 and the K2955 in one and the same description. While it is actually 2 different components. So I do not know what I get ?!
https://www.aliexpress.com/item/K29...0f48-4d5f-a06d-09065ae0916d&priceBeautifyAB=0
the price alone suggest fake, hard to make out from pic. Its interesting how unavailable these seem to be. Try talking to the people who sold you the kit, and tell them you want no fakes.
the price alone suggest fake, hard to make out from pic. Its interesting how unavailable these seem to be. Try talking to the people who sold you the kit, and tell them you want no fakes.
Yes indeed. For the price I can take a gamble. But here again is the description: "K2955 J554 2SK2955 2SJ554". But now I still do not know which one will be sent. And they are 2 different components. Or am I wrong now ?!
I order a new pair of power transistors.
According to someone who has already built this amplifier, the problem is in the power amp. I quote:
"The problem is in the final power transistors. Your tester does not show this because the measurement is made at too low a voltage, in the amplifier transistors work in a different characteristic area and it looks like it is disturbed there."
I Just wait for a new pair of tranisotors. I will let you know if I have made improvements.
According to someone who has already built this amplifier, the problem is in the power amp. I quote:
"The problem is in the final power transistors. Your tester does not show this because the measurement is made at too low a voltage, in the amplifier transistors work in a different characteristic area and it looks like it is disturbed there."
I Just wait for a new pair of tranisotors. I will let you know if I have made improvements.
Another update from my side. It seems that I have now tuned the amplifier as well. Here is a summary of the points that I have encountered which was not correct in the kit:
- Replace the 0.1ohm resistors at the end of the transistors with 0.22ohm resistors.
- The print shows a value of 220R for the resistance below the 1K setting potentiometer. This is incorrect, this must be 620R.
- The 2SK330GR were fake or broken. I replaced it with 2SK246GR. Note that these must be GR types.
- The thermistor is not included in the set. I ordered these separately. The type must be 470 ohms at 25 degrees Celsius. SMD version.
- The working area of the final transistors varied greatly. As a result, it was not possible to set the bias to 44mV for one channel (because the quiescent current must be 200mA and the resistances are not 0.1ohm but 0.22ohm). Because of this I have adjusted the resistance of the relevant channel from 2K7 to 3K9. This makes it possible to adjust this channel to 44mV.
- Then the protection circuit did not work. This had to do with the fact that the supply voltage was not symetric. I had 14.23V and -14.88V. As a result, the setting values of the window comparator were not around 200mV and the -200mV. By changing the 300ohm to 2x 150ohm and then laying the center branch to GND, offer the solution.
Now I can at least finish with the finishing of the amplifier.
I will keep you informed of the result.
- Replace the 0.1ohm resistors at the end of the transistors with 0.22ohm resistors.
- The print shows a value of 220R for the resistance below the 1K setting potentiometer. This is incorrect, this must be 620R.
- The 2SK330GR were fake or broken. I replaced it with 2SK246GR. Note that these must be GR types.
- The thermistor is not included in the set. I ordered these separately. The type must be 470 ohms at 25 degrees Celsius. SMD version.
- The working area of the final transistors varied greatly. As a result, it was not possible to set the bias to 44mV for one channel (because the quiescent current must be 200mA and the resistances are not 0.1ohm but 0.22ohm). Because of this I have adjusted the resistance of the relevant channel from 2K7 to 3K9. This makes it possible to adjust this channel to 44mV.
- Then the protection circuit did not work. This had to do with the fact that the supply voltage was not symetric. I had 14.23V and -14.88V. As a result, the setting values of the window comparator were not around 200mV and the -200mV. By changing the 300ohm to 2x 150ohm and then laying the center branch to GND, offer the solution.
Now I can at least finish with the finishing of the amplifier.
I will keep you informed of the result.
I have this amplifier pending completion a few years ago.
Precisely that is the problem I found when I mounted it 😕😕. I will follow your instructions these days.
Thanks