Hi Paroxd4! 🙂
Simple:
1. Below your new post scroll down to "Manage attachments" button and click on it.
2. New window opens where you can chose the file by clicking on one of buttons on the form.
3. Select more files if you need
4. After you have finished click on te button "Upload..." on he lower right corner of the form.
5. Return to the original window with your post.
5. Click "Preview Post"
That's it.
With respect to all participants, but the Russians have gone far in cloning this amplifier. If interested, there is a Canadian-Russian joint project. For beginners, I have a lot of information and in the photos, I did not want to offend anyone.
Здравствуй, дорогой друг
Also, it would be great if you join this discussion more activerly because I know you had a lot of usefull information we obviously need here.
Здравствуй, дорогой друг.🙂
No you haven't offended anyone here - you are so nice and kind. Perhaps I owe you an explanation: when I have seen more than the double price of that kit on AliExpress.ru I said to myself: "Look, this is a disgrace. Chinese are ripping the Russians off. I must warn Paroxod4 about this." Everything I have said was in good faith.
Also, it would be great if you join this discussion more activerly because I know you had a lot of usefull information we obviously need here.
Здравствуй, дорогой друг.🙂
Thank you very much for this information. I will apply this idea on my recent build which seems to be rather successful.
Большое спасибо. (Rus: Thank you very much.)
Could you please where I can join your Russian-Canadian group. I would like very much to participate. 🙂😎
Last edited:
This is a Canadian-Russian project, made by one good man from Canada, the Russian projected the board, it turned out international Dartzeel
This board looks really great. I would like very much to purchase that board, if it is for sale. 😱
Thank you verymuch for all your recommandation 🙂’ paraxod4 I will put à copper heatsink around the transistors as your picture
At this moment it is burning since 3 hours input random signal output 8 ohm Resistor
I will also Check lower resistor value booth side ou the trimmer and if necessary add supercap but I need do disassemble
Also interested by your project.
At this moment it is burning since 3 hours input random signal output 8 ohm Resistor
I will also Check lower resistor value booth side ou the trimmer and if necessary add supercap but I need do disassemble
Also interested by your project.
Friends, I’ll try to find out how you get such boards; it is located in Canada. I think the moderator will not swear.
@Dougan & Paroxod4 🙂
(PS. Please read the quote at the bottom carefully: it contains important information. It indicates that +-600 mV drift isn't a tragedy, but just a normal inherent feature of the NHB-108))
First, I am confident, Paroxods' suggestion is the right way to go.
Second, I have noticed that you (Dougan) already have slightly lower resistances: your potentiometer is 20K instead of 50K but that could not be an issue. Perhaps you gain more precise control over resistances due to higher resolution.
Also, according to the original Dartzeel manual (please, see the quote below), 600mV is an upper action limit, so such deviations are inherent by design. Obviously, expected issue, however, we may make clones do better, with consistent temperatures at each of 2n5551/2n5401 transistors.
I am confident that keeping 2n5551/2n5401 transistors at uniform thermal conditions is the right way to go as suggested by Paroxod4. I don't see any other reason for spontaneous voltage drift because 15032/15033 and output transistors are close together on the same heat sink and share the same thermal conditions. Also, copper has excellent heat transfer characteristics and is so ductile and easy to process and shape. The first thing I will do is to repeat exactly the same as Paroxod4 did. That solution sounds logical.
Have a pleasant Sunday afternoon. 🙂
Quote from Dartzeel NHB-108 Manual:
(PS. Please read the quote at the bottom carefully: it contains important information. It indicates that +-600 mV drift isn't a tragedy, but just a normal inherent feature of the NHB-108))
First, I am confident, Paroxods' suggestion is the right way to go.
Second, I have noticed that you (Dougan) already have slightly lower resistances: your potentiometer is 20K instead of 50K but that could not be an issue. Perhaps you gain more precise control over resistances due to higher resolution.
Also, according to the original Dartzeel manual (please, see the quote below), 600mV is an upper action limit, so such deviations are inherent by design. Obviously, expected issue, however, we may make clones do better, with consistent temperatures at each of 2n5551/2n5401 transistors.
I am confident that keeping 2n5551/2n5401 transistors at uniform thermal conditions is the right way to go as suggested by Paroxod4. I don't see any other reason for spontaneous voltage drift because 15032/15033 and output transistors are close together on the same heat sink and share the same thermal conditions. Also, copper has excellent heat transfer characteristics and is so ductile and easy to process and shape. The first thing I will do is to repeat exactly the same as Paroxod4 did. That solution sounds logical.
Have a pleasant Sunday afternoon. 🙂
Quote from Dartzeel NHB-108 Manual:
Last edited:
Berlusconi thank you for cote It is exactly what I could see on mine but too much - 800 to + 800 mv I follow the paroxod 4 recommandation and put copper heatsink on the pair or transistors and at this moment the offset seem to be stable the amplificateur is heating since 10 hours . Now I cross the fingers and will see tomorrow when cold. If necessary I will put 50k trimmer at this moment the ajustement is not so easy and a very little turn give big variation.I appréciate your all good recommandation and wich you depending on your location good afternoon or evening.
Attachments
@dougan
Thanks for reply and please keep us informed. I hope we will be able to control drift manually because it would be pitty to sacrifice great sound quality.
buona notte.
Thanks for reply and please keep us informed. I hope we will be able to control drift manually because it would be pitty to sacrifice great sound quality.
buona notte.
