Wow, this board doesnt inform me all the time I get a response...
Anyway, for the first time no smoke
I exchanged the 100 R resistors and Q5, Q1 and Q2.
I measure 0,8 Volts across 100 R at Q1.
I measure 0 V at 100R at Q2.
When I turn the Trimmer it doesnt change anything in the Voltage.
I dont know what U mean with:
try to measure Vce and Vbe for Q5
This thread is excellent, I've been reading and rereading... A few questions. Which version is the best? Are they all the same? Do you recommend buying the kit or just the boards? What power supplies (US) schematics do you use or can you buy a kit? I'm used to using tube amps, would this compare? It looks to be a fun project..... Comments....
if I were you I would get some amp kits like nxv200 from Amplifier Kits - Audio Amplifier Modules - MOSFET Amps. They are excellent amp kits. I was like you! I was going to get the NAP-140 too but, I realized that I could get something way better than that....and I did!.
if I were you I would get some amp kits like nxv200 from Amplifier Kits - Audio Amplifier Modules - MOSFET Amps. They are excellent amp kits. I was like you! I was going to get the NAP-140 too but, I realized that I could get something way better than that....and I did!.
These kits are fully assembled and tested. Where's the fun of soldering and test components? Buy the complete kit and enjoy soldering and adjusting the amplifier. The sound of this amplifier is very good.
Hi,
I don't know about the versions available. IMO, the most practical way is to buy only boards and to use components to your liking. In my amp I replaced almost everything anyway... The output transistors in these eBay kits look like cheap fakes.
About the power supply: I recommend conventional power supply - bridge rectifier (25A or more) and capacitors according to your budget. More is better, but you don't need to go crazy. Dual-mono type of power supply is better for sure. Then you'll need 2x bridge rectifiers and same capacitance but split between the channels.
I did some interesting measurements of the crosstalk of this amp and found that the power supply is of highest importance. Unlike the class A amps, this one doesn't like RC filters in the power supply and the crosstalk is very average (50db) if you have even the smallest resistance on the current path. I removed 0.15 ohms in my power supply and the crosstalk improved 12db. In this manner, I suppose, the heavier wire gauge for the power lines will give you the best result... And the dual-mono, as well.
Well, you can always solder and test something else lol. as you said "These kits are FULLY assembled and TESTED" so you can not make a mistake with the sound and performance.To check if your diy amps are well build you would need an important machine like an oscilloscope which most people do not have or do not know how to use it.This diy amps Joby is not just checking for voltages ac/dc it is more than that!. But again, it just my opinion. as long as you are happy for what you achieve in this diy world....you are fine!
I've been building tube amps and repairing solid state gear for a while. So a kit would be more enjoyable. Thx for the comments. .... The only board I see on Ebay is Jims_audio 140 Naim. I like the suggestion of getting my own parts. It seems everyone replaces half the parts anyway. Has anyone assembled this board? They look different than the blue boards (where ever they come from). I find the pics posted really help. Your opinons are appreciated.... So is Jims Audio OK??
if you want to get them, just e-mail candy at candyhifidiy@hotmail.com
She will help you with any questions. Good luck.
I have both the blue (with kit) and the red (boards only).
With exception of the colour, the boards are similar. They have some different transistor labels, though. For example, on the blue ones the drivers are labeled TIP41/42, these are MJE253/243. Someone in China is reading carefully this thread
Other than that I don't see any difference.
Ruwe, Thx for the reply. You've built both boards and don't have a preference. I will order next week and was seeking opinons since this thread is extremely helpful and complete. The board I mentioned was Jims_Audio on Ebay item number. 2205 0332 3781 (no spaces).... Does Candy have a website to show the boards, etc.? Maybe we can attract more builders. You hooked me....
Actually, I've built only the blue ones. The reds I bought from Jims_Audio on eBay for multichannel, gift for friends or spares, whatever comes first. I just compared them and they look pretty much the same.
As about Candy I have no idea who she is. Lanchile was talking about her.
I live in Canada. The flag is of EU, I was born and spent most of my life in Europe.
Candy is the representative from hifidiy.net they are the ones that build all these amps boards. just check their web.
Ok,
After exchanging Q5,Q2 and Q1 I dont have smoke anymore.
I put the big Transistors 2SC5220 in. Put a Sine Signal in to the Input.
Connected an Old Speaker. I only get big Hum.
Disconnected the Speaker.
I measure at the Output of the Amp now about 10V DC!
Somebody can help me, please?
Sofar these kits are very disappointing, also they looked so cool in the beginning...
Last edited: