I don't know about the version in your picture but I built the A1 clone from Jim's Audio. Im very pleased.
I have not heard this Beyer A1 clone. So my comment are generic.
At the price point of the Beyer clone, it is highly unlikely to find imported genuine Op-amp IC and output transistor in the kit. Genuine BC/550/BC560 and BD139/BD140 are cheap and easy to find in Europe or US. Get the real deal before soldering.
The MC33078 are most likely rebranded locally made NE5532. Fake NE5532 usually has high noise and limited bandwidth. The ideal replacement are LM4562 or LME49720. They are the same IC and can be had from Digi-Key or Mouser (in US) for less than $6 each in small quantity. Genuine LM33078 or NE5532 can work fine too, but the LM4562/LME49720 are better.
http://www.ac-vogel.de/Download/Download/Audio%20Opamps,%20fact,%20no%20myths%20and%20THD%20measurement%20results.pdf
At the price point of the Beyer clone, it is highly unlikely to find imported genuine Op-amp IC and output transistor in the kit. Genuine BC/550/BC560 and BD139/BD140 are cheap and easy to find in Europe or US. Get the real deal before soldering.
The MC33078 are most likely rebranded locally made NE5532. Fake NE5532 usually has high noise and limited bandwidth. The ideal replacement are LM4562 or LME49720. They are the same IC and can be had from Digi-Key or Mouser (in US) for less than $6 each in small quantity. Genuine LM33078 or NE5532 can work fine too, but the LM4562/LME49720 are better.
http://www.ac-vogel.de/Download/Download/Audio%20Opamps,%20fact,%20no%20myths%20and%20THD%20measurement%20results.pdf
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The hypocrisy of these commercial clone vendors. They copy (steal) someone else's work, unless they have licensed that design, which is doubtful, but will only reveal a schematic of their copy if you PURCHASE one from them.
The schematics of these clone are floating around and easy to find. Picture #7.The hypocrisy of these commercial clone vendors. They copy (steal) someone else's work, unless they have licensed that design, which is doubtful, but will only reveal a schematic of their copy if you PURCHASE one from them.
A1 Headphone board Kit Refer Baia A1 amp BD-139-16+Mc33078 Standard Edition | eBay
How much it resembles the genuine Beyerdynamic A1 is everyone's guess! 🙄
Yes, but that wasn't my point. My point was that clone vendors don't usually provide their own (COPIED) schematic unless purchasing from them. As if they had their own original I.P. to protect.
Most electronic kit sellers on e-bay are resellers who know absolutely nothing about electronics. Buyer beware. You need to know what you want to buy DIY electronics on e-bay. I have had some gem and also some which go directly to the trash can.
I bought the red Jim's Audio A1 from ebay and cannot make out the PDF they sent for the AC input. Anyone who built it: what specs are required for the transformer? I assume between and 15 and 18V? ~30VA? Does it need to be a center tap?
High-end stereo headphone amplifier w/protection circuitry A1 PCB 1piece ! 699904410338 | eBay
High-end stereo headphone amplifier w/protection circuitry A1 PCB 1piece ! 699904410338 | eBay
Just send them a quick question, they reply fast.
From the pic of the pcb, we see 2 x AC connections and 1 GND so you’ll need a center tap. I’d say 12-15vac so 24-30Vct. Power wise 25-30VA should do.
BR
Eric
From the pic of the pcb, we see 2 x AC connections and 1 GND so you’ll need a center tap. I’d say 12-15vac so 24-30Vct. Power wise 25-30VA should do.
BR
Eric
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hello.
do you think this clone is better than O2 amplifier? for a pair of beyer dt880 250?
thank you
do you think this clone is better than O2 amplifier? for a pair of beyer dt880 250?
thank you
No.
I actually had a Beyer A2 clone which is based on the same schematic (attached). I sent it back as it couldn't take a normal 2VRMS source without distortion. My O2 doesn't have this issue.
You're better off with something to take on the shrill treble of the DT880 - something tube based perhaps?
Attachments
Take a look at this thread. It takes some work, but is a low cost approach with superiority result.
The JC2-HPA Headphone Amplifier
THE WHAMMY CLASS-A HEADPHONE AMPLIFIER has everything layout for you, but costs more.
WHAMMY Headphone Amplifier – diyAudio Store
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