Phono stage on ebay (stolen trademark)

[anjump123]

Is this any good?

(stolen trademark removed)

What valves and psu would suit this. May be a bit of an ambitious first step into valves for me.

 

[juanesposito]

Hi! I am considering the same kit, did you buy it? If yes, how is the quality?

 

[SY]

Given that this vendor has stolen the trademark, you should be automatically suspicious, since he's clearly unethical. The circuit could be anything, the parts could be mystery meat.

I would absolutely avoid this, and anything else offered by vendors who have demonstrated their dishonesty.

 

[juanesposito]

Thanks for your feedback SY. It did look suspicious for sure, this is why I wanted to know more about it. Regarding the copyright aspect, I did not consider that for first glance. But it does sound logical that a schematic is as protected as any other intellectual property.

 

[atupi]

I suppose is the same like any other chinese clone from ebay. Cheap with average results and zero support.

 

[SY]

What they're stealing is the trademark. The schematic may or may not be anything resembling the original (more likely not), and the layout certainly won't be the same. Safest not to deal with thieves, IMO.

 

[SY]

Don't deal with thieves. It's not only unethical, you are almost certain to be getting crap that has no resemblance to the original. Chances are that the "JC-2" is stuffed with counterfeit parts.

Did I show you my $50 Rolex? I'm sure it's every bit as good as the real thing.

 

[mach1]

JC recently purchased a fully assembled Chinese JC-2 clone and regards it as an excellent buy. I guess he's not really qualified to pass judgment though.

 

[atupi]

JC himself ? That's something!

Sent from my Nexus 5 using Tapatalk

 

[mach1]

In his own words:

By the way, it is not necessary to build a JC-2 line amp from scratch. Just get a completed unit E-Bay online from China. I paid $126 + shipping. The case alone is worth that much................The Levinson JC-2 line stage was designed over 40 years ago, and while quite good at the time, and still one heck of a bargain from China today, is not the latest of this series of designs, but it has all the basic changes that we made to get the best performance in order to exceed what we could get from opamps then, and I still think, today.**

 

[SY]

Why are you assuming the "clones" actually copied the original circuit, rather than just stealing the name?

 

[mach1]

Post 7 link:
http://www.lencoheaven.net/forum/in...08u4f86kihk84&topic=20984.msg290479#msg290479

I´ve ordered a pcb set recently because of interest and for evaluation. Signal PCB is an exact copy of the original EAR 834p schematic which I´ve diy ed some years ago; power supply pcb is slightly but not dramatically changed.

 

[QSerraTico_Tico]

PCB

This is how I got it with some parts loosely plugged in. Picture is of the power supply section.
It contains 4 diodes for the high voltage, 1N5374, and a MJE13009 transitor.
The function of the latter is totally unclear to me. despite my request.
The seller did not provide an up-to-date schematic.

 

[mach1]

The transistor is probably the pass element in a capacitance multiplier. It shouldn't be too difficult to derive a schematic from the pc board.

What information are you actually seeking?

 

[QSerraTico_Tico]

The transistor is probably the pass element in a capacitance multiplier. It shouldn't be too difficult to derive a schematic from the pc board.

What information are you actually seeking?

I just want to know what I am building...

 

[mach1]

Without a schematic it is only possible to give a vague answer based on probabilities.

 

[QSerraTico_Tico]

schematic

Without a schematic it is only possible to give a vague answer based on probabilities.

I received a schematic from the seller.

 

[vinylkid58]

I received a schematic from the seller.

Could we see it please.

jeff

 

[fasterbyelan]

My interest in the circuit on the Lenco Heaven site lead my to obtain a diagram -

An externally hosted image should be here but it was not working when we last tested it.

The 1K3 resistor in the HT PSU is often substituted with a 20H Inductor.

 

[SY]

If this is the circuit that the unethical thieves are selling, there's quite a few improvements that can be done- like most ripoff companies, they seem to be unclear on how the circuit they're stealing actually works.

But first, the RIAA feedback looks incorrect. Is that how the unit is actually wired?