"A good example is the MBL6010D preamp of this thread. The e-bay clone is nowhere near the real preamp. If the buyer has to replace all the AD797, it will cost more than the clone as I pointed out in earlier post."
You make it sound as though you expect the clone to sound as good as the original but with fake parts because you're not prepared to buy the genuine article.
You deserve what you get, pal.
You make it sound as though you expect the clone to sound as good as the original but with fake parts because you're not prepared to buy the genuine article.
You deserve what you get, pal.
$20-30 will get you 2 genuine AD797. You will need $150 of parts to populate the MLB6010D clone we are talking here.
Scott Wurcer said that some fake part from China may work the same as the genuine one. I am very interested in how to find it out.
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I don't think you understand. Let's just agree that we dissagree on this matter.
EDIT: The only way to defeat unfair competitors is to have much broader insight into the matter and capability to convince your clients that you're the only good choice. And I would never ask anyone on internet to protect me from unfair competitors. This all IP circus reminds me to good old Don Quixote protecting his beloved Dulcinea del Toboso.
EDIT2: And don't forget, we are all friends here, sharing similar interests and are all nice to eachother. Let's be friends and share our "secrets".
Cheers, and no offense meant.
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Thanks Scott, as I'm unsure if your statement regarding the voltage burden of
my meter.
I assume that I will measure the pins using the meters 2 wire resistance feature,
not 4 wire kelvin connection?
Also, how would I use and ESD Diode? Where would I place it?
The meters I have are HP34401A. Looking for voltage burden didn't turn up anything in the manual.
screen and
.
The Ohm meter forces current and measures voltage, you want this voltage to be <0.5V so you don't forward bias any internal diodes be they ESD devices or not. VTVM's had an Ohms/Volt for each scale, modern voltmeters don't. In reality just try it you should be OK, reverse the leads and see if it is the same.
Scott, Will do.
Question at least for me.
Should I plug these into a board and supply +-10VDC or +-15VDC to the
amps and measure the voltage readings across the pins? I assume I check
the real V+ and real V- values powering the device, and then follow your
guide to see if they are nulled at the correct pins.
5534: Nulled V+ @ P1-P8
797: Nulled V- @ P1-P5
w/o power:
LT1028: 130ohm P1-P8
5534: 12Kohm P1&P8. (this also being the rebranded LT1028).
Good stuff, thanks.
Cheers,
Measuring the resistances from the null pins to the supplies should be enough.
Hi gigigirl
,The board hasn't arrived yet, but I will let you all know how the board worked before-and-after the replacement of the chip. I alredy have four AD797ANZ purchased from reputable supplier Conrad/Germany. It is interesting that here in Europe AD797ANZ isn't commonly on stock. Even at Farnell UK it is listed as: "Available until stock is exhausted"
This Corrona virus has delayed everything, not just Chinese shipping lines but also across Europe too. Even one delivery from Germany which usually arives within 4-7 days has delayed for three weeks.
And, Good morning. It is dawn here, almost 6 AM, so let's start the day early to get things done.
Gigi, this is a line amp and not a phono stage. I am not even sure how it Refer Germany MBL6010D. It seems to be a NE5534 line amp board only.
The 4 on board trimmer look interesting. Do you know their function?
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There are a number of these "MBL6010D" preamps available in EBAY, Aliexpress and TB. I bought a kit of this version a number of years ago.
?MBL6010D ?? ?????????? ?????-???
I like the PCB design (particularly the symmetrical layout) . Basically two stages of amplification per channel (basically 4 amplification modules for the whole amp). The seller actually provided the schematic of the amp. For this kit, the 4 trimmers are provided to adjust the voltage offset of each opamp in each module. I have 49710 in them and it is very quiet and it sounds very clean and neutral. I use a "clone DACT" type volume port and a R-core tranny.
Regards,.
Sometimes the secret of great sound is also in the details (i.e. parts selection). For instance if panel sockets were not important there would not be market for high quality panel sockets.
One example ... i suspect the volume attenuator used in the real MBL is very very high quality. A precision part.
I am a little obsessed by volume pots lately. I have the feeling that some on ebay are even fake parts.
I would look at a stepped attenuator with a decent mechanism and resistors for good sound.
One example ... i suspect the volume attenuator used in the real MBL is very very high quality. A precision part.
I am a little obsessed by volume pots lately. I have the feeling that some on ebay are even fake parts.
I would look at a stepped attenuator with a decent mechanism and resistors for good sound.
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If it sounds better than the JC-2 with only the NE5534, it has potential.
Did you consider replacing the regulator circuit with an outboard low noise PSU? You can get this board using 317/337 with an opamp de-noiser for about $10. See this post at the power supply forum.
What is this opamp doing in this power supply schematic?
I will take all active components (opamp etc.) off the socket before surgical operation.
Remove the rectifier diodes, main filter caps and anything else between them. Make a red jumper from one of the AC-in (use the rectifier hole) to the positive hole of the positive filter cap and a black jumper from the other AC-in to the negative hole of the negative filter cap. Leave the small caps and other components after of the main filter caps in place.
Check continuity from the new +DC in to the opamp + supply pin. Any of the opamp will do. Check continuity from the new -DC in to the opamp - supply pin. If good, you are ready for action.
Rhodium is a soft metal meant to improve electrical contact. It needs to be on one side of the plug or the socket. The very, very thin layer of rhodium should not have any sound of its own. It may not be exciting, but it is neutral.And yet your picture shows some very durable but average sounding rhodium sockets
I understand. Taking components off an assembled PCB is not my favorite hobby either.
For my line level preamp, I use a clone of the Sugden DAC line output board which is very faithful to the original. I have been using a twin TL1083CP regulator PSU for the past year and am waiting for the opamp servo de-noiser PCB to replace the power supply.
On the lineamp board, I replaced the NE5534 with LME49710 which is much cheaper than the LD797 and very good for line level.
For a simple board with 4 NE5534 and 2 NE5532, the $60 price tab seems way too high. Did you check AliExpress? It seems to be unbalanced in and out only. No balanced port!
What potentiameters and how many does it include for the tone control?
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When it cannot use the AD797 opamp, how does it relate to the MBL6010D? It must have a different circuit topology than the MLB6010D. However, I do realize that AD797 is not the optimal choice for line level preamp. The confusion just deepens.Lusya said: