[Weebyx]

So, I have been away from this site for a looong time now, but I thought I would show you something I have been working on.

This is a complete replacement for PCB8 for the Beogram 4002 and 4004, which includes a RIAA amplifier, and also makes it possible to control the Beogram via Beolink remote through f.ex Beomaster 4500/6500/7000 and the likes.

It has the same logic regarding features, as a BG7000, including 2-way functionality, so the Beomaster will turn on and select Phono, if the Beogram is powered on via the keybord 🙂

What do you guys think ? 🙂

 

 

[Mjoelnir]

This is a really great restomod! I’ve just auctioned a Beogram 4002 (going to get it today) and plan to upgrade it in this way. Where can I get this upgrade part? Is it easy to install?

[Mark-sf]

Very clean. How are you deriving the bipolar phono section supplies? I offered a similar mod back in the 1980s (w/o the remote) using a DC-DC converter plug-in module.

[Weebyx]

On a 4004, it is 100% plug and play, no soldering or anything. A 4002 is also plug and play, however it needs a new DIN cable, as it is missing pins 6 and 7 for the datalink connections.

Where do you live ? Currently the only way of getting it, is through me here in Denmark.

[Weebyx]

I am running powersupply to opamps via LDO voltage regulators, and actually NOT running dual supply. It is running 0-12v on opamps.

[Mark-sf]

I suspected as much. I did not choose that route as I wanted the higher head room and direct coupling to avoid caps in the direct signal path,

[Weebyx]

My design is build on Texas Instruments Reference RIAA design, they already use caps in direct signal path, even B&O’s own RIAA, and others, dont use dual power 🙂

I set out to build a RIAA amp that most people finds “good enough”, and up until now, everyone has been very happy with how it sounds.

I even compared TI’s RIAA curve with this, and they are almost identical.

But yes, there will always be ways of optimizing RIAA’s, and no 2 sound the same, and on top of that, 2 people listening to the same RIAA, will also always agree.

 

[ChristianHak]

Hey mate,

How much are you selling your RIAA upgrade for?

Mvh,
Christian

[Mjoelnir]

I am very new to turntables and preamps and everything, and there are so different opinions that it gets complicated and confusing. For example, are vibrations really a problem of internal preamps? I’d prefer not having yet another box, and not spoiling the design of the Beogram.

[StanfordBeogram]

This is fantastic – and very well laid out. Would it be possible to design one to work with an independent IR sensor so that it may be solely used as with a Beolink remote?

Please let me know how I may purchase on of these beautiful boards!

[Author]

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