Beogram 4002/4004 RIAA/Remote control Upgrade :)

10 replies
WE
Offline
Weebyx
Bronze
Posted March 1, 2024 at 08:06 GMT
#1643367
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 ? :)

 

 

Mark-sf
Offline
Mark-sf
Bronze
Posted March 2, 2024 at 04:54 GMT
#1662892
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.
WE
Offline
Weebyx
Bronze
Posted March 2, 2024 at 09:00 GMT
#1662895
I am running powersupply to opamps via LDO voltage regulators, and actually NOT running dual supply. It is running 0-12v on opamps.
MJ
Offline
Mjoelnir
Bronze
Posted March 2, 2024 at 13:28 GMT
#1662899
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?
WE
Offline
Weebyx
Bronze
Posted March 2, 2024 at 20:25 GMT
#1662908
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.
Mark-sf
Offline
Mark-sf
Bronze
Posted March 2, 2024 at 23:17 GMT
#1662912
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,
WE
Offline
Weebyx
Bronze
Posted March 3, 2024 at 08:26 GMT
#1662915
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.

 
CH
Offline
ChristianHak
Bronze
Posted March 24, 2024 at 02:48 GMT
#1663466
Hey mate,

How much are you selling your RIAA upgrade for?

Mvh,
Christian
MJ
Offline
Mjoelnir
Bronze
Posted March 24, 2024 at 11:32 GMT
#1663473
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.
ST
Offline
StanfordBeogram
Bronze
Posted April 9, 2024 at 19:47 GMT
Edited April 9, 2024 at 19:49 GMT
#1664005
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!
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