Beogram 4500 – bypass the RIAA

[Nils-Henning Reinstorf]

Hello guys,

i´m Nils from germany and i love my beocenter 9500, the innovative design and technology and the sound…

I´ve layed my hands on a Beogram 4500, nearly mint condition, and i like to replace my TX2 with the beauty.

Now i´m looking for an instruction to bypass the RIAA on the 4500….

Anyone to give me a helping hand or hint for my DIY project is welcome!

Hope my english is not too bad

cheers Nils

[Carolpa]

why not connect the BG4500 to ATape2 of the BC9500? Then you do not need to bypass the RIAA…

and you could leave both recordplayers connected

[Nils-Henning Reinstorf]

Hi, thank you for your suggestion but i like to use the remote control of the system as well.

I think for that there is no other way then bypassing the RIAA?

[Carolpa]

Nils-Henning Reinstorf wrote:

Hi, thank you for your suggestion but i like to use the remote control of the system as well. I think for that there is no other way then bypassing the RIAA?

but giving the ATape2 command to the BC9500 should start the BG4500. The only “odd” thing you experience is the use of ATape2.

[Nils-Henning Reinstorf]

The player dosn´t start if connected to ATape2. If i star BG manual then, BC switches from Atape2 to Phono and there is no sound then…

I can use AUX Port playing records but no remote control. Best way for me is find a way to bypass the preamp.

Perhaps you know B&O people who can help me?

cheers Nils

[Guy]

If bypassing the RIAA to use the BC9500’s PHONO input, you will also need to move the Beogram’s datalink connection from DIN pin 7 to DIN pin 6.   Non-RIAA-equipped Beograms use pin 6 for datalink, whereas RIAA-equipped use pin 7 (the same as Tape).  The Tape 2 input socket on BC9500 expects datalink on pin 7, and the PHONO input socket expects datalink on pin 6..

[Nils-Henning Reinstorf]

Hello and thank you for the information!

Do you know the way how to bypass the preamp of the Beogram 4500, please? 😉

[Guy]

Nils-Henning Reinstorf wrote:

Do you know the way how to bypass the preamp of the Beogram 4500, please?

As a Silver Member you are able to download the Service Manual here:  https://beoworld.org/?a=download&key=cae6a88b27cd8dd84ce21c7a01e06b95

As you can see, many Beograms of that era (both with and without RIAA) share the same service manual because they are similar internally.  Basically, you want to disconnect/bypass PCB4 totally, and reconnect with the ‘non-RIAA’ muting circuitry as shown on page 2-1 in the little dotted area labelled ‘in versions without RIAA’.  The circuit diagram also shows that the datalink connection should be  moved from pin 7 to pin 6 as I mentioned earlier.  I haven’t attempted this myself, but if you are confident with hifi electronics it should be no problem.

EDIT:  There’s a photo attached to McGruse post here that shows a BG4500 with RIAA removed – it may be some help! https://archivedforum2.beoworld.org/forums/p/26480/211502.aspx#211502

[Guy]

I can’t vouch for the audio quality (I suspect it would be poor), but if you don’t want  to modify the BG4500 you could always feed it’s output through something like this and then in to the PHONO input:  https://www.ebay.co.uk/itm/154567034473

But you would have to convert DIN to Phono plugs (and reverse) and feed the datalink connect from DIN pin 7 of the input to DIN pin 6 of the output.

[Peter]

Seriously, just connect the pins 6 and 7 on the DIN plug and you will get remote control through the Aux channel. You can of course open up the Beogram and remove the RIAA but this will be far more complicated. Beograms with the built in RIAA are probably worth more than the non RIAA fitted decks as they can be used with all sorts of modern equipment. What you need is a Beogram 9500 (rare) or more reasonably a Beogram 5005 0r 5500 which don’t have a RIAA fitted and will work with the 9500 ( Good choice of system – in my view the best designed system B&O made – just bought another myself!) You can probably sell the 4500 for more than it would cost to get a 5500.

[Peter]

The alternative would be a Beogram 8000 which is a definite step up from a 4500 or 5500.

 

[Guy]

Peter wrote:

Seriously, just connect the pins 6 and 7 on the DIN plug and you will get remote control through the Aux channel.

I don’t think this will work, because being an RIAA equipped deck the datalink will already be on pin 7 and he already tried Tape 2.  I think that when plugged into Tape 2 his Beogram 4500 will be controlled only after selecting PHONO on the remote, but of course the audio is not then connected.

EDIT:  Peter, you must be experiencing a little ‘deja vu’ 😀 – see https://archivedforum.beoworld.org/forums/t/32271.aspx

[Nils-Henning Reinstorf]

Guy, thank you very much! That will do i think 😉

And a german member, Christian from Hamburg, will give me advice!!!

Peter, thank you for your thoughts! Youre right its more worth with RIAA but its just to bypass not to throgh away the RIAA!

I bought the BG in first because it looks so beautiful with the BC9500 and then, its near Mint condition for little, very little money 😉

So, i thank you all and I will gladly keep you up to date if you wish.

cheers Nils

[Peter]

Of interest, when I bought my first BC9500, which I bought new, the dealer also sold me a BG4500 as he had not realised it had a RIAA. Of course it produced a dreadful sound through the phono input and he rather shamefacedly replaced it with a 9500. I cannot remember what I did with the deck – I suspect it might be with the BC9500 which I lent to a friend many years ago! I will probably use a 4004 with my new 9500 if I need a record player.

[Author]

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