Beogram 4500 - bypass the RIAA

14 replies

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Nils-Henning Reinstorf

Silver

Posted October 5, 2024 at 23:32 GMT

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

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carolpa

Bronze

2534 posts

Posted October 6, 2024 at 04:48 GMT

#1666729

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

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Nils-Henning Reinstorf

Silver

11 posts

Posted October 6, 2024 at 11:38 GMT

#1666740

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?

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carolpa

Bronze

2534 posts

Posted October 6, 2024 at 13:04 GMT

#1666742

link
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.

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Nils-Henning Reinstorf

Silver

11 posts

Posted October 6, 2024 at 15:25 GMT

#1666745

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

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Guy

GoldModerator

4528 posts

Posted October 6, 2024 at 16:23 GMT
Edited October 6, 2024 at 16:29 GMT

#1666746

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..

Location: Warwickshire, UK

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Nils-Henning Reinstorf

Silver

11 posts

Posted October 6, 2024 at 17:33 GMT

#1666748

Hello and thank you for the information!

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

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Guy

GoldModerator

4528 posts

Posted October 6, 2024 at 18:50 GMT
Edited October 6, 2024 at 18:54 GMT

#1666750

link
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: 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! /forum/beogram/beogram-4500-riaa#post-2224225

Location: Warwickshire, UK

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Guy

GoldModerator

4528 posts

Posted October 6, 2024 at 18:59 GMT
Edited October 6, 2024 at 19:00 GMT

#1666751

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:

Location: Warwickshire, UK

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Peter

Gold

10830 posts

Posted October 6, 2024 at 19:02 GMT

#1666752

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.

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Beogram 4500 - bypass the RIAA

Nils-Henning Reinstorf

carolpa

Nils-Henning Reinstorf

carolpa

Nils-Henning Reinstorf

Guy

Nils-Henning Reinstorf

Guy

Guy

Peter

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