The Workbench

Re: Grand Prix Moderne Stereo 609

Søren Mexico — Sat, 27 Nov 2010 23:35:33 GMT

soundproof:

The morning's first coffee break became a little longer than planned as I went through this wonderful thread. Well done - maybe it's just me, but these restoration threads read like thrillers, I have to keep myself from looking at the last page!

Martin writes better than Conan Doyle

Re: Grand Prix Moderne Stereo 609

soundproof — Fri, 26 Nov 2010 03:50:04 GMT

The morning's first coffee break became a little longer than planned as I went through this wonderful thread. Well done - maybe it's just me, but these restoration threads read like thrillers, I have to keep myself from looking at the last page! A wish, Martin: could you get the people in Japan to photograph the Grand Prix inside their store? I have been to a few of these stores in Tokyo, and they are Scandinavian vintage furniture paradises. I'm certain a photo of the Grand Prix in that environment would be pure time travel.

Re: Grand Prix Moderne Stereo 609

Dillen — Fri, 26 Nov 2010 02:13:05 GMT

This Grand Prix set and speakers were sold last april and are now residing in a
wonderful decor-shop in Japan where it entertains customers looking for 1950's and 60's
classic scandinavian design teak and palisander furniture.
Far away but it will still feel at home.

Martin

Re: Grand Prix Moderne Stereo 609

Craig — Mon, 31 May 2010 05:24:49 GMT

Well I missed this thread completely at the time. Due to the fact I was not around much when thus was going on. As usual a fantastic resto by Martin. have to say that echo box is a very intersting piece of kit. Did not think the sound difference would be so noticable as it is.

Craig

Re: Grand Prix Moderne Stereo 609

Steffen — Sun, 30 May 2010 18:33:21 GMT

Wonderful job you have done with that old "609" Martin.

Oh, I remember my parents had one of these when I was a kid. It was probably this receiver, that started my affection for B&O. Years after, when I was about 13-14 years old I bought my first B&O -a Beomaster 901. A few years after it was replaced with a BM 2400 -which was replaced by a BM 3300 and so on... Today I have a nice little collection of B&O sets from the 70's, 80's and 90's.

By the way - my parents speakers were in the same design as the cabinet of the radio (not like the speakers you used -though they were very nice ). I also remember, my sister once had a receiver from another danish company -an "LL -Apollo". It had the same knobs as this B&O... Standard knobs fom the 60's..?

Well -it's always nice to read your posts. Keep up the good work.

Steffen

Re: Grand Prix Moderne Stereo 609

Dillen — Fri, 11 Dec 2009 05:56:46 GMT

I've been asked:

The signal from the amplifiers sent to the speakers now contain both the original signal and the echo effect signals.
Note that all this is sent to the echo-unit - which for the produced echo signals means "again" - so what is
preventing this whole thing from going into a howl with the echo effects travelling round and round and never escaping ?

Good question !
Well, since the echo effect is mono in reverse phases, it will equal itself out as the left and right channels are
mixed together inside the EK4, leaving only signals that are not in opposite phases = the original signal to enter
the echo circuit.
So the original signal will only be allowed that one trip through the EK4. As soon as it has been there, the resulting
signals are in opposite phases and are automatically eliminated when it comes around again.
Clever and simple.

Martin

Re: Grand Prix Moderne Stereo 609

Dillen — Fri, 11 Dec 2009 05:40:33 GMT

Yes, it would have been interesting to see the looks on peoples faces when some engineer first
presented his idea of making a hall effect by sending sound through long springs.
A bit cartoon-like, it must have felt at first I suppose, and it's still a bit ackward but it works wonderfully none-the-less.
One thing that beats me though is that the whole echo unit is quite unsensitive to touching. Even tapping it using
finger-force equalling that normally used on a stubborn PC keyboard has no influence on it's functionality
and causes no new sounds to be introduced.
All down to good filtering.

Martin

Re: Grand Prix Moderne Stereo 609

Jandyt — Thu, 10 Dec 2009 18:44:13 GMT

Cheers Martin. Used "Save target as" and played with itunes.
Interesting hearing how the echo is generated through such a simple device. Thanks for sharing.

Andy T.

Re: Grand Prix Moderne Stereo 609

Dillen — Thu, 10 Dec 2009 17:02:30 GMT

Andy,

The above links are to mp3-files. (The links are in the text - it's not the photos).
You need to have your operating system set up to associate mp3 files
with a program capable of playing them and it will automatically launch
that program and play the file when you click on its link.
Alternatively, download the file to your hard-drive by right-clicking
on the link and then choose "save target as". Choose a place where you
can locate the file again and click "save".
Launch your favourite sound programme (media player or similar), open
the file you just saved and play it.

If you have a slow internet connection, the sound files may take a moment to download.

Thanks for the language comment. I try my best.

Martin

Re: Grand Prix Moderne Stereo 609

Jandyt — Thu, 10 Dec 2009 14:49:06 GMT

Martin. As usual, a fantastic thread, I have learned so much. Your use of plain English makes it so easy to follow.
BTW, I think I was there when Peter and Lee commited the crime.

Now, how can I listen to your sound clips? Left clicking just opens a blank screen.

Kindest regards, Andy.

Re: Grand Prix Moderne Stereo 609

Dillen — Thu, 10 Dec 2009 03:49:08 GMT

Next recording is danish speech.
Danes will recognize this as part of the traditional
saturday "Giro 413" programme though with varying amounts of
hall effect.
http://users.cybercity.dk/~dsl42943/Lyd03.mp3

Martin

Re: Grand Prix Moderne Stereo 609

yachadm — Thu, 10 Dec 2009 03:04:44 GMT

Great job - Martin!

I love that valve sound!

Menahem

Re: Grand Prix Moderne Stereo 609

henrik — Wed, 09 Dec 2009 18:09:46 GMT

Great thread! As always, a good read! Thank you!

Re: Grand Prix Moderne Stereo 609

tournedos — Wed, 09 Dec 2009 16:48:13 GMT

Brilliant! A much better effect than I would've expected

Re: Grand Prix Moderne Stereo 609

Dillen — Wed, 09 Dec 2009 16:39:04 GMT

Well Mika, nothing like that - that - that..
More of a hall effect than actual echo'inginginginging.....

A couple of sound recordings were made to demonstrate the echo unit in action.
Both are from FM radio source and recorded "live" using the same method,
microphones and setup as earlier in this thread.

First recording is Elvis Presley, originally mono but play the file
back in stereo and note the roomy "artificial stereo" hall-like sound
as the effect from the echo unit is gradually applied and finally switched
off again :
http://users.cybercity.dk/~dsl42943/Lyd02.mp3

Note also that the Grand Prix makes a short thumb noise when the echo
unit is switched completely out.

Martin