The Workbench

Re: BM 4000 Mexico

Søren Hammer — Tue, 10 Jan 2012 15:25:20 GMT

Søren Mexico:

Step1:

Søren Hammer:

I normally use the quote "Learn from other people's mistakes, you'll not live long enough to make them all"

You know I would have once agreed with that, but then I had kids, and no matter how much you tell them they only ever learn by making their own mistakes! It is true, when you make a mistake you tend to anylise why you did things that way and learn more that you could by not making the mistake - this is how we learn ;-)

Agree with Step, with 4 kids (boys) all grown up now, all my wisdom was wasted, they did their mistakes, and all I could do, was, "I told you so"

Hmm, I guess that you are right that wee just have to make some mistakes to learn from them, but some can be avoided with proper guidance and help from Beoworld

Re: BM 4000 Mexico

Søren Mexico — Tue, 10 Jan 2012 09:11:57 GMT

Step1:

Søren Hammer:

I normally use the quote "Learn from other people's mistakes, you'll not live long enough to make them all"

You know I would have once agreed with that, but then I had kids, and no matter how much you tell them they only ever learn by making their own mistakes! It is true, when you make a mistake you tend to anylise why you did things that way and learn more that you could by not making the mistake - this is how we learn ;-)

Agree with Step, with 4 kids (boys) all grown up now, all my wisdom was wasted, they did their mistakes, and all I could do, was, "I told you so"

Re: BM 4000 Mexico

Step1 — Tue, 10 Jan 2012 04:25:20 GMT

Søren Hammer:

I normally use the quote "Learn from other people's mistakes, you'll not live long enough to make them all"

You know I would have once agreed with that, but then I had kids, and no matter how much you tell them they only ever learn by making their own mistakes! It is true, when you make a mistake you tend to anylise why you did things that way and learn more that you could by not making the mistake - this is how we learn ;-)

Re: BM 4000 Mexico

Søren Hammer — Mon, 09 Jan 2012 13:55:44 GMT

Søren Mexico:

Søren Hammer:

Good work, Søren. More thorough than my "simple" 4400 capacitor replacement thread and you're better at explaining the technical stuff.

As an 18-year-old, I still have a lot to learn in electronics though I was raised by an electrician

As a printing m/c tech. I started 40 years ago and the m/c had open relay circuits to command them, most of it 220 V, some of the m/c's had fotocells where the allso the amps was simple things, easy to repair, I am a mecanic but when standing alone with a 40 ton m/c deep in Africa or in some Chinese province, where the electricians are limited to changing light bulbs once in while, you need to start thinking, so I learned to read E drawings, follow them like street maps, and failure search was simple, as in these open circiuts you could see what happened, later, at the end of the 70s, beginning of the 80s they started putting more sofisticated electronics into the m/c's, today it is all computerized and few open circuits, and the E repair is made simple, like: Water feed in unit 4 is not working, the manual says, check for current at pin 19 on PCB No. 8, no current, change the PCB No. 8 and send the old one back to the factory for repair and update.

Nobody, today goes down to component level on the PCBs, so if you can read a manual you can do it.

Because of this I never followed up on my El. knowledge, kept to the mecanics. And today I am, as you Søren, fumbling around and starting getting into a new world, but with a Danish electrician at hand you are better of than me.

What I have learned with more than 40 years as a trouble shooter is, there are no big m/c's, only a lot of small parts, and thats the same in electronics. You start at the feed lines, using the drawings (street maps), and then goes step by step until you are down to the area or component-s that causes the trouble, with these vintage items the main problem is finding spares that fits. We will never get to Martin level, nothing beats experience.

And as you I feel like 18 year old when I work with these items, but when I get it working, I feel like a 6 year old on Xmas Eve.

And remember, there are no stupid questions, only stupid people that don't ask them. And making stupid failures is part of a learning process, nothing to be ashamed of, but publish also your failures, somebody will learn from it.

If you make the same stupid failure 3 times, you are fired

I get your point, but it is really unfair to compare us with Martin at any circumstance He must be a BeoGod.

My Father took his apprenticeship back in '79, and he can't really remember much about his time working with electronics, but generally a good guide when working on anything. I am very interested in science and how the components actually were "invented", it's a joy to work on B&O, though they sometimes makes "bloopers" that indicates some capacitor is mounted with wrong polarity etc. It was confusing in the start, but got all the caps installed right the first time. Your electrical exprerience must count something when working on B&O

I like to spend some nights being thorough and having fun while working on gear. I hate troubleshooting when the work can be done right the first time.

I normally use the quote "Learn from other people's mistakes, you'll not live long enough to make them all"

Re: BM 4000 Mexico

Step1 — Sun, 08 Jan 2012 19:00:01 GMT

I think you are refering to Dolby Surround Sound Rich Pro Logic was actually quite a bit more complex as there was a little bit of 'encoding / decoding' of extra surround information in the stereo source (+/- 90 signal so that it was canceled out under stereo conditions) but also based on various levels the signal was routed more effectively to its appropriate speaker using the pro-logic part. There is of course ProLogic II but I have never heard this myself.

Connecting a speaker across channel l / r is very useful for setting up channel balance with those little preset pots under the 4000 etc. :) Basically if you have a mono source adjust trimmers until desirable level say, compared to radio, with speaker connected normally. Then connect speaker across L+R positive outputs and adjust one of the trimmers for minimum sound. There will always be some sound coming through due to tolerance of components but this is about as good as you'll get without taking measurements etc... You can do this with a stereo source as long as there is some sort of sound that is equal in both channels. Normally singers have a reverb so while the main content of their singing voice will dissapear, the reverb effect may remain, leaving a ghostly effect...

Rich:

chartz:

Nice work Søren!

There is no "ambio" record. There were quadraphonic ones, but you needed four amps to take advantage of them, along with a special cartridge and a 4 channel decoder (Beomaster 6000, and a Beogram 6000 with the special on-board decoder and an MMC6000 cartridge).

The ambio thing is a pseudo-acoustic trick which involves extra speakers to re-create a depth impression with normal recordings.

Ambio is the left signal minus the right signal, and probably attenuated somewhere between 6 and 12 dB. I would characterize it as attempting to give a spatial impression, rather than a depth impression. (EDIT: on further reflection, I guess "depth" and "spatial" can be essentially the same thing. But when I talk about "depth," its locating sounds behind the plane of the front left and right loudspeakers. When I talk about "spatial," its locating sounds in front of the plane of the front left and right loudspeakers.)

The original Dolby Pro Logic's surround channels were both essentially this, but with 20 millisecond delay as well. Recall Hi-Fi VHS had a two channel audio track, essentially stereo left and right. Dolby Pro Logic basically fed the left and right channels of the audio track to the left and right channels unchanged, and fed left plus right to the center channel, and fed left minus right (delayed) to both surround speakers.

A common late 80s, early 90s DIY was to make something akin to an ambio circuit. You can do it without an ambio circuit (and without electrical attenuation) by simply wiring a second set of speakers like this. Plus terminal of your amplifier right output to the plus terminal of your right speaker. Plus terminal of your amplifier left output to the plus terminal of your left speaker. Then wire both speakers minus terminal together.

Re: BM 4000 Mexico

chartz — Sun, 08 Jan 2012 16:38:04 GMT

Cheers mate!

Re: BM 4000 Mexico

Søren Mexico — Sun, 08 Jan 2012 16:08:43 GMT

Now playing 3 hours, volome level 6, cooling elements get a little more than hand warm, next week I will connect my Bvox 3000 panels as ambio speakers just to hear it, today I'm alone at home, so I will be rocking the whole day, Denver Broncos wild card game with no sound, a good working BM 4000, a cuba in my hand, Suzi screaming har lungs out.

Can life get any better

Re: BM 4000 Mexico

Rich — Sun, 08 Jan 2012 13:17:45 GMT

chartz:

Nice work Søren!

There is no "ambio" record. There were quadraphonic ones, but you needed four amps to take advantage of them, along with a special cartridge and a 4 channel decoder (Beomaster 6000, and a Beogram 6000 with the special on-board decoder and an MMC6000 cartridge).

The ambio thing is a pseudo-acoustic trick which involves extra speakers to re-create a depth impression with normal recordings.

Ambio is the left signal minus the right signal, and probably attenuated somewhere between 6 and 12 dB. I would characterize it as attempting to give a spatial impression, rather than a depth impression. (EDIT: on further reflection, I guess "depth" and "spatial" can be essentially the same thing. But when I talk about "depth," its locating sounds behind the plane of the front left and right loudspeakers. When I talk about "spatial," its locating sounds in front of the plane of the front left and right loudspeakers.)

The original Dolby Pro Logic's surround channels were both essentially this, but with 20 millisecond delay as well. Recall Hi-Fi VHS had a two channel audio track, essentially stereo left and right. Dolby Pro Logic basically fed the left and right channels of the audio track to the left and right channels unchanged, and fed left plus right to the center channel, and fed left minus right (delayed) to both surround speakers.

A common late 80s, early 90s DIY was to make something akin to an ambio circuit. You can do it without an ambio circuit (and without electrical attenuation) by simply wiring a second set of speakers like this. Plus terminal of your amplifier right output to the plus terminal of your right speaker. Plus terminal of your amplifier left output to the plus terminal of your left speaker. Then wire both speakers minus terminal together.

Re: BM 4000 Mexico

Søren Mexico — Sun, 08 Jan 2012 11:34:14 GMT

Søren Hammer:

Good work, Søren. More thorough than my "simple" 4400 capacitor replacement thread and you're better at explaining the technical stuff.

As an 18-year-old, I still have a lot to learn in electronics though I was raised by an electrician

As a printing m/c tech. I started 40 years ago and the m/c had open relay circuits to command them, most of it 220 V, some of the m/c's had fotocells where the allso the amps was simple things, easy to repair, I am a mecanic but when standing alone with a 40 ton m/c deep in Africa or in some Chinese province, where the electricians are limited to changing light bulbs once in while, you need to start thinking, so I learned to read E drawings, follow them like street maps, and failure search was simple, as in these open circiuts you could see what happened, later, at the end of the 70s, beginning of the 80s they started putting more sofisticated electronics into the m/c's, today it is all computerized and few open circuits, and the E repair is made simple, like: Water feed in unit 4 is not working, the manual says, check for current at pin 19 on PCB No. 8, no current, change the PCB No. 8 and send the old one back to the factory for repair and update.

Nobody, today goes down to component level on the PCBs, so if you can read a manual you can do it.

Because of this I never followed up on my El. knowledge, kept to the mecanics. And today I am, as you Søren, fumbling around and starting getting into a new world, but with a Danish electrician at hand you are better of than me.

What I have learned with more than 40 years as a trouble shooter is, there are no big m/c's, only a lot of small parts, and thats the same in electronics. You start at the feed lines, using the drawings (street maps), and then goes step by step until you are down to the area or component-s that causes the trouble, with these vintage items the main problem is finding spares that fits. We will never get to Martin level, nothing beats experience.

And as you I feel like 18 year old when I work with these items, but when I get it working, I feel like a 6 year old on Xmas Eve.

And remember, there are no stupid questions, only stupid people that don't ask them. And making stupid failures is part of a learning process, nothing to be ashamed of, but publish also your failures, somebody will learn from it.

If you make the same stupid failure 3 times, you are fired

Re: BM 4000 Mexico

Søren Hammer — Sun, 08 Jan 2012 06:19:06 GMT

Good work, Søren. More thorough than my "simple" 4400 capacitor replacement thread and you're better at explaining the technical stuff.

As an 18-year-old, I still have a lot to learn in electronics though I was raised by an electrician

Re: BM 4000 Mexico

chartz — Sun, 08 Jan 2012 05:40:23 GMT

Nice work Søren!

There is no "ambio" record. There were quadraphonic ones, but you needed four amps to take advantage of them, along with a special cartridge and a 4 channel decoder (Beomaster 6000, and a Beogram 6000 with the special on-board decoder and an MMC6000 cartridge).

The ambio thing is a pseudo-acoustic trick which involves extra speakers to re-create a depth impression with normal recordings.

Re: BM 4000 Mexico

Søren Mexico — Sun, 08 Jan 2012 01:44:25 GMT

Have been playing now, at volume level 3-5, for about 5 hours, FM, Phono and Cd through tape one, all 6 preset station scales are spot on, main scale spot on, AFC works, filters works, Loudness works, speaker 2 works.

Cooling elements stays at hand warm level all the same.

To play ambio, is it posible without an ambio record ??

Re: BM 4000 Mexico

yachadm — Sun, 08 Jan 2012 00:44:28 GMT

Very good!

I'll learn from you, so I don't make that mistake!

Enjoy it - it's a first-class unit.

Menahem

Re: BM 4000 Mexico

sonavor — Sat, 07 Jan 2012 18:47:33 GMT

Looks great Søren.

-Sonavor

Re: BM 4000 Mexico

Søren Mexico — Sat, 07 Jan 2012 18:43:00 GMT

Got to it today, the failure I made was reading the drawings when I installed the big transistors, in the drawings the placement is different from the real placement, drawings says left to right, 3001, 2501,3001, 2501. Real is left to right 2501, 3001, 3001, 2501, and thats why the left channel didnt work. Good thing is that I learned a lot from searching and measuring, bad thing is that I have to realize that I'm stupid

After changing the transistors and a pair of resistors that showed diff. values right to left channel, I powered up and there it was, what an amp, way better than my 901 and 2400, now I cant wait to get 3702s connected, waiting for parts.

Here the BM 4000 playing, very good amp even with my 2 way S45s it sounds way better than my BM 2400, I'm Happy