General Forum

Re: Beosystem 5500 - Good Value?

tournedos — Sat, 27 Feb 2010 08:06:44 GMT

Hi Paul, welcome to the forum. When you have questions, it is usually better to start a new topic instead of continuing a very aged one like this - those easily get lost in the traffic.

As to your question, do you have the two links inserted in the line in/out sockets in the rear panel of the Beomaster? Do you have headphones you could try to see if the volume is fine there?

A faulty muting relay would not affect speaker 2 outputs.

Re: Beosystem 5500 - Good Value?

paulsartbarn — Tue, 23 Feb 2010 10:48:57 GMT

Hi Peter, I'm new to B & O. I just bought a new used system. Everything communicates and works ok except I have a fraction of the volume I should have. This is from speakers 2. Nothing from speakers 1. Mute switch does not work but will turn the receiver on/off. Is this the mute relay problem you mentioned?

Thanks, Paul

Re: Beosystem 5500 - Good Value?

henrik — Sun, 18 Jan 2009 17:23:48 GMT

Thanks Mika! Then I'll try an external amp for a while, I have an old Luxman power amp gathering dust somewhere...

Re: Beosystem 5500 - Good Value?

tournedos — Sun, 18 Jan 2009 17:19:01 GMT

henrik:
Peter, are the PL outputs of the 6500/7000 done in the same ugly way as the "pre-amp" output of the 5500?

According to the BM6500 service manual, the PL signal is taken from between all the controls and the power amp input (meaning the nice way ). I can't see why the 7000 would be different.

Re: Beosystem 5500 - Good Value?

henrik — Sun, 18 Jan 2009 17:12:11 GMT

Peter, are the PL outputs of the 6500/7000 done in the same ugly way as the "pre-amp" output of the 5500?

Re: Beosystem 5500 - Good Value?

Peter — Sun, 18 Jan 2009 17:06:46 GMT

On the 6500/7000, the line out is before the volume and tone controls - the circuit diagrams are on site.

Re: Beosystem 5500 - Good Value?

Peter — Sun, 18 Jan 2009 16:58:17 GMT

Just finished talking to the author of the capacitor removal wheeze! He says leave the other capacitors alone - he did have a look at this and they will make no difference and do serve a purpose. And don't play with the CD5500 as it is very good already!

On the line out plugs, there are two. The line in and out which are normally linked are before the volume and tone controls - I use this for my headphone amplifier. The so called Pre-Amp out is nothing of the sort and is just attached to the speaker outputs but with big resistors attached! The 5500 doesn't have Powerlink sockets.

Re: Beosystem 5500 - Good Value?

Alex — Sun, 18 Jan 2009 16:40:54 GMT

The signal is from just after the tone, balance and volume controls. I've never used the PowerLink outputs for driving other amplifiers with the exception of once driving a subwoofer from them for a party.

Re: Beosystem 5500 - Good Value?

henrik — Sun, 18 Jan 2009 16:34:14 GMT

Interesting! I've never been impressed byt the sound quality of my bm7000, some of my older beomasters (a 6000 and two 8000s) sound clearer and also have better control of the lower frequencies.

Some of this probably has to do with the M150s I use with the 7000, and I plan to renovate them (I've talked to Martin/Dillen about this), but a couple a weeks ago when I temporarily replaced the 7000 with an 8000 I realised that the main problem in my livingroom system is the bm7000 and not the speakers (I still plan to renovate them, though).

I find this subject very interesting since I want to keep my 7000. However, I've got two rooms (with MCL2AVs) connected to the 7000 via MCL2, so I can't do any alterations that disrupt the MCL service.

I realise that the main problem of the 5500/6500/7000 is the power amp, and I'm tempted to try a good external power amp via the mysterious "line" connector - is this a normal "pre out"/"main in"-loop or is it more of an "exernal eq"-loop? On the other hand, the MCL outputs will be silent if I use the "line" connector. Hmmm. :-/

What about the powerlink outputs? Are they connected at the "correct" point in the signal chain (that would imho be after the volume control and tone controls, but before the power amp), or has the PL signal passed the power amp? Would they provide a good, non-degraded signal for an external power amp and still allow me to use the internal power amp for the MCL rooms?

Re: Beosystem 5500 - Good Value?

Alex — Sun, 18 Jan 2009 16:13:10 GMT

Corrected, I of course mean low-pass filters.

I would be interested if you find any issues related to the filters - I for one have always been impressed with the transparency and musicality of my CD7000.

Re: Beosystem 5500 - Good Value?

tournedos — Sun, 18 Jan 2009 15:48:44 GMT

You of course mean the low-pass filters. This filtering is done before the output buffers, and the bypass caps are after them, right before the signal exits the player. The CD5500 service manual has an enlighteningly thorough discussion on the filtering that is used in the B&O CD players that have similar electronics.

I'm not really sure if I came up with this myself or if I have read it somewhere years ago (I'm getting old you see), but in the early days of CD it had to apologize for its existence by beating the analogue audio by every means measurable. One of these was signal to noise ratio. Even though the antialiasing filtering is good this time, it may pass through high frequency components that can be mistaken for noise especially if the measurement bandwidth approaches the upper limit of theorethical bandwidth (22.something kHz). I believe the puny 2.2nF caps are there to help shunt these HF components and I'm sure they shortcircuit some of the music as well... I'll have to do some tests

(sheesh - I'm supposed to be an engineer in digital signal processing, and here am I discussing the musical merits of tiny button caps )

Re: Beosystem 5500 - Good Value?

Alex — Sun, 18 Jan 2009 15:23:44 GMT

It's possible any high-pass filters are there to eliminate or reduce quantization noise. There's a high probably I'm talking absolute nonsense though!

Re: Beosystem 5500 - Good Value?

tournedos — Sun, 18 Jan 2009 14:36:53 GMT

Alex:
As soon as I ditched the DM7s and went for a (much) easier to drive speaker, the issues became much smaller. Therefore I can conclude that the Beomaster 6500 does seem to struggle with higher-than-normal loads.

As some readers probably remember already, I have Beovox Pentas which have been said to bee "too difficult" for these Beomasters. I recently upgraded their crossovers with new (and considerably better) caps, and now I begin to feel it was worthwhile - this combination sounds now so silky smooth that I probably have to relisten through all my CDs

Encouraged by this, I will probably tackle the preamp board later, as well. Most equipment has some components that from purely audiophile standpoint are unnecessary - the most notable of these IMHO are the small bypass caps across each input. They are probably there to filter out some noise and/or to protect the Beomaster from external interference (or vice versa) - or just to keep the signal/noise ratio great on paper - but I can't see them doing any good to the actual music in environments where they are not needed. In fact, the CD5500-7000 seems to have two HF filter caps across both signal outputs, and I'm sure they need to go...

Re: Beosystem 5500 - Good Value?

Alex — Sat, 17 Jan 2009 15:21:49 GMT

Percussion is something that I too have found to be a little disappointing with the BeoMaster 6500. I remember listening on my B&W DM7s (which I have since sold) and finding them a little on the dull side when it comes to percussive transients when connected to my Beosystem. However, when listening to them on the end of £14k of Naim amplification at my local hi-fi dealer, I couldn't believe the sound produced! In fact they sounded so good that even a pair of Linn Ninkas (admittedly not the most exciting sounding speaker) sounded comparatively dull and lifeless with percussion.

Now this I would expect seeing as the Naim power amps, power supplies and pre-amp cost £14,000, and my Beomaster 6500 cost me ~£200 But upon listening back at home, the differences between my Nad amplifiers and my Beomaster 6500 seemed quite large.

As soon as I ditched the DM7s and went for a (much) easier to drive speaker, the issues became much smaller. Therefore I can conclude that the Beomaster 6500 does seem to struggle with higher-than-normal loads. These modifications would be quite interesting to hear, although I doubt I'm skilled enough to attempt the modifications.

Re: Beosystem 5500 - Good Value?

tournedos — Sat, 17 Jan 2009 07:34:25 GMT

OK, job done - it took almost an hour including de- and restacking the Beosystem and I don't have another amp from this series to make comparisons. A revelation may be too strong a word, but there definitely is a difference. For a test drive, I listened to Dire Straits' Telegraph Road before and after, and I'm pretty sure the percussions sound clearly nicer now.

It's not a quickie job since you have to open both the top and bottom of the Beomaster and the caps are under the fan channel, but fortunately the bottom is much easier to expose than it seems at first. I'll try and post a couple of pictures after Keith lifts his curfew