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Yamaha DSP-A1 Centre Channel Issues

Discussion in 'Integrated Amplifiers & Receivers' started by ChuckMountain, Apr 17, 2009.

  1. ChuckMountain

    ChuckMountain Member

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    I have had my Yamaha DSP-A1 since new and used daily as the main TV sound for 10 years and apart from a few missing character on the display which I have fixed its never skipped a beat.

    However it now seems to be having an issue with the centre channel whereby it will suddenly go quiet and no output will be heard. I have checked the wiring and the speaker and they work ok so it must be the amp. Ocassionally if I play around with the volume or if a particular loud programme comes on it will kick back in again.

    It sounds like a loose connection or failing component but I wonder if anybody has any ideas as to what I can check.
  2. diamondmask

    diamondmask Member

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    Can't help with your problem but would be interested in any solution found. I have a similar problem with my Yamaha receiver of similar vintage, but on mine its the rear left channel. Turning the volume up then down a couple of times, usually sorts it out until the amps turned off.

    Fingers crossed someone knows a cure, cos I cant buy a new amp yet, cos no ones got any to sell!!!!
  3. Meridius

    Meridius Active Member

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    I have the yamaha A2 and my left did the same went realy low compaired to the other channels. I tried everything and could not get it to go so what i did was used the main B channels and not the A Main channels and it worked.

    I tried going back to Main A again and still no go so i think your amp might have a faulty amp to that channel, every time i read about faulty A1 or A2 its seems that 1 channel seems to go.

    so your options are to try and get it fixed or buy a new amp i bought a new amp which is the Yamaha RX-V3900.

    i am even thinking of selling my A2 as it can still be used as a 5.1 and music system as long as you dont use the Main A channels

    i was abit lucky as i could do this but if the centre goes which rubys did on here or the rears your buggered abit.

    but this seems to be a comon fault with these amps after this age as i have had my A2 for 10years to

    hope you get sorted
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    Last edited: Apr 19, 2009
  4. SupplementMan

    SupplementMan Member

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    Hi Chuck, I've been researching this same problem for my Yamaha DSP-AX1 for the last day and this is essentially the same amp as your A1 with a few extra bells and whistles. I've only had the thing a month and everything was working fine until 1 of the channels went out, then a second :eek:

    The only difference being my Main A and B, left channel had the problem (or was it right?)

    It does seem to be a fixable problem, here's some quotes I found that talk about fixes:

    Quote 1:

    'That is easily fixed, the problem which occured on some units was due to a sticky switch that wouldn't make correct contact. It was only ever an issue on the front 3 channels, all of which can very easily be connected from pre-out to power amp in, using a short rca-rca which bypasses the mini switch all together. :smashin:'.

    Quote 2:

    'If you don't want to use a service center then use some short phono leads to join the 'pre out' jacks to the 'main in' jacks. All the relays are, are links between those jacks anyway. :smashin:'

    Quote 3:

    ' Could this be the dreaded main in/main out switch problem on the speaker output pcb?

    This was very common on the DSP-AX1.

    At the rear of the phono socket on the DSP-AX1 there was a small switch to sense if another pre amp was being used on the main channels.

    Sometimes they got dirty and some, if not all of the sound was lost on the affected channel.

    Get some switch cleaner and a tiny toothbrush (those really dinky ones...or a cotton bud) and spray down the center of the affected channel main input on the back of the amp (2nd from bottom on AZ2 next to speaker sockets) and work the cotton bud in and out to move the switch on and off to work the switch cleaner into the switch.

    The amp MUST be off whilst this is being done.'

    Now I'm not a technical man but I fancy having a go at fixing mine myself as it sounds simple enough, anyone else fancy having a go and sharing the wealth of wisdom to fix out mutual problem? I don't even know what a phono or rca-rca lead is, I've only been running it as a 2.0 as I'm completely new to HC. Any help would be very very welcome
  5. ChuckMountain

    ChuckMountain Member

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    Thanks for the info but unfortunately the A1 I don't believe has the micro switch, instead it relies on an external jumper that plugs the pre-out into the amp. Effectively its already doing what is suggested in option 2.

    When I get the wee hernia inducing thing out I will have a better look :)

    As for a phono-lead (or rca-rca) its just the leads you would normally use to plug your CD/DVD/TV player into the amp when you using the analog outputs. The cheapest ones are normally have white and red plugs. It would be recommended if you need to go down this route to get the shortest possible good quality lead so you don't get any interference.
  6. Replicant

    Replicant Member

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    Hi Chuck,
    Same thing has just happened to my A1 only its affecting the left and right main channels, I'd been toying with the idea of upgrading to the Z7 and this made me finally crack. However initial impressions of the Z7 are that it isn't the same build quality of the A1 and I'm not getting the wow factor I was expecting. I'm certainly going to try and repair the A1 its still too good to let go.
  7. ChuckMountain

    ChuckMountain Member

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    Thanks. I was looking at the Z7 as well though funds are too tight at the moment. The build quality interests can you elaborate a bit more.

    What speakers are you driving with it. I found the auto setup in the play room (Yammy 2600) turned a lot of the bass so whilst it might have been truer it didn't sound as good. However the biggest diff was listening to Casino Royale over LPCM rather than DD over optical (admittedly via PS3) but it was totally subdued compared to DD.
  8. SupplementMan

    SupplementMan Member

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    So if I do attempt the RCA-RCA fix do I have to take the thing apart and patch it together from inside the unit, removing the cover, or just connect from the ins-outs on the back of the receiver (I said I had no tech skills) :lease:
  9. SupplementMan

    SupplementMan Member

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    Not sure if this is any use to you considering you have a PS3 but I found this info:

    You still may be able to hear Uncompressed PCM, Dolby TrueHD, or DTS-HD Master with your older model receiver. (by "old school", I mean non-HDMI)

    For those of you who have a standalone bluray player (not the PS3, as it does not have multichannel analog output)...there is hope for you yet.

    I am posting this for those who are not very tech savy. For those who may be using an optical cable still, and have no idea that lossless audio can be achieved even with older model receivers. To cut to the chase...

    if your receiver has mutlichannel analog inputs...then you can hear lossless audio. You will need to buy 3 sets of these analog cables. Just connect to your bluray player, and you will have lossless audio in no time.


    This thread is intended for those who do not have an HDMI receiver but do have a Bluray player with Multichannel Analog outputs and an old school receiver with analog in's.

    I know this is fairly common knowledge but there are still those out there who have no idea. And Im all about bringing everyone the best blu experience possible. This can work for audio in conjunction with component cables to the receiver, or even HDMI directly to the TV for video and the analog cables to the receiver for audio. So stop using optical, and get with the HD audio. [​IMG]

    EDIT: TrueHD and Dts-HD can only be passed as Bitstream using an HDMI cable. For Multichannel Analog you would need a Bluray player with Internal decoding capabilities (into Linear PCM).
  10. ChuckMountain

    ChuckMountain Member

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    No need to take apart just plug a lead in on the outside from the preamp out of the affected channel to the power amp imp. Should be fairly obvious which one.

    At the moment I have my A1 in the lounge with a HTPC which I use for movies and Sky HD so works ok at moment.

    My (kids) play room has pj with 2600 which is doing LPCM from PS3.
  11. SupplementMan

    SupplementMan Member

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    Hmm the RCA wouldn't plug into the back of the out but would go into the in. I'm really puzzled with this fix :confused:

    However after having the AX1 powered down it worked anyway :confused: I doubt it will be uninterupted use though

    PS has a post been deleted on this topic, I had a post emailed to me on this thread but its not on the actual thread
  12. Replicant

    Replicant Member

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    Hi
    I'd posted a reply to Chuckmountain and then decided it was too much waffle for everyone so I thought I'd emailed it to chuck and then deleted the post, probably screwed that up so sorry for any confusion. Teach me not to try and rush posts during lunch.
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  13. Ruby

    Ruby Member

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    I'm having a similar problem as described on this thread with my DSP-A2 - the centre channel seems to be weaker compared to the other channels. I've tried to replace the A2 with a 1900, but I've discovered that it's not in the same league. So I plan to go back to the A2 (without a centre channel if I have to). I've attached a picture of the back of the A2. Is there anything I can possibly do to get the centre channel working at its full capacity again?

    Attached Files:

  14. Matyam

    Matyam Member

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    Unfortunately i had same problem with my A1 the centre stopped working and started again but then i started getting crosstalk between channels.Itook it to a repairer who told me the DSP board was gone and it would be £450 thank you.Funds dictated buying a AX1 fo £300 and perhaps a decent analogue out bluray player if one exists to make use of that yamaha sound.
    On perhaps a more useful note try cleaning the centre contacts or plug in to other centre connection good luck
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  15. ChuckMountain

    ChuckMountain Member

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    I might try a different centre connection. It did seem to start after I did a tidy up of cables but who knows.

    I suppose the alternative is to not use the centre channel (set the centre to none) although it does sound different like that strange having the sound come for the front sides :)
  16. Ruby

    Ruby Member

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    Sorry guys, but what do you mean when you say other or different centre connection?
  17. ChuckMountain

    ChuckMountain Member

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    On the A1 out of the box there is a jumper between the pre-out and power amp in for the left, right and centre channels. If you disconnect this jumper you will not get any sound on the particular channel.

    The idea is should you wish you could use a separate power amp for the front 3 channels you can hook it up by removing these jumpers and putting a phono cable to the amp.

    If there is a fault with this jumper or the connection then you could lose a channel. A lead with a slightly longer centre pin might resolve it if that was the problem.

    On the newer AX1 the jumpers were removed and a microswitch inserted which if a phono lead was plugged in switched off the amp. These over time would get stuck and you would loose a channel.
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  18. SupplementMan

    SupplementMan Member

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    So I need to buy a seperate power amp to connect to the AX1 Pre-Amp for the affected channel?? Will the power amp maintain the sound quality?

    1 of the Mains and centres went out again today, worked fine for the last week, so frustrating.

    Cheers - Andy
  19. ChuckMountain

    ChuckMountain Member

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    No, my understanding on the AX-1 if its the microswitch is you just need to put a phono lead from preamp to the power amp in for the affected channel. You should be able to test with a cheap cable to see if this does the trick. If it does buy a better cable to replace it.
  20. IAN P

    IAN P Member

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    Just to chime in here,I had the AX-1 left front channel issue and resolved it by using the jumper bars from my 3090.Fixed the problem straight away.

    So using RCA cables would be the same.


    Still can't part with it even though i've got the Sony.
  21. phantom8

    phantom8 Member

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    I've a DSP-A1 and it exhibits similar issues on both the main left & right channels. The main speaker volumes sometimes goes down for a while and then back to normal. It's very frustruting while listening to stereo music.

    I tried to replace both the jumpers with BNC cables at the back for pre-amp & power amp, but it didn't fix anything. Unlike the AX1, there is no switch to clean. Does anyone know how to fix this volume issue for DSP-A1? Thanks in advance!
  22. Dave H

    Dave H Active Member

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    I have the same problem with my main left :(

    Dave.
  23. ricobilly

    ricobilly Member

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    I have the exact same problem with both of my main channel it is driving me crazy, but I found solution that temporarily by passes it. The A1 actually will have the volume jumped to a muted level for the affected channel, so to bring all the channel back to the same level, I press the mute button on the remote, what this does is to mute all your channel to the same low level, then i simply turn the volume back up. However, I call this a temp fix is because I think the sound don't sound as good as it did before. (it kinda of lost the high range) from what i feel.

    the other day I was told that I can spry some kind of oil into the knobe of the volume, It kinda work for a while, but soon the problem comes back.

    If anyone found a real solution that can preeminently fixes it :lease: help.

    although the A1 is really old, but I love the sound from it.
  24. Ruby

    Ruby Member

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    I was having problems with the centre channel with my A1. I today tried the fix of replacing the centre in and out connections with an phono cable, and it does seem to have made a difference.
  25. pele1977

    pele1977 Member

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    I have problem too. Sound level is more quiet in left channel than it is in right channel. Anybody got any solution for that?
  26. Ruby

    Ruby Member

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    Although I tried the fix mentioned in this thread, and it has made a difference, the amp still doesn't produce sound to the level it should. I am honestly beginning to think that about a decade is the useful life you can expect from and A1 or A2. A lot of people seem to be having problems with them after that period.
  27. Jaruzel

    Jaruzel Member

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    Hi All,

    Found this thread while searching for a solution to my AX-1 centre channel suddenly going quiet....

    Well, doing the 'pre-amp-out-to-main-in short' has fixed that problem nicely (thank you previous posters!) I discover that my rear left channel was intermittent, and while working on the centre fix, it went silent also.

    Now, you can't do the pre-amp trick on the rears as the AX-1 doesn't support that, but it DOES have a line-out phono for the rear effects in case you want to drive them with another amp (seriously, has anyone ever done this? the AX-1 is powerful enough I think), so my guess was that there is ALSO a microswitch inside that phono socket - I shoved a phono (rca) plug into it, and wiggled hard (technical term) then removed it, and the dead channel sprung back into life at full volume. Yay! 2 1/2 hours later of testing with Revenge of the Sith (hehe), and I'm sure it's working fine...

    Posting this for others to read and find useful.

    -Jaruzel
    Last edited by a moderator: Sep 10, 2009
  28. jasonf01

    jasonf01 Member

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    Hi everyone,

    If you ever looked up a Youtube video showing someone fixing a DSP-A1 screen on a channel called "the home zone" or something like that, that was me doing the soldering, dismantling and reassembling of my friends A1. :hiya:

    I used to have a DSP A1, and had a similar audio problem with the subwoofer outputs. They would be completely dead unless you pressed in on the volume dial, or occasionally they would suddenly spring to life if I cranked it up. I also noticed that occasionally the volume light was a little intermittant.

    In my case, the cause was worn/dirty tracks and sliders in the main volume potentiometer, and its an extremely involved operation to dismantle to do much about.

    However, its possible. I did mine, and it worked fine until I sold it early last year.

    >DISCLAIMER<
    This is what I did. It worked for me, your mileage may vary. Please dont blame me for damage/loss/breakage/electrocution of yourself/dog/cat/budgeriegar or any other underqualified animal/person.

    What you have to do is dismantle the front and top to the point where you can extract the volume control board from the unit (this is an absolute pig of a thing to get out if I remember right), then check for bad joints (these crack with the heat cycling in the same way as the flourescent displays pins, or can crack and break if the volume control has taken a knock, its a rarer fault but worth checking before going further as this is an easy fix if this is the fault).

    If all the solder joints look/test OK, check for other signs of knocks, eg, metal tabs broken off, bent out etc, these will all affect the ability of the slider to reliably touch against the track inside the potentiometer. Again, if theres physical damage, try and fix this and see if it solves the problem before going to the last posibility.

    Your last chance here is not a nice one. Desolder the whole potentiometer from the board, then dismantle it. Its not supposed to be dismantled, so you do have to be gentle with some parts - especially the metal tabs that you have to bend straight to dismantle and bend back again to reassemble. Once youre inside, you should be able to see the hub holding multiple sliders which contact the tracks on the multiple small PCBs which sit around the hub (which lead to the pins you just desoldered).

    Its usually these sliders that need either cleaning or a little reforming to provide more "spring" against the track, though a little contact cleaner on the tracks wouldnt go amiss.

    This is a very complex volume potentiometer and a known weak point (in my opinion) of the DSP brand though I believe the RX-V2700 I upgraded to might use a digital control instead, so they might have sorted it in recent models (though that doesnt really help if you still use the DSP-A1). Keep notes where everything goes, because if you forget how to put it back together, youre in biiiig trouble.

    So for the people who tried plan A with the pre-out/power-in connectors and it didnt work, or for the people who are having problems with other channels, this is a possible culprit and a possible solution. Its just not an easy solution.

    Ive got to say though that the DSP-A1 was a great machine and apart from a few known weak points should last decades, so its definately worth fixing...

    ...or giving to me for parts. I wont fix it and sell it on...honest! :)

    Jas.
  29. samhain

    samhain Active Member

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    I just received a second hand (Mint) AX1 and the centre channel test tone as well as the rear surrounds are extremely loud and vibrant. THe front left and right channels are making a test tone noise but are very quiet by comparison.

    I have dropped the other channels by -10db just to get any kind of consistent listening level. Is the solution the RCA to RCA that everyone talks about?

    Could someone tell me exactly what RCA needs to go where for me to try and fix this.

    Thanks
    Stu
  30. Jaruzel

    Jaruzel Member

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    Hi Samhain,

    I'm pretty sure you need to connect the 'Main In' sockets to the 'Main Out' sockets - these are located on the rear of the unit at the bottom next to the 'RS-232' port and the B/A Main Speaker terminals.

    Using a normal cheap phono cable (looks like a metre long black cable with Red and White phono plugs on each end - comes free normally with new kit), connect the white plugs to the white 'Main In' and 'Main Out' sockets, and do the same with the red plugs into the red sockets.

    This may or may not solve your problem, but is what people are discussing in this thread.

    Cheers,

    -Jar
    Last edited: Oct 4, 2009

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