Distortion on centre channel after prolonged use - time to change receiver?

Alex P79

Active Member
Hi

Edit - I appreciate I asked a similar thing a few months ago but after lots of research I am going around in circles a bit with this. I am weary about buying used AV amps due to head build up/reliability/complexity so new or ex-demo with warranty are the options. Ultimately I don’t want to spend circa £1k and still have the same problem - this would cause discord within the household.

I have a Teac AG-H550 Reference Series 5.1 receiver (about 18 years old!) Celestion AVF302 fronts (the glass ones), Piega S4c centre, Piega T-60 micros rears (yes the best speakers are the rear ones!) and BK Gemini II subwoofer. The TV is a Loewe Art 40 full HD And audio is fed via digital coax from TV to amp. Streaming by Amazon 4K fire stick directly connected to the TV.

After watching a film etc. for an hour or so the sound of the centre channel can sometimes distort and go quiet. It does not always happen but it is annoying when it does. Is this usually the sign of something giving up in the receiver? It has never gone into protect mode and does not appear to distort in the other channels. All the Piega speakers are 4ohms and I have selected the 4 ohm switch on the back.

I know receivers have come on along way technology wise in the last 18 years. What’s the opinion on buying a new one (if i can get one at the moment), taking advantage of the latest tech/room EQ/connectivity in the hope that this solves the distortion problem?

My short list is:
Marantz SR5015 or 6015 if its worth the extra £300 over the 5015? Silver/gold would be preferable.
Denon AVC-3700 (the £1,000 one)
Arcam AVR390 that Peter Tyson are doing on run out.
All of the above must be happy supporting a full suite of 4 ohm speakers as I will probably replace the Celestions with another pair of Piegas at some point. Adding a second BK sub and front heights would be long term goals too.
The receiver also needs to have a full set of preouts in case I add power amps in the future, so the Denon 2700 is no good I’m afraid.

Of course Hyperfi offer the previous generation Marantz/Denon models at a significant saving as B-stock - is this a good idea or not?
I don’t use this system for music or gaming - just 100% film/TV series use for a few hours a week if were lucky.

Regards

Alex
 
Last edited:

DaveWillo

Member
Have you tried connecting one of your L/R speakers to the centre channel terminals of your AVR, to identify if the issue is with the AVR or the centre channel speaker?
 

Alex P79

Active Member
Have you tried connecting one of your L/R speakers to the centre channel terminals of your AVR, to identify if the issue is with the AVR or the centre channel speaker?
That is a good idea - I had thought about it but wonder if the speakers need to be 4 ohms to repeat the problem? The trouble is that it’s an intermittent fault but I could try swapping with one of the rears - will give it a try.
 

stranger

Well-known Member
Regardless of the fault- put the switch back to 8-16 ohms (even though your speakers are 4ohms) They are being starved of power at the 4ohm setting.
 

Alex P79

Active Member
Regardless of the fault- put the switch back to 8-16 ohms (even though your speakers are 4ohms) They are being starved of power at the 4ohm setting.
Thanks - yes I pulled everything apart and cleaned everything this afternoon. I put the switch back to 8 ohms.
 

Alex P79

Active Member
Slight update on this. Ran the Piega centre speaker for a few hours listening to music at quite high volume on another system and there were no apparent problems.

Also played DVDs/Blu-rays on the av system and the fault did occur, which rules out it being related just to the Fire stick.

Yesterday I replaced the thin rear speaker wire with QED strand 79 14 AWG wire (now routed under carpet) and the rear Piegas now sound so much better - rear effects are now so much more pronounced and sound field more immersive.

Last night we watched the Hobbit and all was fine until about 1 hr 15 in when there were a few quiet moments from the centre and slight distortion but nothing major. Unlike previous sessions with the older rear speaker wire where all the other speakers also went quiet (though no apparent distortion) this time all the other speakers sounded fine. The amplifier was clearly warm/hot to touch but perhaps not as warm as previously.

Would this suggest that, thanks to the better speaker wire, the amp in under less strain than before (less resistance in the cable) but some heat build up in the amp is still causing issues when it gets hot? The amp is 18 years old after all…

My next test will be to try another 4 ohm Piega speaker as the centre and see what happens there. Hopefully this will give a definitive result. I don’t want to spend the thick end of £1k on a new receiver only to have the same problem - my name would be mud!
 

Gasp3621

Distinguished Member
Slight update on this. Ran the Piega centre speaker for a few hours listening to music at quite high volume on another system and there were no apparent problems.

Also played DVDs/Blu-rays on the av system and the fault did occur, which rules out it being related just to the Fire stick.

Yesterday I replaced the thin rear speaker wire with QED strand 79 14 AWG wire (now routed under carpet) and the rear Piegas now sound so much better - rear effects are now so much more pronounced and sound field more immersive.

Last night we watched the Hobbit and all was fine until about 1 hr 15 in when there were a few quiet moments from the centre and slight distortion but nothing major. Unlike previous sessions with the older rear speaker wire where all the other speakers also went quiet (though no apparent distortion) this time all the other speakers sounded fine. The amplifier was clearly warm/hot to touch but perhaps not as warm as previously.

Would this suggest that, thanks to the better speaker wire, the amp in under less strain than before (less resistance in the cable) but some heat build up in the amp is still causing issues when it gets hot? The amp is 18 years old after all…

My next test will be to try another 4 ohm Piega speaker as the centre and see what happens there. Hopefully this will give a definitive result. I don’t want to spend the thick end of £1k on a new receiver only to have the same problem - my name would be mud!

Have you bumped the crossover setting at the Teac menu 120-150hz for the centre cause that S4C centre has tiny 3" drivers in small cab so it´s no suprise this small lifestyle speaker doesn`t perform as you would hope. I don´t think the receiver upgrade is needed purely for this issue, i would rather look better larger speaker especially if you listen at louder levels cause the small drivers can only do so much and run in to distortion.

However now i noticed you talking about dual subs and heights for Atmos so the receiver change is ahead anyway. You could wait little bit to see the new Onkyo/Pioneer receivers at 1k£ range with Dirac Live and Yamaha comes soon too with RX-A4A model. Availability is poor now for most stuff and due to that the prices are higher than when they were released! Don´t buy SR5015 it´s basically X2700H with preouts and not the Audussey version you want. But first i would look better center channel. However it´s always bit risky to mix brands at front and those Celestion speakers are early 2000 so perhaps it`s time to look new LCR from same brand & range. Or at least make sure you have return option for the new center channel.
 

Alex P79

Active Member
Have you bumped the crossover setting at the Teac menu 120-150hz for the centre cause that S4C centre has tiny 3" drivers in small cab so it´s no suprise this small lifestyle speaker doesn`t perform as you would hope. I don´t think the receiver upgrade is needed purely for this issue, i would rather look better larger speaker especially if you listen at louder levels cause the small drivers can only do so much and run in to distortion.

However now i noticed you talking about dual subs and heights for Atmos so the receiver change is ahead anyway. You could wait little bit to see the new Onkyo/Pioneer receivers at 1k£ range with Dirac Live and Yamaha comes soon too with RX-A4A model. Availability is poor now for most stuff and due to that the prices are higher than when they were released! Don´t buy SR5015 it´s basically X2700H with preouts and not the Audussey version you want. But first i would look better center channel. However it´s always bit risky to mix brands at front and those Celestion speakers are early 2000 so perhaps it`s time to look new LCR from same brand & range. Or at least make sure you have return option for the new center channel.
Hi - thanks for the reply. I run the centre as small (same as the fronts) which are crossed at 90hz. Unfortunately the Teac does not have the ability to adjust the frequency of the crossover - the settings as none/small (90hz +)/large (full range). That’s it. Volume level I tend to run is circa 45 out of 80 - never any more than 50. All speakers are set at 0 for relative volume.

Ref the S4c, this morning I have been running it full range as a left speaker on the bedroom system (Arcam Movie 2.1) while painting the ceiling (joys of a holiday) and had no problems for the last two hours. The specs for the S4C are a lower frequency of 80hz (no roll off specified) and power wise the Teac is well within specs. Therefore, provided it is fault free (which it appears to be) then it should be up to what I require. I appreciate a larger centre speaker would give me more but bear in mind I have an Arcam/Naim/Tannoy/dual BKs HiFi system at the other end of the lounge I’m not convinced my wife would want anything more ‘visible’. The Piega centre stores out of sight when not in use. Ref timbre matching with the Celestions, they work remarkably well together - better than I expected TBH so I’m happy with the front set-up for now provided it is all working!

Ref receivers, the feedback on the 5015 is useful thanks - clearly the 6015, Denon 3700h or the Arcam 390 are the best options. I appreciate that at the moment availability is a major issue and therefore, even if one can find stock, there are very few deals to be had. Tonight I’m going to watch the rest of the Hobbit with a different 4ohm speaker and if the problem appears again I know it is the receiver rather than the speaker.

Regards
Alex
 

Alex P79

Active Member
Another update - watched more of the Hobbit saga (I forgot there are 3 films!) over the last few nights. One evening I replaced the the Piega centre with a Piega TS3 from the bedroom system - another 4ohm speaker. Net result, no issues but I had to turn the centre up a bit to get the same level - speech also not so clear.

Yesterday evening I removed the grille from the S4c to visually inspect it - no apparent problems - all looks as it should be. Watched more of the Hobbit with the S4c reinstalled + I borrowed a second sub from the HiFi system to see what it was like - same type of subs. Ref the S4c - no issues at all - lovely clear sound and dialogue all the way through. Ref the system overall - the second sub really added to the system and brought a big improvement - so much so that, in combination with the better speaker wire for the rears, I had so turn the system down a few clicks as I found it uncomfortably loud yet there was no strain coming from anywhere. I was happy with it TBH.

Net result 🤷🏻‍♂️ Possibly:
1) Much bigger/better gauge rear wire has put less strain on the amp? rear channels certainly sound much better - even my wife said the result was obvious.
2) When tested in different combinations everything seems to work fine.
3) Adding a second sub really does improve the experience in terms of headroom, volume and immersive effects. Installing one permanently in the correct position isn’t really possible (domestic harmony) so I wonder if BK will build me a passive version (easier to move) with the plate amp in a separate box that I can hide out of site behind the cabinet - failing that they may sell me the driver and amp so I can build my own version.

So provided everything continues to work properly I am happy at the moment - a second sub might be first on the list, followed by a receiver upgrade at some point when availability/choice/deals have improved so I can take advantage of the latest tech.
 

Gasp3621

Distinguished Member
Usually dual subs does bring benefits, but have you tried to move the original Gem II to where you placed the 2nd sub? Just to test has it been in poor position. Also if you going to add 2nd sub it really needs to be identical one, so another Gemini II in this case. And yeah time to upgrade that old receiver, it`s too lacking in settings if you can´t even bump the crossover higher. Sadly the brand is bit unknown these day so you like have hard time selling it, perhaps for some friend.

There is X3700H on the classifieds if you act fast and try to haggle the warranty move to 2nd owner. The guy lives at London which is little trip for you, but you would save about 300£ to new one.
 

Alex P79

Active Member
Usually dual subs does bring benefits, but have you tried to move the original Gem II to where you placed the 2nd sub? Just to test has it been in poor position. Also if you going to add 2nd sub it really needs to be identical one, so another Gemini II in this case. And yeah time to upgrade that old receiver, it`s too lacking in settings if you can´t even bump the crossover higher. Sadly the brand is bit unknown these day so you like have hard time selling it, perhaps for some friend.

There is X3700H on the classifieds if you act fast and try to haggle the warranty move to 2nd owner. The guy lives at London which is little trip for you, but you would save about 300£ to new one.
Thanks for the reply.
Ref the sub - I have not tried the original Gemini II in that position but it was a Gemini II that I also used - have dual Gemini IIs in the main HiFi system and it was one of those that I ’borrowed’ for the experiment. Unfortunately, neither of us would be happy with a second being permanently sited in the required position. This is why I wondered about a purpose built passive version using the same amp and driver/cabinet design/volume etc. It would be so much easier to unplug and pack away when not in use. I have just built dual passive 6.5 inch ‘bass modules’ using Dayton Audio drivers for the office which I am very pleased with so I could build the cabinet if required. The chap at BK suggested that I could buy the plate amp and driver if required, though we didn’t get round to discussing pricing. I guess they might be interested in a ‘custom build’ but I’m happy to DIY if required.

As for the receiver, I agree that it is time to move on. Unlike the matching DVD player, the receiver has lasted 18 years and it only cost me circa £200 as an end of line deal from Richer Sounds. It hasn’t been over-used but certainly no complaints. I appreciate that tech (formats/set-up/room correction) has really moved on but, from what I have read, I am a little concerned about the essentials/basics in a modern AV amp - the ability to deliver decent power for movies only, be free of glitches and with long term reliability - all things which I take for granted with my 2 channel equipment. Assuming that heat is the real enemy of AVR reliability long term, perhaps I should also invest in a fan system such as the AC Infinity range?

The 3700 you have linked to is certainly with consideration thank you.
 

Gasp3621

Distinguished Member
Thanks for the reply.
Ref the sub - I have not tried the original Gemini II in that position but it was a Gemini II that I also used - have dual Gemini IIs in the main HiFi system and it was one of those that I ’borrowed’ for the experiment. Unfortunately, neither of us would be happy with a second being permanently sited in the required position. This is why I wondered about a purpose built passive version using the same amp and driver/cabinet design/volume etc. It would be so much easier to unplug and pack away when not in use. I have just built dual passive 6.5 inch ‘bass modules’ using Dayton Audio drivers for the office which I am very pleased with so I could build the cabinet if required. The chap at BK suggested that I could buy the plate amp and driver if required, though we didn’t get round to discussing pricing. I guess they might be interested in a ‘custom build’ but I’m happy to DIY if required.

As for the receiver, I agree that it is time to move on. Unlike the matching DVD player, the receiver has lasted 18 years and it only cost me circa £200 as an end of line deal from Richer Sounds. It hasn’t been over-used but certainly no complaints. I appreciate that tech (formats/set-up/room correction) has really moved on but, from what I have read, I am a little concerned about the essentials/basics in a modern AV amp - the ability to deliver decent power for movies only, be free of glitches and with long term reliability - all things which I take for granted with my 2 channel equipment. Assuming that heat is the real enemy of AVR reliability long term, perhaps I should also invest in a fan system such as the AC Infinity range?

The 3700 you have linked to is certainly with consideration thank you.

Do you have any other options to place the dual Gemini`s in that room so that wife would agree on that? I don´t know how you tried them, but scroll about midway this link and you start to see the options which are most often used. It just sounds too much hassle and you require some DSP amp, i don`t know about those..

X3700H is quite tough to beat if you get new one for 1k£. It offers everything including great performance and handles 4ohm loads without issues. There is also preout for poweramp so no need to change receiver if you someday get dedicated room and need more power. The fan system you mentioned is very good idea. I see it used in US very often as people believe it will give longer life for the receiver so go for it! Another option is the upcoming Yamaha RX-A4A but it´s stuck on 7.2 if that matters. Yamaha is known from best reliability and they do offer 5year warranty as Denon/Marantz 2years in UK, however Peter Tyson gives 6year for X3700H and 5years for Marantz as total.

 

Alex P79

Active Member
Do you have any other options to place the dual Gemini`s in that room so that wife would agree on that? I don´t know how you tried them, but scroll about midway this link and you start to see the options which are most often used. It just sounds too much hassle and you require some DSP amp, i don`t know about those..

X3700H is quite tough to beat if you get new one for 1k£. It offers everything including great performance and handles 4ohm loads without issues. There is also preout for poweramp so no need to change receiver if you someday get dedicated room and need more power. The fan system you mentioned is very good idea. I see it used in US very often as people believe it will give longer life for the receiver so go for it! Another option is the upcoming Yamaha RX-A4A but it´s stuck on 7.2 if that matters. Yamaha is known from best reliability and they do offer 5year warranty as Denon/Marantz 2years in UK, however Peter Tyson gives 6year for X3700H and 5years for Marantz as total.

Hi - I have attached a few pictures of the room (ignore the party bags - we have my son’s birthday party today) - as you can see, space near the TV cabinet is limited - I re-position the speakers as required when watching a film.

The main HiFi system is at the other end of the room - they are not connected. There are two IKEA Kallax units, one either side of the main hifi rack. I have measured up and a passive version of a Gemini Ii (without amp controls) could fit in the ‘spare’ unit on the left for storage when not in use. When in use it could go next to the left main speaker as seen from the viewer’s perspective. This would have the added advantage of being stain black to match the Kallax and the two Gemini IIs in the main rig and it would be more resistant to marks when being moved than the gloss black! A final advantage would be that, if I purchased another plate amp, I could run a third central sub in the main rig.

As you can see, many of our walls are quite bare (plasterboard construction - reluctant to put anything too heavy up) but we might invest in some Nature Wall SlatWall acoustic panels to modernise the interior of the room. See the link below.


As for Atmos (once I replace the amp - thanks for info ref warranty at Peter Tyson - very useful) I think a couple of Minx 22s on suitable brackets just below the coving above the TV would be best. I think in ceiling speakers are out of the question as this room has a second floor above it.

On the plus side, we have an extension next to this that is single story - planning ahead, we might make it into one single room, insert bifold doors (wife’s plan but a good idea -it faces the garden) and put in a full in-ceiling Atmos set in there - that will be a long term project though…

Regards
Alex.
 

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