Audio issue

[RobertN]

I am puzzled by issues with my stereo.

I have an older mid 80's(I got it new in '85) Yamaha A-700 integrated amp. Pretty decent older unit, 105wrms, 0.005thd at 8 ohms. The thing is built like a tank. Pop the top and there is a heat sink set that could cool a house. It is hooked to a set of Bose sattelite system with a passive sub. Pretty basic system. The DVD player, CD player, tuner, cassette, and yes, a turntable, are plugged in.

A few weeks ago, it started clicking on for 5 seconds, off for 5 seconds. Not the main power, but the speakers. It has always had a 5 second delay at powerup; there is a relay in the circuit. I have not had time to tear in to the unit till tonite.

I checked speaker and subwoofer connections. They looked fine, so I pulled the amp out, popped the top, and blew the dust out. Everything looks fine; no signs of overheating ect. I couldn't find anything visibly wrong.

I have a stereo, with a 5 cd turntable, in the garage too. I have some funky old car speakers hanging from the rafters(2). I also have a nice set of RCA in/outdoor speakers on the front patio hooked up.

So, I disconnected all that stuff and hooked up the Yamaha. Wanted to see if I could hear the relay cut out with the lid off the amp. Everything worked fine... I turned it up as much as I could without blowing the old car speaker; this is with both A and B turned on so the car speakers and patio speakers were going pretty good. It still worked fine! It's not the same load as the Bose, but if it was a load issue, the garage/patio combo should have made it tweak out.

Any idea what to look for in the sattelite/sub system? I wonder if a cross-over is flaky or something. I was going to check it with an ohm meter; not sure what to expect...

This has been a solid amp. previously I have had bigger speakers attached. I had a set of JBL's a while back that could shake a house off it's foundation. The thread about Klipsch peaked my interest; I would love to get another set of high end speakers hooked up some day...

 

[_RaT_]

I am puzzled by issues with my stereo.

I have an older mid 80's(I got it new in '85) Yamaha A-700 integrated amp. Pretty decent older unit, 105wrms, 0.005thd at 8 ohms. The thing is built like a tank. Pop the top and there is a heat sink set that could cool a house. It is hooked to a set of Bose sattelite system with a passive sub. Pretty basic system. The DVD player, CD player, tuner, cassette, and yes, a turntable, are plugged in.

A few weeks ago, it started clicking on for 5 seconds, off for 5 seconds. Not the main power, but the speakers. It has always had a 5 second delay at powerup; there is a relay in the circuit. I have not had time to tear in to the unit till tonite.

I checked speaker and subwoofer connections. They looked fine, so I pulled the amp out, popped the top, and blew the dust out. Everything looks fine; no signs of overheating ect. I couldn't find anything visibly wrong.

I have a stereo, with a 5 cd turntable, in the garage too. I have some funky old car speakers hanging from the rafters(2). I also have a nice set of RCA in/outdoor speakers on the front patio hooked up.

So, I disconnected all that stuff and hooked up the Yamaha. Wanted to see if I could hear the relay cut out with the lid off the amp. Everything worked fine... I turned it up as much as I could without blowing the old car speaker; this is with both A and B turned on so the car speakers and patio speakers were going pretty good. It still worked fine! It's not the same load as the Bose, but if it was a load issue, the garage/patio combo should have made it tweak out.

Any idea what to look for in the sattelite/sub system? I wonder if a cross-over is flaky or something. I was going to check it with an ohm meter; not sure what to expect...

This has been a solid amp. previously I have had bigger speakers attached. I had a set of JBL's a while back that could shake a house off it's foundation. The thread about Klipsch peaked my interest; I would love to get another set of high end speakers hooked up some day...

Probably have a voice coil in the mid or woofer that is exceeding the minimum ohm rating on the amp (typically 4 ohms) which causes to much current through the thermal overload protection or breaker. My guess is you were listening to ZZ Top cranked up to high and melted some wire on the speakers windings. Adding in A and B speakers still keeps a load of approximately 4 ohms to protect the amp. Continued high current driving will trip the amp output protection. I've blown the woofers on my ADS, M&K and KEF speakers. I don't listen nearly as loud anymore and have a Adcom 555II power amp so I rarely clip my speakers.

 

[goaliedad]

silly question- have you hooked it back up to the original speaker system? could you have "fixed" the problem while cleaning and inspecting?

 

[Soundguy]

I'm not sure what ODP that amp has.. but I'd be inclined to think as the others.. It was dropping into an Output Device Protection mode.. thermal or otherwise.. and cutting out. ( some newer systems use ACL as a method ODP .. and you won't hear a cutout.. but rather distortion.. ).

I agree with the others.. hook it back up and check it. If it's ok.. i'd say it was dirty and something may have been getting hot.. If it isn't working.. then I figure there must be a fault at the input of the load, or in a non-isolated stage of the load.

Soundguy

 

[RobertN]

I checked the sattelites; each was about 4 ohms. I checked the passive sub; one channel was about 5.6ohm on the input and output. The other channel was about 4M ohm. Something funny is happening there.

I tried pulling the input panel off the sub, but it will not come out of the box all the way. It's like they had it installed in the side panel, hooked up to the sub, and then assembled the whole cabinet together. The circuit board on the inside is bigger than the hole... No other screws are visible.

I always wanted a powered sub... Don't want to pay the $$$ at the moment though.

 

[_RaT_]

Try pulling the woofer itself out, on many older models, thats how you pull the crossover out of the box.

 

[RobertN]

There is no obvious way to disassemble the box. That is the puzzling part. It's like they hooked up all the parts, and then glued it all together. I've looked it over closely for screws and fasteners but have not found anything. I don't want to bust it open.

It was probably affected by Stevie Ray Vaughn... Or, I have cranked Tull's "A classic Case". Locomotive Breath sounds pretty cool with a full symphony backing it up! I don't tend to crank the Bluegrass as much...

 

[_RaT_]

I think Locomotive breath killed a few woofers in my younger days or was it Allman Brothers Jessica, or was it Eric Clapners Layla, no, come to think of it, I think it was Locomotive Breath. It was Paul Simons Kodachrome that ate a tweeter.

 

[Soundguy]

Try pulling the woofer itself out, on many older models, thats how you pull the crossover out of the box.

Not just the old ones.. I've got some concert series EAW bi-amp'ed cabinets flown at one of the gig's i work at.. and you have to take the 15's out to get at the passive crossover...

That's a nice job up on the lift...

Soundguy

 

[Soundguy]

I'm a 'tull fan myself... aqualung and locomotive breath are my favorites of his. Of course there's sabath.. and the old kenny rogers ( and the first edition ).. like.. 'what condition my condition is in'... excelent use of a flanger and a rotary speaker.. probably a leslie.. etc..

Soundguy

 

[RobertN]

Have you checked you Tull's "Classic Case"? It is amazing the dynamic range the symphony adds. It's and older album, from about 1985.

My wife is a huge Moody's fan; it's cool what they do with symphonies too. Of course, they do the synthesized stuff too. Mike Pinder lives over in Auburn, not to far from me and _RAT_. He still has the early Melotron the Moodies used on the early albums. He writes childrens books, then puts them on audio tape with accompanyment from the Melotron.

I checked some oneline sources(Amazon, Crutchfield). It is amazing the number of active subs that are out there. If this is not an easy fix, then I'll probably go that route.

 

[Soundguy]

Speaking of the M'blues... One of their favorite songs of mine is "I'm just a singer in a rock-n-roll band'.

Awsome performance piece.

Of course 'nights in white satin' is classic too.

lets see.. other good / odd music.

'The night chicago died' by paperlace is an interesting piece.. and another favorite of mine, as well as 'hair' by the cowsills, 'convoy' by c.w.mccall, and 'Conquistadore' by Procol Harum.

Soundguy

 

[sendero]

I checked the sattelites; each was about 4 ohms. I checked the passive sub; one channel was about 5.6ohm on the input and output. The other channel was about 4M ohm. Something funny is happening there.

Keep in mind that is it not DC resistance that the amplifier is dealing with. It is AC impedance, and you cannot measure it with a DVM. If you have a coil or capacitor somewhere in the crossover that is fried, it will not necessarily show up with a DC measurement.

 

[HomeBrew2]

... probably a leslie.. etc.. Soundguy

That sure triggered a memory. My dad went to high school with Don and Bob Leslie (and kept in contact till their deaths). Later in life, my dad took a job in the R&D dept. of ElectroMusic, the Leslie speaker plant, in Pasadena, CA. He was awarded a patent for, what I remember them laughingly calling, the monkey motion machine. I think I was only about 10 then but, IIRC, the device created a truely random rotational speed for the speaker rotor (or something like that).
In case some don't know, the guys were truely organ freaks. The Leslies built a pipe organ on the premisises as a basis for the speaker design. The legendary George Wright would come by and tune all the pipes, by ear, every so often. The goal was to create a speaker that would be as close as possible to a pipe organ sound using a common electronic organ. Thus a rotary speaker. When the rockers got ahold of the speakers, things kindof changed at the plant. Of course sales soared but it wasn't really the same for some of the old timers.
Eventually, the pipe organ burned down, Electro Music was sold, one of the brothers retired to count his money, the other brother only kindof semi retired and continued his long time business of manufacturing the foam speaker rotors.
Cheers!

 

[RobertN]

Keep in mind that is it not DC resistance that the amplifier is dealing with.

100% understood. A DVM is only for very basic checkout. At least on a speaker, it gives a basic idea of the winding resistance, but not the actual AC load. And, every resistive divider, coil, and cap with throw a kink in things.

I was looking at some stuff at work yesterday. One way, I got a stable ohm value; reverse the leads and you could see the value change as the polarity of the leads charged a cap.

 

[RobertN]

Speaking of the M'blues... One of their favorite songs of mine is "I'm just a singer in a rock-n-roll band'.

Of all the bands I have seen multiple times, the Moody Blues have consistently put on excellent shows. I think I have seen them six times with my wife. A few times were in Lake Tahoe, at Ceasars. It is a smaller, intimate venue. They have been just great every time. Even with the new floutist. And yes, they crank it out good on "Singer".

 

[_RaT_]

I purchased the CD of the Moody Blues live in England, don't remember the album name. It's one of the latest recordings. I heard a new tune on there called English Sunset that will give your speakers a workout. The Moodys were/are indeed one of my favorite groups. I even have some of the Justin Hayward "Bluejays" music. Its been great with computers to compile my collection of "speaker rattling" tunes. Be it Erich Kunzel to John Jarvis to the Eagles to Jethro Tull (was he really the inventor of the plow?) Its when having a amplifer with lots of headroom a benefit. My old Yamaha R9 would have clipped a few speakers by now had I not upgraded. Robert, check out Audioholic for lots of information/opinions about subs.

Of all the bands I have seen multiple times, the Moody Blues have consistently put on excellent shows. I think I have seen them six times with my wife. A few times were in Lake Tahoe, at Ceasars. It is a smaller, intimate venue. They have been just great every time. Even with the new floutist. And yes, they crank it out good on "Singer".