volume motor noise feedback in speaker

[TLS Guy]

Hello folks, just came here googling for the same issue with the volume knob. Nothing to add, Parasound fault. Big fault. I'm from Argentina, member of the most important local forum, in touch with several dealers and users and waiting the third replacement of my Parasound HINT. There's no too much units here, but at least there's 2 more integrated amps waiting for a recall, also a few P5 and 2100 preamplifiers. And exactly the same issue. Appears to be some IC on the front board, from the preamp stage, maybe the one assigned to the volume knob, but IMHO, not the ALP itself.
I'll follow your updates on this thread.
Best regards.

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That is useful information. I figured this was not an old fashioned passive fader circuit, but and analog IC feedback arrangement.

This is another great creation of Baxandal.

There is the classic Baxandal preamp.

This is a dual op amp with the traditional Baxandal tone control circuit between the two opamp sections. The volume control works by the 100 K pot changing the sensitivity of the second amplifier stage. This is across pins 7 and 6. This is the feedback loop. As well as lowering the volume by decreasing sensitivity and therefore gain, headroom is increased so making clipping less likely from that stage.

It works very well, but I can tell you from personal experience that if this is not implemented correctly you get the exact problem complained of in this thread.

Most consider a digital volume control the way to go now, but I know you can make the analog feedback volume control work well.

Unfortunately this Parasound unit is not designed correctly.

 

[dxburbuja]

That is useful information. I figured this was not an old fashioned passive fader circuit, but and analog IC feedback arrangement.

This is another great creation of Baxandal.

There is the classic Baxandal preamp.

This is a dual op amp with the traditional Baxandal tone control circuit between the two opamp sections. The volume control works by the 100 K pot changing the sensitivity of the second amplifier stage. This is across pins 7 and 6. This is the feedback loop. As well as lowering the volume by decreasing sensitivity and therefore gain, headroom is increased so making clipping less likely from that stage.

It works very well, but I can tell you from personal experience that if this is not implemented correctly you get the exact problem complained of in this thread.

Most consider a digital volume control the way to go now, but I know you can make the analog feedback volume control work well.

Unfortunately this Parasound unit is not designed correctly.

Thanks for your feedback. I don't know how the P5 and HINT were designed, but linking the exactly same issue at they 2100 preamps, the cheap TI 5532 appears to be again on these new lines.

It's good at least to know that South America hasn't all the bad assembled units, but come on Parasound, same mistake from the 2100 series?

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[TLS Guy]

Thanks for your feedback. I don't know how the P5 and HINT were designed, but linking the exactly same issue at they 2100 preamps, the cheap TI 5532 appears to be again on these new lines.

It's good at least to know that South America hasn't all the bad assembled units, but come on Parasound, same mistake from the 2100 series?

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All OP amps are cheap as chips. That Texas instruments IC op amp is an excellent device and widely used without problems. It has been around for years. It is the premier chip for the type of circuit I Posted above. It has a Buffer amp followed by the variable gain amp.

I used this chip before without the problems you have had.

My view is that there is a misapplication/design fault that is causing this chip to undergo degraded performance in use.

Parasound now have a terrible problem. I suspect they have lots of completed boards on hand, which I suspect can not be neatly modified. They should have caught this at the prototype stage or at least early production before ordering a huge number of boards. In their defense a small production may not have been possible from their supplier. I understand the Chinese are very uncooperative in this regard. They are more accommodating in Taiwan, but costs are a little higher.

Parasound now have no good options.

They can buy back the units.

They could take back the units and offer customers another product.

They can redesign the board in question and when satisfied can order a production quantity of boards. Then install the boards in the already sold units as well as new production.

This latter will keep customers without properly functioning units for a very extended period of time.

This all begs the question as to whether Parasound have the financial resources to make this right with their customers. Given the state of the industry they may well not have.

It may well be that their customers will in the end have to eat the loss.

 

[slipperybidness]

Thanks for your feedback. I don't know how the P5 and HINT were designed, but linking the exactly same issue at they 2100 preamps, the cheap TI 5532 appears to be again on these new lines.

It's good at least to know that South America hasn't all the bad assembled units, but come on Parasound, same mistake from the 2100 series?

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Dunno, but the 2100 has been around quite a while, and this is the first time I've heard of any problems on it.

 

[TLS Guy]

Dunno, but the 2100 has been around quite a while, and this is the first time I've heard of any problems on it.

I have not heard of it either, but I live in the Boonies. The P5 seems to be a problem unit though and I suspect improper application of a device, most likely the OP amp chip now we know the set up.

 

[dxburbuja]

All OP amps are cheap as chips. That Texas instruments IC op amp is an excellent device and widely used without problems. It has been around for years. It is the premier chip for the type of circuit I Posted above. It has a Buffer amp followed by the variable gain amp.

I used this chip before without the problems you have had.

My view is that there is a misapplication/design fault that is causing this chip to undergo degraded performance in use.

Sure, totally agree, it's a design failure and not the Texas IC itself, by cheap I mean, cheaper than an AD8610 in the same way that the HINT is in front of another integrated using another ICs, Krell or any other brand some steps above Parasound.
In the States, or Europe, people maybe can wait for kind of "mea culpa" from Parasound or any "official" feedback, an updated unit, a V2.. unfortunately in Latin America I just can ask for a money back from my local dealer and search for another similar integrated stereo amp with that gentle features. And the variety of gear at this latitudes, sucks, we have just one Parasound distributor, and due to the recalls, forget the Halo series in the near future..

Dunno, but the 2100 has been around quite a while, and this is the first time I've heard of any problems on it.

Just from friends, I know at least 3 faulty units in Argentina..

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[Truthslayer]

I know old thread, but I might as well update and chime in. The P5 is definitely one big problem. My 3rd unit has had to be shipped back in for this same vol pot issues. It's down right aggravating and disappointing. Who wants to have such a simple unit have to be taken apart and worked on, only to know the issue will come back. Hopefully they will do the right thing and replace it for the P6, which seems to have a proper working pot. I think this is why you see these units always up for sell, people just get fed up. We will see if Parasound stands up and does the right thing. And if they do, I will not only praise them, but will continue to be a customer.