Funny I had same issue with a 200 watt McIntosh MA 6600, even with speakers turned off you would near a popping sound through speakers when first powered up. The amp was maybe 10 years old. Talking to McIntosh service they couldn’t say what the problem was, they suggested just bring it in to local dealer for them to check. They wanted me to leave it 6-8 weeks. Minimum charge of $300 and no idea if they could solve issue. I decided just to sell the amplifier. Upgraded to a Class A Luxman that works flawlessly. Great video. 🫡
Great video! A few years ago I had an issue with an earlier but larger Kenwood. This wasn't the usual "thunk" but an intense BANG on both speakers, that made me fear for them. Since it had been on the bench just days before with some caps replaced, I sent it back in and got a full recap. It is has been working smoothly ever since.
There are generic speaker protection boards that you can install in units like this that act as both speaker protection circuits and a soft start relay. Lots of space in that unit to install one.
This may be a good candidate for adding a module type protect circuit. I added one to an Adcom GFA-545ii and it works really well, gives you the 4 second delay with relays. they are not expensive and pretty easy to install, and this amp you have there has some empty space you could put it easily.
Hi Joe! Actually there is a solution for that problem only you need to ask the customer if they are willing to pay for upgrading the amplifier. You can easy buy speaker protection module of shelf and maybe you will need also a power supply for it usually they get powered with 12v or 24v depending which relay is using on board. And it's easy to install inside the amplifier.
Joe, yes it's the way it's designed, but one thing that can be done that minimize the pop is to increase the value of the filter caps. It's not certain, but can help. Another solution is to install a soft start kit or a protection speakers circuit kit.
G,day Joe from Sydney Australia. Nice Kenwood amp (without relay "click") very interesting the DC surge 4.4v at the speaker jacks and the Max button on the DMM to recall reading. * Large capacitors, Panasonic seem to be quality products. Are the assorted AliExpress kits OK ? * Can you show your benchtop turntable underside mechanism?
There is an audio delay (not relay) circuit on these which should have kept the amp circuit OFF until the power supply stabilized. If it's not too late, get the schematic and check that. Harman Kardon did much the same thing on their older units.
Had same problem on a McIntosh amplifier, McIntosh service mentioned this could have been my issue as well, ie. relay switch not delayed enough, I bailed on the amp. I was having firmware issues as well, amp would just shut down for no reason then turn on back on with front display turned off. Nothing more frustrating when electronics start acting up. 🤓
The capacitor attached to the power switch is C3. It is not 103 nF. In all worldwide models of this Kenwood, that capacitor is 10 nF but the voltage rating differs from country to country. This is an old design (that is a safety hazard) that attempts to attenuate high-frequency EMI noise. A better solution would simply be to add an X-rated safety capacitor across the hot and neutral which will provide differential mode noise filtering as well as providing safety.
Another Good Learning Experience for us Newbies. Thanks So Much For making These Videos For US, Joe.👍
You're very welcome!
Funny I had same issue with a 200 watt McIntosh MA 6600, even with speakers turned off you would near a popping sound through speakers when first powered up. The amp was maybe 10 years old. Talking to McIntosh service they couldn’t say what the problem was, they suggested just bring it in to local dealer for them to check. They wanted me to leave it 6-8 weeks. Minimum charge of $300 and no idea if they could solve issue.
I decided just to sell the amplifier. Upgraded to a Class A Luxman that works flawlessly. Great video. 🫡
Thanks for sharing your experience with the McIntosh!
Great video! A few years ago I had an issue with an earlier but larger Kenwood. This wasn't the usual "thunk" but an intense BANG on both speakers, that made me fear for them. Since it had been on the bench just days before with some caps replaced, I sent it back in and got a full recap. It is has been working smoothly ever since.
There are generic speaker protection boards that you can install in units like this that act as both speaker protection circuits and a soft start relay. Lots of space in that unit to install one.
I like the way you use the Max/Min of your multimeter on this case...very smart ! thank you for this vidéo.
This may be a good candidate for adding a module type protect circuit. I added one to an Adcom GFA-545ii and it works really well, gives you the 4 second delay with relays. they are not expensive and pretty easy to install, and this amp you have there has some empty space you could put it easily.
Hi Joe! Actually there is a solution for that problem only you need to ask the customer if they are willing to pay for upgrading the amplifier. You can easy buy speaker protection module of shelf and maybe you will need also a power supply for it usually they get powered with 12v or 24v depending which relay is using on board. And it's easy to install inside the amplifier.
Thanx Joe.
✌️❤️😁
Thank you sir, I really enjoy your videos ! To connect the 1000 Hz signal generator of your phone, how do you proceed please ? ❤
Joe, yes it's the way it's designed, but one thing that can be done that minimize the pop is to increase the value of the filter caps. It's not certain, but can help. Another solution is to install a soft start kit or a protection speakers circuit kit.
I’ve asked how to get in touch with you but never got a answer? Can u help me out ? Thanks Joe
G,day Joe from Sydney Australia.
Nice Kenwood amp (without relay "click") very interesting the DC surge 4.4v at the speaker jacks and the Max button on the DMM to recall reading.
* Large capacitors, Panasonic seem to be quality products.
Are the assorted AliExpress kits OK ?
* Can you show your benchtop turntable underside mechanism?
Hi John!!! I'll keep that in mind for future videos!
Hi Joe, according to the service manual there is a "delay circuit" (Qm17, Dm17 ...): have you checked all the related components?
Thank you for an excellent video .understandably an early thump model, amp
😮
Appreciate the comment!
Love the turntable whilst working on a amp
Glad you liked the turntable.
There is an audio delay (not relay) circuit on these which should have kept the amp circuit OFF until the power supply stabilized. If it's not too late, get the schematic and check that. Harman Kardon did much the same thing on their older units.
Had same problem on a McIntosh amplifier, McIntosh service mentioned this could have been my issue as well, ie. relay switch not delayed enough, I bailed on the amp. I was having firmware issues as well, amp would just shut down for no reason then turn on back on with front display turned off. Nothing more frustrating when electronics start acting up. 🤓
The capacitor attached to the power switch is C3. It is not 103 nF. In all worldwide models of this Kenwood, that capacitor is 10 nF but the voltage rating differs from country to country. This is an old design (that is a safety hazard) that attempts to attenuate high-frequency EMI noise. A better solution would simply be to add an X-rated safety capacitor across the hot and neutral which will provide differential mode noise filtering as well as providing safety.
THX, now I know what to look for when servicing my KA-3750 - promising though, delivering 27WPC from an amplifier rated to 20W/8Ohm without clipping?