Hi I have a issue with my 1977 Kenwood Ka-7100 with a Fluance Rt-85 turntable. I bought the amp fully serviced. Caps replaced and a few noisy transistors replaced.
The sound is amazing below half volume. Around 6 or 7 I get a pretty loud hum/feedback like a bad ground?
I thought maybe it was my ac line in my house so I bought a cheap line conditioner from amazon. No help.
The amp still has the 2 prong power chord.
I have a few new 180 gram albums with very little hum. But older original albums seem to be more prone to the hum.
Where should I start?
Thanks
The sound is amazing below half volume. Around 6 or 7 I get a pretty loud hum/feedback like a bad ground?
I thought maybe it was my ac line in my house so I bought a cheap line conditioner from amazon. No help.
The amp still has the 2 prong power chord.
I have a few new 180 gram albums with very little hum. But older original albums seem to be more prone to the hum.
Where should I start?
Thanks
Welcome to the form!
I presume you have connected the earthing post at the rear of the turntable to a suitable grounding point on the chassis of the amplifier?
I presume you have connected the earthing post at the rear of the turntable to a suitable grounding point on the chassis of the amplifier?
I see that there is a large GND post at the rear left of the amplifier - could it be that simple?
First try reversing the Kenwood's AC plug in the wall socket.
Is there any difference in the noise?
Is there any difference in the noise?
Agree with Galu...happened to me as well.
Ground post of Thorens table needed connection to TL072 pre-amp.
But why is it that it is more evident with old records?
Ground post of Thorens table needed connection to TL072 pre-amp.
But why is it that it is more evident with old records?
Ok I should have stated that sorry. Yes my turntable is grounded to amp.
This is the power conditioner I purchased .
https://www.amazon.com/gp/product/B0002D017M/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1
Ok that I have not tried.
This is the power conditioner I purchased .
https://www.amazon.com/gp/product/B0002D017M/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1
Make sure the tonearm of the turntable is situated some way from the mains transformer in the amp to avoid induced hum in the cartridge.
If your amp and turntable are situated side by side, you may require to reverse their locations left to right.
If your amp and turntable are situated side by side, you may require to reverse their locations left to right.
Feedback can occur with a closed dustcover from the TT.
Try shorting the phono inputs on the amp and see if the hum persists.
I have tried switching the plug no change. Dust cover no change.
My next option in my mind would be to run the ground form the turntable to the amp. Then a separate ground from the amp to maybe the outlet screw?
I put on a ELO album last night the volume was at 5 and the hum was so bad I just turned it off.
I have 2 guitar tube amps and I get very little hum from them.
Maybe it is time to take it to a tech?
My next option in my mind would be to run the ground form the turntable to the amp. Then a separate ground from the amp to maybe the outlet screw?
I put on a ELO album last night the volume was at 5 and the hum was so bad I just turned it off.
I have 2 guitar tube amps and I get very little hum from them.
Maybe it is time to take it to a tech?
Can you try the amp with another turntable in order to eliminate the Fluance set-up as the source of the problem?
How does the Kenwood amp perform on the aux input?
If aux is hum free, then perhaps you could connect an external, low price, RIAA preamp to it.
Fot just a few dollars, you could then tell if it is the internal phono stage of the Kenwood that is at fault before letting a technician loose on the problem!
If aux is hum free, then perhaps you could connect an external, low price, RIAA preamp to it.
Fot just a few dollars, you could then tell if it is the internal phono stage of the Kenwood that is at fault before letting a technician loose on the problem!
The Kenwood is quite old.... the RIAA stage / voltage rails may have bad capacitors. Or, the RIAA stage voltage regulation is failing. Please take a photo or 2 and post it here.
... check power lines 1 and 2 for ripple...
... check power lines 1 and 2 for ripple...
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Try as Netlist suggested. Fabricate shorting phono plugs (center pin shorted to shell) and install. Unplug turntable AC and any connection ground wires. If hum still remains, the hum must originate within the Kenwood. But if then OK, then it's an interface issue. Let us know--- there are further diagnostics to pursue.
