|
Vintage Audio (record players, hi-fi etc) Amplifiers, speakers, gramophones and other audio equipment. |
|
Thread Tools |
18th Aug 2017, 12:50 am | #1 |
Retired Dormant Member
Join Date: Apr 2016
Location: London, UK.
Posts: 3
|
Garrard 2025TC connected to Onkyo TX-NR646
I am in desperate need of advice
I have an Onkyo receiver which some of you might baulk at etc It suits my needs and functions (Airplay, Tv etc ) I also have a collection of 78's that I want to digitise and vinyl records that I listen to now and again I bought a Garrard 2025tc mainly for the 16rpm feature so I can digitise at that speed reduce scratches and speed up digitally. It doesn't like the Onkyo, I believe this is because it has a ceramic cartridge I have tried using the CD, Aux etc inputs instead of the Phono input but it still hums really loudly. As I use the amp more than the turntable I will have to resolve the turntable side of things somehow. Would I be better getting another turntable (Ideally with 16rpm) - If so which would you say was my best option (on the cheaper scale) that will work with th Onkyo (has magnetic cartridge I suppose) Or Do I change the cartridge (Currently a KS 40A) somehow for a magnetic one if so which do you suggest. Or maybe there's an option that isn't obvious to me. Thank you for any help for this inexperienced hifi virgin. If anyone has been through this process already please help... I've had the Garrard for ages now and keep looking at it, turning it on in the vain hope its resolved itself and then switch it off and put the lid back on for another few months when it sounds like a reactor about to explode. |
18th Aug 2017, 11:52 am | #2 |
Rest in Peace
Join Date: Mar 2006
Location: N.W. Oxfordshire(Chipping Norton)
Posts: 7,306
|
Re: Garrard 2025TC connected to Onkyo TX-NR646
The output from the KS40A cartridge should be a good match, level-wise to any aux. input, which, essentially is what CD, Tuner, and Tape inputs are. The hum problem may be caused by the fact that the metalwork of the 2025TC isn't earthed to the chassis of the Onkyo.
How is the Garrard turntable being powered? If only a 2-core mains lead is being used, then a wire connected between the deck plate of the Turntable and the earth terminal on the amplifier (There is usually a screw terminal provided for this purpose on HiFi amps. & receivers) The 2025TC has a very narrow hearshell so it might be difficult to fit a magnetic cartridge to it. Other members may advise differently, but the above method should minimise hum pickup. |
18th Aug 2017, 9:46 pm | #3 |
Retired Dormant Member
Join Date: Apr 2016
Location: London, UK.
Posts: 3
|
Re: Garrard 2025TC connected to Onkyo TX-NR646
Thank you for your reply.
I have already connected an earth to the Onkyo earth, It was one of my first thoughts and it didn't cure it. Today just using the line out from the 2025 I went straight into the computer bypassing the amp and recorded. It has a horrible hum/buzz so I was thinking maybe the cartridge is kaput? |
19th Aug 2017, 12:09 am | #4 |
Heptode
Join Date: Dec 2016
Location: Sheffield, South Yorkshire, UK.
Posts: 539
|
Re: Garrard 2025TC connected to Onkyo TX-NR646
Check the connections on the cartridge for if they are slack hum will get into the system. You could also try removing the earth connections from the cartridge. To see if they are the cause of the hum.
Some amps don't like the earth of the mains cable. I once had an amp that would hum all because the deck mains lead had the earth connected. |
19th Aug 2017, 6:13 pm | #5 |
Retired Dormant Member
Join Date: Apr 2016
Location: London, UK.
Posts: 3
|
Re: Garrard 2025TC connected to Onkyo TX-NR646
Oh thank you Grubhead for those tips,
I will try them next time. Like you say it could be any number of possible issues... I suppose it keeps my brain occupied! |
19th Aug 2017, 10:27 pm | #6 |
Moderator
Join Date: Feb 2006
Location: Wembley, Middlesex
Posts: 7,219
|
Re: Garrard 2025TC connected to Onkyo TX-NR646
Crystal and Ceramic cartridges need to be connected to a high impedance input of an amplifier, ie 1M ohm or more. The input impedance of the Onkyo is probably around 50K ohm, so I'm not surprised it doesn't work. You would have to find or build a small preamp with a high impedance input to buffer between the ceramic cartridge and a modern amplifier.
|
21st Aug 2017, 11:02 am | #7 |
Octode
Join Date: Jun 2006
Location: St Osyth, Nr Clacton, Essex, UK.
Posts: 1,482
|
Re: Garrard 2025TC connected to Onkyo TX-NR646
Another option to try is to feed your cartridge into the microphone input of your computer. The signal level without an attenuator would be too high and the input impedance of the mic input too low. A simple attenuator will fix both of these though the random noise will be a fraction higher - not enough to worry about.
The attenuator would consist of a 1 MegOhm resistor in series and a resistor in the range 1k to 10 k Ohm across the mic input. Earthing will still be an issue to solve. I have very often just joined the 3 middle tags on the bottom of the 2025 thus earthing the cartridge and the deck-plate at the same time. Graham
__________________
Half my stuff is junk - trouble is, I don't know which half! |