Denon HA-500 Head amp + Hummmmmm

[davstev]

Hi all,

Got the lovely looking and lovely sounding HA-500 Head amp to pair with my Denon 103 Zu. Sounding great, except...... for the.... Hummmmmm

It irks me, because it's sounding great except for the hum, which is pretty evident when turned up. Also it seems to be mostly in one channel, but not entirely in one channel. And yes, I have the ground wire from the tonearm connected to the ground post on the HA-500.

When I move my hand onto the top cover of the unit, the hum quiets down by about 50%, but it's still there.
Any ideas? It seems logical to me that it's something on the inside. The unit hasn't been recapped, it's all original inside. But, everything appears good to the eye when i look inside.

Anyone have this experience before?

Thanks.

 

[4-2-7]

And yes, I have the ground wire from the tonearm connected to the ground post on the HA-500.

Try disconnecting the ground wire.

It's also very important to use good interconnects, and do not cross your input/output wires at the head amp. Also run the IC to the preamp loose and away form other wires.

Play around with your loading and gain, high gain might not be the best for you..

 

[4-2-7]

BTW if your testing and hearing hum with no music playing and then on top of that you turn your volume up with the cart hanging in the air, you going to have hum.

Are you hearing hum while a record is playing?

 

[davstev]

Hi 4-2-7, Thanks for the ideas. You know, I've solved the problem. I searched AK for any other posts on this issue. It turns out that the HA-500 (and it's big bro HA-1000) is not truly grounded unless you ground your tonearm on the post but also run a wire from that grounding post to the post on your amplifier or preamp. So I just ran a wire also to a grounding post on my preamp. Problem is 90% solved. That is to say, it made a huge difference, but there's still a very small trace of a hum with the volume way up, but you need to turn it up quite loud just to hear it. I can live with a trace of a hum. It doesn't get in the way of the music at all, and maybe if I try better shielded cables it will improve.

Thanks again for your help. Now to chase the buzz on one channel of my amp. On a mission here tonight....

 

[davstev]

See post #9 here.

http://audiokarma.org/forums/index.php?threads/denon-ha-1000-questions.671033/

 

[4-2-7]

Problem is 90% solved. That is to say, it made a huge difference, but there's still a very small trace of a hum with the volume way up, but you need to turn it up quite loud just to hear it. I can live with a trace of a hum.

Good sometime grounds cause hum, sometimes they get rid of it.

You "Can Not" test you phono staging by cranking your volume up while no music is playing, you will "Always" hear hum, no phono stage is that quiet.

 

[rothwellaudio]

You "Can Not" test you phono staging by cranking your volume up while no music is playing, you will "Always" hear hum, no phono stage is that quiet.

I agree, but you can use a pair of shorting plugs in the phonostage's input sockets instead of the turntable. That will eliminate the hum in the turntable/cartridge/tonearm and tell you what level of hum is inherent in the phonostage. That can be useful, but it should really be referenced to the typical music level on a record to give you some idea of the signal-to-noise ratio.
But yes, too many people expect to max out the volume control and hear no hum whatsoever. That's unrealistic.

 

[4-2-7]

I agree, but you can use a pair of shorting plugs in the phonostage's input sockets instead of the turntable. That will eliminate the hum in the turntable/cartridge/tonearm and tell you what level of hum is inherent in the phonostage. That can be useful, but it should really be referenced to the typical music level on a record to give you some idea of the signal-to-noise ratio.
But yes, too many people expect to max out the volume control and hear no hum whatsoever. That's unrealistic.

You know if grounding the head amp box helped a lot, the shorting plugs you mention might help for the extra input.

You know the preamp that @davstev has is quite interesting, and now on my radar as something I might want to try. It would even look at home with old McIntosh amps but check out the phono stage, it has built in gain controls for both inputs and L&R. I didn't find the owners manual.

But saw someone say this....
The Accuphase C 200 is a pure jewel : transparent phono stage, superb architecture and design, a lot of gain ... ( So much gain in fact, that I had to buy a pair of 20 db attenuators to match the preamp and my Leak Stereo 20 ).



So I think the gain that's set on the preamp need adjustment as well as knowing all about this stage and the Head Amp mix.

 

[4-2-7]

It irks me, because it's sounding great except for the hum, which is pretty evident when turned up. Also it seems to be mostly in one channel, but not entirely in one channel.

Try some adjusting of the phono gain pots on the back of the c200, they might not be all that accurate and left or right can have more gain than the other. You also might want to try the other set of inputs to see if they work better.

 

[JP]

But yes, too many people expect to max out the volume control and hear no hum whatsoever. That's unrealistic.

True, and unfortunate, but I wouldn't use the word always. There's some 60Hz and 180Hz ~9dB out of the noise floor, though not bad for a PCB sitting open on a bench. https://www.dropbox.com/s/df1xmc88gr7t90t/20161230-T001.wav?dl=0

 

[rothwellaudio]

The Accuphase C 200 is a pure jewel : transparent phono stage, superb architecture and design, a lot of gain ... ( So much gain in fact, that I had to buy a pair of 20 db attenuators to match the preamp and my Leak Stereo 20 ).

The Leak Stereo 20 is notoriously sensitive and often benefits from attenuators at its inputs. There's probably not too much gain in the C200.

 

[davstev]

You know if grounding the head amp box helped a lot, the shorting plugs you mention might help for the extra input.

You know the preamp that @davstev has is quite interesting, and now on my radar as something I might want to try. It would even look at home with old McIntosh amps but check out the phono stage, it has built in gain controls for both inputs and L&R. I didn't find the owners manual.

But saw someone say this....
The Accuphase C 200 is a pure jewel : transparent phono stage, superb architecture and design, a lot of gain ... ( So much gain in fact, that I had to buy a pair of 20 db attenuators to match the preamp and my Leak Stereo 20 ).

View attachment 843143 View attachment 843144

So I think the gain that's set on the preamp need adjustment as well as knowing all about this stage and the Head Amp mix.

Just for the record, I really, really like my C200. You'll rarely find a C200 owner say otherwise. It sounds fantastic, to the point where I cannot believe that it might sound better if recapped. A pleasure to use, super well built, quality in very aspect. Maybe some modern designs surpass it, but i've never compared. For me it's a keeper.

 

[Cesari0]

Hi all,

Got the lovely looking and lovely sounding HA-500 Head amp to pair with my Denon 103 Zu. Sounding great, except...... for the.... Hummmmmm

It irks me, because it's sounding great except for the hum, which is pretty evident when turned up. Also it seems to be mostly in one channel, but not entirely in one channel. And yes, I have the ground wire from the tonearm connected to the ground post on the HA-500.

When I move my hand onto the top cover of the unit, the hum quiets down by about 50%, but it's still there.
Any ideas? It seems logical to me that it's something on the inside. The unit hasn't been recapped, it's all original inside. But, everything appears good to the eye when i look inside.

Anyone have this experience before?

Thanks.

I don't mean to revive this thread.
I just bought the Denon HA-500 unit online, the guy said it was in "excellent" condition.
When I hooked it up to my AU20000..using a denon 103D cartridge... here is what I got:
MM = hum
24db = more hum
32db = all hum

I recapped it, less hum, but still very audible.
I was very frustrated, I couldn't explain how much hum was coming from a unit built by Denon, I started to think this thing was a complete dud.
So I started playing with the RCA cable/connection...Lo and behold... it was the female RCA connectors that were the culprits.
I just changed the RCA connectors, and it's VERY quiet, on all three... MM, 24, and 32.... who would have guessed where the fault would lie.

I hope this helps.
Ps. don't forget to ground the HA-500 to your main unit.

 

[hifitommy]

i had one briefly but hum wasn't the problem, intermittent sound dropouts (very small) so i returned it. got a marcof and am happy.

 

[davstev]

Hi, funny you should be reviving this old thread, since I just got this unit back from my tech yesterday. It sat unused for a couple of years, because I just got fed up with the hum. I figured that I should ask my tech to re-cap it, just to eliminate the possibility that the hum was coming from something wrong internally. So he did recap it. He said he used it with a Koetsu MC cartridge after the recap and was very impressed and said it was super quiet, and I really trust his opinion, he`s an experienced audiophile. When I have some time, I will hook it up again to my system and see if the hum persists. If there's a hum, it's because of an error on my part; I can safely say. I think this unit is actually excellent, and worth the effort in ridding the hum. Glad you took care of your hum- yes, maybe unsheilded RCA cables are the problem. More posted at a later date after I`ve had a chance to hook it up and use it. (PS I use a Denon Zu 103).

 

[808_state]

Hi, funny you should be reviving this old thread, since I just got this unit back from my tech yesterday. It sat unused for a couple of years, because I just got fed up with the hum. I figured that I should ask my tech to re-cap it, just to eliminate the possibility that the hum was coming from something wrong internally. So he did recap it. He said he used it with a Koetsu MC cartridge after the recap and was very impressed and said it was super quiet, and I really trust his opinion, he`s an experienced audiophile. When I have some time, I will hook it up again to my system and see if the hum persists. If there's a hum, it's because of an error on my part; I can safely say. I think this unit is actually excellent, and worth the effort in ridding the hum. Glad you took care of your hum- yes, maybe unsheilded RCA cables are the problem. More posted at a later date after I`ve had a chance to hook it up and use it. (PS I use a Denon Zu 103).

Had the same originally posted problem with my Yamaha HA-1 headamp. Extra ground wire between the HA-1 and my C-2x pre fixed the hum (about 3-4 months ago). This also eliminated similar hum with my iFi iPhono 1. The HA-1 is nice but def needs a recap.

 

[L-82]

I just connected my HA500 I found it to be very quiet. After reading some of the post I raised the volume on my ma7000 and guess what, hmmmmm.

So I moved as far away I could - about 3 feet and no more hmmm.

 

[L-82]

Well I left it on for 24 hours and when I came back I found that there was no more gain available! Looks like something must of burnt out? The only sound that was available was on the off/mm position.
I was lucking in being referred to a retired mainframe electrical engineer, the nicest guy I ever met.
He took it and found that 2 resistors in the power supply were burned out, so in at the same time he recapped it for me, a real beautiful job I have to say. Now like Juan says it will sing for an other 40 years....
I have to say the AT33e with denon ha500 sound