Bellari VP130 Hum Problem

[Bassphil]

I have a hum that I can't get rid of, and I've tried everything. Here's the set up:

Technics SL-1800MKII
Bellari VP130
Grado Black
Shure M97xE

To keep things simple for troubleshooting, I moved only the TT and the Bellari into my office where I have a brand new electric line going straight to the fuse box.

On the TT, I opened it up and ran a piece of speaker wire as a 2nd ground cable to the metal plate in the inside (the original is grounded there as well). I also soldered in a new set of RCA cables since the old ones were getting funky.

I've tried every combination of grounding that I could think of with the two ground wires (the Bellari has a headphone jack, by the way, in case you're wondering how I'm was listening to the hum...). The directions for the Bellari recommend that you run them both on the same circuit. It seems that the only way I can reduce the hum to a very low level is by running them on separate circuits.

When I finally reduce the hum a bit, I start picking up radio stations. I've also tried to troubleshoot the problem while it's hooked up to my system. Nothing else actually has a ground knob, but I've tried every screw I could- nothing.

To check the TT, I wired it to a Kenwood preamp that actually has a built in phono stage and it was dead silent.

Unless someone here has been through this and can offer some advice, I guess I'm going to have to send it back. I'm not looking forward to searching for something that's comparable at that price range :scratch2:

If anyone has any insight at all, I'd greatly appreciate it- I love a good mystery, but I love find solutions even better!

Thanks in advance,

-Phil
www.philpalombi.com

 

[JohnVF]

Call Bellari. It's a defect in the VP-129, so maybe it's the same with the VP-130. I've heard they may fix it, and should if it's under warranty (I have a VP-129 but haven't sent it back yet. Sounded fantastic until the hum set in).

 

[Bassphil]

Thanks for the reply, John.

I called them before I posted, but the best they could come up with was "get creative with your grounding". They really need a forum on their website for these kind of things.

Anyway, I took his advice to heart and grounded it to just about everything in the house, excluding the wife. Actually, here's what I did. Each step reduced the hum a little bit more.

1- took the TT apart and soldered a new set of RCA cables into it, as well as attached an additional ground wire to the steel plate on the inside.

2
- A- Ran the ground from the TT to the ground pole on the Bellari.
- B- Ran the new ground from the TT to the decorative steel post that protects the tube
- C- Ran a 3rd ground from the Bellari ground pole to the main amp

3- spread the prongs apart a bit on the Bellari AC plug

4- Folded the TT RCA cables over and bound them tightly to the RCA cables connecting the preamp and amp

Hmmm, I think that's everything. What was left was a very low level hum that, at the level I listen to music to, was practically inaudible. I noticed the same pitch of hum through my studio speakers in our computer room, so I'm guessing that may be from the cable-coaxial connection. I ordered one of those Jensen coaxial hum filters today to see if that does the trick.

I hope that this info helps someone!

-Phil
www.philpalombi.com

 

[JohnVF]

Before my Bellari went all hum-happy, I did some tube rolling with some vintage 12ax7 tubes, and they were a vast improvement over stock tube. I settled on three that I liked best..a Mullard, telefunken and an RCA. All were very subtly different and all three presented a better midrange, more detail, and a lower noise floor than what came with it. It's a shame that so many of them have the hum defect, as it really is an excellent sounding phono pre when it's quiet (which is never in mine, even after trying various things to eliminate the hum).

 

[ETI_5000]

I have a hum that I can't get rid of, and I've tried everything. Here's the set up:

Technics SL-1800MKII
Bellari VP130
Grado Black
Shure M97xE

To keep things simple for troubleshooting, I moved only the TT and the Bellari into my office where I have a brand new electric line going straight to the fuse box.

On the TT, I opened it up and ran a piece of speaker wire as a 2nd ground cable to the metal plate in the inside (the original is grounded there as well). I also soldered in a new set of RCA cables since the old ones were getting funky.

I've tried every combination of grounding that I could think of with the two ground wires (the Bellari has a headphone jack, by the way, in case you're wondering how I'm was listening to the hum...). The directions for the Bellari recommend that you run them both on the same circuit. It seems that the only way I can reduce the hum to a very low level is by running them on separate circuits.

When I finally reduce the hum a bit, I start picking up radio stations. I've also tried to troubleshoot the problem while it's hooked up to my system. Nothing else actually has a ground knob, but I've tried every screw I could- nothing.

To check the TT, I wired it to a Kenwood preamp that actually has a built in phono stage and it was dead silent.

Unless someone here has been through this and can offer some advice, I guess I'm going to have to send it back. I'm not looking forward to searching for something that's comparable at that price range :scratch2:

If anyone has any insight at all, I'd greatly appreciate it- I love a good mystery, but I love find solutions even better!

Thanks in advance,

-Phil
www.philpalombi.com

Look, as an electrical engineer, I can tell you, if you've got two parallel ground lines, then you've got one too many - you'll end up with a ground loop.:nono: What's that? Well, when you have two wires, both connected together at each end, with one end earthed, you may think there's no problem, but if they come within an electro-magnetic field from a nearby transformer, then you'll get tiny circulating AC currents flowing around the loop at 50 or 60 Hz, depending on the power supply frequency. The result will be hum. Disconnect one of those parallel earth wires, and the hum should disappear, or at least reduce in level.:thmbsp:

Also, make sure you don't run a separate wire to ground the RCA cable shields from the turntable - they should be connected only to the cartridge ground pins at the turntables end, and to the amplifier's zero volt input at the amplifier, but not earthed. To check if you have an earth loop around the RCA shields, turn the amp off, and pull the RCA plugs slightly out, so only the centre RCA pins are making contact with the socket. If, when you try out the turntable, you still get sound, but less hum, then leave them partially unplugged. If you get no sound, switch the amp off, and then plug one plug fully in, leaving the other one with the shield unplugged still. If you now get sound from both channels, leave them the way they are, but if only one channel plays, then plug them both in fully.

Another thing to look for is if the cartridge has a metal body, like some Stanton cartridges. The tonearm will be earthed, using the ground wire to the amp. If this is also connected to an input ground pin, as it often is with a small copper strap with Stanton cartridges, then that may be redundant - on the Stanton cartridges you can slip it off the cartridge pin, but leave it hanging out of the rear of the metal body. If hum reduces, then it was redundant, and the cartridge body is earthed adequately by the tonearm earth wire (not wires - see above!).

Also, don't get the turntable within about a foot (300 mm) from an amplifier - the electro-magnetic field from the transformer(s) within many amps can induce significant hum into magnetic cartridges, which is then amplified many times by the RIAA preamp and following amp stages. They should never be stacked with the turntable on top of the amp, as you are ceratin to get hum induced.

Finally, Grado cartridges are infamous for hum. Trty other cartridges to see if hum reduces.

If you pick up radio stations, try using a ferrite or powdered iron core or loop (sometimes called a toroid, or toroidal loop or core) - something like this: http://www.radioshack.com/product/i...gkw=ferrite&kwCatId=2032058&parentPage=search or this http://www1.jaycar.com.au/productVi...d2=&pageNumber=&priceMin=&priceMax=&SUBCATID= . Do a search at a website for an electronic parts retailer near you. The small cores can just have the cables run through them, while with the larger loops, try several turns of cable around them, and it should suppress RF. Long speaker leads can also pick up RF, and winding them through a ferrite or powdered iron toroid should cure it.

Hope that helps.

-Don

 

[Bassphil]

Before my Bellari went all hum-happy, I did some tube rolling with some vintage 12ax7 tubes, and they were a vast improvement over stock tube. I settled on three that I liked best..a Mullard, telefunken and an RCA. All were very subtly different and all three presented a better midrange, more detail, and a lower noise floor than what came with it. It's a shame that so many of them have the hum defect, as it really is an excellent sounding phono pre when it's quiet (which is never in mine, even after trying various things to eliminate the hum).

Thanks John! Where do you find your tubes? The only one I've seen is the Mullard, but I don't know if it's vintage or not. Here's the link:

http://www.needledoctor.com/Mullard-12AX7-ECC803S-Tube

Thanks for the info!

-Phil
www.philpalombi.com

 

[Bassphil]

Look, as an electrical engineer, I can tell you, if you've got two parallel ground lines, then you've got one too many - you'll end up with a ground loop.:nono: What's that? Well, when you have two wires, both connected together at each end, with one end earthed, you may think there's no problem, but if they come within an electro-magnetic field from a nearby transformer, then you'll get tiny circulating AC currents flowing around the loop at 50 or 60 Hz, depending on the power supply frequency. The result will be hum. Disconnect one of those parallel earth wires, and the hum should disappear, or at least reduce in level.:thmbsp:

Also, make sure you don't run a separate wire to ground the RCA cable shields from the turntable - they should be connected only to the cartridge ground pins at the turntables end, and to the amplifier's zero volt input at the amplifier, but not earthed. To check if you have an earth loop around the RCA shields, turn the amp off, and pull the RCA plugs slightly out, so only the centre RCA pins are making contact with the socket. If, when you try out the turntable, you still get sound, but less hum, then leave them partially unplugged. If you get no sound, switch the amp off, and then plug one plug fully in, leaving the other one with the shield unplugged still. If you now get sound from both channels, leave them the way they are, but if only one channel plays, then plug them both in fully.

Another thing to look for is if the cartridge has a metal body, like some Stanton cartridges. The tonearm will be earthed, using the ground wire to the amp. If this is also connected to an input ground pin, as it often is with a small copper strap with Stanton cartridges, then that may be redundant - on the Stanton cartridges you can slip it off the cartridge pin, but leave it hanging out of the rear of the metal body. If hum reduces, then it was redundant, and the cartridge body is earthed adequately by the tonearm earth wire (not wires - see above!).

Also, don't get the turntable within about a foot (300 mm) from an amplifier - the electro-magnetic field from the transformer(s) within many amps can induce significant hum into magnetic cartridges, which is then amplified many times by the RIAA preamp and following amp stages. They should never be stacked with the turntable on top of the amp, as you are ceratin to get hum induced.

Finally, Grado cartridges are infamous for hum. Trty other cartridges to see if hum reduces.

If you pick up radio stations, try using a ferrite or powdered iron core or loop (sometimes called a toroid, or toroidal loop or core) - something like this: http://www.radioshack.com/product/i...gkw=ferrite&kwCatId=2032058&parentPage=search or this http://www1.jaycar.com.au/productVi...d2=&pageNumber=&priceMin=&priceMax=&SUBCATID= . Do a search at a website for an electronic parts retailer near you. The small cores can just have the cables run through them, while with the larger loops, try several turns of cable around them, and it should suppress RF. Long speaker leads can also pick up RF, and winding them through a ferrite or powdered iron toroid should cure it.

Hope that helps.

-Don

Holy cow, thanks Don! I'm going to have to print this one out and carry it over to the next room to process all of that info!

About the multiple grounds, I thought that was weird also. The Bellari people recommended that I try to run one ground to the Bellari, and another to the amp. With each ground I added, the hum got a little quieter...

The ground wire that I attached on the inside of the turntable is attached to a screw that seems to be there specifically for grounding purposes. The original ground wire ran into the tonearm circuit board, where it was soldered. Pressed on top of the solder point was a flap of metal, which had another (grey) wired soldered to it. That grey wire was attached to the center sheet metal plate by the aforementioned screw. I just added another wire to that point as an experiment.

I'm going to experiment with your RCA suggestions to see what that does. Then I'm going to move my TT a bit- it's sitting right beside the poweramp :thumbsdn: If that doesn't fix it, I'll check out the cartridge wires. I did A-B it with a Shure M97xE and the hum remained the same, though...

Okay, time to get to work! I'll report back. Thanks again!

-Phil
www.philpalombi.com

 

[JohnVF]

Thanks John! Where do you find your tubes? The only one I've seen is the Mullard, but I don't know if it's vintage or not. Here's the link:

http://www.needledoctor.com/Mullard-12AX7-ECC803S-Tube

Thanks for the info!

-Phil
www.philpalombi.com

I two of them at a vintage stereo shop and paid too much. Since then, I found a bunch of 12ax7s at an estate sale, maybe a dozen for a quarter a piece. Ask in the tubes forum and they could probably lead you to the best place to find them.

 

[Bassphil]

I two of them at a vintage stereo shop and paid too much. Since then, I found a bunch of 12ax7s at an estate sale, maybe a dozen for a quarter a piece. Ask in the tubes forum and they could probably lead you to the best place to find them.

Now that that I know what to look for, I'll have to keep my eyes open locally as well :scratch2:

As for the ground issue, I'm beginning to think the problem lies in the crappy power supply that the Bellari came with. The cable seems to be a little flimsy, and the power brick feels downright cheap. Also, I've found that if I move the wire, or change the direction of the power brick (I plugged it into a separate power strip to fool with the 3-D orientation) I can get the hum to change in intensity. Same thing with the orientation of the Bellari itself.

I'll have to swing by RadioShack to see it they have a better adapter. Hopefully, they still have a few people there that know what their talking about- that place looks more and more like a mini-BestBuy every time I walk in there!

Also, I fooled around with the ground wire configuration like Don suggested, but no matter what I tried, it seems that the only thing that really stops the hum is 4 ground wires (forgot about the one from the chassis leg to the other post on the Bellari). Between the octo-groundwire-a-pus and the careful orientation of the Chinese power supply, cable, and Bellari, I've managed to just about completely get rid of the hum. Oh, and I had to hog-tie the RCA's together again as well. It sure does look pretty back there

I'll post again when I get a power supply. With any luck, I'll be able to take a pair of wire cutters to the ground-apalouza,

-Phil
www.philpalombi.com

 

[ETI_5000]

About the multiple grounds, I thought that was weird also. The Bellari people recommended that I try to run one ground to the Bellari, and another to the amp. With each ground I added, the hum got a little quieter...

The ground wire that I attached on the inside of the turntable is attached to a screw that seems to be there specifically for grounding purposes. The original ground wire ran into the tonearm circuit board, where it was soldered. Pressed on top of the solder point was a flap of metal, which had another (grey) wired soldered to it. That grey wire was attached to the center sheet metal plate by the aforementioned screw. I just added another wire to that point as an experiment.
www.philpalombi.com

The best way to earth it is to run one wire from the earth point from the turntable to the ground connection on the Bellari, and then one wire from that, to the earth on the amp - it should have an earth point for the phono connection on your main amp. However, if you have an earth wire from the power point earth to your Bellari preamp earth connection point (check with an ohmmeter between the earth point on the Bellari and the power plug earth), then you don't need a wire from the preamp to the main amp - just make sure you plug your amp, and your Bellari, into a multi-outlet power board, so they go to the same earth point, which will minimise ground loops via the power, and keep the one wire from the turntable earth point to the Bellari earth. Any more wires from the turntable earth to the Bellari earth will just be redundant, and candidates for earth loops, unless one of the earth wires you currently have is open circuit. The inside solder connection in the turntable earths the tonearm, platter and motor, and should be the only thing that's earthed on the turntable. Just check the original earth wire with an ohmmeter, to make sure it does connect to the metal tonearm etc.

Ultimately, when we build amplifiers, we want everything to be earthed by the power amp, or integrated amp, single point connection to the power earth. On preamps, a metal case should be connected to earth, but that's the ONLY thing that should be connected (for safety, if it has a power point connection, otherwise the case will be live if the active lead comes loose and makes contact with it - if it only has a plugpack power supply, then it doesn't need to be earthed), but unfortunately some manufacturers do the wrong thing.

I'll guarantee that if the Bellari is picking up RF, then it's not well designed - all RIAA preamps I've ever seen and made have a toroid at the input, to minimise RF. But then, I'd expect that - most of those clowns reviewing for hi-fi magazines really don't understand electronics too well, so they don't know how to test them properly.

-Don

 

[JohnVF]

It's a testimony of how good they sound when working that people put so much effort into getting rid of the hum when it occurs. Google "bellari"+"Hum" and you'll get dozens of pages. It really is a great sounding unit! Too bad it's so poorly designed otherwise.

 

[RickB]

We had a Bellari, VP-530, the one with USB, that had a hum no matter what...we called the distributor and they sent us a replacement power supply that cured the problem...the first power supply was an AC output kind, the replacement was a little switch mode DC supply.....cured the problem on that unit....

We found this out by switching the power supply for a later model unit (the first was a return from a customer due to it's hum) and finding that the hum went away...

So, check and see if you have an AC or a DC power supply and that may be your problem...if not...well, there have been a bunch of other great suggestions here...

.

 

[JohnVF]

I have a Bellari microphone preamp that comes with the same power supply/wall wart thing. I'll dig it out and make a switch and maybe dig through my pile of other power adaptors for all my music stuff and try them on the bellari. I'll report back when I get this done...maybe it will help. My hum is so bad that there's really nothing to lose at this point. It just went nuts one day and I couldn't bring it back.

 

[pbda]

My VP129 had a bad hum when I first received it; I tried everything (well, everything barring opening up the case) and in the end returned it to the manufacturer, who upgraded the ground connection on the unit. That solved the problem, for the most part. I found that alternatively connecting the ground wire to the preamp or my receiver, or reversing the plug in the socket (high tech, eh?) would fix the problem.

My cartridge is a Grado Reference Sonata, so I also have the "Grado hum" to contend with. I'd probably have given up a long time ago, but the combination sounds so darned great. :thmbsp:

 

[Bassphil]

Well, I'm happy to say that the mystery has been solved. GREAT PREAMP....... unbelievably cheap power adapter. Man, how could they go that far with a product only to undermine everything with something that simple. Charge $210 and include a better adapter.

I went to Radio Shack and bought another adapter- after talking to Bellari and double checking what would be safe voltage wise. Sure enough, I got home and plugged it in and BAM- no hum. I was able to take off all of the ground wires (except the original) and unbind the RCA cables.

Now that that's settled, I really like the preamp. Next stop is tube town.

JohnVF- what do you think about that Mullard I posted a link to. I'm assuming it's a new tube, but do you think it would be an improvement over the Electro Harmonix that's currently in there. For that price, I was thinking if it was a little better, it could hold me over until I found a real NOS to drop in.

Thanks to everyone who posted, by the way. I learned a lot!

-Phil
www.philpalombi.com

 

[wordherder62]

For the sake of documentation, can you give us the Radio Shack Catalog Number for the power supply you used? It's good to know of one that works so we really should get the info down. A photo of it would also be helpful for confirmation purposes!

Thanks,
Richard

 

[Bassphil]

For the sake of documentation, can you give us the Radio Shack Catalog Number for the power supply you used? It's good to know of one that works so we really should get the info down. A photo of it would also be helpful for confirmation purposes!

Thanks,
Richard

Sure, here's the info. Bellari said that it has to be more than 700mA- this on is 1000mA. Also, it had to be between 12 to 15 VDC, and this one is 15VDC.

The box simply says 15V - 1000mA Compact AC-to-DC Power Adapter. The part number may be 273-1691.

I had to buy the connector separately (the tip that goes into the Bellari). I got the one that has 5.5mm O.D. and 2.1mm I.D. That's outside and inside diameter, for those of you not familiar with plumbing (part number is possibly 273-1716)

I hope that this helps someone. I'm going to call Bellari today and see what they have to say about their plugs.

-Phil
www.philpalombi.com

 

[darkdork]

I just fixed this issue with mine. It had a weird "woshhhhhh" hum in the right channel with the stock 12v power supply. The 15v from radio shack that was mentioned before this fixed this... but then it gained a different hum! I ran a ground cable from the ground on the back of the bellari to my PC case (I use headphones, and my headphone amp is battery powered, doesn't have a ground.)

The unit is now dead silent. I couldn't believe it.

 

[scar]

what about using a power supply that has three-prongs?

 

[Bassphil]

what about using a power supply that has three-prongs?

Good question. I didn't see one at Radio Shack, but the 2 prong model worked fine for me. I wonder if it's a shielding issue more than a ground issue...