Paradisea Problem - Need Assistance Please

Scott F. · « **Reply #40 on:** 12 Dec 2006, 09:17 pm »

Quote from: nakolawala on 12 Dec 2006, 08:45 pm

....When connected to my preamp, after 12 oclock position I can hear a slight hum and becomes louder if you increase the vol......

Do you listen with your preamp volume set past the 12:00 position?

F-100 · « **Reply #41 on:** 12 Dec 2006, 09:58 pm »

I have Tvad4's Paradisea and also experiencing an audible hum starting at 12 o'clock on my preamp and increasing as the volume goes up. But I have never gone past 11 o'clock on my preamp. My normal listening session is around 75-80db with the volume set around 8 o'clock.

shooter · « **Reply #42 on:** 12 Dec 2006, 10:14 pm »

Captain Humble let me know when you want to bring it over, my system is in my office, so day time is alright too.

Scott F. · « **Reply #43 on:** 12 Dec 2006, 10:17 pm »

Quote from: F-100 on 12 Dec 2006, 09:58 pm

I have Tvad4's Paradisea and also experiencing an audible hum starting at 12 o'clock on my preamp and increasing as the volume goes up. But I have never gone past 11 o'clock on my preamp. My normal listening session is around 75-80db with the volume set around 8 o'clock.

If that is the case, I (personally) don't feel that is a problem. Going beyond 12:00 (guessing at the actual gain of your pre) most likely puts your pre into clipping mode. I know it does mine. Heck, one of my pre's drives my amps into into clipping just above 10:00.

Without benching it I'd say that puts your signal to noise somewhere near -90db (thats a pure guess so don't crucify me if you think I'm off). For a piece of tubed gear, that is pretty normal. You should hear some of the single ended triode designs. Their S/N is nearing -60db. Granted, solid state gear is near -110db S/N but that is a completely different animal.

That said, if you have a passive pre or one who's gain goes beyond 12:00 without driving your amp into clipping then you likely have a hum problem (like Jeff has). All that assumes that you have taken any external factors out of the equation (power cords, interconnects, location, etc, etc.).

edit - added quote

nakolawala · « **Reply #44 on:** 13 Dec 2006, 12:09 am »

I have a preamp with only 6 db of gain and it is driving a Mcintosh amp. Some times I have to go beyond 12 oclock position and the hum is audible. No matter how good the sound is, they need to rectify this problem. Look like all recent paradisea sold over ebay have this problem.

NewBuyer · « **Reply #45 on:** 13 Dec 2006, 12:34 am »

Quote from: Scott F. on 12 Dec 2006, 10:17 pm

...For a piece of tubed gear, that is pretty normal. You should hear some of the single ended triode designs. Their S/N is nearing -60db. Granted, solid state gear is near -110db S/N but that is a completely different animal...

I wish more people would try the Constantine, the non-tubed version of the Paradisea.

By the way, I have always heard it claimed, that some amount of hiss and/or hum is present on all tube gear (compared with solid-state gear). Even some very well-respected tube gear manufacturers have told me this. I personally have actually tried very little tube gear, so I wonder what the experience of others can show about it. Is this claim true, is tube gear inherently vulnerable to these things?

Scott F. · « **Reply #46 on:** 13 Dec 2006, 01:08 am »

Quote from: nakolawala on 13 Dec 2006, 12:09 am

I have a preamp with only 6 db of gain and it is driving a Mcintosh amp. Some times I have to go beyond 12 oclock position and the hum is audible. No matter how good the sound is, they need to rectify this problem. Look like all recent paradisea sold over ebay have this problem.

Yep, you've definitely got an issue then. I'd get a hold of MHDT and explain the issue. Be sure to let him know that you have a low gain preamp and that your system is sensitive the slightest noise. Hopefully he has a solution.

Keep us posted on your communications. I may see if I can get my hands on some better measuring equipment and see what the S/N ratio is on these. I'll test mine that is about a year old and has no issues and two new ones that a couple of the local guys just received in the past two or three weeks (they haven't mentioned any issues but you never know). It will take me a week or two to get this done IF I can borrow the test gear.

Scott F. · « **Reply #47 on:** 13 Dec 2006, 01:16 am »

Quote from: NewBuyer on 13 Dec 2006, 12:34 am

By the way, I have always heard it claimed, that some amount of hiss and/or hum is present on all tube gear (compared with solid-state gear). Even some very well-respected tube gear manufacturers have told me this.

You are correct (at least with all the tubed gear I've had experience with). Usually the noise isn't objectionable but in some cases it can get really annoying. Case in point, nakolawala and his low gain pre and Capt Humble.

It's odd, there have been quite a few of these sold in the past few months. Most people seem extremely happy but then there are a few that have had issues. Guessing, its in the single digit percentages of those sold. Not sure if it's system or parts related. It may take some time to ferret out what the issue is.

And yes, the Constantine is quite the performer. I can easily listen to either and not feel that something is lacking. My choice of the Paradisea is merely the preference for tubes.

woodsyi · « **Reply #48 on:** 13 Dec 2006, 02:28 am »

My current preamp has a gain of 30 which means I don't ever go over 12 in my current set up. I don't have any issues with the DAC but I tried turning it up without music playing. I compared it with my other inputs without signal. I hear just a tad bit more hum compared to other inputs as I turn it up to 3 or so. As I don't go past 12 hum is not an issue for me at all. I got my unit about a month ago.

Captain Humble · « **Reply #49 on:** 13 Dec 2006, 11:53 am »

Quote from: shooter on 12 Dec 2006, 10:14 pm

Captain Humble let me know when you want to bring it over, my system is in my office, so day time is alright too.

Shooter,
I really appreciate your offer and look forward to meeting you.

This Thursday works well for me.
I sent you a PM yesterday with my cell number.
The pm also askes where you're located and what time is good for you.
Please advise here if the pm didn't go through and I'll try again.
Thanks,
Jeff

avahifi · « **Reply #50 on:** 13 Dec 2006, 12:12 pm »

In general, the volume control in a preamplifer is ahead of the active line circuits. Thus, any noise or hum originating in the line circuits will be a constant, not affected by where the volume control is set. So changing tubes, as I would have expected, did not change the hum issue.

What is left?

Three possibilities:

First, the hum is being generated in a source connected to the preamp. Try disconnecting all source cables at the preamp and see if this eliminates the hum. Reconnect one at a time to isolate the culprit.

Second, external enemies such as dimmer switches, water bed heaters, or anything else nasty thereabouts. Move the equipment to a different location and try again. Connection of anything in the system to a cable video source can be the problem. A three prong AC plug on any of the componets can make a ground loop too.

Third, internal grounding issues. It is really easy to design in a tiny grounding error that is very hard to track down. We did this when we first introduced a mute protect circuit in our preamps. We had to tear our hair to trace down the simple fact that we had the mute ground and input ground to the mute board connected and that was the problem.

Hope this is helpful.

Frank Van Alstine

nakolawala · « **Reply #51 on:** 13 Dec 2006, 01:15 pm »

With reference to the above post issue #1, I have disconnected everything from the circuit with only the Paradisea and preamp connected to my amp and the hum is there. If I disconnect the cable from the dac to preamp, the hum disappears. Hence the dac is the source of the hum. In my audio system, I never had any issues until the introduction of the Paradisea. Also with issue #3, the paradisea uses a mute relay at the output and I wonder if this is leading to any hum issues.

Today's tube amps and preamp are dead silent with S/N ratios very close to SS amp designs.

avahifi · « **Reply #52 on:** 13 Dec 2006, 09:25 pm »

If the mute relay board is a separate unit, then the ground side of the mute relay (which shunts the audio output circuits to ground when muted) must be separate from the power supply ground wiring to the mute board. If they are common, you will have ground loop induced hum.

Frank Van Alstine

shooter · « **Reply #53 on:** 15 Dec 2006, 01:55 am »

jeff bought his Paradisea over this afternoon, there was no hum problem, My dac with the WE 396a played louder and warmer than his Tungsol though.

Scott F. · « **Reply #54 on:** 15 Dec 2006, 04:28 am »

Having it work fine in your system and having it hum in his.....these are the kind of problems that are really frustrating.

Beside changing the cables, power cord and location as I suggested above, try using a digital or toslink out from a completely different player. It doesn't matter the quality (ie; a cheap dvd player would work for testing purposes). Be sure to try both the Toslink and the RCA digital outs.

Captain Humble · « **Reply #55 on:** 15 Dec 2006, 04:30 am »

Quote from: shooter on 15 Dec 2006, 01:55 am

jeff bought his Paradisea over this afternoon, there was no hum problem, My dac with the WE 396a played louder and warmer than his Tungsol though.

Shooter, it was a pleasure meeting you today and I truly appreciate you letting me try my DAC in your system. I also enjoyed hearing a few tunes on your system. Very nice!

Our little experiment proved that I don’t have a defective DAC.
The hum I’m experiencing is definitely system specific.

The good news is I can’t hear the hum over the music so I’ll probably keep it and just enjoy the music.

I liked Shooter’s WE 396a. As he said it’s warmer than my Tung-Sol and plays a bit louder. I’ll order one tomorrow.

I guess the next step is to swap out my Dodd Battery Preamp with my Usher pre and see what happens.

Thanks to all of you that have offered suggestions.

I’ll post any new developments.

Jeff

Captain Humble · « **Reply #56 on:** 15 Dec 2006, 04:31 am »

Quote from: Scott F. on 15 Dec 2006, 04:28 am

Having it work fine in your system and having it hum in his.....these are the kind of problems that are really frustrating.

Beside changing the cables, power cord and location as I suggested above, try using a digital or toslink out from a completely different player. It doesn't matter the quality (ie; a cheap dvd player would work for testing purposes). Be sure to try both the Toslink and the RCA digital outs.

Thanks Scott. I'll give that a try as well.

lonewolfny42 · « **Reply #57 on:** 15 Dec 2006, 05:28 am »

Jeff.....Glad to hear its not the DAC....guess you need a whole new system....

Quote

I liked Shooter’s WE 396a. As he said it’s warmer than my Tung-Sol and plays a bit louder. I’ll order one tomorrow.

No need.....trade ya.....one WE396 for your Tung-Sol. I'm waiting for two WE's to arrive from an auction I won.....an extra for me, and one for you....then I don't have to hunt down a Tung-Sol.

Sound OK ?

tvad4 · « **Reply #58 on:** 15 Dec 2006, 07:29 am »

I encourage everyone to investigate the 1950s GE 5 Star 5670 with black plates. I found it to be a nice "tweener" to the stock 1970s era GE 5670 and the WE396a. I bit warmer than the WE396a, and more resolving than the stock GE tube. I recently sold my Paradisea (I may buy another down the road), but I kept the GE 5 Star. It's the only 5670 I've kept in reserve.

F-100 · « **Reply #59 on:** 15 Dec 2006, 04:52 pm »

My WE396A tube should be here today.

Do you have to remove the top cover to swap the tube?