AudioNervosa

Systemic Development => Bipolar System Disorders => Topic started by: Nick B on October 05, 2018, 07:46:41 PM

Title: tube issues with new preamp
Post by: Nick B on October 05, 2018, 07:46:41 PM
Last night I turned on the tubes to warm up my Border Patrol dac and Audio Hungary preamp.  I then promptly fell asleep as I’m still recovering from our wonderful vacation to Washington state. I woke up a few hours later to a scratchy type sound. The volume was all the way down on my preamp and I immediately turned off both pieces. The amp is solid state and has a sensor to turn on, so that couldn’t be the problem. The pre has already given me problems with a very noisy pot. It’s happened 8-9 times, but does go away if I wipe the pot manually. The manufacturer will not resolve the problem. It really sounds wonderful, but so what... Can anyone suggest what I should do or how to troubleshoot this problem? I didn’t smell any burning. I have opened the top on the pre before. It’s not hard to do.
Title: Re: tube issues with new preamp
Post by: Jack on October 05, 2018, 08:30:46 PM
Didn't you just buy that new from Charles a few months ago? Is the noise on one side or both?  If one have you swapped the tubes left to right?
Title: Re: tube issues with new preamp
Post by: Nick B on October 05, 2018, 08:42:03 PM
Didn't you just buy that new from Charles a few months ago? Is the noise on one side or both?  If one have you swapped the tubes left to right?

Yes, same preamp. The noise freaked me out after waking up, so I immediately turned it off. I’m asking if I should turn it on and what I should be doing. I really don’t want to do further damage.
Maybe I should take off the cover and just inspect the tubes. I’ve lived blissfully and trouble free without tubes for over 20 years, but this current setup does sound great.
Title: Re: tube issues with new preamp
Post by: Jack on October 05, 2018, 09:48:16 PM
Nick

I agree that the 1200AS amps sound best with a tube preamp as my Mivera Purepower was really good with both the Modwright and the BHK so I would try to get to the bottom of it.  If the volume is all the way down and you still get the noise you may have a tube that is going bad so the problem is figuring out which one especially if it is on one side.  The noise should not be of a level to hurt anything down the line since we're not dealing with power tubes.  First thing I would do is take them all out one at a time and re-seat them then fire it up.  If that doesn't work then swap each matching pair from side to side and see if the noise moves or stops when the other half of the triode is in play.  Over the years I have had many a tube that acted up periodically while warming up then cleared up and then the noise came back with no warning.  If Qualitron is just using standard issue current production tubes from Russia or China it could be an easy fix as they don't have the highest quality control. 
Title: Re: tube issues with new preamp
Post by: Nick B on October 05, 2018, 10:10:40 PM
Nick

I agree that the 1200AS amps sound best with a tube preamp as my Mivera Purepower was really good with both the Modwright and the BHK so I would try to get to the bottom of it.  If the volume is all the way down and you still get the noise you may have a tube that is going bad so the problem is figuring out which one especially if it is on one side.  The noise should not be of a level to hurt anything down the line since we're not dealing with power tubes.  First thing I would do is take them all out one at a time and re-seat them then fire it up.  If that doesn't work then swap each matching pair from side to side and see if the noise moves or stops when the other half of the triode is in play.  Over the years I have had many a tube that acted up periodically while warming up then cleared up and then the noise came back with no warning.  If Qualitron is just using standard issue current production tubes from Russia or China it could be an easy fix as they don't have the highest quality control.

Jack,
Ok, I’ll fire it up tomorrow and check if the noise is in both channels and then switch the tubes. Maybe Charles will see this tomorrow as well. It’s been about two weeks since I played some tunes and I’m raring to go for some listening sessions 🎵 🎻 🎷
Title: Re: tube issues with new preamp
Post by: Jack on October 05, 2018, 10:42:27 PM
Sounds good.  If at some point you can't get the problem resolved and decide to abandon tubes a preamp that will give you a similar sonic signature is the W4S STP-SE.
Title: Re: tube issues with new preamp
Post by: Nick B on October 06, 2018, 08:56:00 AM
Sounds good.  If at some point you can't get the problem resolved and decide to abandon tubes a preamp that will give you a similar sonic signature is the W4S STP-SE.

First time I’ve heard of that preamp. I’ll also check the origin of those tubes
Title: Re: tube issues with new preamp
Post by: shadowlight on October 06, 2018, 10:28:02 AM
Nick, which tubes does the preamp use?
Title: Re: tube issues with new preamp
Post by: Emil on October 07, 2018, 04:59:55 AM
Didn't you just buy that new from Charles a few months ago? Is the noise on one side or both?  If one have you swapped the tubes left to right?

Is Rollo aware of the noisy pot problem that the manufacturer refuses to do anything about it?
Hard to believe that that would sit well with Charles.
Title: Re: tube issues with new preamp
Post by: Emil on October 07, 2018, 05:02:07 AM
Nick, which tubes does the preamp use?

http://audiohungary.com/termek/apr-204/16
uses 4 12AX7 in the line stage and 2 6922 if it has a phono stage
Title: Re: tube issues with new preamp
Post by: Hugh on October 08, 2018, 01:56:14 PM
Nick,

Isn't your preamp still under warranty?
Title: Re: tube issues with new preamp
Post by: Nick B on October 09, 2018, 06:35:24 AM
Sorry for the late response, guys. I was in Las Vegas.  I had a listening session before I left and again last night after I got home. That presumably noisy tube problem has gone away for now. The unit sounds perfect. That darned noisy pot is getting worse. Manually wiping it gives me only a brief respite. The preamp is under warranty and Charles and I have discussed it. I think it will get resolved soon. 
A few months ago, I did discuss the noisy pot with the manufacturer. This preamp did not have a motorized pot in it originally and this particular Alps pot fit into the limited space. Apparently some Alps pots can be noisy due to the graphite within. It seems to me there might be room for a different brand and I’d be willing to pay for any price difference. But I never discussed that with the manufacturer. The unit is built like a tank and the workmanship inside is stellar. The sound is very, very good, especially at this price point.
I used to be somewhat of a “detail freak”, but when I listen now, I don’t even think about that. The combination of this pre, the amp and the Border Patrol dac is wonderfully synergistic.
I will let Charles comment if he wishes. I’m grateful for the nice discount and it’ll get resolved at some point I’m sure.
Nick
Title: Re: tube issues with new preamp
Post by: tmazz on October 09, 2018, 09:44:16 AM
Is there any way to squirt some kind of old fashioned contact cleaner into the noisy pots? Perhaps that will clear some of the problem causing graphite out of the way
Title: Re: tube issues with new preamp
Post by: Nick B on October 09, 2018, 09:55:18 AM
Is there any way to squirt some kind of old fashioned contact cleaner into the noisy pots? Perhaps that will clear some of the problem causing graphite out of the way

Iirc, I did an online search on this some weeks back and these are sealed units. But I will look up that model again to verify. It sure would be interesting to know what else might fit in there and I’d gladly pay the difference. But this is Audio Hungary’s basic, entry level preamp and I never got the impression that they were interested in even considering the possibility. I’ll say this...if their entry level preamp is this good, their top of the line must be truly outstanding. Charles was right as to the quality and bang for the buck on my APR 204
Title: Re: tube issues with new preamp
Post by: rollo on October 11, 2018, 08:28:43 AM
Nick I told you if the pot noise persists after warranty expires I would  personally take care of problem. Tubes go now and then which the Manf. or I have control over. Sometimes tubes when they settle make a slight noise and then gone.
Is tube noise still present ? Try switching tubes ?
I'm starting to think maybe a tube issue all along. Maybe not pot. We need to try different tubes. FYI no other customer has had this issue. Your the only one. Get a Shamrock already.


charles


















Title: Re: tube issues with new preamp
Post by: rollo on October 11, 2018, 08:36:48 AM
Didn't you just buy that new from Charles a few months ago? Is the noise on one side or both?  If one have you swapped the tubes left to right?

Is Rollo aware of the noisy pot problem that the manufacturer refuses to do anything about it?
Hard to believe that that would sit well with Charles.


  Got that right Emil. We need to clarify and stop this wrong information. The Manf. has dealers and USA distributor to handle any issue that arises. That is called customer service.
The Manf. directed the issue to the USA  distributor and Rollo Audio. I would have never known about "tube noise" until I read it posted here.


charles
Title: Re: tube issues with new preamp
Post by: Nick B on October 11, 2018, 08:55:50 AM
Nick I told you if the pot noise persists after warranty expires I would  personally take care of problem. Tubes go now and then which the Manf. or I have control over. Sometimes tubes when they settle make a slight noise and then gone.
Is tube noise still present ? Try switching tubes ?
I'm starting to think maybe a tube issue all along. Maybe not pot. We need to try different tubes. FYI no other customer has had this issue. Your the only one. Get a Shamrock already.


charles

Charles,
Yes, you did tell me that. I’m a pretty patient guy, but I do get frustrated at times. Being a tube novice, I really don’t know how to handle these issues. All I can tell you is what the guy at Audio Hungary told me. He acknowledged that this particular type Alps pot has graphite and that they can get noisy. I have manually turned that pot back and forth and that kept the noise away for a time. What’s happening lately is the same procedure doesn’t help much now...the noise is back very quickly. What is interesting is the other night when I turned the pot manually, the noise was present..or more present..in the right channel. Maybe it is both the pot and a tube.
I just had a minor surgical procedure today, so I’m not going to open the preamp and switch tubes etc for a couple of days. I will switch tubes then and keep you posted and I assume it will be obvious as to which tubes go to the right and left channels. The noise issue(s) has been consistent and I’d like to resolve it within the warranty period. As I mentioned previously, this is a fantastic sounding preamp and maybe Murphy’s law has dictated that I am the one ... and only...customer with this issue.
The workmanship on this unit is stellar, but I just want to get this resolved. Any one of us on this forum would be frustrated having issues with a new piece of equipment.
So I’m going to kick back right now,  keep ice on my knee and live happily with pain meds for a couple of days.
I appreciate the discount you gave me and the superb sound of this unit  :thumb:
Nick
Title: Re: tube issues with new preamp
Post by: Nick B on October 11, 2018, 09:13:43 AM
Didn't you just buy that new from Charles a few months ago? Is the noise on one side or both?  If one have you swapped the tubes left to right?

Is Rollo aware of the noisy pot problem that the manufacturer refuses to do anything about it?
Hard to believe that that would sit well with Charles.


  Got that right Emil. We need to clarify and stop this wrong information. The Manf. has dealers and USA distributor to handle any issue that arises. That is called customer service.
The Manf. directed the issue to the USA  distributor and Rollo Audio. I would have never known about "tube noise" until I read it posted here.


charles

To clarify a couple of things, I had contact with Audio Hungary before I bought the unit as I had a number of questions I wanted answers to before I ever considered a purchase. Then when the pot noise issue arose, I contacted them again to discuss because we had already exchanged emails. He acknowledged the potential of a noisy pot, but didn’t seem interested in resolving it via replacing the pot. That didn’t sit well with me, but I just did the manual wipe thing as it was my only option. Then when the other noise arose, I did post here to get quickly get opinions on that.
I am not the type to disparage anyone or any manufacturer. We read about those ugly discourses on other forums. But geez, this was happening on a new unit and frustration did set in.
In a few days, I’ll switch tubes and advise. This is just one of those things that happens and being a solid state guy for the last 25 years, I was concerned a bit about the potential for tube issues.
I’ll let the matter rest for a few days as I recoup. I’m sure it’ll get resolved soon. I still like  the
company, the sound and Charles, I appreciate your concern and thanks for your contributions here on the forum. Your enthusiasm for audio is refreshing and appreciated.
Title: Re: tube issues with new preamp
Post by: rollo on October 11, 2018, 10:35:29 AM
Nick I'm starting to think it is a 12AX7 tube. As I said if it is pot you will get proper customer service. When you feel better try switching tubes around. It just may be the issue. We WILL get you happy.

love
charles
Title: Re: tube issues with new preamp
Post by: Nick B on October 11, 2018, 12:31:45 PM
Nick I'm starting to think it is a 12AX7 tube. As I said if it is pot you will get proper customer service. When you feel better try switching tubes around. It just may be the issue. We WILL get you happy.

love
charles

Charles,
I’m feeling pretty good and will switch them soon. Maybe it’s those pain meds that are making me happy 😃. If it’s a tube, I’m guessing there’s a 90 day warranty and I’m past that. Deepak said he has some extra or I might upgrade. Not sure where those stock tubes are sourced.
Thanks!
Nick
Title: Re: tube issues with new preamp
Post by: tmazz on October 11, 2018, 08:53:08 PM

So I’m going to kick back right now,  keep ice on my knee and live happily with pain meds for a couple of days.


Pain meds? Sounds like the perfect time to pull out DSOTM.  :D

(https://m.media-amazon.com/images/M/MV5BMDI4NjVmYmUtNDU1Yi00NzU2LWE3MmUtMzc0NTA2MjY3YTc1XkEyXkFqcGdeQXVyMjQ0NzE0MQ@@._V1_UY268_CR76,0,182,268_AL_.jpg)

Title: Re: tube issues with new preamp
Post by: Nick B on October 12, 2018, 12:35:56 AM

So I’m going to kick back right now,  keep ice on my knee and live happily with pain meds for a couple of days.


Pain meds? Sounds like the perfect time to pull out DSOTM.  :D

(https://m.media-amazon.com/images/M/MV5BMDI4NjVmYmUtNDU1Yi00NzU2LWE3MmUtMzc0NTA2MjY3YTc1XkEyXkFqcGdeQXVyMjQ0NzE0MQ@@._V1_UY268_CR76,0,182,268_AL_.jpg)

That’s really rad, dude... 🚬
Title: Re: tube issues with new preamp
Post by: rollo on October 12, 2018, 07:33:31 AM
Nick I'm starting to think it is a 12AX7 tube. As I said if it is pot you will get proper customer service. When you feel better try switching tubes around. It just may be the issue. We WILL get you happy.

love
charles

Charles,
I’m feeling pretty good and will switch them soon. Maybe it’s those pain meds that are making me happy 😃. If it’s a tube, I’m guessing there’s a 90 day warranty and I’m past that. Deepak said he has some extra or I might upgrade. Not sure where those stock tubes are sourced.
Thanks!
Nick

   Nick if a tube I will get you tube required from Audio Hungary. Out of warranty or not. However some NOS Raytheon or RCA 12AX7 would be just marvelous. Brent Jessie has them.


charles
Title: Re: tube issues with new preamp
Post by: Nick B on October 12, 2018, 10:24:18 AM
Nick I'm starting to think it is a 12AX7 tube. As I said if it is pot you will get proper customer service. When you feel better try switching tubes around. It just may be the issue. We WILL get you happy.

love
charles

Charles,
I’m feeling pretty good and will switch them soon. Maybe it’s those pain meds that are making me happy 😃. If it’s a tube, I’m guessing there’s a 90 day warranty and I’m past that. Deepak said he has some extra or I might upgrade. Not sure where those stock tubes are sourced.
Thanks!
Nick

   Nick if a tube I will get you tube required from Audio Hungary. Out of warranty or not. However some NOS Raytheon or RCA 12AX7 would be just marvelous. Brent Jessie has them.


charles

Thanks for the tip, Charles. I will likely upgrade the tube for my Border Patrol dac as well. Gary Dews told me what his favorite tube is for that application.
Nick