Aiqin/Oldchen Tube Amps
- Thread starter bubba42
- Start date
mjw21a
Super Member
Using some vintage cabinets which previously had some Plessey Rola 8 inch full rangers. The Daytons are much more detailed though lack the nice coloration of the drivers they replaced
Generally NO. Is the buzzing comes from speakers or amp itself? Speakers should be silent if your ear is a feet or more away from it. Transformers can produce slight buzz, but you should not hear it from listening position either.
For what it's worth, zero hum/buzzing out of my Oldchen. Ever so slight hum from the speaker(s) but only with ear pressed directly against the driver. Completely unnoticeable when moving even 4 inches away. So far, really happy with this amp. I've never gone passed noon on the volume knob. Can I, or is that ill advised?
Of course you can.
On a Tube amp unlike a SS amp, nothing bad can happen. Your amp will start to clip and you'll get distortion but that's all. That does not damage the tubes.
If your buzz does not come from the speakers, it's a mechanical vibration coming for either the power transformer, or the choke.
Before you go further, make sure both of them are fixed tied on the chassis.
On a Tube amp unlike a SS amp, nothing bad can happen. Your amp will start to clip and you'll get distortion but that's all. That does not damage the tubes.
If your buzz does not come from the speakers, it's a mechanical vibration coming for either the power transformer, or the choke.
Before you go further, make sure both of them are fixed tied on the chassis.
Poultrygeist
Lunatic Member
nice
bubba42
Active Member
Great idea for the speaker enclosures, mjw21a! Does anyone else have other ideas for inexpensive ready-made speaker enclosures that would take this 8-inch full range driver? I was thinking about an open baffle, but if I could put them into a nicer enclosure, that would look better.
Bartkess, are you going to get another? I don't think the rest of us are experiencing any buzzing.
Bartkess, are you going to get another? I don't think the rest of us are experiencing any buzzing.
mjw21a
Super Member
If done right, open baffles would look great. I just lack the necessary skills to build. These old vintage speakers look good though 
The advantage of open baffles is space saved. My living room is rather crowed due to the size of the B&W DM-16 speakers. They stay as they were Dad's. Sound great though.
The advantage of open baffles is space saved. My living room is rather crowed due to the size of the B&W DM-16 speakers. They stay as they were Dad's. Sound great though.
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DoctorJa
Active Member
Hold on for a second. I went through this with my Oldchen. Since I had my amp in a cabinet, it took me awhile to track down the source of the buzz. With a cotton cloth I covered/dampened each tube and found one of the Psvane EL-34s to be the culprit. I contacted the seller (Hifimusic 2014) and he sent out a replacement tube. However, when it arrived I still got the buzzing. Did the same thing as above and now both were buzzing. To make a long story short, went to Tube Depot and picked up some cheap JJs and voila, no buzz. So the Psvanes have some issues. That said, I am still running them because they sound better than the JJs. Try this before sending back. I just swapped in the JJs to reconfirm and still no buzz.
And just to be clear, I am talking about the amp itself making the buzzing sound, not buzzing from the speakers.
bartkess
New Member
Hey thanks for the info. I haven't sent it back yet. Besides the buzz it does sound very good with my sansui SD 3500 speakers. Been playing it all day. Can't stop listening to it.
I'm hooked. Did you see the pic I posted with the ding on the right side. Might have it exchanged because of that.
I'm hooked. Did you see the pic I posted with the ding on the right side. Might have it exchanged because of that.
DoctorJa
Active Member
Missed that. Sorry. I just didn't want you to send it back because of the tubes.
Speaking of tube rolling, has anyone else done any? I tried a pair of Sylvania JAN CHS 6SL7WGT preamp tubes, which seem to be, from my research, the ones that have the most 3D-like sound, which is what I am going for. They have not given me a huge leap over the stock tubes, but they do project a bit wider soundstage and have more air between the instruments. I also tried some RCA 6SL7 (clear glass) tubes. They have a very lush sound with some spectacular bass. Good tube for rock but not as refined as the JAN CHS 6SL7WGT. According to the seller, the 6SN7, not the 6SL7, is the exact replacement of the 6N9P, although he confirmed that the 6SL7 works fine. Does anyone know the difference? It seems like the 6SL7 has a tad less gain than the stock 6N9P.
I have also tried a Sylvania 5U4G for the rectifier. I did seem to dig a little deeper than the Chinese rectifier, but I didn't notice that much of an improvement.
I know I need to try many more tubes, but I wouldn't run out right away to get new tubes. I found the Oldchen itself improved my sound over the APPJ Miniwatt by about 30%; the tube upgrades only got me about 5% more at best.
Poultrygeist
Lunatic Member
Not sure about the buzzing y'all are describing but it you lightly tap the tube and you hear an amplified sound then the tube is microphonic and will need to be replaced. It's not uncommon.
Some noisy tubes can be dampened with rubber washers.
Some noisy tubes can be dampened with rubber washers.
