Tube Buffers!!! Anyone using them here?

machone

Thanks. Just curious. I built a Dynaco St-70 back in the 70's and drove it with an Advent 300 receiver (pre-outs). Sold them for very little in the mid 80's. Could not believe the asking price for a ST-70 today.

heiney9

Depends on what you mean by typical. Signal tubes last a lot longer than power tubes or rectifier tubes simply because they are many times less stressed. As the type of circuits signal tubes are used in tend to put less "stress" on the tubes and old stock tubes from the 50's 60's 70's can last upwards of 10,000 hours. A typical signal tube you should be able to get 3000-5000 hours. I am not so sure about current production tubes.

Power tubes if run efficiently and not at the ragged edge can last a long time as well maybe a typical tube can run 2000-4000 hours. Think of all those Mullard EL34's still out there running strong.

These are just guesstimates and it can vary greatly based on the circuit design and tube manufacturer. I think it's safe to say in general tubes from yesteryear last longer and are more consistent than current production tubes.

The old world craftsmen, tooling and materials were much better and purer than today. No expense was spared back in the day, today a lot of penny pinching goes on and there are more environmental regulations. Some substances have been banned (atleast in the US) so alternatives must be found today.

H9

machone

I got a Yaqin CD3 to test and it is producing a electronic gurgling noise. Could this be a bad tube?

erniejade

Sounds like that might be it.

dhart86

what kind of 6sn7 tubes are you using?

machone

It came with a pair of Chinese 6N8P but will take a 6SN7 or 6H8C.
My preamp and amp are dead silent. I inserted this between the DAC and the preamp. The noise shows up around 10 o'clock. The sound is a whine with a kind of gurgling or intermittant white noise.

machone

Now I believe that the somehow the noise is created by my laptop. When I move the mouse around the screen the pitch of the whine changes? Never happened without the Yaqin in the circuit. I had to add an additional set of cables. Maybe one is bad. Would not be the first time.

machone

Changed the cable. Same noise. The DAC is powered by the computer USB so noise could be coming from the computer but why do I hear it only with the tube buffer in the circuit. Also the tube buffer is sitting next to the DAC.
Any ideas? Help!

machone

Confirmed. The noise is coming from the computer. I closed the Audiogate3 Player and the whine stopped. I turned of the computer and the gurgling whitenoise stopped. I wonder why I never heard this before the tube buffer was installed?

tonyb

machone wrote: »

Confirmed. The noise is coming from the computer. I closed the Audiogate3 Player and the whine stopped. I turned of the computer and the gurgling whitenoise stopped. I wonder why I never heard this before the tube buffer was installed?

Maybe you have heard it before, but at a lower volume that inherently becomes part of the music as grunge. The better your system becomes, the more it's weaknesses become apparent.

Are you using a decent USB cable ? You don't have to spend a fortune on one but you do need one of good quality.

machone

Thanks Tony.

Maybe the noise has always been there.
I will listen closer without the tube buffer in the circuit to see if I hear the noise. Also I need to disconnect the USB cable and make sure that is the path that the noise is traveling.
If the noise is traveling through the USB I can fix it with a Uptone Regen. It has its own power supply for the DAC isolating it from computer power. Also it regenerates the signal to help eliminate noise in the digital stream. I have been wanting to try one of these anyway. They are getting very good reviews.
I have good USB cables (Starlight 7).

I don't know about the sound of the tube buffer yet. It has not been turned on for very long so I don't want to get carried away positive or negative. Right now I would say that imaging, vocals, strings and complicated passages are very good but the bass seems loose and not as dynamic. I expect things will change as everything burns in and there is always the opportunity to roll the tubes.

EndersShadow

Is your computer a laptop by any chance? if so see if the problem goes away or appears when your on battery or the charger.

Also a full list of whats connected how would be useful.

machone

Dell Precision M4400 laptop connected to its stock charger. Never tried it with only the battery--yet.

External hard drive>Starlight 7 USB>laptop>Starlight 7 USB>Korg DSDAC-100>RCA cable >Yaqin CD3>RCA cable>Hafler 110>RCA cable>Hafler 500>out to speakers.

Never heard the noise until the Yaqin and the extra RCA cable was inserted between the DAC and the preamp.

dhart86

The tubes may be amplifying. I had a similar problem when playing music in my system and the source was my computer. My problem was solved by applying a cheater plug to the computer. (cheater plug is an adapter plug that converts the 3-prong(ground) plug into a 2-prong plug. Give that a try. cheap fix!

dhart86

Different tubes (I mean better) may change your sound.....some help with bass. Different tubes =different sonics

tonyb

Could be one of the tubes is going bad in the Buffer too. I'd switch out the tubes to be sure anyway. Best way is to eliminate the 'puter from the signal chain and maybe use a cdp with the buffer in there and see if the noise is still present.

txcoastal1

You definitely need to try battery only. When I program my fire alarm panels via laptop>>>USB serial adapter>>> alarm panel, the fire panel will show ground fault if I am plugged into a receptacle.

erniejade

On my lapotop, the power supply for the usb drive was the issue causing my noise.

machone

Your right. It is the power supply. Unplugged it and no noise.
Thanks guys.

machone

dhart86.
Bingo.
Tried the two prong adapter and no noise.
thanks

I will probably order a matched pair of tubes. These resonate when tapped.

dhart86

I have some 6sn7 tubes on hand if you are interested send me a pm

machone

I ordered a noise tested matched pair of NOS Sylvania 6SN7GTB tubes from Brent Jessee. Got them in three days.

Put them in the Yaqin CD3 and let them burn in for a couple of days. Boy do they make a difference over the Chinese tubes. The bass is back and tight. Highs float. Mids and vocals sound very natural. Huge soundstage with depth.

Very happy. It will be interesting to compare the Yaqin to the iFi.