AudioCircle

Audio/Video Gear and Systems => Tube-o-phile Circle => Topic started by: Golden_Era on 28 Oct 2018, 11:29 pm

Title: Do I need these features on a set of tubes?
Post by: Golden_Era on 28 Oct 2018, 11:29 pm
Hello, I'm looking at getting a set of Genalex Gold Lion 12ax7 tubes for my preamp from Tube Depot. I see they have several options/upgrades available.

Balanced Triodes (add $2.00 each)
High Gain (add $2.00 each)
Low Noise & Microphonics (add $4.00 each)
Matching (up to 5 tubes) (add $2.00 each)

I know matching is critical but is anything else listed a recommendation? Thanks for any help.
Title: Re: Do I need these features on a set of tubes?
Post by: FullRangeMan on 28 Oct 2018, 11:33 pm
Hello, I'm looking at getting a set of Genalex Gold Lion 12ax7 tubes for my preamp from Tube Depot. I see they have several options/upgrades available.

Balanced Triodes (add $2.00 each)
High Gain (add $2.00 each)
Low Noise & Microphonics (add $4.00 each)
Matching (up to 5 tubes) (add $2.00 each)

I know matching is critical but is anything else listed a recommendation? Thanks for any help.
These features are quite desirable for hifi audio,
although if you listen only Heavy Metal dismiss it
I would add they are asking very low money for.
Check the competitors prices at UpScale or VTS.
Title: Re: Do I need these features on a set of tubes?
Post by: mick wolfe on 29 Oct 2018, 03:23 am
You would definitely want to select the low noise variety if they're to be used in a phono section.  Aside from that, the only other option I've been offered from sellers is matched pairs.  This in reference to the Russian GL 12AX7 variety that go for roughly $90 a pair. Maybe someone can chime in on the importance of the remaining options.
Title: Re: Do I need these features on a set of tubes?
Post by: FullRangeMan on 29 Oct 2018, 03:52 am
Balanced Triodes (add $2.00 each) is useful when one double Triode tube as 6SN7/12AX7 drive two output tubes, which is a bargain for $2.

Low Noise small tubes are useful in power amps too if your speaker are more than 100dB/W/M as Klipsch RF7-II or hi gain horn.

High Gain (add $2.00 each) I dont see how gain can be adjusted in a tube :scratch:

Matching (up to 5 tubes) (add $2.00 each) $2 its a bargain also to match 4 tubes for PP amps as the Decware Torii Jr. (four EL34).
Title: Re: Do I need these features on a set of tubes?
Post by: Tyson on 29 Oct 2018, 03:54 am
The closer to the source a tube is, the more important it is to be low noise.  In a DAC or a phono preamp, spring for the extra low noise tubes.  After that, it's still important, but it's less critical. 
Title: Re: Do I need these features on a set of tubes?
Post by: JackD on 30 Oct 2018, 02:14 am
Depends on the preamp and the purpose of the 12AX7 in that design. So their is no universal answer.
Title: Gold Lion 12Ax7s
Post by: Golden_Era on 2 Dec 2018, 03:28 pm
I've got the Gold Lion's and have about 10 hours on them currently. They are very liquid as according to their description. Blues and softer passages, saxophone and other woodwins sound amazing.

Heavier passages seem to tell a different story. Harder rock, Who type stuff, seems somewhat strained. I'm not sure if more break-in could be necessary?

I've also been told a tube like a Tung Sol is a more rock and roll type tube. Perhaps something I should look into? 
Title: Re: Do I need these features on a set of tubes?
Post by: Tyson on 2 Dec 2018, 03:48 pm
Give those GLs a good 50 to 100 hours and they will open up. 
Title: Re: Do I need these features on a set of tubes?
Post by: Golden_Era on 2 Dec 2018, 05:54 pm
Thank you! Very green in the tube game yet. Sounds great.  :D
Title: Re: Do I need these features on a set of tubes?
Post by: Golden_Era on 2 Dec 2018, 06:00 pm
Another green question I'm noticing I'm getting a higher more clear volume level out of my right channel over my left. It just appeared last night. It's subtle but noticeable. Could this be an attribute to the break in as well? They are matched.
Title: Re: Do I need these features on a set of tubes?
Post by: I.Greyhound Fan on 3 Dec 2018, 12:23 am
Another green question I'm noticing I'm getting a higher more clear volume level out of my right channel over my left. It just appeared last night. It's subtle but noticeable. Could this be an attribute to the break in as well? They are matched.

It may be a bad tube.  It happens, but give it another 10 hours and see if it corrects itself.  If not, try and have the tubes tested if you can, otherwise send them back as they should have a warranty. 
Title: Re: Do I need these features on a set of tubes?
Post by: Golden_Era on 3 Dec 2018, 12:38 am
Thanks. I hope that's the case and it's not speaker related. Lol.
Title: Re: Do I need these features on a set of tubes?
Post by: Ericus Rex on 3 Dec 2018, 03:36 pm
Another green question I'm noticing I'm getting a higher more clear volume level out of my right channel over my left. It just appeared last night. It's subtle but noticeable. Could this be an attribute to the break in as well? They are matched.

Switch the L & R channel tubes and see if the problem goes away.
Title: Re: Do I need these features on a set of tubes?
Post by: avahifi on 3 Dec 2018, 04:41 pm
High gain 12AX7 tube?  If used in a single tube per channel phono section, you need all the gain you can get.

Low noise?  Again in a phono section this is important, especially in the first tube in any circuit.

Matched sections?  This is most important if the two triode sections of a tube are sharing two separate audio channels, one triode per channel.  Then you definitely want matched gain between the two sections.

Matched sets of tubes?  Of course  any of the selections offered means that the tubes you get have had more testing than just individual tube selections.  This probably lowers the risk of infant mortality.  We do this in our Ultravalve tube amplifier, ordering matched quad sets of  output tubes and very rarely do we have a premature output tube failure.

Note that there is a difference in gain between sample to sample of  any brand and type of tube.  There is usually a bigger difference in gain from brand to brand.

In general, too much tube gain for a given circuit increases feedback and feedback related transient distortion, causing excess brightness and listen fatigue.

Too low a tube gain for a given circuit reduces feedback, possibly too much, causing increased harmonic distortion and muddy sound in extreme cases.

It is nice to know what the designer of the circuit really wanted to select the best tubes for that circuit.  In randomly doing "tube rolling" you results may vary substantially, and not because of  the apparent brand, age, or other advertised virtues, just because of gain differences.

A tube tester is a useful device, kind of like having a tire pressure gauge when making tire tests.

Frank