[Asterix]

My Luxman amp uses 4 12AX7's and 2 12AU7's and some other tubes. Let's say I use 3 or 4 different brand 12AX7 tubes (actually using 5751's in this case) and 2 different brand tubes for the 12AU7's. I am wondering, is it better to use tubes of the SAME brand or does it make no difference? Anybody know the answer to this question? Thanks.

 

[sacd lover]

I always use the same brand myself. Tubes sound different and using different brands you will end up with a differt sound in each channel. Now if the tubes are not performing like fuctions(right/ left outputs for example) then you would simply be tuberolling.

 

[Asterix]

Quote:

Originally Posted by sacd lover I always use the same brand myself. Tubes sound different and using different brands you will end up with a differt sound in each channel. Now if the tubes are not performing like fuctions(right/ left outputs for example) then you would simply be tuberolling.

How do I know if the tubes are not performing like functions, like right/left outputs?

 

[sacd lover]

Quote:

Originally Posted by Asterix How do I know if the tubes are not performing like functions, like right/left outputs?

You need to read the manual or ask the builder or seller what they do. See what the tube compliment is in the amp and learn what each tube does. If the amp uses say... single tubes like in the Eddie Current hd25 (one 6sn7 for gain/ one 6as7 for output) you can use any 6sn7 or 6as7 in their respective sockets you want; thats an easy one. An amp like the Moth 2a3 uses a 5u4g for rectification, a 6sn7 for gain and a pair of 2a3 tubes as outputs. The single tubes can again be any brand while the output tubes need to be the same brand for consistency between channels. Another example would be the singlepower mpx3 which uses three 6sn7's. Here the first tube(left to right) is the gain tube and the last two are the output tubes. The gain tube can be any brand but the other two need to be the same brand for consistency. You can use three of the same type if you wished but you really need to have the R/L outputs be the same brand. Some amps require not only the same brand of tube but that the tubes themselves must be matched in their output characteristics. This is especially true of balanced amps. I guess the best answer is you need to educate yourself about your own amp; what tubes does it use and what are the tubes for. Tubes can be used in many capacities so you need to do some research.

 

[Asterix]

Quote:

Originally Posted by sacd lover You need to read the manual or ask the builder or seller what they do. See what the tube compliment is in the amp and learn what each tube does. If the amp uses say... single tubes like in the Eddie Current hd25 (one 6sn7 for gain/ one 6as7 for output) you can use any 6sn7 or 6as7 in their respective sockets you want; thats an easy one. An amp like the Moth 2a3 uses a 5u4g for rectification, a 6sn7 for gain and a pair of 2a3 tubes as outputs. The single tubes can again be any brand while the output tubes need to be the same brand for consistency between channels. Another example would be the singlepower mpx3 which uses three 6sn7's. Here the first tube(left to right) is the gain tube and the last two are the output tubes. The gain tube can be any brand but the other two need to be the same brand for consistency. You can use three of the same type if you wished but you really need to have the R/L outputs be the same brand. Some amps require not only the same brand of tube but that the tubes themselves must be matched in their output characteristics. This is especially true of balanced amps. I guess the best answer is you need to educate yourself about your own amp; what tubes does it use and what are the tubes for. Tubes can be used in many capacities so you need to do some research.

My amp is vintage and I haven't been able to find a lot of info about it other than this:


LUXMAN LX-33
Pre- main amplifier * Tube sphere type pre- main amplifier
* Output tube: 6CA7/EL34
* Output: 30W+30W (4/8 ohm)
* Frequency characteristic: 30 - 35,000Hz
* External size: 450 (W) x158 (H) x325 (D)
* Price: \138,000 (1983 years) [in yen]

Also:

> "To cater for the specific requirements of sophisticated audiophiles this
> model is designed under full command of perfect knowledge about vaccum
state
> technology of existing tubes".
> From the LX33 front panel... No kidding.


> www.zenn.com.sg/LX33_fret.JPG


> The LX33 was an assembled derivative of the Luxkit A1033 sold at the end
of
> the '70s/early '80s. It's a basic integrated amp with a very nice vintage
> sound, very good build quality (albeit below "real" Lux amps) and
excellent
> output iron (Lux OY15-5).


> The tube complement and topology are very classical. The amp can be wired
in
> ultralinear for around 30 w per channel, or in triode mode for 15 w.


> It uses the following tubes:
> 4 x 6CA7/EL34 (push-pull power stage)
> 2 x 12AU7 (driver)
> 1 x 6AQ8 (power amp input)
> 4 x 12AX7 (preamp)

 

[Swampwalker]

Quote:

It uses the following tubes: > 4 x 6CA7/EL34 (push-pull power stage) > 2 x 12AU7 (driver) > 1 x 6AQ8 (power amp input) > 4 x 12AX7 (preamp)

Asterix- you would need to use a matched quad of the EL-34s.
the 12AU7s should match since there is one in each channel only.
The 6AQ8 is obvious
The 12AX7s- you should match the two halfs of each pair. In other words, the right channel first 12AX7 should match the left channel first 12AX7.

However, to complicate matters, if you are using NOS tubes, many tubes were rebranded either for OEM use or aftermarket sellers. So there are lots of RCA tubes that may have come from different manufacturers; same for GE, Westinghouse, etc. YOU will want to do some research on Joe's Tube Lore at Audio Asylum, which will give you lots of detail on the 12A?7 tubes.

 

[Asterix]

Quote:

Originally Posted by Swampwalker Asterix- you would need to use a matched quad of the EL-34s. the 12AU7s should match since there is one in each channel only. The 6AQ8 is obvious The 12AX7s- you should match the two halfs of each pair. In other words, the right channel first 12AX7 should match the left channel first 12AX7. However, to complicate matters, if you are using NOS tubes, many tubes were rebranded either for OEM use or aftermarket sellers. So there are lots of RCA tubes that may have come from different manufacturers; same for GE, Westinghouse, etc. YOU will want to do some research on Joe's Tube Lore at Audio Asylum, which will give you lots of detail on the 12A?7 tubes.

Thanks...

Is it important to use 12AX7's or can I use 5751's?