Author Topic: Tube advice  (Read 879 times)

Offline zaru

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Tube advice
« on: June 05, 2017, 07:06:26 PM »
Good evening everyone.  I'm new to replacing tubes.  I have a little bear t7 pre-amp that I am looking to get replacement  tubes for.  It came with 3 x 6J1 tubes but I broke 1.   Apparently I can replace the tubes with the following 5654, 6AK5, EF95, etc. I'm looking for an upgrade/backup....

I have the following options from Mr valve.

6AK5 Teonex
6AK5 Haltron
6AK5 / EF95 Mullard
EF95 Philips Miniwatt
EF95 Heintz & Kaufman
5654 Toshiba
5654 RCA
5654W General Electric

I have no idea the differences between them. Does the brand and model make a difference to the sound quality?

Any advice would be appreciated for a tube noob.
Thx
Zaru





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Offline fdlsys

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Re: Tube advice
« Reply #1 on: June 05, 2017, 07:16:37 PM »
Mr Valve closed down a while ago...?
The four building blocks of the universe are fire, water, gravel and vinyl. Dave Barry
Come back when you’ve lived a little. Miles Davis

Offline zaru

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Re: Tube advice
« Reply #2 on: June 05, 2017, 07:18:25 PM »
I got an email from Sanita with these ones available. Seems like they clearing the stock. I hope

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Offline Hi-Phibian

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Re: Tube advice
« Reply #3 on: June 05, 2017, 07:18:54 PM »
Think they decided to get up again after some ROE recovery. 







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Offline fdlsys

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Re: Tube advice
« Reply #4 on: June 05, 2017, 07:20:16 PM »
Oh, cool!
The four building blocks of the universe are fire, water, gravel and vinyl. Dave Barry
Come back when you’ve lived a little. Miles Davis

Offline zaru

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Re: Tube advice
« Reply #5 on: June 05, 2017, 07:20:57 PM »
So any advice?

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Offline Ac!DLeAk

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Offline Ampdog

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Re: Tube advice
« Reply #7 on: June 13, 2017, 11:18:18 PM »
Zaru,

Seeing that you did not get much response,

This is almost as difficult to give a simple answer to as are cables ( :sh1tstirrer: ) The problem being that 'tests' like the one quoted (and NO offence to Ac!DLeak; he is merely the messenger) is firstly very subjective, and secondly usually using one valve of a brand only.

If you have followed previous threads about spreads in valve characteristics, you would have noticed a spread of almost +30% to -30% in present-day valves of the same make! Thus totally unacceptable (in my early days at CSIR we returned valves +/- more than 10% out), but that is the situation.

Folks list hearing results of tests, but never show what the measured characteristics of the used valve was to begin with. I have mentioned in the past that in such a comparison years ago, where the reporter - to his credit - did also give the working current of a particular valve under test. For the same type, some 5 samples showed a current variation of a factor of 1,8 between them!! Small wonder that they sounded different.

How does this help you?....  It doesn't. Even if a local outlet was available, they are not likely to have you bring a valve tester along and go through the entire stock.

Bottom line: Forget about subjective one-off tests however well-meant. Basics: There should be no difference in the sound of same-numbered valves - a valve's only influence is to vary electron flow according to applied voltages to its elements. It has no concept of music; it cannot make bass fuller, high frequencies more crisp or whatever human emotion is claimed. It is not influenced by how rapidly the cuirrent varies (i.e. frequency responce) at least for audio frequencies. (This as said apart from a gross deviation from specs.) So unless you have a valve tester ready, discussion is irrelevant. Use whatever is available - and hope that it is on spec.

   

Audio must be the only branch of engineering where lack of basics' knowledge is considered a superior form of wisdom. (Anon)

Offline zaru

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Re: Tube advice
« Reply #8 on: June 14, 2017, 01:28:43 AM »
That's great advice Amp dog.  Much appreciated.

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Offline zaru

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Re: Tube advice
« Reply #9 on: June 14, 2017, 01:31:56 AM »
@ Ac!dLeak - thanks for the link.

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Offline Ac!DLeAk

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Re: Tube advice
« Reply #10 on: June 17, 2017, 12:24:13 PM »
@ Ampdog, no offense taken at all.

My knowledge is nowhere near enough where it should be to give a detailed technical advice.

What I can attest to however is that I own 3 of these sets: Voshkod 6ZH1P-EV, Mullard CV5654 and GE 5654 W and I could here differences on my little dot 1. Whether they ACTUALLY exist or I am imagining them based on reading the thread could be another topic for debate.

Zaru, I am in the Randburg area if you would like to listen to these. Happy for you to come through.


 

Offline Sten

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Re: Tube advice
« Reply #11 on: June 20, 2017, 04:40:09 PM »
Well said Ampdog! Agree completely. And yet Mullard, RCA, Siemens and Philips do sound somewhat better sometimes, depending. Well, maybe not Philips, I may be biased, being Dutch!
"In music the passions enjoy themselves"  Nietzsche.

Offline fdlsys

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Re: Tube advice
« Reply #12 on: June 20, 2017, 05:09:37 PM »
... I may be biased
Cathode biased or fixed?
The four building blocks of the universe are fire, water, gravel and vinyl. Dave Barry
Come back when you’ve lived a little. Miles Davis

Offline Nidri

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Re: Tube advice
« Reply #13 on: June 20, 2017, 07:29:59 PM »

Offline Sten

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Re: Tube advice
« Reply #14 on: June 21, 2017, 07:02:18 AM »
Dutch bias is always fixed! There's not much "give" in them you know.
"In music the passions enjoy themselves"  Nietzsche.