[Slipmyster]

Hi everyone I'm sorry if this is a daft question but this is my first full tube amp.
It's a Spartan Music Helot 2x
The tubes are 12bh7 in the back socket and a 12au7 in the front socket.

I'm just wondering if replacement tube's will need to be balanced or am I ok just to buy new ones and not worry with them being 2 different and separate tube's.
Any advice would be great.

Thanks in advance
Martin

 

[Deleeh]

Hello,
No would not be necessary to buy a matched pair.
As they are two different families of tubes.
So fire away in that respect.
Here you have a list of which genera are compatible with the individual families.
https://tubemaze.info/tube_equivalents/

 

[Slipmyster]

Hello,
No would not be necessary to buy a matched pair.
As they are two different families of tubes.
So fire away in that respect.
Here you have a list of which genera are compatible with the individual families.
https://tubemaze.info/tube_equivalents/

That's awesome thank you very much.

 

[Deleeh]

No Problem

 

[Slipmyster]

No Problem

If you don't mind me asking what do you think the lifespan of the tubes will be in this amp. And do you think I'm better off with new old stock of going for new production tube's.

Martin

 

[Deleeh]

If you don't mind me asking what do you think the lifespan of the tubes will be in this amp. And do you think I'm better off with new old stock of going for new production tube's.

Martin

Oouu hard to say as far as lifespan is concerned.
It depends on whether you listen daily, several times a week or only weekly.
From what I've read, 2000-5000 hours.
Some people have never replaced their old units, it all varies a lot.

Nos or new old stock is a huge controversial topic.
From today's point of view we have much more precise machines but less staff and less interest than we had back then.
Where the machines were not as precise but the experience of the manufacturers was greater.
And the production volume was also much higher than today.

Both have advantages and disadvantages and much is a matter of taste.
Of course, today we benefit a lot from Nos tubes because of the better capacitor, transformer and resistor technology than we did 20-30 and more decades ago, objectively speaking.

I also have a Lin Lai or Tung Sol tube in my inventory from the new production that are really good.
The Nos are also very good and maybe a bit more rounded in sound which is again a matter of taste of the listener.
But you also have to watch out in the nos market for extortionate prices and counterfeits.
There are good sources of information where you can check and make sure.
But that comes with time and the necessary peace of mind.

You can't necessarily go wrong with the new production.
Firstly, prices have remained stable and unaffected despite the crisis.
The quality is also very good and affordable in many respects.
And you don't fall victim right away.

So if you are still new, I recommend you stay there for the time being and familiarise yourself with the new market.
Even if it's only small tubes you need, it would be a cheek to pay £50-100 when you can get them cheaper elsewhere.

Since you are in the UK, I can recommend Billigton and langerex if you want to get a taste of nos tubes.
They also deliver acceptable quality and remain affordable.

 

[tomb]

If you don't mind me asking what do you think the lifespan of the tubes will be in this amp. And do you think I'm better off with new old stock of going for new production tube's.

Martin

Lifespan is not a concern, but matching should be, despite the earlier posts.

If you have two different tubes - and only two - it's 99% certain that they each handle different parts of the amplifier circuit. Otherwise, you'd have a massive channel imbalance based on the two totally different tubes. Typically, the 12AU7 would be for the initial signal stage, only. A 12BH7 could be used for that, too, but more likely, it's a buffer or secondary amplification circuit in the overall amp, because it's generally more powerful than a 12AU7.

So what? Well, you want stereo. That means two channels. Both of those tubes are known as dual triodes, which means that they have two separate channels in each tube. So yeah - not necessary at all to match the two tubes, 12AU7 to 12BH7, but pretty damn important that the triodes in each tube are matched to each other.

It is more common than not, that dual triode tubes do not have separate triodes that match each other in output.

 

[Slipmyster]

Oouu hard to say as far as lifespan is concerned.
It depends on whether you listen daily, several times a week or only weekly.
From what I've read, 2000-5000 hours.
Some people have never replaced their old units, it all varies a lot.

Nos or new old stock is a huge controversial topic.
From today's point of view we have much more precise machines but less staff and less interest than we had back then.
Where the machines were not as precise but the experience of the manufacturers was greater.
And the production volume was also much higher than today.

Both have advantages and disadvantages and much is a matter of taste.
Of course, today we benefit a lot from Nos tubes because of the better capacitor, transformer and resistor technology than we did 20-30 and more decades ago, objectively speaking.

I also have a Lin Lai or Tung Sol tube in my inventory from the new production that are really good.
The Nos are also very good and maybe a bit more rounded in sound which is again a matter of taste of the listener.
But you also have to watch out in the nos market for extortionate prices and counterfeits.
There are good sources of information where you can check and make sure.
But that comes with time and the necessary peace of mind.

You can't necessarily go wrong with the new production.
Firstly, prices have remained stable and unaffected despite the crisis.
The quality is also very good and affordable in many respects.
And you don't fall victim right away.

So if you are still new, I recommend you stay there for the time being and familiarise yourself with the new market.
Even if it's only small tubes you need, it would be a cheek to pay £50-100 when you can get them cheaper elsewhere.

Since you are in the UK, I can recommend Billigton and langerex if you want to get a taste of nos tubes.
They also deliver acceptable quality and remain affordable.

Again thank you that's awesome. I'll stick with new. At the moment it has jj tube's that seem very good but I thought it won't hurt to have some spare.
Again thank you

 

[Slipmyster]

Lifespan is not a concern, but matching should be, despite the earlier posts.

If you have two different tubes - and only two - it's 99% certain that they each handle different parts of the amplifier circuit. Otherwise, you'd have a massive channel imbalance based on the two totally different tubes. Typically, the 12AU7 would be for the initial signal stage, only. A 12BH7 could be used for that, too, but more likely, it's a buffer or secondary amplification circuit in the overall amp, because it's generally more powerful than a 12AU7.

So what? Well, you want stereo. That means two channels. Both of those tubes are known as dual triodes, which means that they have two separate channels in each tube. So yeah - not necessary at all to match the two tubes, 12AU7 to 12BH7, but pretty damn important that the triodes in each tube are matched to each other.

It is more common than not, that dual triode tubes do not have separate triodes that match each other in output.

Thank you for your reply. Is it possible to get balanced triodes or will they always have that imbalance ?

Martin

 

[sonnysound]

Hi everyone I'm sorry if this is a daft question but this is my first full tube amp.
It's a Spartan Music Helot 2x
The tubes are 12bh7 in the back socket and a 12au7 in the front socket.

I'm just wondering if replacement tube's will need to be balanced or am I ok just to buy new ones and not worry with them being 2 different and separate tube's.
Any advice would be great.

Thanks in advance
Martin

Hello Martin. I am a long time audiophile and guitar player and I use predominantly tube amplifiers for everything. To improve sound quality I would suggest that you buy vintage USA tubes. Vintage USA and European tubes are simply better sounding and made better than anything that is manufactured today. You can buy NOS(New old Stock) vintage tubes and you do not have to worry balanced tubes or any issues, just simply plug and play. If you buy used tubes, which is fine if they are tested and strong, the same thing applies. The tube replacement with vintage tubes would increase fidelity and sound quality. Cheers and Good listening, SonnY

 

[tomb]

Thank you for your reply. Is it possible to get balanced triodes or will they always have that imbalance ?

Martin

It's no different than with separate tubes. The triodes in a single, dual-triode tube simply need to be tested. If the triodes don't match, the tube is rejected. Other tubes are tested until one is found where both its triodes match.

BTW, this is why many tube amps use two identical, dual-triode tubes - one for each stereo channel. The triodes within each tube are paralleled together in each channel's circuit. That means you can use the average of the two triodes's outputs to match the other channel's tube. The statistical chances of matching the tubes are greatly increased.

Your amp has two dissimilar tubes, so they cannot be there for the left and right channels, but for two-stage amplifucation, instead.

 

[Slipmyster]

It's no different than with separate tubes. The triodes in a single, dual-triode tube simply need to be tested. If the triodes don't match, the tube is rejected. Other tubes are tested until one is found where both its triodes match.

BTW, this is why many tube amps use two identical, dual-triode tubes - one for each stereo channel. The triodes within each tube are paralleled together in each channel's circuit. That means you can use the average of the two triodes's outputs to match the other channel's tube. The statistical chances of matching the tubes are greatly increased.

Your amp has two dissimilar tubes, so they cannot be there for the left and right channels, but for two-stage amplifucation, instead.

That's good to know thank you. I've been in touch with langrex here in the UK and they will do balanced tubes no problem so I should be ok.
I've found that some have black plates but the majority have grey is there any difference between the two

 

[tomb]

That's good to know thank you. I've been in touch with langrex here in the UK and they will do balanced tubes no problem so I should be ok.
I've found that some have black plates but the majority have grey is there any difference between the two

Now you're getting into the esoterics of tubes and their sound characteristics.

Look up Brent Jesse Recording and look up his pages on the 12AT7 or the 12AU7. You'll get a picture.

To answer your question directly, some tubes have black plates, some have grey plates. Some have large getters on top, some have small ones on the side and vice-versa. It's all a way to distinguish one tube from another. When the mfr made them, they often used the parts on hand or available for other reasons than the sound quality (depending on the tube). Tubes that GE or RCA made of the same type might have used very different construction during their production life. The ratings of any given tube type would be more or less the same, but the actual sound quality could differ greatly - or at least to us today with headphones and guitars.

Distinguishing between the different sound quality of the same tubes from the same mfr is often accomplished by using a description of their construction, so that you know you're getting the "good sounding" one, as opposed to one that's perhaps not as sterling in sound quality.

 

[sonnysound]

Hello Martin. I am a long time audiophile and guitar player and I use predominantly tube amplifiers for everything. To improve sound quality I would suggest that you buy vintage USA tubes. Vintage USA and European tubes are simply better sounding and made better than anything that is manufactured today. You can buy NOS(New old Stock) vintage tubes and you do not have to worry balanced tubes or any issues, just simply plug and play. If you buy used tubes, which is fine if they are tested and strong, the same thing applies. The tube replacement with vintage tubes would increase fidelity and sound quality. Cheers and Good listening, SonnY

There would be no issue buying new tubes as they triodes will be balanced. There is little risk in buying used tubes as long as they have been tested and verified to have balanced triodes and that they test strong. Good listening, SonnY

 

[tomb]

There would be no issue buying new tubes as they triodes will be balanced. There is little risk in buying used tubes as long as they have been tested and verified to have balanced triodes and that they test strong. Good listening, SonnY

Almost every tube dealer charges extra for matching triodes within a tube and for matching tubes. Check TubeDepot, for example, one of the better reputable dealers. Price depends on matching and how many matches you want done (pairs, quads, etc.).

Many ebay sellers think the definition of "matching" means they look the same. Worse, many don't even test the tubes they sell.

Buyer beware applies, just about the same as anything else in the audio world (or elsewhere)

P.S. No offense, but "balanced" is a very misleading term to use for matching tube outputs. "Balanced" has a very specific meaning with regard to audio equipment cabling. It's loosely used in place of "fully differential" with regard to amplifiers, but even in that case, it's a misnomer.