Yet another Aikido? NOVAL vs OCTAL

[gmonno]

OK, I just finished a Tubelab TSE with 300B (Tubelab SE | Tubelab)

The actual preamp is a Pete Millett low-mu preamp running with a 6H13C (6SN7 russian clone) (Low-mu preamp)

The speakers are Cornu (http://www.diyaudio.com/forums/full...k-building-cornu-spiral-horn-now-you-can.html) with Jordan Eikona drivers.

And around the house have another two or three projects done (like "Lo Scherzo" amp).

I'm realizing I've always been doing one amp - one preamp alternatively, so now would be time for a new preamp.....

Thinking of an Aikido, seem a very nice preamp, fairly open with lots of possibilities...

But I'm stuck between octal and noval : which one should decide, and why?

I don't need much gain so this is not the point, my questions are more of the type :

- are noval more prone to microphonics than octal (or reverse)?
- may have more hum problem with one of the solutions?
- is there a good experience about sound quality comparing the two?

If I'm correct 6CG7 should be the noval equivalent of 6SN7 so that shouldn´t be a problem, and don't think I'm going to change tubes a lot.

Any suggestions?
I've looked around and haven't found a clear answer, seem as there is the "Noval Clan" vs the "Octal Clan".

Any help will be warmly welcome as I'm really unable to decide on this philosophical question.

Thanks a lot

 

[JonSnell Electronic]

Why do you think there could be a difference?

 

[gmonno]

Why do you think there could be a difference?

That’s exactly what I’m asking : understand if there is a real difference between octal and noval or it’s more of a sense of aesthetic, or a feeling or something equally subjective.

It’s equally possible that topology should be taken in count as a strong actor in the quality of the sound, so I’m back with the first question :

Are there any criteria to decide between octal and noval in a new preamp?


Thanks

 

[Einric]

I'm running a 6CG7 Aikido into my F4 and I love it.

 

[TrippleM]

Tube industry changed from octal to noval (for the small tubes) because of tube capacity.
With lower (miller)capacity frequency respons is better.

 

[marsupialx]

I'm running 12sn7 octals, because they are less sought after than 6sn7. Sounds great, no hum, no perceivable micophonics.

 

[marsupialx]

There are more tube choices in noval (nine pin), so I'd probably use those if I were to do it again, ESP. In high gain situations. No complaints with my non- phono needs. I like the retro look of octals.

 

[Steve Morley]

See link to my experiences with Aikido LSA

It's a noval version but it might help.

Cheers, Steve

http://www.diyaudio.com/forums/tubes-valves/268290-aikio-line-stage.html

 

[hcbonfim]

Hi , i never heard a noval but i have an octal and the sound is wonderful, now i will start
tube rolling with NOS types,

cheers

 

[gmonno]

Thanks all for answering and giving me possibility to think : confronting ideas, debating, listening to other's opinions is always important and rewarding, so after reading and thinking this is what I'm going to do :

given that I already have a 6SN7 preamp and am not totally convinced about octal......will go and build one LV Aikido, a low voltage one, using 6S27P tubes, they work with only 24V !!!!

A nice experiment, and if works will have the perfect gift for a first preamp for my daughter 🙂
If not, these tubes are relatively cheap and all experience is good.

So thanks all, will give info as the project go on.....

 

[jlangholzj]

en-process of building one with 6N1's and 6N6's right now. We'll see how it turns out...

 

[Steve Morley]

Giuseppe,

Are the 6S27P tubes the Russian equivalent of the ECC86?

I've built an Aikido LV and an Aikido 12Vac using ECC86 tubes (I lowered the voltage to about 55 volts B+).

All the ECC86s I've seen were made in western Europe and though a bit pricey now might still be worth tracking down.

My tube rolling experience with ECC86s listed by factory of manufacture:

Valvo Hamburg A-frames with pizza pan getter: Kind of rock 'em sock 'em with full bass and treble extension, very dynamic but not harsh at all. Good for livening up a polite system.

Valvo Hamburg ring getter with shield: A toned-down version of the A-frame, nice balanced tube, good dynamics.

Telefunken: Nice mids but a bit rolled off on the highs and lows. Dynamically a bit soft

Philips Heerlen: Even more rolled of at the frequency extremes than the Tele, not very dynamic at all.


All the best, Cheers, steve

 

[gmonno]

Hi Steve, it seems so, both share the same low voltage plate caracteristics.

I'm in Spain so for shipping reasons prefer to buy from European sellers --> it's more easy to buy russian equivalent ones.


Regards

 

[Steve Morley]

Giuseppe,

I have some gear I've bought with Russian tubes and they sound great. I've always found that with my home made projects the Russian small signal tubes don't make the grade. Not to pick on the Russians, I've had some ghastly sounding US made tubes as well. What I'm saying is that when you get your project working and if you like it, it might be worthwhile tracking down some European made ECC86 tubes. There should be some tube dealers in western Europe that have some.


Steve

 

[gmonno]

OK Steve many thanks for the experience, I'll follow your advice.

I've sent two emails to J.Broskie to have info about the order of Aikido PCB but got no answer, hope this is normal.....

 

[Steve Morley]

Giuseppe,

That's about par for the course for Broskie. He sometimes mentions in his blog that he gets several thousand emails a day and he just doesn't have time to respond. Good luck with your project.

Steve

 

[jameshillj]

For those that want to try using some 8 pin valves in a 9 pin socket, (and 9 pin in 8 socket too) there are quite a few converter plugs that are made specifically for differently configured valves so this expands the list of options - quite a few of the 8 <-> 9 pin valves have similar characteristics and don't require a change in circuit component values, or initially anyway.

 

[gmonno]

For those that want to try using some 8 pin valves in a 9 pin socket, (and 9 pin in 8 socket too) there are quite a few converter plugs that are made specifically for differently configured valves so this expands the list of options - quite a few of the 8 <-> 9 pin valves have similar characteristics and don't require a change in circuit component values, or initially anyway.

Hi jameshillj that's quite interesting but at my level of knowledge is kind of generic.
Could you please elaborate the concept and give some example?
Are you saying that there are 8 pin low voltage tubes that could be used with this project (Aikido LV)?

Many thanks and regards

 

[jameshillj]

Ah, no Giuseppe, not at all

I haven't tried the LV Aikido at all - only used the higher voltage 8 and 9 pin versions and wanted to try some of the 9 pin valves in the 8 pin pcb (added some pcb connectors for resistor changes, etc)

 

[Steve Morley]

I believe 12SX7 is an octal tube will work on low voltages but they are getting rare (read pricey). A plain old 6DJ8 will run fine on 80 volts. Just sayin'.

Cheers, steve