Octal or 9 Pin Preamp Tubes

[Keither]

I think I know where to find comparative recordings.
I remember hearing this over 10 yrs ago.
On the wattkins or sewatt forums. Back to back recordings of guitars played through 9 pin and octal versions of the same basic circuit. I'd sign up for both wattkins.com and sewatt.com and start searching for the octal threads.

From what I remember the point was octals where supposed to have relatively more even-order harmonics there for sound smoother and warmer.

I do remember the distortion being sort of like a Brian May guitars solo.

Octal power tubes seemed to make more of a difference than preamp.

With low gain it was practical the same as 9pin.
Thats what I remember.
Those threads are about 15yrs. old hopefully the recordings are still up!

 

[ole Jason]

Jul Monique is highly regarded by many TB members. Monique runs two 6SL7GTs, one 12AU7, and a 6CA4/EZ81 rectifier.

You can buy Monique as a stand alone pre or integrated with a 700W class D power module. AFAIK Jule does not package Monique with a tube output section, but I am sure it would drive a tube power amp just fine.

I believe Jule used to make some low powered (all-tube) guitar amps. AFAIK his webpage currently appears to offer solely bass gear.

Awesome! Sounds like a great option for OP.

 

[Keither]

I may know where to find comparative recordings if they're still up 15 yrs later.
I
On the wattkins or sewatt forums.
Back to back recordings of guitars played through 9 pin and octal versions of the same basic circuit.
I'd sign up for both wattkins.com and sewatt.com to search through the octal threads.

From what I remember the octals where supposed to have relatively more even-order harmonics. Thus sounding smoother and warmer than 9pin.

I do remember the distortion being sort of like a Brian May guitars solo.

Octal power tubes seemed to make more of a difference than preamp.

With low gain it was practical the same as 9pin.
Thats what I remember.
Those threads are about 15yrs. old hopefully the recordings are still up!

 

[KenD]

I may know where to find comparative recordings if they're still up 15 yrs later.
I
On the wattkins or sewatt forums.
Back to back recordings of guitars played through 9 pin and octal versions of the same basic circuit.
I'd sign up for both wattkins.com and sewatt.com to search through the octal threads.

From what I remember the octals where supposed to have relatively more even-order harmonics. Thus sounding smoother and warmer than 9pin.

I do remember the distortion being sort of like a Brian May guitars solo.

Octal power tubes seemed to make more of a difference than preamp.

With low gain it was practical the same as 9pin.
Thats what I remember.
Those threads are about 15yrs. old hopefully the recordings are still up!

Thanks for the reference and the info.

 

[Snaxster]

Assuming equal quality of manufacturing and amplification factor, can anyone hear the difference between an octal and a 9 pin preamp tube?

With respect to both preamp and power tubes where equivalent types are available, yes, typically both for 1. circuits designed to use each in the same role respectively, and 2. in a circuit designed to use one, employing an adaptor to use the other instead.*

* Beware tube type adaptors, especially for power tubes. The pinout must be absolutely correct to avoid damage to the host circuit.

Addendum: You can extend the comparison to include "big bottle" vs. "small bottle" octals. It isn't the envelope (the glass, aka bottle) that matters, but the technology typical of the era in which each form was made. For example, in my collection, among 6V6 types, in a given application I can hear what I believe is a characteristic difference between a 1939 Ken-Rad 6V6G or a Cossor 6V6G (assumed to be 1930s) and pretty much any small bottle 6V6GT.

 

[Snaxster]

@juledude works with 6SL7 as well.

Made me look. Here is something I wrote to Jule (ten years ago!) as I was ordering a Monique from him:

"The 6S?7 I use in 12A?7 slots via custom adapters. I have found this to be a great way to impart 1960s and 70s preamps with an aspect of the 1940s tube audio sound. In my experience, current day musicians usually are not familiar with the sound of octal preamp tubes and big bottle power tubes. Luxurious and slow, with an enormous sound field (even in mono) that features spatial presentation of bass frequencies. That’s how big bottle tubes sound to me."

And Jule replied:

"I was at an outdoor, back yard party, and this amazing guitar player was using a Gibson Hawk combo amplifier. Truly as you describe. I of course had to get my nose into the back of it after he quit playing. A much larger tonal envelope than any of the 9 pins. Beautiful. Gibson also used them on the very popular (in the vintage world) Lancer amplifier. I was sold."

 

[juledude]

One of these might help. About $8 (Aliexpress). Allows us to use a 9 pin in an octal socket. Works with all the 12A... and 6S... stuff I've seen.

Yup. Still remember that Hawk. Other than that, I have no opinion. Mongo was right.