Balanced phase inverter tube?

[zzmoore]

Re: Balanced phase inverter tube?

Sovtek LPS are good PI tubes

Are they.?
I know, for a long time, EH was having problems with their AX7 tubes in a PI/Cat Follow due to the Cat to Heater Voltage offset.
I do not know if the LPS was included in that.

 

[ken361]

Re: Balanced phase inverter tube?

Are they.?
I know, for a long time, EH was having problems with their AX7 tubes in a PI/Cat Follow due to the Cat to Heater Voltage offset.
I do not know if the LPS was included in that.

they been popular for a long time in the PI adds some fatness over others and top end

 

[Demanic]

Re: Balanced phase inverter tube?

I used to think that way, until I tried a JJ. Then my ears perked up and said, "This, I like this!"

Finally, someone else who likes JJ's.

Sent from my MotoE2(4G-LTE) using Tapatalk

 

[Hank-]

Re: Balanced phase inverter tube?

Are they.?
I know, for a long time, EH was having problems with their AX7 tubes in a PI/Cat Follow due to the Cat to Heater Voltage offset.
I do not know if the LPS was included in that.

Just the CF spot is trouble for some new sensor made tubes. The PI spot can take any of their 12AX7 tubes without them frying. I very much like the Ehx12ax7 for PI slot, not any place else though.

 

[zzmoore]

Re: Balanced phase inverter tube?

Just the CF spot is trouble for some new sensor made tubes. The PI spot can take any of their 12AX7 tubes without them frying. I very much like the Ehx12ax7 for PI slot, not any place else though.

Isn't the typical LTP phase inverter a Cat Follower.?

 

[Gone_Shootin]

Re: Balanced phase inverter tube?

they been popular for a long time in the PI adds some fatness over others and top end

I tried the Sovtek LPS that came in a 5150 that I used to have in other amps. It sounded kinda sterile to my ears in the PI hole.

 

[Gone_Shootin]

Re: Balanced phase inverter tube?

Finally, someone else who likes JJ's.

Sent from my MotoE2(4G-LTE) using Tapatalk

Just for the PI and buffers. They're too dark sounding for my tastes in gain stages.

 

[MetalManiac]

Re: Balanced phase inverter tube?

Huh? I never have

https://www.google.com/url?sa=t&rct...9_j4xMS3uRTP5RwnQ&sig2=_uJe3lbou4Q8jeLem8XXUA

 

[Little Pigbacon]

Re: Balanced phase inverter tube?

Yeah, that's one place where I saw it.

Here's another:

If you are replacing the power tubes, replace the phase inverter; I would use a balanced 12AX7 in this socket. Don't worry about using balanced preamp tubes in the other sockets.

Bill

 

[Chickenwings]

Re: Balanced phase inverter tube?

I've always been happy just using any strong or new tube in there. I didn't even know it was something you had to think about. I know phase inverters work hard especially in a 5e3 or a musicman, but seems to me that as long as they are working, then all is fine.

 

[Gone_Shootin]

Re: Balanced phase inverter tube?

https://www.google.com/url?sa=t&rct...9_j4xMS3uRTP5RwnQ&sig2=_uJe3lbou4Q8jeLem8XXUA

I've read something along the lines of that article, and I still only change tubes when something sounds f***y. And I know that the phase inverter gets abused, I just don't feel that it's necessary to change the PI Everytime you change power tubes in your own personal amp. If I were doing it for a living and servicing a customer's amp, yes, I would, but for my own personal stuff I don't.

 

[Phantasmagoria]

Re: Balanced phase inverter tube?

I've got balanced Sovtek LPS's in 2 of my amps. They are a big improvement over the many other types (both balanced/unbalanced/gold pins/no gold pins/short plate/long plate etc type tubes) I tried in those amps before.

Stuck to the stock PI tube (I guess Chinese) in my Bugera 333XL & the stock Sovtek 12AX7WB in my Cicognani Brutus Live head ..they sounded better than the balanced LPS (and other tubes) I tried to swap them for. The LPS's did sound "sterile" in those two heads. I guess it depends on the particular amp..

 

[zzmoore]

Re: Balanced phase inverter tube?

More good Info/Comments.
Like so many things in amps and life in general.....It Depends.
Anyway, taking a break from the boring topic of Balanced Phase Inversion.....Cicognani....i have heard this name whispered now for several years, like a secret password. :reporter:
Of all the amps in the world, how did you end up with this.?
He/His Company have an interesting History/Heritage.

http://www.cicognaniamps.com/catalog/Cicognani Catalogue -January 2008.pdf

http://www.cicognani.eu/references.html

 

[JeffB]

Re: Balanced phase inverter tube?

I'm no expert, but I have tried roughly a dozen tubes as a PI in my Dsl and my Orange and my two faves are

Sovtek LPS

And a Groove Tube silver series "5751". Which to my understanding was GT's take on a old short plate mullard 12ax7 that didn't make the gain grade and so they threw the 5751 designation on it. It was pretty hard and crunchy as a V1, but as a PI it was fantastic. I sold it though as part of an amp sale, IIRC

The Mullard RI is a decent PI too, but for me that tube is a disappointment in every position. Even most of the tube dealers say to keep it to high end audio gear and away from guitar amps.

 

[Phantasmagoria]

Re: Balanced phase inverter tube?

More good Info/Comments.
Like so many things in amps and life in general.....It Depends.
Anyway, taking a break from the boring topic of Balanced Phase Inversion.....Cicognani....i have heard this name whispered now for several years, like a secret password. :reporter:
Of all the amps in the world, how did you end up with this.?
He/His Company have an interesting History/Heritage.

http://www.cicognaniamps.com/catalog/Cicognani Catalogue -January 2008.pdf

http://www.cicognani.eu/references.html

Interesting reads^^ :bigthumb:

Though I don't recall anything about Cicognani, I'd vaguely heard of the 'Brutus' amps years ago when they were first introduced. I remember them being pretty favorably spoken of at the time/checking out some sweet sounding audio samples etc.. but then they were way beyond my budget ..so "not for me" and that was it.

Then, last year I came across one on ebay...new in the Box. The guy had listed it at a price that was just about "within reach" so to speak lol, though it was listed as a "Cicognani Brutus" head so I assumed it was the 11 watt "Brutus" which frankly, I thought was fascinating, especially after watching the Donato Begotti (well regarded Italian guitar teacher ...it's his "signature amp" demo's on yotube) but maybe not practical for me /giggable etc.

Anyway..I decided to ask him if he also had it's bigger brother ..the 30 Watt "Brutus Live" head, for sale by any chance and he replied to say that it WAS the 30 watt "Brutus Live" that he'd listed. What a pleasant surprise(!!) lol, because I'd expected to have to have paid a bomb more for the "Live" version, but there it was within grasp! Pulled the trigger right away! Dude shipped it to me from his store in Poland...& all was well that ended well!

Really killer unique little TONE monster..that sounds huge ..I absolutely love it

 

[Rex_Rocker]

Re: Balanced phase inverter tube?

I like the Sovtek LPS in the PI spot too. It's fat, open, and tames some harshness on my amps.

Isn't the typical LTP phase inverter a Cat Follower.?

Not AFAIK. I think it's the tone stack driver in Marshall-style amps that's the cathode follower.

Finally, someone else who likes JJ's.

Sent from my MotoE2(4G-LTE) using Tapatalk

I like JJ's, just not in their ECC83S in the PI position where I want headroom. Their ECC803S is nice in that position, though.

 

[jeremy]

Re: Balanced phase inverter tube?

Not AFAIK. I think it's the tone stack driver in Marshall-style amps that's the cathode follower.

this is my understanding as well. the cathode follower and the phase inverter are two separate things. not all amps have a cf, most non single ended amps have a pi. tweed bassmans and old marshalls do have the cf, a tweed deluxe and a blackface deluxe dont. if your amp has two or more power tubes working in a push/pull config then you probably have a pi tube but there are some amps that have a transformer to do the job. there are three types of pi that i know of: long tail pair, cathodyne, and paraphrase. i believe the cf is a specific type of circuit although obviously values will chage

 

[zzmoore]

Re: Balanced phase inverter tube?

Look at the schem for a LTP PI. The grid of V1b is run from the cathode of V1a.
The Heater to Cathode voltage is going to be big. Somewhere in the 40-60 Volt range.
Most push-pull amps are going to be using that LTP.
Shoot an email to New Sensor and see what they say about running their spiral filament tubes in a CF/Phase Inverter.:dunno:

 

[Little Pigbacon]

Re: Balanced phase inverter tube?

I'm glad none of this is complicated.

 

[Little Pigbacon]

Re: Balanced phase inverter tube?

Here's what Tube Depot's website says about it:

"The 12AX7EH provides high gain with ultra low noise and a detailed - musical tone that rivals the most desirable NOS types. Unique spiral filament eliminates that filament-to-cathode induced hum common on AC-powered amps. This tube can be used in phase inverters / preamp sections / driver sections - It really does well in all applications."