Beating a dead horse no last time...

[talbany]

... Get a Shovel! 8)

You don't think changing a quad of E-84's in a cathode biased amp especially a Liverpool can have a dramatic effect on tone?...Curious

Tony

[dartanion]

... Get a Shovel!

You don't think changing a quad of E-84's in a cathode biased amp especially a Liverpool can have a dramatic effect on tone?...Curious

Tony

Duh! Compare some JJs to a set of Saratovs in a Liverpool. Well, that would be hard since there is no comparison

Although, I think the shovel reference is probably more aimed at the whole thread. That's how I read it at least.

[selloutrr]

my opinion on tubes and tone...

by design no two tubes sound the same. and some very quite widely even in the same batch. even tubes that test good on a basic tube tester can sound lithargic.
From what i've observed in regards to a TW you should be able to take the same basic parts, the same build, and the same brand tubes, and get closer then you would think to a "wreck" after all this is how they all began.
then if you had the "ear" or a frequency chart as to what you were looking for in the "magic" KF voicing. you could either: A: sort threw tubes and try them one by one getting closer or farther until you settle much like an eye exam. or B: if you knew how a certain tube behaved and plotted it and tested it's specifications.. i.e. Amplitrex you could then recall that tubes data and search the data base for other tubes with an exact or similar response. resulting in a voicing that would be KF approved.
I feel a little bad saying this but it's an amp not a god... there is no magic just choices. but those choices can be plotted and recreated if you take the time to understand them.
It science, we have the technology to measure frequency response and sound pressure levels. if you give the amp a calibrated full frequency flat test noise. say 0hz-30Khz and measure what comes out. or (pink noise 20-20k) there you go what comes out is the trainwreck sound. It's not a sweet les paul but it's the amplifiers limitations and voicing. YOU can conclude that the trainwreck produces those frequencies at those volumes... what ever they may be... as long as your control is not changed being the microphone and cabinet speaker cable and room. you could then voice the clone to be the same as the original.

if you wanted to be even more TW correct as a whole.... get as many Wrecks as you can. the more you plot the more trends you can conclude.

the nice part about the frequency response approach it takes into acount the small differences in parts. and gives you a final target goal.

[selloutrr]

yeah the shovel wasn't a direct reply to anyone.
it was a general response to the horse being beaten to death.

i did really enjoy reading the Thread though!

[talbany]

yeah the shovel wasn't a direct reply to anyone.
it was a general response to the horse being beaten to death.

i did really enjoy reading the Thread though!

selloutrr
Thanks..
If you kind of pick it apart the cathode bias method is a big part of the inconsistency associated. Meaning current draw through the cathode resistor makes the grid potential negative with respect to the cathode. And, changes in tube conduction are automatically compensated by changes in bias... The keyword here is current draw.. Just as different tubes from different manufacturers will draw varying amounts of current in a fixed-bias amplifier, the same is true of a cathode-biased amplifier. Finding a new set matched 84's with a spec-ted current draw may not be that tough.. However finding a quad of NOS ( Ken's preference) might not be that easy.., since current draw is directly related to the bias point or where it puts you in the Trans-curve has a direct bearing on tone and breakup character.. We all agree. The only way to compensate for current draw of various tubes is changing cathode resistor and who does that.. It's not so much that that set sounds bad it's that this set (That biases up different) sounds better...
Just like preamp tubes that are cathode biased you may have a nice NOS Amphrex or Mullards but for some reason doesn't sound as good as your new JJ why?.. It could be pulling too much or not enough current ( in relation to the anode voltage) biasing somewhere off the sweet spot. For most amps it really wouldn't be as noticeable, but since Ken's design methodology left very little in the way of tone shaping or clamping (Don't bore me with caps pots and resistors get me to the tubes) This only exacerbates the sonic performance of both cathode biased pre amp and output tubes..

In cathode biased amps.. You don't pick the tubes..The tubes pick you.. What a great Topic

Tony

[Jana]

The tests you describe are, for the most part, static. A frequency response curve says little about how a certain tube will react in a dynamic situation. Response time in relation to picking attack, compression, the internal impedance which will have an effect on the impedance coupled to the OT, the list goes on. I'm not saying that, given enough beer and test equipment that it can't be done--I'm saying that it isn't as simple as plotting a frequency curve with pink noise.

As for the dead horse--well, the horse may be dead but there are some good boots to be made from the hide.

[Cliff Schecht]

The tests you describe are, for the most part, static. A frequency response curve says little about how a certain tube will react in a dynamic situation. Response time in relation to picking attack, compression, the internal impedance which will have an effect on the impedance coupled to the OT, the list goes on. I'm not saying that, given enough beer and test equipment that it can't be done--I'm saying that it isn't as simple as plotting a frequency curve with pink noise.

As for the dead horse--well, the horse may be dead but there are some good boots to be made from the hide.

This! Frequency response curves give you a time invariant representation of a time varying system and only give you half of the story. You have to look at the corresponding phase and group delay graphs as well which will tell you how the amplifier will react time-wise at different frequencies. But even all of this, as Jana states, can't truly capture the essence of what is happening in the amplifier as far as dynamic changes and how the amplifier reacts as a whole.

[ckpop]

Selloutrr

I wish it was that easy using Smarrt and it would certainly tell you some things but it's too general. There is too much interaction and colorization within the parts themself that contribute to the end result. LOL if we had the technology I wish someone would make a audio console today that sound as good as old Midas XL4.

[redshark]

I would like to ask a simple question...how many people in this forum took the RCA tube training course in the 60's? I think if someone did they will look at tubes a little bit diferent than most of us....for many of us tubes are obsolete technology. Back in the day they were everything and I'm sure the people that went deep in the topic like Kenny or JM or a few others could show us a trick or two. I'm not an expert but I think the magic could be reproduced with knowledge. Also the other tube aficionados, the hi-fi guys could show us their approach.

[andrew4566]

The "voicing" is a sum of parts thing... which includes the components of the guitar, playing style of the player and the "ear" of the listener...far too many variables to think tubes or caps are the only factor.

Ken may very well have had a certain sound he wanted his amps to achieve from a certain guitar and playing style... but once you start deviating from that I say be true to the tone in your head and tweak to get it.

[talbany]

I would like to ask a simple question...how many people in this forum took the RCA tube training course in the 60's? I think if someone did they will look at tubes a little bit diferent than most of us....for many of us tubes are obsolete technology. Back in the day they were everything and I'm sure the people that went deep in the topic like Kenny or JM or a few others could show us a trick or two. I'm not an expert but I think the magic could be reproduced with knowledge. Also the other tube aficionados, the hi-fi guys could show us their approach.

Redshark..
With all do respect..And don't get me wrong Ken designed a wonderful amp.. But I wouldn't consider the Liverpool, Express or Rocket, exactly ground breaking designs with a different approach ..Not by a long mile...I've played and heard several real wrecks and admit Ken no doubt had a great ear and could voice the shit out of an amp.. But from a design standpoint it's as basic as it gets...100k plates 1.5K cathodes bypass 25uf..
Tony

[redshark]

Talbany
the super powerful clean to mean in the express, so close to being unstable and producing the harmonics it does and the musical feedback excuse me but I don't hear those attributes in any amp. It might not be groundbreaking from a design point of view but it is from a performance point of view and that is what sets it apart from other amps..

[Jana]

Take a look at the bassman AA864 schematic and compare it to an express.

[redshark]

Play a bassman AA864 and then play an express....

[talbany]

Talbany
the super powerful clean to mean in the express, so close to being unstable and producing the harmonics it does and the musical feedback excuse me but I don't hear those attributes in any amp. It might not be groundbreaking from a desing point of view but it is from a performance point of view and that is what sets it apart from other amps..

RS
I totally agree with you.. The beauty is in the simplicity.. Very little to get in the way of all that harmonic content...

I am more of a Plexi guy!!
Tony