Another theory on the 25-watt resistor.

['67_Plexi]

Many Ampegs used TRW power resistors. .......think a little over analyising might be going on here.
Given that Ginger was (suprise suprise) built using a bunch of surplus Ampeg parts from the 70's, I would say he could well have picked up a box of 1K resistors at some time that were maybe no longer used and he just found a use for them, rather than them being thrown away. All time served Engineers are taught to be lucrative 'trash rats' as part of their apprenticeship. Waste not, want not. Why buy 10W resistors when you already have a bunch of 25W ones for free.
I highly doubt for one minute the rationale was tone or even reliability

[rooster]

OK, 67_Plexi, that last statement got my attention. Also let it be known that I am a big fan of your amp designs and amp building skills. I have also enjoyed talking to you on the phone - you are smart, witty, helpful, and also very funny. IMO, you are without question one of the premier amp 'gurus' currently alive and breathing on planet earth. ....but I digress.

Since I have played an Express that you built, a BEAUTIFUL sounding amp, BTW, I want to disagree with what you said - and use the amp you built - as my testimony. In it you used a 1K 25 watt resistor.

I realize that you were building a *copy* amp, but are you saying that a 10 watt resistor of a different value would sound the same - and also be as reliable?

KF by his own admission was a 'tweaker' and not an engineer, per se. I can understand and accept that a person with some serious EE skills might quickly see some 'errors' in KF's work. Your ground plane ideas/executions, for example, I think are way advanced relative to what is seen in most gtr amps, KF's included. Which is a good thing, advancing the product and all. But lets remember what a tweaker does? He tweaks. Tweaking is a skill, too, and in this endeavor KF may have been the 'King of Tweak'.

To suggest that KF bought a box of resistors and decided to use them up in a particular circuit because they were cheap is a pretty silly notion to me. You're joking right? No, this is not the process of a tweaker. In fact a tweaker probably would have tried every resistive load in that circuit before he committed. And then he certainly would have considered how long it would survive there. I still stick to my guns here, he knew $2000 was a chunk of change to ask for a gtr amp. He knew it had to sound great and it had to last - and I think he put his heart and head into it. Was he cheap? I don't see it. And I certainly think he could afford a $ .50 'cemet' resistor if he knew it would improve his $2000 amp . Did he use cheap trannys? I don't see this in his behavior either.

So there, I said my piece, and 67_Plexi, you still make a great amp. KF also made a great amp. Yes, I realize that some people get very anal about what could be insignifcant details. Or are they? Either way, IMO there are many ways to present that thought without taking a poke at a cat who was into it, just like you are. ....Do you use a bunch of cheap-ass parts in your amps because you need to use them up? I doubt the hell out of that.

[Zippy]

And on that note, I have replaced a few in the large Peaveys, 5 watt resistors, actually, that didn't exactly fail per se, but that put out so much heat in the chassis inards area that they were dropping out of the pc boards - melting solder at the resistor leads, in other words. ..........So the larger 25 watt resistor will only get warm in the same situation, something that is also mighty important.

A resistor rated at 5W will generate the same heat as a resistor rated at 50W given the same resistance and current. The power rating is just an indication of how much heat the resistor can dissipate before failing. The difference in perceived heating is a function of how well the heat is shared with the environment - a larger surface area leads back to a lower heat flux (energy per cross-sectional area). Hence you get the same total heat released to the local area but a lower local temperature on the surface of the resistor.

[dartanion]

I don't think that he was taking a poke at KF. Those that have spent a great deal of time researching the Wreck circuits, reading the TW pages, different web sites, and first hand personal knowledge (conversations, letters, etc.) have a good understanding of what Ken was all about. IIRC, the first Wreck was built from what Ken had on hand, and this trend continued throughout every Wreck built. Each one was a little different and each one has it's own character. Ken was a tweaker, and Wrecks really require tweaking for each amp to sound right. He preferred certain types of components, however there was a lot of parts bin building there as well.

[rooster]

dartanion - I, too, talked with KF and shared a letter or two - if that matters here? FWIW, he struck me immediately as a sincere cat who was totally into tone and his product. The comment that I took exception with from 67_Plexi was:

"I highly doubt for one minute the rationale was tone or even reliability."

That's a poke, Brother.

[Zippy]

"I highly doubt for one minute the rationale was tone or even reliability."

That's a poke, Brother.

Plexi's statement does not say that the intent was to compromise the tone or reliability. I read it more as "Tone and reliability were already covered and the oversize resistor was handy in the parts bin."

Let's please not start imagining affronts.

[dartanion]

Agreed, let's not start a squabble over this. There is no need for that.

I didn't know Ken, but I gather the same as you, that he was a cool dude who cared about tone. No one is questioning that. I find that some people get so wrapped up in what Ken used and making sure you got the exact same components, when certain items don't equate to huge tonal differences. I'm fairly sure that Ken didn't sweat it out that he had TRW 25 Watt 1K resistors when almost any 25 watt 1K would do.

I didn't read this comment as a poke at all, just stating a common amp builders theme. If I need a certain resistor value in a 1/2 watt, but only have 1 watt, I'll use the 1 watt.

[UR12]

Interesting comments. So I wonder why Ken "chose" the 25w cathode resistors for the Liverpools? He could have also gotten away with using a 10w resistor there also but didn't. So either he had a boxcar load of these 25w resistors of different values laying around or he made a conscientious descision to use the 25w over something smaller. My personal opinion is that he picked these wattages on purpose to over build his amps and add a reliability and quality factor to the design. Of course the only man that could really answer that question is'nt here anymore and any opinion on the matter is pure speculation.

Nothing to see here, no mojo, move on

[2tone]

Ken was more than a tweaker. He had an extensive electronics background and also had the great ear, and experimented beyond the rules. He knew the rules, and sometimes broke them. Eg, the Rocket has 80 u filtering on a GZ34...not recommended usually but will still work if a high quality tube is used...

[dartanion]

It wasn't just Ken who broke the rules.

Dana, how many Liverpool were built in total? I would think that with so few Wrecks being built that he may well have parts bins full of enough 25W resistors for these amps, but you are correct, only Ken would be able to answer that question. It is also true that the overspec'd resistors are of no harm tonally and would add to reliability.