Just finished servicing 'Ginger'

['67_Plexi]

Since Kens untimely passing I have had the task of servicing several TW's. Several of my own amp customers own originals, one actually has 5. So they have become to trust me with their amps.

Last week I got 'Ginger' in the shop, she was sounding a little under the weather to say the least. I'm sure most people on here are familiar with 'Ginger' as she was Kennys first TW amp.

The following information I am sharing with the understanding it WILL NOT be used to try to clone her, but be used to open doors and give people who are 'stuck in a rut' some things to think about that may help them build better amps. Anyone that knows me, knows I am not interested in the exact make, model and date code of pots, caps etc etc. There are some basic engineering parameters that are important, but an hollistic approach is way more valuable than say spending $$$ on buying Rubycon caps. From Kens amps I have now worked on, there is a common tonal signature with all of them regardless of their topology or tube type. None of them are bright or harsh and they are all very mid range foccused and obviously designed to cut the mix in a real live scenerio. Use this information to help create your own tonal signature.

Firstly, what was wrong with 'Ginger' and why was she sounding a bit out of sorts ?
Firstly, the Mullard EL-84's were meauring at about 30% on the tube tester. Given this amp was serviced in 04 by Ken, these were not changed then. Maybe they were even the original tubes. Anyway I went through several sets of NOS tubes to find the best fit. I ended up using a matched quad of NOS 60's Amperex Holland tubes.
The other issues with the amp were related to the fact that Ken had used flea clips. Several solder joints had become 'dry' with the years of passing current through a weak joint. This is a common problem with flea clips over time, made worse by the fact solid core wire is used.
Everything else seemed OK, the smoothing caps were all still working well and none of the other components had drifted too far out of spec.
All of the preamp tubes were still measuring well. V1 was a little noisy, but still sounded killer, so it was not worth changing and potentially upsetting the balance. Once the work was done she sounded awesome again. Really smooth and balanced, fairly tight on the bottom and bloomed in to feedback on virtually every note.

Here are some interesting things about her.

She is fitted with a half power swich, basically she uses two cathode resistors/bypass caps, one for each pair. One pair lis lifted from ground for half power.
First stage Resovoir filtering is 160uF, yes 160uF (2x80uF in parallel) !!
The remaining filtering stages use 80/60/60
Filter caps are original and not Mallorys.
Bright switch has one position.
The pots are original and are bog standard CTS (Fender style), not RV4s.
There is a cap/res filter network in parallel with the 100K plate load on the second stage to dump some high end.
Mallory Orange Drop caps were not used at all in this amp. They look like the caps Ampeg were using at the time...LOL
No 9.1K dropping resistors, they were all CC 10K's.
The coupling cap value between stage 2 and 3 is 70nF (a poly and a ceramic in parallel), not 10 or 22 as shown in the schems here.
The coupling cap to the PI entrance is 20nF.
The Presence control is a 5K with 100nF cap.
She has a line out, a pot via a 220K resistor.
The O/T has a 6.6K primary and is the exact same tranny model as an early Express (Nancy) I recently worked on !!!!

If anyone can show me a 4xEL-84 amp that sounds better than this, I am all ears. I normally don't care for 84's, and to be honest all the Liverpool and Rocket clones I had heard have sounded frightful in comparison. However this implementation is really good, to my ears anyway. I tend to prefer slightly darker sounding, mid-range biased amps anyway. I'm not in to mojo or voodoo or think Ken was blessed by the muse, but he certainly knew how to take a bunch of anything he had laying around and make a great sounding amp. This is all about tone at the end of the day, not building models !!!

I hope people find this info useful in the right ways. Please use it with the intention it was given.
And please, if you send me a PM asking what a particular component make or value is, please dont' be offended if I refuse or don't answer. Having to ask means you haven't understood why I posted or where I'm coming from.

BTW, Before anyone jumps in, I do know that later Liverpools were more like the Express circuit, still this one is very special, and not because she's probably the most valuable EL-84 on the planetm that's irrelevant, she just sounds so good. Wonder if the owner would mind me gigging her..LOL !!


Alan.

[Bob-I]

Excellent information. Thx for posting!!

[keithrick]

Thanks for posting Alan.

If Ken used the regular cts type pots can you tell us how the faceplate was attached to the chassis? Were the threads long enough to hold it in place?

Thanks again for your comments.

[jedd63]

What kind of pots did Ken typically use?

From the title, I thought this thread was going to be about a fun weekend on Gilligan's Island.

[Tubetwang]

interesting read...

Thanks for sharing...

This is Tonequest material if i am so bold as to say...

['67_Plexi]

Thanks for posting Alan.

If Ken used the regular cts type pots can you tell us how the faceplate was attached to the chassis? Were the threads long enough to hold it in place?

Thanks again for your comments.

Not all faceplates on these amps are the same thickness, I have noticed that. The pots don't have a lot of thread sticking through, but enough to be functional.

While it's on my mind, a note for the 'correct weatherstripping' guys. Every TW I've seen has had a different type (brand) of weatherstripping to fill the gap between the FP and the cab. Green, grey, off-white, squishy, not-so squishy, 1/4"/ 1/8" etc etc. Obviously, sometimes this is needed to renewed when he serviced them so basically whatever the hardware store had in at the time works. Use the same philosophy.

One really funny thing as well....he wrote "Patent Pending' on the top of Gingers chassis in marker pen. You can almost always find some note or comment by Ken in his amps. Sometimes even a piece of paper with a full service history stuck to the underside of the bottom plate, other times hand written notes on the chassis.

Alan.

['67_Plexi]

What kind of pots did Ken typically use?

Military spec RV4s. Clarostat, Allen-Bradley etc etc. The make doesn't really matter.

[Fischerman]

From the title, I thought this thread was going to be about a fun weekend on Gilligan's Island.

Then it would have been titled; "Just finished servicing 'Mary Ann'."

Mary Ann>>>Ginger.

Curious how different half-power sounded from full-power? Everytime I add this sort of half-power switch...I end up setting it on full-power and leaving it there because it sounds so much better. But then again, just about everytime I build an Express circuit (but never a clone) it's bright, harsh, and too aggressive.

If somebody can hear the difference between 9.1k vs. 10k dropping resistors, they are a much better man than I (or they're just fooling themselves).

Thanks for the info.

[Allynmey]

The pots are CTS. They are the "Pick a shaft" style. He ordered the taper and shaft length. They are finished off with the familiar "flying saucer" back covers. I have a few thousand to pick from and have some correct values. The taper is different...like early Fender pots. They are closer to 30% if I remember correctly.

I have used 9.1K and 10K. I can't say that I noticed a difference. Seems like Ken liked PEC better than Clarostat as he used them in more recent builds and repairs. Komet must have got a bunch in surplus early on. They now use PEC. One note on "gingers" values. The three Liverpools I've seen were all the same as the current layout. Ginger was a prototype and he went with different values for the later ones. I understand Ginger didn't have that top end sparkle (told to me by the original owner).

I'd take Ginger over Maryann BTW

['67_Plexi]

From the title, I thought this thread was going to be about a fun weekend on Gilligan's Island.

Then it would have been titled; "Just finished servicing 'Mary Ann'."

Mary Ann>>>Ginger.

Curious how different half-power sounded from full-power? Everytime I add this sort of half-power switch...I end up setting it on full-power and leaving it there because it sounds so much better. But then again, just about everytime I build an Express circuit (but never a clone) it's bright, harsh, and too aggressive.

If somebody can hear the difference between 9.1k vs. 10k dropping resistors, they are a much better man than I (or they're just fooling themselves).

Thanks for the info.

Agreed on the half power switch, just loses it balls but doesn't really get quieter.

Agreed on the 9.1k / 10k to a point. However the CCs drift upwards 10-30% in value over time, especially any that have been subjected to high voltages and heat all their life. Everything else being equal, the difference between new 9.1k's and the old 10K's in Ginger would be audibly noticeable. The dropping string resistors along with the associated smoothing caps affect the tone and feel of an amp a lot. Each stage has to be thought as not just a decoupling stage, but also a filter. I've see some guys just changing the dropping resistors to try to get to a specific target plate voltage on a 12AX7 without realising the side-effects this may have. Changing one component in any circuit rarely affects just one thing.

['67_Plexi]

The pots are CTS. They are the "Pick a shaft" style. He ordered the taper and shaft length. They are finished off with the familiar "flying saucer" back covers. I have a few thousand to pick from and have some correct values. The taper is different...like early Fender pots. They are closer to 30% if I remember correctly.

I have used 9.1K and 10K. I can't say that I noticed a difference. Seems like Ken liked PEC better than Clarostat as he used them in more recent builds and repairs. Komet must have got a bunch in surplus early on. They now use PEC. One note on "gingers" values. The three Liverpools I've seen were all the same as the current layout. Ginger was a prototype and he went with different values for the later ones. I understand Ginger didn't have that top end sparkle (told to me by the original owner).

I'd take Ginger over Maryann BTW

I would tonally take Ginger over any other EL-84 amp I've played, including other Liverpools and my own 1960 AC30. The EL-84 doesn't do top end sparkle it has blackboard grating high end, but I did qualify my thoughts earlier by stating I prefer darker amps.

Well we'll see, I have another Liverpool coming to me shortly that has a hand-written note from Kenny to the original owner stating that this Liverpool is his favourite of all that he built. I'm interested to hear this.

The point I was making in the beginning of this that no-one should care to a finite degree what he used. I couldn't care less if he used pots only used by NASA or some generic chinese part...he used them in a way that worked. The process is more important than the minutia.

All I know from experience, is that these are the same pots found in a brownface Fender, I have no idea exactly what type they were, nor do I have any reason to care because I will never use them. I'll leave that detail to someone else.

I have a fascination with building good tube amps, not with Ken and what he used. How he used it....now we're talking !!!! Get my drift ?

[kec]

I'd take Ginger over Maryann BTW

Mary Ann was hotter IMO

[jaysg]

I'd take Ginger over Maryann BTW

Mary Ann was hotter IMO

What's wrong with you guys...clearly it was a lifetime opportunity for a three-way....stupid Professor.

[LeftyStrat]

I'd take Ginger over Maryann BTW

Mary Ann was hotter IMO

What's wrong with you guys...clearly it was a lifetime opportunity for a three-way....stupid Professor.

LOL, you beat me to it. Great minds think alike.

[Allynmey]

Alan, to tell the truth, I think Ken used what ever he had laying around. It looks like he bought a lot of surplus stuff. Some of the coolest sounding amps I've made were of stuff I had laying around that day.