Just finished servicing 'Ginger'

[Bob-I]

Bob, build it with a pair of el-84's. If I have time I'll throw one together for Gregs get together. I have some stancor Iron that is suited 9K primaries.

Very cool.

['67_Plexi]

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.

Alan.

Thanks a whole bunch for your time and insight!

What is the issue with flea clips and solid core wire becoming "dry"? Only thing I can think of is amount of metal-to-metal contact surface area is less with these two??

I am sticking to solid core wire, but just got 100 -old- Vectorboard flea clips similar to the GC Electronics ones. Grack.

(so old that the VB part # has NO hits on google, lol)

The old style flea clips are just plain crap. All the solder drains down to the bottom leaving a small amount of surface area that is actually making the joint. The new style clips are much better, still I wouldn't ever use them myself.
The other thing you will have to be wary of if you are using ancient clips are tarnish issues. Make sure your iron is hot enough to burn that stuff away. I've seen folks use these and all that was holding the wire in place was a blob of flux !
I don't use solid core on anything, but thats my preference. My standard chassis are steel , also a preference. I've got used to building amps around these parameters. Ken liked Al + solid core, it doesn't mean you have to. Think outside the box and experiment

[Mark]

Dear Alan

I have heard about Liverpool amps with a first filter cap of 160uF. I seem to recall that the first filter cap of the Liverpool should be larger to hold the same charge as an Express amp.

I did experiment and record (with a microphone etc) the results for later comparison, and I honestly couldn't hear any difference between an amp with a 80uF first filter caps and a 160uF filter cap. I was curious about this and I looked towards the sag of the Liverpool power supply, I came to the conclusion the sag of the power supply wasn't really enough for the larger capacitance value to have an impact on tone

I dare say Ken Fischer must have felt the same way, as he decided to use 80uF in later amps. If 160uF had the better tone they would be in all Liverpool amps.

Anyway, just a thought on the matter.

[jelle]

Thanks for sharing this info!

Jelle

[Mark]

Dear Jelle

I agree it is always good to hear more about these amps. This amp was the starting point for Ken Fischer and it is interesting to see what he tried and what he dropped from the design. The presence control is a typical example, KF later used the Fender 6GXX series style (25K) presence control which a lot of builders prefer in this amp. (Mind you, quite a few builders have incorporated some of Kevin O'Connor's circuits in these amps with great success too. It's always good to keep an open mind on the matter, for example how many builders incorporate a pull pot allowing both a 47/50pF and 470/500pF treble cap?)

I had a bit of a look at some notes I took when I was fooling with the Liverpool circuit, I have the sag in the pre-amp stage with the amp running flat out at around 33VDC. This is a big part of the Trainwreck sound as it delivers consist tone as the gain is increased.

Alan mentions the Clarostat RV-4 pots, but I'm 99.9% sure these were never used in Trainwreck as they have a linear taper. I accidently put a 1 Meg linear taper pot as the bass pot, and I wondered why the bass tone control didn't work properly, once the log pot was in, it worked as intended. I suspect the Clarostat pot that Alan meant to say was the 53C series which are log pots. BTW I tried CTS pots and I thought they worked quite well in these amps due to the taper. I found it was easier to dial in tones as I had "room" on the (volume, treble bass) control before it was running flat out. I know it isn't a big deal, but it is something to consider.

Hope this helps.

[jelle]

Dear Mark,

I think that it is cool to see how a design has developed into a great design. I really appreciate the initial post for this reason.
Isn't it the best part of ampdesign, to combine info from other amps, the old books and your own ideas to improve or create an ampmodel?
I do not care too much about the brands of the components used in Ginger and this was not the intention of Alan who posted the info.

Thank you for the tips about the taper of the CTS pots, I'll try that! Cool info!

Did you ever find out what caused it that some AC30's are so gainy? I'm curious! Is it that one half of the first triode stopped working?.....

Thanks,
Jelle

['67_Plexi]

Dear Jelle
Alan mentions the Clarostat RV-4 pots, but I'm 99.9% sure these were never used in Trainwreck as they have a linear taper.
Hope this helps.

For clarification. RV-4 is a military spec designator and not brand specific and can be found on any manufacturers pots that have been built to that spec. They can linear, log, reverse log or any custom taper.

Alan.

[LeftyStrat]

For clarification. RV-4 is a military spec designator and not brand specific and can be found on any manufacturers pots that have been built to that spec. They can linear, log, reverse log or any custom taper.

Alan.

What he said ^^^^

I purchase my clarosats from here:

http://westlabs.com/Frames.HTML

Pretty good prices. Labeling on the box has (for a 250k):

RV4NAYSD254A
250K - S
53C3-250K-S

Notice both designations.

[Doug H]

I know this is an old thread and I'm late to the party but I just wanted to thank Alan for the info. It is valuable and insightful.

There was a soundclip of Ginger bouncing around Ampage around 8-10 years ago. (I have it at home saved on a cd somewhere.) From as much as you can tell from a clip, it was/is/always will be the holy grail of amp tone for me. The way the notes bloom, it sounds like the guitar is playing itself and is very sensitive to touch. It is also very smooth and beautiful sounding- not harsh or bright like many of the clips I hear of clones today.

Alan's comments that the amp is midrange-focused ring true. It has to be, to produce this smooth of a sound. I have heard in the past that he used an RC network in parallel with the 2nd stg plate R to smooth things out- in at least one of his amps (must have been Ginger).

But the biggest point of this thread IMO (as I have also mentioned in the past) is that the emphasis should be on the building process- listening to the amp and making the appropriate changes to get the desired sound. This is as opposed to religiously following a schematic and agonizing over wire, component types, layout and every nut, bolt, and screw that was supposedly used- Building an amp vs. building a model of an amp.

I suspect Ken had a pretty clear vision of how he wanted his amps to sound. And given a set of parameters- tubes, speakers, guitar, pickups etc- he could get there. This also implies there was more than one way to get to his desired tone, depending on the particular parameters he had to work with at the time. I don't know about anyone else but I find that pretty freeing.

I built a vox-derivative last year and have been living/gigging with it a few months now. I've been getting the creeping feeling that I needed to do a slight tweak to the tone selector to tighten the bass. So this thread inspired me to finally get that done last night- one simple tweak and it really sounds great now. So keep tweaking your amps until you get what you want out of them.

Thanks for the post, Alan.

[My-Co]

Hi,
I have worked on 8 TW, and Ken was a mentor to me. I have Many Cards(X-mas) Schematics and letters from Ken to back it up. I miss talking with him. Ken would use what ever he had in the shop. Thats also what alot of people miss on the builds.
My-co

[My-Co]

On that amp it was ampeg caps, OR Tone amps, Ken had a few Ampeg B-15's. Ken said thay make a good door stop. He would pull all the stuff he could use and rest went to trash. He gave me one one day. If I would just take it upstairs and put it in my car.
My-Co

[keithrick]

Hi,
I have worked on 8 TW, and Ken was a mentor to me. I have Many Cards(X-mas) Schematics and letters from Ken to back it up. I miss talking with him. Ken would use what ever he had in the shop. Thats also what alot of people miss on the builds.
My-co

I don't believe you! Post some of the schematics to back up your claims! Just kidding!,...sorta Welcome to the forum!

[Pyrojason]

Hi,
I have worked on 8 TW, and Ken was a mentor to me. I have Many Cards(X-mas) Schematics and letters from Ken to back it up. I miss talking with him. Ken would use what ever he had in the shop. Thats also what alot of people miss on the builds.
My-co

I don't believe you! Post some of the schematics to back up your claims! Just kidding!,...sorta Welcome to the forum!

If you're still around, do please post those scheme. The history here is wonderful!