Like you said, almost identical circuit wise. Variables such as, resistor/capacitor additions/value variations, transformer variants, pot values/tapers, presence circuit variations, filtering, tubes and various layout and material changes. Seemingly very minor tweaks that suited Kens ear prior to him shipping the amp.
I'm gunna have to disagree with you on this one. I've seen about 10 or more and the only variables that are visually noticeable would be the double .0022 coupling cap and the 4k7 on the presence control. Seen that combo on two amps Ingrid and Malou (didnt Dave funk build that one?) Sure some amps had amperex or mullards and who knows if those are still original to what Ken put in there. Both great sounding (and similar) tubes. Some parts changed likely due to what the local electronics stor had at the time. Not sure Id agree with you on filtering, transformer variants and layout changes. Pot values tapers we may never know.
I have followed Trainwreck amps for twenty years and differences between the circuit are negligible. The filter cap values are Mallory brand caps and they are 80uF, 40uF and 20uF. The resistors compose of 9K1 resistor.
The transformer choice was Stancor til availability issues where Ken went with Pacific.
I think when he said there's no mojo, it's science, he meant there's no magic pixie dust .. so many silly things have been said about these amps and Ken was playing with people when he said things like red wire sounds better etc etc.
It's in the design. Caps , resistors, layout. Not mojo or magic..
From what I gather...
Mullardnerd wrote: ↑Sun Mar 24, 2024 2:56 pm
I think when he said there's no mojo, it's science, he meant there's no magic pixie dust .. so many silly things have been said about these amps and Ken was playing with people when he said things like red wire sounds better etc etc.
It's in the design. Caps , resistors, layout. Not mojo or magic..
From what I gather...
I’m not taking aim at dblgun but I have heard so many people repeating stuff that they can’t prove or defend. I don’t think we should entertain myths at this site.
I agree that Ken had a standard circuit with given values and materials that were the basis of the amp models he developed. I also know that my 70 JMP50 doesn't sound the same am my 76 JMP50 even though they are the same circuits. I'm accepting that some of the components in each vary in their actual values. Some of them were this way when installed and others have likely drifted over the past 35-40 years. Ken was said to have tweaked a build for the person he was building for and I think is where he may have made a few changes to components within that amp. A few of the Expresses have been good examples of this possibility. Ken built Suzzane for George Lynch in 92 which looks to have Pacific transformers and is a more aggressive sounding amp compared to Kens personal Express, Sarah, which was built in 87 with Stancor grey bells. Many say that the amps with Pacific transformers were more aggressive overall, but I don't know. I do know that I like the way they sound.
There is a lot written about what people think are hearsay or myth and I can understand why. Also written is that all of the details, information, and documentation is out there and available to any who are interested. Although I think there is a significant of information in the possession of some, the information once available has expired or faded away and therefore has become fodder for those who profess to be in the know.
Case in point, when Brian Wallace went through Trudy (1985) in 2002 what he found was variances from the accepted values. He was then willing to post the schematic of the amp he documented with little opinion just simply what was found. Ex: 500K volume pot, 87,47,20,20,20 filtering, 9.2k node dropper resistors, and mixture of 612 and 622 400v as well as CDE 600V caps. Were these an example of Ken tweaking to taste?
I'm here to share and learn so am all ears and eyes. I'd love to see more of anything that is out there that documents the similarities or differences of each of the amps that have been seen/photographed.
Last edited by dblgun on Mon Mar 25, 2024 12:05 pm, edited 1 time in total.
dblgun wrote: ↑Mon Mar 25, 2024 3:27 am
I agree that Ken had a standard circuit with given values and materials that were the basis of the amp models he developed. I also know that my 70 JMP50 doesn't sound the same am my 76 JMP50 even though they are the same circuits. I'm accepting that some of the components in each vary in their actual values. Some of them were this way when installed and others have likely drifted over the past 35-40 years. Ken was said to have tweaked a build for the person he was building for and I think is where he may made a few changes to components within that amp. A few of the Expresses are an example of this possibility. Ken built Suzzane for George Lynch in 92 which looks to have Pacific transformers and is a more aggressive sounding amp compared to Kens personal Express, Sarah, which was built in 87 with Stancor grey bells. Many say that the amps with Pacific transformers were more aggressive overall, but I don't know. I do know that I like the way they sound.
There is a lot written about what people think are hearsay or myth and I can understand why. Also written is that all of the details, information, and documentation is out there and available to any who are interested. Although I think there is a significant of information in the possession of some, the information once available has expired or faded away and therefore has become fodder for those who profess to be in the know.
Case in point, when Brian Wallace went through Trudy (1985) in 2002 what he found was variances from the accepted values. He was then willing to post the schematic of the amp he documented with little opinion just simply what was found. Ex: 500K volume pot, 87,47,20,20,20 filtering, 9.2k node dropper resistors, and mixture of 612 and 622 400v as well as CDE 600V caps. Were these an example of Ken tweaking to taste?
I'm here to share and learn so am all ears and eyes. I'd love to see more of anything that is out there that documents the similarities or differences of each of the amps that have been seen/photographed.
I was corresponding with Dave Funk for a while before the Express circuit surfaced (which was the work of Allyn Meyer and we are all indebted to him). He was telling me about people banging on about Ken using solid core wire, Dave said the real reason Ken used it was because it was readily available where he got his parts. I thought that was hilarious.
Yes, I don't know that the opinions of the significance of original components will ever be settled or agreed upon. I think that we sometimes forget that manufactures are/were in business to make a profit. They generally look to purchase materials that are a good value (cost vs. quality) rather than what is the best available. I hate to keep using Marshall or Fender as examples but they are great examples. Piher, Iskra, Mullard, Hunts, RS, Allen Bradley, and Mallory all made satisfactory components but were used because they could be purchased in bulk at a price point from regional venders. Here we are 10's of years later and the value of NOS example of these components may or may not be way overinflated.
It's one thing that is most interesting to me about the components Ken used in his builds. I'm not sure how much he bought of a particular item at one time but I doubt that price/profit was a big factor compared to performance, availability or consistency. What I see when I look at his work is function way over form. I believe he would think these people paying hundreds of dollars for a partial roll of RS red/black to wire their Marshall 4x12 a bit crazy and I do too.
Mullardnerd wrote: ↑Sun Mar 24, 2024 2:56 pm
I think when he said there's no mojo, it's science, he meant there's no magic pixie dust .. so many silly things have been said about these amps and Ken was playing with people when he said things like red wire sounds better etc etc.
It's in the design. Caps , resistors, layout. Not mojo or magic..
From what I gather...
I’m not taking aim at dblgun but I have heard so many people repeating stuff that they can’t prove or defend. I don’t think we should entertain myths at this site.
Absolutely. I was referring to Vince's comments. Rang true.
dblgun wrote: ↑Mon Mar 25, 2024 3:27 am
I agree that Ken had a standard circuit with given values and materials that were the basis of the amp models he developed. I also know that my 70 JMP50 doesn't sound the same am my 76 JMP50 even though they are the same circuits. I'm accepting that some of the components in each vary in their actual values. Some of them were this way when installed and others have likely drifted over the past 35-40 years. Ken was said to have tweaked a build for the person he was building for and I think is where he may have made a few changes to components within that amp. A few of the Expresses have been good examples of this possibility. Ken built Suzzane for George Lynch in 92 which looks to have Pacific transformers and is a more aggressive sounding amp compared to Kens personal Express, Sarah, which was built in 87 with Stancor grey bells. Many say that the amps with Pacific transformers were more aggressive overall, but I don't know. I do know that I like the way they sound.
There is a lot written about what people think are hearsay or myth and I can understand why. Also written is that all of the details, information, and documentation is out there and available to any who are interested. Although I think there is a significant of information in the possession of some, the information once available has expired or faded away and therefore has become fodder for those who profess to be in the know.
Case in point, when Brian Wallace went through Trudy (1985) in 2002 what he found was variances from the accepted values. He was then willing to post the schematic of the amp he documented with little opinion just simply what was found. Ex: 500K volume pot, 87,47,20,20,20 filtering, 9.2k node dropper resistors, and mixture of 612 and 622 400v as well as CDE 600V caps. Were these an example of Ken tweaking to taste?
I'm here to share and learn so am all ears and eyes. I'd love to see more of anything that is out there that documents the similarities or differences of each of the amps that have been seen/photographed.
Ken had Pacific make his transformers because he couldn't source off the shelf Stancor. They do sound a bit different. Its said he would listen to each transformer and take notes of how they sounded and tweak each amp with those different output transformers.
Are you sure your JMPs are identical? Id say its quite likely the later JMP has less voltage in the power transformer. If its lead spec 1987/1959 the circuits are different.
Trudy is the one file I have that is corrupt. I can't seem to locate it in the files section. Would you be so kind to email it to me? Id say that Trudy was a very early amp and maybe Ken didn't know what parts he liked or its just what happened to be available. Also the filtering 87,47,20,20,20,20. Filter caps have such a huge tolerance in the + 20% (maybe more forget) that it doesn't really matter. Its likely that's what he had available to him. Also I would take Wallaces notes for a gain of salt as I found a bunch of questionable things in his historical data section of Marstarn,com years ago that I dont use that site anymore.
RockinRocket,Yes both JMP's are the same circuits down to plate voltages, presence/NFB, pot vales etc.. It's been a journey but very enlightening. I apologize for my part in the unintended hijacking of your Logo thread. I have a great interest in continuing the discussion related to everything Trainwreck, specifically variations. It may be better to move these discussions to a separate thread so that it is searchable. Much of the documentation here has expired and those who contributed have either moved on or are very infrequent visitors. I would be happy to send you what I have on Trudy. Like many things Trainwreck this amp and it's travels are interesting. PM me your email.
dblgun wrote: ↑Thu Mar 28, 2024 12:43 pm
RockinRocket,Yes both JMP's are the same circuits down to plate voltages, presence/NFB, pot vales etc.. It's been a journey but very enlightening. I apologize for my part in the unintended hijacking of your Logo thread. I have a great interest in continuing the discussion related to everything Trainwreck, specifically variations. It may be better to move these discussions to a separate thread so that it is searchable. Much of the documentation here has expired and those who contributed have either moved on or are very infrequent visitors. I would be happy to send you what I have on Trudy. Like many things Trainwreck this amp and it's travels are interesting. PM me your email.
Thanks bud I sent you a Pm. I ended up finding a logo so we can keep derailing this thread lol it happens!
One mod that doesn't get any love is the Maloo picture where there is a small ceramic cap in series with a ten turn pot across the 100K plate resistor of the second triode stage. It was for high output pickups, but I noticed (depending on the cap value) it can boost bass after the tone controls. I have heard of people putting a cap across this resistor to drop the treble response.
Wow great catch. Never thought to much of the ten turn pot and just figured it was a snubber. I never noticed that ceramic snubber hiding in there!
Also, the shielded wire on V1 second stage is plate "grounded". I've never tried this type of shielding but its said to knock off a bunch high frequency's. I saw a Headfirst youtube video of him fixing a Jcm 800 I think it was that had this mod and the amp sounded like it had a blanket over the speaker cab.
I'm guessing Dave Funk had a hard time keeping this build stable.
Malou is a very interesting example. The pots themselves are a great source of consideration for me as they each appear to have been selected for a reason. Either that or they were just sourced from a box of various pots! I know that Marshall used the "hot shield" regularly in their cascaded amps in that specific era to combat oscillation. I've used it some but found that a small ceramic 7-8pf 1kv cap works well too.
Malou's pots are identical to Ingrid with the exception of the presence pot being a mill spec Clarostat. Anyone know the birth date of Malou?
Ingrid 92 and Kitty being older but also uses a AB mill spec middle pot. I think the switch to CTS and AB pots was likely because the first type with the PCB mount becoming extinct. If anyone knows what brand they are id be grateful to know. I've searched and searched for anything leading to who made them but nothing. Never found one on ebay even in a lot of random pots for sale.
This seems to be a bit confusing because Ingrid (92) and Kitty (91) are Expresses. Malou is a Rocket from 97 from what I see, so something is amiss. The images in the below link, said to be Malou, certainly show a Rocket amp front and back but the "gut shot's" look to be a Liverpool. Great topic for reference and discussion.
