Clone Kit Am I asking for to much?

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Clone Kit Am I asking for to much?

Post by spider »

I've been searching for a while now & have been reading thru forums, checking you tube videos for a JTM 45 hand wired clone kit that is 18 watts(give or take) and can run KT66 power tubes.
Does such a kit exist?
Can anyone recommend one?
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Re: Clone Kit Am I asking for to much?

Post by JMPGuitars »

You wouldn't want to run KT66 tubes that cold. A pair would likely work in a 36W amp. KT66s are basically the same as 6L6, and you'll find EL34 version 36W (usually biased at 40W) amps in our downloads section. Personally, I much prefer the EL34 sound to the 6L6 or KT66 variety.

If you want lower wattage, you could build a single-ended KT66 amp. You'd likely find useful information about that at our sister site sewatt.com.

Thanks,
Josh
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Re: Clone Kit Am I asking for to much?

Post by zaphod_phil »

JMPGuitars wrote:
Thu 03/03/22 6:59 am
You wouldn't want to run KT66 tubes that cold. A pair would likely work in a 36W amp. KT66s are basically the same as 6L6, and you'll find EL34 version 36W (usually biased at 40W) amps in our downloads section. Personally, I much prefer the EL34 sound to the 6L6 or KT66 variety.

If you want lower wattage, you could build a single-ended KT66 amp. You'd likely find useful information about that at our sister site sewatt.com.

Thanks,
Josh
I wouldn't say that KT66s are "basically the same" as 6L6s.
I would say that they're quite similar, having come out of the same joint development project, which created the beam tetrode tube. The 6L6, however, features a "hard" vacuum, while the KT66 has a British-style "soft vacuum", IMO yielding slightly nicer harmonics compared to the 6L6.
If you want to build an 18W version of a JTM45, I would recommend using 6V6s instead, which will run very nicely with a regular 18W transformer set:) 6V6s sound awesome in "big Marshall style amps. You could use the same PA and PSU design as the 6V6 Plexi- see http://www.ppwatt.com/plexi-6v6-mods As some folks know, I first played a 6V6 Plexi some years ago, at a friend's place in Ogden Utah and the sound of that amp totally blew me away! It had transparently-clear, shimmering liquid clean tones, with creamy distortion where you could hear all the overdriven layers of the different parts of the amp, with great touch-sensitivity. 8O It was a real epiphany for me.
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Re: Clone Kit Am I asking for to much?

Post by spider »

Much thanks Josh for the info. I had a vintage JTM45 that I was running kt66's in and miss it. Only reason I got rid of it was due to the volume it needed to sound sweet. I didnt have alot of fans when I played that in the house. :lol:
I was looking at some of the other amps out there with KT66's in em but theyre all 30 to 50 watt. I came across the Vintage modern(50w) but read it sounds good at all volumes. Not sure how true that is but its hard finding that amp now that its discontinued. Kinda high priced as well even for the combo version which I wouldnt mind having.

Is there any nice JTM45 clone kits that are under $1k shipped? I really wanna go with KT66's as I gassing for them again. I read about the PPIMV, power scaling, and using a attenuator but getting mixed reviews on using all that as it changes the tone. I would like to have at least tv volume or a little louder but dont want to scarifice the tone so much that it changes the sound of the amp to something horrible.

I was looking at the KLD JTM25 & saw a couple people using KT66's in em but not sure the build quality nor how it really sounds.

I also considered a bluesbreaker but again cant seem to find a HW used deal on one yet. I saw they have KT66's in them as well.

Any more info would greatly be appreciated.
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Re: Clone Kit Am I asking for to much?

Post by JMPGuitars »

I agree with what Phil said above, but if you're stuck on KT66 tubes, 6V6s won't likely fly.

My opinion regarding dealing with the volume is that power scaling toys like PPIMV doesn't do the job well. You can use a combination of a less efficient speaker with a high quality attenuator if you really want a PP amp.

If I was jonesing for that specific tube at lower volume, I would either build a 36W amp with the KT66s, or better yet, try making a single ended version. That could be fun. Marry the 18W Tremolo or TMB with an SE KT66 power amp.

If you're absolutely set on getting a kit, Ceriatone has a JTM45 KT66 kit that might be along the lines of what you want, but it will still be loud.

Thanks,
Josh
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Re: Clone Kit Am I asking for to much?

Post by spider »

Thanks Phil. I must have been typing out the response right after you posted as I just saw your post now. I did read that about the KT66's being a bit different than a 6l6 and they do seem to be a nicer sounding tube in my opinion or its just that I'm really having a desire for that tone from them again.

Josh,I was checking out ceriatone and I agree I think it would be too loud and I would probably end up selling this off too for the same reasons I did my '66 JTM.
Ill have to do some searching for a 36w amp kit and see whats all out there. I did consider a single ended amp but some of the prices on them are out rageous. Im not a experience amp builder. Looking to get into it though and trying to read all I can to find out more on the how to and understanding of how they work. Got some books and checking out videos so the 18w tremolo & single end mating is a little over my head. I believe it would be taking one part from the 18w and the power section from the other correct?
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Re: Clone Kit Am I asking for to much?

Post by JMPGuitars »

spider wrote:
Fri 03/04/22 1:12 am
Thanks Phil. I must have been typing out the response right after you posted as I just saw your post now. I did read that about the KT66's being a bit different than a 6l6 and they do seem to be a nicer sounding tube in my opinion or its just that I'm really having a desire for that tone from them again.

Josh,I was checking out ceriatone and I agree I think it would be too loud and I would probably end up selling this off too for the same reasons I did my '66 JTM.
Ill have to do some searching for a 36w amp kit and see whats all out there. I did consider a single ended amp but some of the prices on them are out rageous. Im not a experience amp builder. Looking to get into it though and trying to read all I can to find out more on the how to and understanding of how they work. Got some books and checking out videos so the 18w tremolo & single end mating is a little over my head. I believe it would be taking one part from the 18w and the power section from the other correct?
Yup.

Look in our downloads section. Any of my 36W EL34 designs could be fairly easily adapted to KT66 if you want to go the 36W route. Don't worry so much about kits, sourcing the parts will get you better quality stuff. If you look at my Tremolo TMB series, I have a BOM in there which could help too.

I could put together a partial kit for you including chassis, transformers, and faceplates, but if I have any 36W transformers, they'd be Mercury Magnetics, and they're expensive.

Thanks,
Josh
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Re: Clone Kit Am I asking for to much?

Post by spider »

Much thanks for the point of direction to the 36w download section. Im fairly new to the site so I wasnt aware of that.

I did some more google fu searching last night for 36w amps or similar. Along my search I found a pretty cool little single end amp called Fargen Mini Plexi mk2 that was mentioned in a forum. Its 12 watts and can be turned down to bedroom volume. I see that version has been discontinued and they have an mk3 version available now.

Today I found there is some sort of a flaw in the design about the placement of the mounted K bypass caps. And read it will cook them and shorten their life sitting right on the K R's. That statement is a lil over my head at the moment & I just copied/pasted the gentlemans comment. But I enclosed a photo of what he saw on the board. He circled it in red in case you were curious on what he was talking about.

It sounds very interesting but Im not a wealthy man so the price is out of range for me. I found a marshall vintage modern combo 2266c and the seller is stringing me along with wanting to sell but then not wanting to sell. Today he messaged he would sell. I wont hold my breath on it going thru though.

The fargen mini plexi is/was something I have been searching for for a very long time since I have others in the house that do not like to hear me play anything louder than a tv. Not to mention I have a celestion blue speaker that I wanted to finally put to use as well.
But I have an itch inside me for the past 4 years to build one and learn how these things really work. If done I would have the self enjoyment of knowing I build it and learned about something that interests me as well. The older I got the more I wanted to learn how these things really work. That's when I started my search on how to build them. I have yet to make any head way on the subject though. Just trying to find my way.

I am aware of mecury magnetics being pricey but I have read they are of good quality at least the last I read a few years ago. If Im not mistaken the fender twin reverb (hand wired) had them in it. At least the one I sold off some time ago did.


As for making a parts list I assume I would need to look over the schematic and find out what parts I would need? I have never done this before so it seems a bit of challenge when you're not exactly sure of yourself. I have read it is cheaper to do it that way. But that was one reason why I was looking at kits again. I only know of digikey and mouser website to source the parts. Its a bit of a challenge looking on their sites though.

Would you have a price in mind on a partial kit? Also would it be possible to make a clone of the fargen mini plexi or one that has similar characters? It seems to have the jtm45 tone from some youtube videos I watched last night. I would make alot of people happy in my house over the bedroom volumes and also make myself happy to have such good tone at low volumes esp one with KT66's again. My ears might thank me too? :lol: What really surprised me was the options of so many other power tubes it is capable of using.
Is there anything in the download section like this?
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Re: Clone Kit Am I asking for to much?

Post by JMPGuitars »

I won't have time to look at a kit setup for at least a couple days.

I think you might want to consider going easier for your first build. In your case, I would consider this: https://guitaramplifierpcbs.com/products/plexi-se-pcb

You could potentially modify the values in that circuit a little bit to work with a KT66. Might also need to use a specific output transformer with it. Maybe Zaphod_Phil or somebody else could help figure that out. This weekend is a little crazy for me.

Thanks,
Josh
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Re: Clone Kit Am I asking for to much?

Post by ViperDoc »

I built a JTM45 head from a kit that included a 3.4K primary OT intended for 2xEL34 tubes. I put in a 50KL bias trim pot to allow correct biasing for KT66 and find that the amp sounds incredible and is very loud, but not so loud as you would expect from a 6.8K OT primary setup when using the 8 ohm secondary. I believe that is effectively a one-step output attenuation via impedance mismatching, if I am not mistaken. With 2 x KT66, you'd probably need a PPIMV to get your audible level where you need it. I have a Carr Telstar that uses VVR and, while a very different and unique circuit, I find it sounds incredible. Not a bad tone on that particular amp anywhere.
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Re: Clone Kit Am I asking for to much?

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ViperDoc wrote:
Sat 03/05/22 1:57 am
I built a JTM45 head from a kit that included a 3.4K primary OT intended for 2xEL34 tubes. I put in a 50KL bias trim pot to allow correct biasing for KT66 and find that the amp sounds incredible and is very loud, but not so loud as you would expect from a 6.8K OT primary setup when using the 8 ohm secondary. I believe that is effectively a one-step output attenuation via impedance mismatching, if I am not mistaken. With 2 x KT66, you'd probably need a PPIMV to get your audible level where you need it. I have a Carr Telstar that uses VVR and, while a very different and unique circuit, I find it sounds incredible. Not a bad tone on that particular amp anywhere.
Did you ever consider using one half of the HT secondary for attenuation? I think it's an overlooked option on many builds
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Re: Clone Kit Am I asking for to much?

Post by zaphod_phil »

spider wrote:
Thu 03/03/22 5:43 pm
I came across the Vintage modern(50w) but read it sounds good at all volumes.
And Marshall's marketing department says it alsohas a hyper-stellar warp drive! : :P :lol:
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Re: Clone Kit Am I asking for to much?

Post by zaphod_phil »

I could put together a partial kit for you including chassis, transformers, and faceplates, but if I have any 36W transformers, they'd be Mercury Magnetics, and they're expensive.

Thanks,
Josh
I would instead recommend Heyboer's 36W transformers for really solid quality, without the MM brand name's ridiculous price premium :twisted:
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Re: Clone Kit Am I asking for to much?

Post by JMPGuitars »

zaphod_phil wrote:
Sat 03/05/22 4:09 pm
I could put together a partial kit for you including chassis, transformers, and faceplates, but if I have any 36W transformers, they'd be Mercury Magnetics, and they're expensive.

Thanks,
Josh
I would instead recommend Heyboer's 36W transformers for really solid quality, without the MM brand name's ridiculous price premium :twisted:
Heyboer's are good too, but I don't have any 36W Heyboers, and they never return my calls or emails, so that's on them. MM may cost more, but they sound great, and have great customer service.
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Re: Clone Kit Am I asking for to much?

Post by spider »

Josh, Take your time certainly no rush. Ive been researching this for a long time now and still havent made up my mind. Sorta glad I didnt as I started out wanting to build a 5F1 amp.I read that was a good kit to start for a beginner. I felt that would be enough of a challenge in its own. So I agree. I was thinking along the same lines if I went with a clone of a Fargen it would be just too advanced for me. I wasnt aware of the kit you linked me to Ill definitely check it out.

Thanks for chiming in ViperDoc. I really was considering another JTM45 since I really miss having that tone. Its been at least a decade since I sold mine off. Definitely jonesin for kt66's again. The best complaint Ill hear is "turn it down" "I have a migraine and cant tolerate your amp being that loud". So its the only reason I have search for other alternatives which I did find that Fargen to be very interesting. I did come across reading some comments about PPIMV and VVR. Honestly I had to research it as I never heard of it before. I got mixed reviews on each and some say the tone changed. Others were saying just to use a attenuator which again I shied away from as I read it was hard on the amp and ya cook the tubes pretty fast. So it brought me back to step 1. :lol:

zaphod_phil I better hold on when that warp drive kicks in. :lol: Honestly dont know much about the amp except for reading it doesnt do some things too well like for solos. Really wanted to stick to a hand wired amp and get to build one. I have a Heyboer OT for a epiphone valve jr and when I bought that I didnt have much luck with them sending me it. I waited 3 weeks and it still wasnt sent. Ended up calling and leaving messages asking if someone can call me back and all went unanswered. I called Heyboer directly and they were able to get my order sent in. So what happened? I honestly cant say. It was the first and last time I ordered from them. Not that Ive built anything anyway. Since then I heard about classic tone which I considered as well.
Last edited by spider on Mon 03/07/22 1:31 am, edited 1 time in total.
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Re: Clone Kit Am I asking for to much?

Post by spider »

Josh, Just wanted to give ya a great big thank you for posting that link. It looks very interesting and a huge help to me. I have a epiphone valve jr sitting here. I use it for a talk box but also wanted to mod it sometime ago since its the lowest wattage amp I have. I found a mod by Pat Furlan called Billy Gibbons tone that I wanted to try out. I joined SEWatt.com and some time ago they mentioned they have a schematic on their site that is better than Pats mod. I have their schematic. Its called wild thang. I havent gotten all the parts just yet though. I did get the heyboer ot for it which I know was kinda expensive for a valve jr but again for a beginner I felt it was a start for meddling on these things.

I think the link you provide would be a good 2nd step for a beginner as well. I think Im gonna just try this out and see where it all goes. I cant thank ya enough for the push in the right direction.
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Re: Clone Kit Am I asking for to much?

Post by JMPGuitars »

spider wrote:
Mon 03/07/22 1:29 am
Josh, Just wanted to give ya a great big thank you for posting that link. It looks very interesting and a huge help to me. I have a epiphone valve jr sitting here. I use it for a talk box but also wanted to mod it sometime ago since its the lowest wattage amp I have. I found a mod by Pat Furlan called Billy Gibbons tone that I wanted to try out. I joined SEWatt.com and some time ago they mentioned they have a schematic on their site that is better than Pats mod. I have their schematic. Its called wild thang. I havent gotten all the parts just yet though. I did get the heyboer ot for it which I know was kinda expensive for a valve jr but again for a beginner I felt it was a start for meddling on these things.

I think the link you provide would be a good 2nd step for a beginner as well. I think Im gonna just try this out and see where it all goes. I cant thank ya enough for the push in the right direction.
Once you put the new PCB in, it isn't a Vjr anymore. With the better OT, and setup properly for the tube you want, I think you'll really enjoy it.

Good luck, and be safe on your amp build/mods!

Thanks,
Josh
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Re: Clone Kit Am I asking for to much?

Post by zaphod_phil »

You really don't need a Heyboer OT for that amp. I instead recommend the Hammond 125 DSE, which should be perfect and much more affordable.Always keep in mind that the OT is the foundation of a guitar amp's tone.
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Re: Clone Kit Am I asking for to much?

Post by spider »

Josh, Will I be able to run a KT66 in it?

zaphod_phil, Yes I was inexperience when I made the purchase for the Heyboer a few years back. I was reading some forums on people modding them as I was never happy with the original tone from it. But when I read about most mods I still wasnt set on doing anything. Then I read someone said the OT was the main culprit on the map and that they bought a Heyboer. I took his advice and after the purchase I learned that there were other cheaper options available. I was bummed I spent so much on it.

The only mod I found was Pat Furlan Billy Gibbons tone that got me wanting to really take a stab at doing it myself. I found SEwatt thru some more research and also found a member there that has a schematic for his Wild_Thang mod. I have yet to meddle trying to do the mod. I need a little more research on how to find the parts they used from the schematic. Im a lil vague reading them yet and picking the parts. Needed some guidance or walk thru on what to do. That's when I searched for a kit with parts as I figured it would be easier.
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Re: Clone Kit Am I asking for to much?

Post by Daviedawg »

" I found SEwatt thru some more research and also found a member there that has a schematic for his Wild_Thang mod."

Several years ago I built the Wild Thang from scratch based on that thread on SEWatt. It is still here, is used irregularly and is great for home recording. But since it is a "spare" amp it is also useful as a tool for practical learning about mods to the preamp. That may be because it is a single knob circuit with very few losses. Mine has a 6X4 rectifier and 6AQ5 power valve but the EL84 is just as good for this design.

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