Yeah, it can be really a pain in the ass for sure, even with big brands.
A couple of guys brought me Marshalls to fix them and those had some really crappy PCB mounted sockets, I hated them cause I had to replace 3 of them (never fix an amp with PCB mounted tube sockets, it's hell). Oh since we're talking: The switches are the same thing - particularly the standby switch is a useless piece of crap. There was this one guy who brought me 5 Marshall heads to repair, none of them were working and 3 of those heads had a broken standby switch. And.. you know the standby switch doesn't do anything, you are still cooking those tubes if the amp is on, so I don't really understand why they even exist. Btw I used APEM switches when I built the JTM45, just look at those: https://www.apem.com/int/600h-600nh-series-352.html ![]() They are a bit pricey (SPDT around 3,5€, DPDT on-on is about 7-8€) and pretty big, but worth the money, cause they have a crazy spec: 10.000 cycles at full load. Full load means: switching back and forth continuously. They will survive everything! |
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The standby switch was originally intended for amps with solid state rectifiers so that you wouldn’t send B+ to the tubes before they had a chance to warm up. A GZ34 takes longer to warm up so the rest of the tubes have already warmed up by the time the GZ34 gets B+ going
Guitarists did not understand the technical reason for standby switches and saw them as a “feature” that would be desireable to have in an amp, so amp makers started including redundant standby switches to appeal to customers Those cheap PCB mounted tube sockets and cheap switches were designed by Satan :P |
I'm back. New project!
Tube-town is selling a reactive load kit, and since my band is preparing to record our first EP, I figured - this should be my next project. Home recording, here I come! I bought the 50W 8ohm kit (100W versions and 16ohm versions are available as well), I thought it would be cool for the JTM45. Only costs 79 € + chassis -> ends up at about 100 €. It comes with a good build layout and schematics, a good one hour build, pretty easy and sounds good! The sounds hugely depend on the cab impulse response that you are using with. I used the Rosen Digital Audio pulse plugin for the IRs, sounds freaking great, no hurting freqs at all, it is easy to mix too! Latency was also not an issue with a cheap 2 channel Lexicon USB interface - I could easily record with the Pulse VST plugin in real time. Link to the kit: https://www.tube-town.net/ttstore/Kits/Power-Suckers/Kit-TT-Tonehound-Light-50W-8-Ohm::8084.html Looks like this: ![]() |
In reply to this post by Travis
It's been so long since we posted here, but let's fire up the topic! I just finished another beauty, it's a clone of a Friedman Dirty Shirley, that I just put together last weekend, let me know your thoughts!
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Looks super clean! More importantly, how does it sound??
Through all the worry and pain we move on
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Quick demo.. I recorded at midnight, so I was freaking tired, playing is subpar at best :D - plus I just heard some clipping.. silly me.
But the amp is so great. I'll record a complete song demo later when I have the time, and show how many great sounds can you get from this amp - the gain switch is a really great feature. The highest gain setting is really nothing I ever heard, no overdrive pedal can do that kind of musical quality of overdrive I think. https://www.youtube.com/watch?v=l2h4UxBb6ao (Recorded with my diy reactive load, with a Friedman impulse response, no eq or compressor, anything really) |
Oh yeah that's super sick. Congrats
Through all the worry and pain we move on
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I just finished the whole thing, finally managed to learn how to cover the corners with tolex nicely. It's still not 100% perfect, only around 90%, the next one will be better I'm sure - it's just takes practice.
I designed the faceplate based on the PDF layout of the chassis (chassis is from Tube-Town and they are supplying PDF drawings), printed on paper so that I can test-fit the parts. Then it was laser-engraved at a local workshop, and everything lined up perfectly. Bias test points are on the back, so a simple DMM is enough to bias it - I don't usually put the bias pot "outside", because people like to turn things even when I specifically say that "don't turn it". ![]() ![]() ![]() |
Nice work
Yeah, 220, 221. Whatever it takes.
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In reply to this post by balazs.bencs
The funny thing is that the first head that I built (the orange one that I posted in this topic years ago) was not my favourite, never really took it out for a gig or even practice, so I just took out board, cleaned it up and since I loved the Dirty Shirley so much, I figured... hey I just need some capacitors, resistors and pots to make a Little Sister clone (the schematic is up on the ampgarage forum). So that's what I did between Christmas and new year.
I drew the layout myself for this amp - based on the pictures of the real thing, so it is very close to that, came out very nice. ![]() Sounds absolutely fenomenal too, I never knew that EL84s can sound so thick and chewy, I'm really happy with this one. |
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