New 36w Build Thread

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geoff 1965
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Re: New 36w Build Thread

Post by geoff 1965 »

we are drifting away from the subject thread here so come on "GlassTornado" let's see some more pics & info!
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Re: New 36w Build Thread

Post by JMPGuitars »

geoff 1965 wrote:we are drifting away from the subject thread here so come on "GlassTornado" let's see some more pics & info!
We're WAY off topic. ;)

I agree, more pics!
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Re: New 36w Build Thread

Post by GlassTornado »

Alrighty! We'll get back on track here. Sorry for the delay. Band's been recording, and we've had some shows getting in the way of my building! haha.

Let's see, where were we:
Got all the connections hooked up on the power tubes. I prefer individual 100ohm resistors for the b+ on each socket rather than 1 larger single. It also works out with me using a 18w sized board because I chose to do bias cathode resistor/cathode for the two pairs of tubes instead of one for all four. I also moved the four 8.2k grid stoppers directly on to the sockets because there wasn't room on the board either. This is the setup I have going on my currrent 36w and it does just fine.
36-build-046.jpg
Obligatory cliff jack wiring pic
36-build-047.jpg
After wiring the OT primary and secondary and the output jacks.
36-build-048.jpg
Another angle of the cable routing as it starts to build up
36-build-049.jpg
I like the next picture because of what it becomes afterwards...but this is the board with 90% of the leads soldered on it waiting to be installed.
36-build-050.jpg
And now for one of my shining achievements of this build. I decided to lace the two larger groups of wires instead of just zip tying. It was a bit of a pain at first, but I'm 100% stoked of how it came out.
36-build-051.jpg
This is last of my progress as of 10:30 last night. Actually I have the whole "pot side" of the board done except for the two caps on the trem side pots.
36-build-052.jpg
I know it's a lot, but I would work a little, and take pics, and then they've just build up. I'm getting pretty close though. Hopefully I'll get to light some filaments by next weekend!
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geoff 1965
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Re: New 36w Build Thread

Post by geoff 1965 »

you're attention to detail with the wiring is superb! makes mine look like a bowl of spaghetti!
can i ask what gauge & type of wire you used,is it ptfe? also did you use single core or stranded for your heater supply?
keep it up! if this amp sounds as good as it looks it's going to be awesome!
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Re: New 36w Build Thread

Post by GlassTornado »

Thanks for the kind words! On this one I've been really keeping "measure twice, cut once" close to my heart. Plus I got a little jealous...I have a buddy that has done some NOS style builds of a 45/100, Black Flag 50, and a 12,000 series Super Lead, and his lead dress and routing is tough to beat. So this one I wanted to see if I had the hand and patience.

As far as the wire I'm using it's the 22awg that Valvestorm.com sells. The technical info they have for it is: 22 AWG UL Style 1015 VW-1 105°C 600 Volts CSA TEW 105°C Wire

All the colors I'm using is just from their plexi amp wiring kit: http://valvestorm.com/Products/Wire

So the heaters are also 22awg stranded. But all the wire is pre-tinned, so there's no stray whiskers when you strip it.
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Re: New 36w Build Thread

Post by JMPGuitars »

Very nice work!

The wiring does look really good, but the heater wiring could create a noise issue (though it might not). For best results, heater wires need to be tightly wound, even up to the point of contact on the tube sockets.

According to Valve Wizard, apparently almost everybody supposedly wires the preamp tube heaters wrong. Here's what he says about that: http://www.valvewizard.co.uk/heater.html - scroll down to layout / lead dress and he shows 3 examples of preamp heater wiring.

I haven't tried his "better" way yet, but I will on my current build when I have time to continue with it.

BTW- I love the laces. Your patience and attention to detail on this build is pretty awesome.
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Re: New 36w Build Thread

Post by geoff 1965 »

Thank's for the valvestorm link glasstornado!
i'm impressed with their wiring kits but i'm U.K. based so it depends on the postage costs.the valve wizard site Josh posted has some good info as well and like Josh i'm tempted to try the "over tube" wiring method next time.there's a lot of different methods i.e. look at the fender blackface amps where the heater supply loops over from tube to tube and does'nt touch the chassis!
mine is a mess to look at "i lost patience" but ironically has no hum!
another way of reducing noise is to switch phase between the el84's,have a look at this "ampmaker" layout
p18it06.jpg
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Re: New 36w Build Thread

Post by WilliamBrama »

Awesome job, congrats!
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Re: New 36w Build Thread

Post by GlassTornado »

The wiring does look really good, but the heater wiring could create a noise issue (though it might not). For best results, heater wires need to be tightly wound, even up to the point of contact on the tube sockets.
I can totally see the benefits of doing the heaters that way for sure. From an EE (which I am not) perspective, I totally understand the benefits of it. The twisting of the wires is to eliminate hum and if you leave the ends untwisted near the sockets, it's essentially un-doing some of what your twists were doing. On the other hand there is a bit of the artist (which I am) that thinks there's a happy medium between ideal EE and elegant work. The "Marshall way" as I would put it might have it's flaws, but it's also what I like to see, I guess. I've also never had a hum issue with it up to this point. Nothing more/less noticeable than any other amp I play. My '77 Super Lead looks like they flopped the wire over once and called it good! hahaha. I would be very curious as well to try that method on a build to try and get some comparison. Is the juice worth the squeeze kind of thing. Thanks for the link. I tend to land on that page when I'm in the middle of builds and always forget about it.
another way of reducing noise is to switch phase between the el84's
The phase switching of the el84's is super interesting. I guess it makes a lot of sense that switching phase would cancel out potential noise. I feel like my other 36 watt would be a great test bed to go back and try both of these methods out. I've been playing it for a long time now. I know how it sounds and what it's noise floor is like. I'd be interested in pulling the heaters and re-doing them with twist to socket and phase swapping on the power tubes. This might be the first time you've ever heard someone say they WANTED to re-do heaters, folks!

Thanks again for all the helpful advice and kind words. I have two connections to finish the preamp sockets tonight. Oh, and I somehow forgot to order the 1.5k resistor for the mains cap, so the waiting game has begun...again. haha!
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Re: New 36w Build Thread

Post by GhengisKahn »

Morgan Jones in his book "Building Valve Amplifiers, " also recommends the top down filament wiring. I have used it for some time on many amps and it seems to work the best, keeping all unwound leads to the tubes short as possible. Some amps seem to have hum problems and some less so, some of it is tubes, maybe sometimes it's the transformers, but with a grounded center-tap on the filament winding, it's usually not much of a problem. EF86s are almost always more hum prone, especially when used as the 2nd stage in a 3 gain stage amp with no cathode follower. EF86s are noisier in general, it seems, but they also have gain and tone all their own and at volume, the hum and noise are completely swamped by the signal, so it can be worth it.
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Re: New 36w Build Thread

Post by geoff 1965 »

Yeah i've read the same about the EF86's tending to be a bit microphonic but they work well in the vox's and have a listen to Josh at JMP's amp! sounds great and very touch responsive.
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Re: New 36w Build Thread

Post by JMPGuitars »

geoff 1965 wrote:Yeah i've read the same about the EF86's tending to be a bit microphonic but they work well in the vox's and have a listen to Josh at JMP's amp! sounds great and very touch responsive.
Thanks. ;)

If you keep the amp build clean, and are careful in your tube selection, it's a lot easier to avoid the microphonics. My EF86 amps have the EF86 in the first stage, so I have no experience to share regarding other stages as he mentioned.

Theory is nice (in theory), but real world application is the only way to know what kind of noise you'll actually experience. There are some specific NOS EF86 tubes you can find with thicker glass (real RFT tubes for example) that are much less prone to microphonics than others. That's what I used on my combo version.
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Re: New 36w Build Thread

Post by geoff 1965 »

a couple more idea's ive seen regarding the EF86, one was a guy on youtube who mounted the tube socket on rubber gromets which he claims makes a big difference. the other is i recently bought a 1960's ex-royal air force amp on ebay for spares and all the components were absolute top quality! including 4 mullard ecc83's! and one thing i noticed was the cans that covered the preamp tubes were covered in a thick black matt paint which i'm sure is some kind of "screening" paint.
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Re: New 36w Build Thread

Post by JMPGuitars »

I use small rubber grommets too, sometimes. I did for the combo version. I don't know if it really makes a difference, but I figured it couldn't hurt.

I don't know if I would bother on my head version. I guess if they were in front of me within arms reach, but I wouldn't go down into my shop to get them if I forgot. ;)
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Re: New 36w Build Thread

Post by GlassTornado »

I really lucked out on my last 36w build. It's got an ef-86 channel and it's as quite/noisey as I would imagine one being. There doesn't seem to be any excessive noise and the tube I use (old national) seems to be just fine.

Sorry to be lax on the posts on here. I finally have this build up and running, but I have failed to take pics because I'm not done. I say that because the normal channel rips, but the trem channel is giving me grief.

I'm sure it's something dumb like a bad solder or whatever but when I have v3 plugged in for the trem channel, it makes crazy noises like a ray gun. When I pull the v3 tube and just run the normal channel it sounds like a million bucks.

Though I'm slowly working my way through it, have any of you guys had any crazy noises like that? Or any ideas on what to look for?
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