Nobelium - tube bass preamp project

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nobelium pronunciation: How to pronounce nobelium in German, English, Dutch, Danish, Finnish, Swedish, Azerbaijani, Czech, Interlingua, Luxembourgish, French

Pronunciation guide: Learn how to pronounce nobelium in German, English, Dutch, Danish, Finnish, Swedish, Azerbaijani, Czech, Interlingua, Luxembourgish, French with native pronunciation. nobelium translation and audio pronunciation
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I liked the Finnish "Know Belly Ohm"

French was good, very similar to the Azerbaijani pronunciation.


Interlingua, not so much.



However, since the e is followed by a single consonant and then another vowel, shouldn't the e be long?

"No BEEEEEEE liam"
 
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vigilante398 said:
Just realized I missed this question, sorry about that. People on the interwebs are divided on the max current of the NE555-based SMPS, I've seen numbers as high as 40mA, but I don't think it's that high. The most I've ever pulled from one (on purpose) was around 20mA, so I'm not sure what the max is. But fortunately we're not running the 12AU7 anywhere near their max, so they're not pulling the full current that they're capable of as an amplifier.
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Would a 555 SMPS be able to run a JJ EL844 single ended? I might just be reading the datasheet wrong but I just discovered these earlier this week and that nominal 10 ma plate looks promising. I was trying to math out if it could be run off MAX1771s but I didn't know 555s could go that high.
 
Dysvalence said:
Would a 555 SMPS be able to run a JJ EL844 single ended? I might just be reading the datasheet wrong but I just discovered these earlier this week and that nominal 10 ma plate looks promising. I was trying to math out if it could be run off MAX1771s but I didn't know 555s could go that high.
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I don't think so, EL84 plate current is 48mA in single ended pentode configuration. I don't think you would damage anything by trying it, but I would admittedly be surprised if it worked.
 
vigilante398 said:
I don't think so, EL84 plate current is 48mA in single ended pentode configuration. I don't think you would damage anything by trying it, but I would admittedly be surprised if it worked.
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I'm not sure I get it, wouldn't 844s draw less than an 84 in the same configuration?
 
Dysvalence said:
I'm not sure I get it, wouldn't 844s draw less than an 84 in the same configuration?
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owlexifry said:
interesting....



looking at these datasheets: 844 draws 10ma, 84 draws 48ma
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Oh I misread that, I'm not familiar with the EL844, I just assumed you had said EL84. Looking at the EL844 datasheet it looks like it could be doable with the NE555 SMPS.
 
602e7400-4ed5-4b1c-937b-97296a104d8b-jpeg.60168


Mine came in with a few extra goodies that I couldn't fit into my last Sushi-C2CE order's budget.

The faceplate is WAAAYYYYYAHAYYYY better in person than mere photos can convey. 😻

I've got tube sockets, at least one 12AU7, but will undoubtedly need to order more at this point, if I want to finish all these tubers up.
Yet to order the transformer, too.


Oh, and I couldn't resist throwing on my favourite knobs from my private stash of NOS parts I gleaned from an HK shop that just wanted them all gone.
Now that they're on there, I'm not sure if the gloss-knobs go with the flat-black face-plate. Might have to go with different knobs *gasp*, or even more drastic
might have to forgo the face-plate! *gasp gasp* !


Thank you, @vigilante398, for making this circuit available to us.
 
jrhevron said:
Okay... really want this one! @Feral Feline how will you know how to put it together? Just waiting for the schematic?

Also... any idea what your total cost is?
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I have all the pictures for the build doc, I'm hoping to find time this weekend to get it put together. But honestly if you've built a couple of my pedals this one should be pretty intuitive to assemble.
 
I took your advice and mounted the transformer first. I don’t have much experience with them so i treated it like I was soldering an ic directly to a board. 2-3 seconds of heat on a pin and waiting 10-15 seconds before moving to the another pin. I pre-threaded the xlr jack with some 3mm machine screws then mounted it to the enclosure. I then mated it with the board and was able to flip the enclosure on its side and solder the xlr jack with plenty of room to get to it. I then took it off and did the same for the switch. Everything else was just like your others, slow and steady wins the race. I also agree that the xlr/transformer board seems to be really sturdy with just the two screws. I was pleasantly surprised.
 
jrhevron said:
Okay... really want this one! @Feral Feline how will you know how to put it together? Just waiting for the schematic?

Also... any idea what your total cost is?
Click to expand...
No idea what total cost will be. I doubt I'll keep a tally, either; this one is a keeper just for me. Whatever the cost, I bet it's still cheaper than for me to buy one used, even. Then there's the satisfaction of tackling the build...
 
What about putting a some kind of dense foam or something to support that board against the other one? And can you fit a nut on those screws? Or maybe it’s ok as is?

IMG_9229.jpeg
 
Honestly its pretty sturdy with just the two screws. You could probably get a nut on one of the screws but i am not sure about the second one. The xlr jack has a metal strip that actually goes through one of the holes and connects it to a ground. Because of the strip i am not sure you can get a nut on that side. I havent tried it though. I did think about some foam. I build an install pickups a lot and thought about using some of the pickup mounting foam. Once again though at this point it seems pretty sturdy so i am not going to worry about it. Unless you are flipping the ground lift switch all the time i doubt you would ever remotely have an issue. Also if you do want to mount some foam it would only really need to behind the switch itself. That is the weakest point but as i said after putting it together I really don't think it would be necessary.
 
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@vigilante398 I'm going to assume that the dot on the LBA transformer matches up to the dot on the pcb, am I right in assuming that? Also, would I be correct in assuming that the xlr board wires line up top and bottom with the main board pins? As stuff trickles in for this I plan on testing before boxing so just wanna make sure I have it right since the build doc isn't up yet.
 
Guardians of the analog said:
@vigilante398 I'm going to assume that the dot on the LBA transformer matches up to the dot on the pcb, am I right in assuming that? Also, would I be correct in assuming that the xlr board wires line up top and bottom with the main board pins? As stuff trickles in for this I plan on testing before boxing so just wanna make sure I have it right since the build doc isn't up yet.
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Correct on all counts. The dot on the transformer casing lines up with the dot on the PCB (also the case for the Jensen, but it sounds like most people are going with LBA) and the pads for the XLR daughter board line up top and bottom with the main board pads.

I have all the pictures for the build doc, just need to get it put together now. I'll try to get to it this week.
 
vigilante398 said:
Correct on all counts. The dot on the transformer casing lines up with the dot on the PCB (also the case for the Jensen, but it sounds like most people are going with LBA) and the pads for the XLR daughter board line up top and bottom with the main board pads.

I have all the pictures for the build doc, just need to get it put together now. I'll try to get to it this week.
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Awesome, I'll be good from here on out. Now I wait on tayda drilling 😑⌛
 
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