My first tube project help thread (NYD one bottle)

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buildafriend

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This is a thread for a new-to-tubes builder who is making a NYD 1 bottle. 

I am sorry for the annoying and idiotic questions that I must ask.. Unfortunately it's all part of my learning curve.

A friend of mine designed a PCB for this project that is designed to mount in a classic style chassis and I am currently in the troubleshooting stage of the build.

Page 4 will show you where I currently stand with this.

This site is amazing! LONG LIVE G-DIY!!!





 
I haven't built this yet. My understanding is the output transformer is *optional depending on what input you are driving. (balanced/unbalanced and what impedence.) AFAIK, the prototype did include an output transformer.
 
Note to self from NYD:

"Any well-filtered 300V supply capable of 7mA or more will do. Here's what I put together--it's pictured next to the preamp. The parts choices were driven mostly by what I happened to have laying around."

But where do I find a schematic for this?
 
I'd highly recommend putting in some reading time on tube basics.  One of the best places to start are the Naval (NEETS) training manuals.

Module 6 is the one to start with.  Covers basics and power supplies.  Easy and clear to read.

http://www.tpub.com/neets/
 
Blue Jinn said:
I haven't built this yet. My understanding is the output transformer is *optional depending on what input you are driving. (balanced/unbalanced and what impedence.) AFAIK, the prototype did include an output transformer.

the original NYD 1b was unbalanced 10k output, no transformer.

The output can be unbalanced 10k, if you're driving 10K inputs or higher, and you aren't driving more than say, 25' of cable.
 
...and what you see in NYD's original photo was one preamp and one power supply. He built them into separate enclosures, with big terminals blocks so he could wire up additional modules.
 
PSS

read up.

http://valvewizard.co.uk/

There's a pretty good starting point, which helped me when I first dove into guitar amps (basically the same with some minor differences which you will learn about as you go)

Learn the different topology, what they're good for, benifits, limitations, etc. When you learn them well, you'll see that the NYD 1B is two triode plate output voltage gain stages with variable negative feedback to control the overall gain.

Use this site to look up very basic tube data:

http://www.nj7p.org/Tube.php

Just punch in 12av7 and compare to a 12ax7, 12au7, etc... specifically, note the max power dissipation rating for each type... preamp (voltage gain) tubes have low power dissipation, power tubes (output stages) have more, but less voltage gain.

Good luck! and don't fry yourself! always keep one hand in your back pocket when you're working around tube voltages... that way it's less likely to travel through your heart... Just a quick zapppp....
 
There are a couple of PSU schematics floating around, I think on the twin-x site. Also a tag board layout. PM me and I can send you the files.  I'm pretty sure (and others can correct me if I'm wrong) that the PSU for the MILA-1 can be used for this one.  The PSU itself is fairly conventional,  you're looking for a B+ of 300V. For Gemini, I'm pretty sure I read somewhere about using a 5:1 or 4:1 on the output, I had incorrectly believed the inputs I'd be driving with this were 10k so I was worried about that. I have the tubes and one tag board, and a power transformer, and most of the caps. Now I just need to buy and/or fish out of the box the correct resistors. Also, I have an order in for more time....
 
link to a pic of the original NYD psu:

http://i261.photobucket.com/albums/ii49/aaronmoore82/NYDpsu_p01.jpg

the link should work, but if not, go to the NYD one-bottle thread, and use the forum search engine for "NYD PSU". I built my pair with this PSU (some values changed for feeding 2), and had some hum. moving layout around fixed most of it, but when I crack the chassis next time, I'm going to try a rebuild with more filtering. However, this PSU works fine, and the hum is really only evident at highest gain settings.

Re: input tx - cinemag is great... any reason that you're using the CMMI 7 instead of the CMMI 10? Strikes me that the higher step up should give some free gain, which could be handy if you decide to add an output tx.

Re: output tx - I used one (a gapped carnhill 9600:600 from audiomaintenance - I like it). The original NYD build didn't. The result of having one is less overall gain, but you can plug your one-bottle into whatever without reservations. Also, colouration can be fun. I think that max gain with an output tx was around 36db. Despite what I thought at the time, that's hasn't been an issue.

Re: reading - do lots of it. Read the NEETS stuff, read RDH, and most importantly, read up on how to safely work on tube gear. I've done a couple of tube builds, and I still go over safe working habits every time I think about opening anything.  300 VDC = no second chances.

Also, it's probably worth it to re-read the original one-bottle thread through. It meanders, but there's a lot of good info in there, and I'm pretty sure that eventually there's a revised schem that has an output tx, a DI point, and some different (optimized) parts values. A lot of it is stuff that many folks on here could (and did) figure out themselves, but I was definitely happy to have it on paper in front of me. 
 
JAB... thanks for locating the PSU schem...

I had not saved it to my PC after all... likely because it's a by-the-book design.

buildafriend, if you're doing a PCB, I recommend NOT running any AC heater lines. Just wire it up by hand with a tightly twisted pair. Other than that a heavily filtered DC supply is needed, and some sort of regulation would be needed to keep the voltage where it needs to be. (zener dump, some series diodes, etc whatever works) Or just rip the heater supply straight out of the G9 schematic. I doubt you're going to get that much benefit out of DC heaters, so save the headache, K.I.S.S., and wire AC heaters by hand.

 
output tx - I used one (a gapped carnhill 9600:600 from audiomaintenance - I like it). The original NYD build didn't. 

Gapped for cap coupled output stage?  Was this the Carnhill designed for SE direct coupled output?
 
Blue Jinn said:
the PSU for the MILA-1 can be used for this one.

Yeah. Find MILA-1 schematic. The PSU is perfectly compatible with this project as well, for 1-2 channels.

Also see MILA-1 for the output transformer configuration. I wouldn't play with any gapped transformers here. the project wasn't designed for it and you're wasting the potential of that transformer. I'm not sure if that Carnhill transformer will pass enough current in a real SE configuration (using the transformer directly on the plate, replacing plate resistor).

On the other hand, any 10k/600ohm (roughly 4:1) output transformer is optimal here, using the cap coupling shown in MILA-1 schematic. Cinemag has a really good one, and Edcor has a couple of good choices too. I would recommend using the 1:10 Cinemag input transformer for this project. 1:7 is ok, but the input can handle even bigger step up.
 
How do you guys feel about the sowter 9735 as an input transformer? Is it ideal or sufficient?

Here is the basic info:
http://www.sowter.co.uk/cgi-bin/sh000001.pl?REFPAGE=http%3a%2f%2fwww%2esowter%2eco%2euk%2facatalog%2fsearch%2ehtml&WD=9735&PN=SOWTER_TRANSFORMERS_PRO_VINTAGE_TRANSFORMERS_5%2ehtml%23a279#a279

Here is the schematic:
http://www.sowter.co.uk/schematics/Ampex%20351%20input%209735.pdf

I have never had to purchase tube sockets before, will a GE5965A fit in this tube socket:
http://www.smallbearelec.com/Detail.bok?no=148






 
I should clarify about the gapped output tx; I had ordered it thinking I may do some experimenting with the output, and then I had some misgivings similar to what Kingston mentioned, and just cap-coupled and threw the gapped iron in after the cap. As Lassoharp hinted, not ideal, kind of a waste, but ultimately, I used what I had, and the sound is pretty damned good. For anyone else, I agree that there is absolutely no reason to use a gapped output tx.  sorry for any confusion this may have caused.

buildafriend - 
that sowter looks like it would work. Why that model?
the tube socket you linked should be fine.
You may also want to check
http://www.tubesandmore.com/
They have pretty much everything but the transformers for this project. It will save you $ to ship from one supplier.

you mentioned 5965 tubes... why? None of the data I've seen on them suggests that they're  direct replacements for 12AV7. Could be wrong though...


 
ah, cool, those do look pretty close. Thanks for the links.

Did some re-reading in the original thread, and it looks like these work pretty well in the one-bottle, although some people found them noisier than 12aV7. 

 
data sheet says it's meant for "on-off" control, or switching, involving long cutoff time periods. Doesn't mention audio use, so it's likely not designed for it.

12at7 may be a good sub also.

gain of about 60, 2.5watts dissipation.
 
Oh look at that, I almost grabbed a bad sub. I'll just grab RCA 12AV7's. I like small bear because they are near me and drop stuff off right here personally. Community! I am going with the sowter input xfrmr, and I want to use all military metal resistors and high end axial caps.
 
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