Lots of G9 parts questions for the newbie - pre parts order.

[R. Weiss]

First off, I will state that the below questions are things your average, fresh out of the box novice will probably be wondering when first attempting this project (That being the G9 dual mic tube preamp based off of Jakob's website: http://www.gyraf.dk/gy_pd/g9/g9pd.htm). I myself am extremely new to this science and this community. So far I've very much appreciated all of the advice given to me, and all that I've learned from others. My PCBs from Gustav should be here shortly, and I'm about to place an order with DigiKey for the majority of the components. I am following Paul Stephan's parts list (http://home.houston.rr.com/lpstephan/G9parts.xls), and have a pretty decent list of questions before I place this order. I've been sitting here all day (no, really, 10am to, currently, 2am) looking up all of these parts, and rounding up all of these questions. As I mentioned, I'm pretty new to electronics, and have very vague ideas as to what some of the components do, and what purposes they serve in this particular project. I have read over all of the threads in the G9 meta, and have come up with some "unique" questions below. Hopefully this thread can serve as a helpful starting point for the newbie G9 DIY'er. I've also titled each question for faster referencing for future enthusiasts. You may laugh at the possibility of some of these questions seeming so "dumb", but to newbies like me, they really are foreign.

Many of the parts shown on Paul's list (majority from DigiKey) no longer exist at DigiKey. I have listed these changes, and once I get everything situated and the order made, I will post an updated list (with alternative sources) on my site for all of the obsolete items. There are also many price updates that need to be made.

So, without futher ado, the questions...


POWER TRANSFORMERS
(1) On the list, there's 2 choices for power transformers (#48 and #49). I believe the one listed with 15V 2.332A is for the US 110V mains supply, while the other (30V 1A) is European. Am I correct in assuming this?

MOUNTING SPACERS
(2) The spacers for mounting the PCB are listed as 3mm (Is this the depth?), but how wide should they be with reference to the screw holes on the PCB itself? And do these spacers normally come with the mounting screws, or should I pick them up at the local Radio Shack?

TOROID MOUNTING HARDWARE
(3) Jakob's list say that I need "hardware for mounting the toroids" (toroids being the power transformers, those big round wound up mounds of copper that look like donuts, for the newbie). What hardware do I need to get? Does he just mean a long bolt to go through both toroids into the chassis underneath?

FRONT PANEL POWER LED HOLDER
(4) Jakob also says to get a front panel light holder for the power led (LA1). Is this necessary, or do most of you just drill a hole for the led and stick it through?

ISOLATION SETS
(5) What exactly are the "TO-220 isolation sets for PSU regulators" (I think I would need TO-110 for US mains?), and where could I get ones suitable for them?

THE FUSE
(6) Paul's list doesn't have the fuse that Jakob's does (F1). This WON'T come with the "fuseholder" IEC connector I am buying, right (DigiKey #Q202-ND)? So it would be necessary to buy it seperately? If so, do I need a specific fuse with a specific size and voltage rating?

10K 48V TRIMMER
(7) What purpose does the 10k trimmer (PR1) serve? It says "Trim 48V", but, in lamen's terms, what does it do? I am guessing it is something external on the back of the chassis that is used to "adjust" the phantom power to reach exactly 48 volts, something I will need to gauge with my multimeter, or am I wrong?

LINE SELECT RELAYS
(8) What do the "line select" relays do (RY1, 101), and which ones do I need? Are they something external on the casing that I can control, or totally internal? Quoting "uk03878" in another thread, he says "The parts list says 12V 2xCO RELAY - What this means is 2 lots of a 'change over' relay e.g. DPCO [Double pole change over] or DPDT [Double pole double throw]". Unfortunately, this does not help the newbie DIY'er locate what relays he will need. There are many different results when searching for "12v change over relay". Could someone please clear this up for me?

HEATSINKS
(9) Heatsinks. There's lots of them, but I don't feel comfortable in assuming which ones I'll need (for IC1, IC2 specifically). What would be suitable for these two regulators, and am going to need something of a specific size in order to fit into that area?

ROTARY SWITCHES
(10) Could someone please explain how the rotary switches work, as far as poles and positions go? What does "2-6 position" or "2-12 position" mean? Obviously they're suggesting 6 and 12 turning positions, but what does the 2 pole mean? This is a part of the panel which I plan on customizing (wanting to seperate the 48v phantom power from the rotary switch to a single pushbutton), so I feel I need a better grasp on them before I do that. Also, are all of the rotary switch "poles" (referring to the things that stick out on them) 1/4" wide, so that any "1/4 inch" knobs I buy will definately fit onto them? Do these so-called "poles" have to be a certain length?

Okay... take a break... *cracks fingers*
On we go...

CAPACITOR MOUNTING COLLARS
(11) What are the cap mount collars for, and what purpose do they serve? (parts list item #19)?

PANEL JACKS
(12) What do the panel jacks do, the "2-conn" and switched ones (#26, #27)? Are these just the 1/4" instrument inputs I'm going to be putting on the front panel? Also, on the list it says "(option -inst out)" for #27, the 2-conn panel jack. Does this mean it's completely optional. Could someone shed some light on what purpose it would serve?

CAPACITOR SWITCHUP?
(13) On Jakob's list, it lists caps C12 and C112 as 63V, but on Paul's list he has them at 100V. Is this intentional, or detrimental in any way?

POWER SWITCH
(14) I've read that the Lorlin mains power switch (SW5) is "too weak" for this application. Is this a myth, or would I better off getting something "stronger" (how so?)?

CONNECTORS
(15) On Paul's list, there's a bunch of connectors without a source (#37-#41). The first three have voltage and size specifitions, but the other two (#40, #41) do not. What kind of connectors should I use, or does it not matter? I'm sure they'd have to be of a certain size to match the PCB holes, no?

WIRING
(16) Wire. Hookup wire. Stranded. Solid. Gauge. What the heck am I going to need for this project. I realize this question is very vague, as looking at some pictures ( http://img.photobucket.com/albums/v359/zee1usa/G9/HeatsinkG91.jpg and http://img.photobucket.com/albums/v359/zee1usa/G9/HeatsinkG92.jpg - thanks to Zee1usa!) I see tons of different wire. Would it be possible for someone to walk us newbies through what kind of wire is necessary for each section, possibly all of them? The lists don't suggest which wire to use, and, seeing as how this is my first project and I don't have any wire, I am pretty much in the dark here.


You did it! That's it!
First let me apologize for the length of this, and if you sat there and read it all, many thanks to you. I'm hoping at least a few of these can be answered so myself and others may be able to source our parts in confidence, and hopefully get a grasp of what they do before we stare at them under a magnifying glass for hours!


Okay, it's almost 3am, goodnight.

Thanks again,
Ryan

 

[Skylar]

Well, it's 2am here, so I'll answer as many questions as I can at this hour.

First, have a look at an updated spreadsheet that I have compiled here:

http://www.groupdiy.com/index.php?topic=14031

Keep in mind that I went kind of overboard on some of the components, so a lot of money can be saved using lower priced/lower quality parts (OEP xformers, cheaper knobs, cheaper caps, etc). I recommend using Mouser as your primary supplier--their selection is larger, and their search engine is waaaay better.

(1) The power transformers I have on my list will work fine. You will have to take a look the datasheet for these xformers for info on how they should be wired. When I actuallly get mine finished, I will try to put together a (US) power transformer wiring guide for the G9.

(2) 3mm is likely the height. I say stick with the spacers on my sheet. You will need to buy 6/32 screws for these.

(3) The toroids will come with the mounting hardware you need (bolt, rubber spacer, and metal plate)

(4) Typically, you'll want some kind of mounting hardware for your LED/lamp for aesthetics. I used a guitar amp jewel for my indicator. Using an LED with mounting hardware will save money.

(5) This is a voltage regulator. The idea is that your mains power supply will supply more voltage than what is necessary. The voltage regulators will kick in and bring the voltage down to the proper level for the circuit.

(6) Get a fused IEC connector (it's on my sheet) and 10A 250V fuse--size GMA (5x20mm).

(7) The voltage through the trimmer will likely be more than 48V. Measure the voltage across the trimpot with a multimeter, then turn the trimpot until your voltage is 48V.

(8) this'll take time to explain...skipping this one for now, sorry

(9) The heatsinks on my list for IC1 & T1 are really too big--Best to go with something smaller. The heatsink for IC2, though, is a good size, but it needs a hole drilled thru the middle for mounting.

(10) lengthy explanation...skipping this too...for now I can say that it's easier than you think.

(11) Your filter caps C14/C15 will be large in physical dimension. These will not be mounted to the circuit board, but must be mounted somewhere...the chassis...with mounts/clamps. If you use the ones on my list, turn the caps upside-down, put the clamps around them, and bolt them to the bottom of the chassis.

(12) skip

(13) In most cases, you can use caps rated at higher voltages than what the BOM/Schematic calls for. The point in the circuit that calls for the 63V cap probably has at least 48V running through it (for phantom), so you'll need a cap that can handle at least that much voltage. 63V can handle it...100v definitely can. But beware of using too high of voltages as tolerances begin to increase as voltage increases.

Sorry, that's all I've got for you tonite. I'm sure others will help with the rest and/or correct any of my mistakes.

 

[R. Weiss]

Holy cow! Don't know how I could've missed that updated parts list thread! ...That helps a TON!

As for your answers, thank you! They were VERY helpful. (Though I may look for some cheaper parts elsewhere, your list helps figure out what I will need immensely). In reference to the expensive WIMA caps you've chosen... are these going to make a huge difference in sonic quality, or can I afford to save a few dollars on the ones Stephan has without regretting it? Also, I'm still not sure which power trafo's are for a 110V source. You say you are going to write up a US wiring guide, and I see you are in Oklahoma, so is everything on your list (e.g. the 30VA 15v+15v tranformers) suited for a 110V mains? I'll compare lists and ponder your answers a bit more. Will hopefully get to place some orders today!

Thanks a lot Skylar,
Ryan

 

[R. Weiss]

Another one...

I found what I think are the same tubes that Triode is offering at Allied for a lot cheaper. The Triode part# is 12au7jjmp ($19.90 each!), and the Allied number is 866-0053 ($11.30 each). Unfortunately, Allied says they only have one left in stock, which may even be gone. I'd still like to know if this is the same thing as the Triode ones, if anyone knows.

Thanks,
Ryan

 

[Skylar]

The power transformers that I got from parts express will work for both 110v and 220v, depending upon whether you wire the primaries in series or parallel. I have already made a diagram, but I am hesitant to post it until I have fully built my G9 and troubleshot the unit to confirm that my wiring is accurate [right now I'm waiting for a new soldering station I ordered before I can continue]. And yes, everything on my list is suited for US 110v mains.

From what I have heard, folks around here really dig the WIMA sound. I went with WIMA 'cause Jakob recommended them...and he's the man. But there's no reason not to use cheaper caps--the difference is bound to be slight.

Actually, the $19.90 price is for two matched tubes--and I bought 2 matched pairs (4 tubes). So, the price-per-tube is more like $9.95.

 

[alk509]

[quote author="R. Weiss"]The Triode part# is 12au7jjmp ($19.90 each!)[/quote]

That's $19.90 for a matched pair (that is, two tubes with very similar electrical characteristics). Anyway, AES has the same tube (JJ brand 12AU7) for less than 9 bucks.

About caps: Caps are relatively cheap components. You really owe it to yourself to buy a few diffrerent brands and listen to them in circuit. Some time ago, I posted a real eye(ear)-opening test you can do: put some Solen caps in one channel, and Orange Drops in the other. That will give you a good idea of the kinds of sonic differences caps can make.

About toroid transformers: remember to use a nylon (or otherwise non-magnetic/non-conductive) bolt for safety.

Good luck!

Peace,
Al.

 

[R. Weiss]

Hmm, I realized they came in pairs on Triode's site, and I was assuming Allied's were too because they say "twin triode" in the description. I took this to mean a quantity of two, but I now realize it means something else...

I'll be getting the matched pair from Triode, thanks guys.


I'm boiling down to some last questions here... Another full day of parts sourcing, and I'm almost finished.


a) Do I need to subsitute the relays for RY1/101 if I only want two line dial options (just "MIC - LINE"). I'd rather integrate the phantom power seperately as a pushbutton. I can probably figure out the push button thing, but what relays could I substitute for RY1 and RY101 to offer only two options?

b) I'm getting C14 and C15 from DigiKey (P5938-ND - $7 cheaper than Triode). I think if I do this, I'll need different sized mounting collars than the ones you have on your parts list for the caps from Triode, right? These caps at DigiKey don't have a spec sheet... does anyone know what mounting collars I need, or would I just be better off using the more expensive caps from Triode (seeing as how these are your most expensive caps, maybe they sound a lot better?)?

c) Farnell is out of the OEP screening caps. Digikey, Allied, Mouser, PartsExpress, and Triode don't have them. Any other ideas where I could look?

d) Mouser is out of the 2-position terminal blocks (158-P02EK500A2-E). I looked around, but am not positive of which ones I need and what kind of affect the different specs might have. Does it really matter? ...Can I just use any 2-position, 5MM terminal block?

Thanks... again...
Ryan

 

[Skylar]

Ryan,

A) If you're a beginner, my recommendation is to not change the circuit too much. This is already kind of a rough first project. Ya know, high voltages and all.

B) The C14/C15 caps are filter caps for the power supply and are not in the tone circuit. So, these caps won't affect the tone of the pre per-se. Their purpose is to smooth out the voltage output of the power supply, which can have a pulsating quality otherwise. If you want to save money here, I advise getting some cheaper caps like Nichicon VR series [Mouser 647-UVR2E101MHD or Digikey 493-1196-ND].

C) I don't know of another place to get the OEP screening cans other than overseas. Maybe someone else knows...

D) Now that you mention it, the terminal blocks on my list don't fit very well on the PCB. This is because I got blocks that had a 35 degree angle on the connectors, hence a bigger footprint. The best idea is to use 158-P02ELK508V2-E and 158-P02ELK508V3-E for 2 and 3 position respectively. If these are out of stock, just make sure the footprint on the terminal blocks you buy are 8mm or smaller.

 

[R. Weiss]

What would I do without you Skylar?

I've got the Nichocon caps from Mouser, and the suitable terminal blocks. For these different cap types, am I going to need a different size/kind of mounting collar?

And about the switch, it's really the only thing I want to change; the only challenge... I will most likely be able to work this out without getting myself killed, but it is possible to do right, change the 2-6 pos switch to a 2-4 (I think?) and then just run the wiring for a seperate pushbutton off the 48v line?


I think I'm going to place some orders now. Got most of the sources complete, thanks to Skylar and Al. Ordered the chassis earlier today, and the PCB should be here soon. And my Fluke 73III multimeter just got here. :grin: I'll let you know how things go.

Thanks,
Ryan

 

[R. Weiss]

OEP A262 screening caps available at Canford:

http://www.canford.co.uk/commerce/item_23-055_2003831.aspx

 

[R. Weiss]

Heyas, I just got the tubes in from Triode. I ordered a quantity of TWO on their website, and I recieved 2. The website (and you guys) say that is for a matched pair. So shouldn't I have recieved FOUR total? (2 orders of 2 matched pairs?)

Thoughts?

Ryan

 

[Skylar]

I had the same problem when I ordered from them a couple weeks ago. They said that they were training new employees which is why there was a mix-up. Seems strange that they're still screwing up orders for these tubes even after two weeks of training....

You'll probably just have to call them and sort the issue out. I contacted them, and they straightened everything out for me. Good luck.

 

[R. Weiss]

Yeah, gave them a quick phone call yesterday and they shipped 2 more, no questions asked.

Thanks,
Ryan

 

[peritus]

How's it comin' guys? That price list is beautiful Sky.... Cool stuff..

Thanks

 

[Svart]

I usually order Polyester caps, switches, pots and resistors from Mouser, much cheaper. I then order the toroids and electrolytics from Digikey.

I built my G9 for around 400$ or so. I used OEP trafos though. Using lundahls would have jacked the price considerably.

 

[Whoops]

WIRING
(16) Wire. Hookup wire. Stranded. Solid. Gauge. What the heck am I going to need for this project. I realize this question is very vague, as looking at some pictures ( http://img.photobucket.com/albums/v359/zee1usa/G9/HeatsinkG91.jpg and http://img.photobucket.com/albums/v359/zee1usa/G9/HeatsinkG92.jpg - thanks to Zee1usa!) I see tons of different wire. Would it be possible for someone to walk us newbies through what kind of wire is necessary for each section, possibly all of them? The lists don't suggest which wire to use, and, seeing as how this is my first project and I don't have any wire, I am pretty much in the dark here.

Can someone please answer this???

Thanks

 

[michal_k]

Ok, I'll try to answer this one. So, it doesn't really matter what kind of wire you use as long as you will not exceed maximum amperage for a diameter. That should give you any idea of amperage ratings:
http://www.ilsco.com/newweb/IlscoHome.nsf/Web+Pages/Wire+Amperage+Rating+Chart
Usually you don't have to worry about amerage of your wires unless you wire heaters for a larger amount of tubes(if you use some bigger power tubes you may have even a few ampers flowing in your wires). If you're not sure if the wire has a correct diameter just check if it's getting hot. If not, everything is fine

Now, solid vs stranded wire. Solid wire is much easier to bend, I mean that if you bend it for the right angle, for nice look for example , it's gonna stay like that. It's going to be much more difficult wih stranded wire, but on the other hand stranded wire is much less prone to be broken.
As far as I'm concerned I use solid wire if I know i won't be moving or straining it any way - for me it's easier to work with, and I use stranded wire if I need to connect some parts that aren't firmly connected to enclosure or if I know that project will need a lot of debugging and moving pcb's and so on.

Also I think that if you use some kind of connectors(molex for example) stranded wire is the way to go. 

You may also want to use shielded wire to connect your inputs with first stages of your device. You can see a shielded wire on the pictures you pasted. It's the thick grey one. It consist of a main wire and a shield, for best results you want to connect one side of that shield to the ground.

hope it helps a bit

michal