String Ringer build.

[digi2t]

can anyone advise if the BC549c  is specific requirement?

  or can any bc549 do?

  i have 3 x bc549c ,

heaps of bc549b,

and a couple that say bc549?

Try 2N5089. Just watch the pinout.

[njkmonty]

so your first preference is 2N5089 ?
I know smallbear has a few  bc549c's left

[digi2t]

so your first preference is 2N5089 ?
I know smallbear has a few  bc549c's left

I built mine with bc549c`s, only because they were spec`d, and the result was already validated. Besides, I wasn`t in any rush. On the other hand, looking at the spec`s 2N5089`s will probably do the job just fine. High gain, low noise.

What the hell man, have some fun with it! That`s what sockets are for.

[Vince_b]

I'm currently building a String Ringer and I have almost finished populating the board but I have a question about one of the components. Does C20 (2,2 uF between blend and volume pot on the board) has to be non-polarized? Otherwise what should be the orientation?

[Strategy]

I have been building mine for ages and adding a few more parts to an order. I also have some parts questions on this project:

- 2200k resistor. Same as 2.2M???

- 460 ohm resistor. I cannot find this in Mouser!!! is this a hard to find value?

thanks!!!
STRATEGY

[garcho]

Strategy, you need a E192 resistor for that value.

Regarding big NP caps:

From R.G.:

You can make a quick and dirty NP cap by tying together the negatives of two equal-sized polar caps.

In the series-NP connection, the capacitance value is funny. Normally caps in series are a smaller capacitance than either cap by itself. If you had two 3.3uF polyester caps, then the expected value for two of them in series is 1.65uF. However, electrolytic caps actually conduct in the reverse direction, so two 3.3uF polarized aluminum electrolytic caps act like they each have a diode in parallel with them that conducts when the voltage is backwards for that one cap. So two 3.3uF caps hooked up as series non polar (i.e. negative to negative) look like a single 3.3uF NP cap.

[Strategy]

E192? 

thanks Garcho any more explanation appreciated 

Strategy, you need a E192 resistor for that value.

[digi2t]

I have been building mine for ages and adding a few more parts to an order. I also have some parts questions on this project:

- 2200k resistor. Same as 2.2M???

- 460 ohm resistor. I cannot find this in Mouser!!! is this a hard to find value?

thanks!!!
STRATEGY

2.2M is correct.

If memory serves me correctly, I used 470 ohm. Seemed to work fine for me.

[Strategy]

thanks digi2t and garcho! string ringer strategy build inches forward!

I have been building mine for ages and adding a few more parts to an order. I also have some parts questions on this project:

- 2200k resistor. Same as 2.2M???

- 460 ohm resistor. I cannot find this in Mouser!!! is this a hard to find value?

thanks!!!
STRATEGY

2.2M is correct.

If memory serves me correctly, I used 470 ohm. Seemed to work fine for me.

[garcho]

It's the 'preferred number' system, from manufacturing. A resistor with 10% tolerance is in the 'E12' series of values (5k6, 6k8, 8k2, etc.). The 5% resistors are of the E24 series of values, 1% are E48, etc. For a 459 Ohm resistor, you need E192. I think that's only available in SMD. I think it's also 'military' grade, or as I like to call it, 'life or death' grade, so it will be unavailable or expensive.

Read up on resistor values here.

[LaceSensor]

470r is fine
You can get the 2.2uF as np if you look around.

[digi2t]

It's the 'preferred number' system, from manufacturing. A resistor with 10% tolerance is in the 'E12' series of values (5k6, 6k8, 8k2, etc.). The 5% resistors are of the E24 series of values, 1% are E48, etc. For a 459 Ohm resistor, you need E192. I think that's only available in SMD. I think it's also 'military' grade, or as I like to call it, 'life or death' grade, so it will be unavailable or expensive.

Read up on resistor values here.

Thanks for the link. Going to bed less stoopid tonight.

[Strategy]

Sorry to bump and older thread but I suspect i am not the only one with an 85% complete String Ringer on the bench? 

I have a puzzle with the transformers I received, I think they're LT44's (from the recommended ebay seller who sells matched xfm and diode sets for this sort of project).

On the build docs, the "P" side of the xfm has 2 legs and the "S" side 3.
On the xfm's I received, the "P" side has 3 legs and the "S" side has 3 legs - the middle one having been cut short on both xfms.

I just want to be sure I don't have a goof with the parts - haven't done a lot of projects with these little transformers. Should I trim out the middle leg on the "P" side of the ones I received? Anyone encounter this with the transformers they got? Possible that I have the wrong parts?

thanks much for anyone who can help.
Strategy

[digi2t]

Here's an LT44 diagram;



Primary = 2 leads.
Secondary = 3 leads.

Which begs the question; What have you got? 

[Strategy]

Yeah I'm thinking I've got a wrong part, I'll double check when I get back to the studio later. Thanks for posting that!

[digi2t]

Yeah I'm thinking I've got a wrong part, I'll double check when I get back to the studio later. Thanks for posting that!

No problemo amigo.

[Strategy]

I can't remember the part number now..maybe LT117 or smething...these are definitely not LT44's!
Anyone know of a consistent source? having trouble finding.

[digi2t]

This is the kit that I bought, from this dealer. It's what is in my ringer.

http://www.ebay.ca/itm/2X-LT44-Transformer-and-4-X-BAT48-Schottky-Diodes-Ring-Modulator-Kit-Of-Parts-/121233210635?pt=UK_Sound_Vision_Other&hash=item1c3a0ffd0b

[Strategy]

Yep that's the seller I ordered from, same Ebay entry. I'll write them and see what's up.
Strategy

[digi2t]

Yep that's the seller I ordered from, same Ebay entry. I'll write them and see what's up.
Strategy

Weird.

Yup, I would send a message pronto, send him a photo of what you got as well. I'm sure it was a muck up somewhere on their end. That guy's been dealing those kits for a long time now, he should be receptive to correcting the situation.