Firefly layout

[tubenit]

Here is a version I made up for no apparent reason. For a complete chassis layout, the diyguitarist has one under 'guitar amp' then 'build a firefly amp'

http://www.diyguitarist.com/LG-index.htm

Sawdust posted this

[shortfuse]

Tubenit - I didnt pay attention at 1st to your note at the bottom about it being Sawdust's post prior to the reply and saw the original Sawdust post further down but maybe you or someone else could answer anyway?

I stumbled upon your board tonight while surfing through the site.  That DIY site is where I got the idea to build and obtained the schematic for the firefly I am doing now.  So now you have raised questions from me.
  
I noticed you have the 2 caps which are most likely C1 & C3 as 1uf 50v as electrolytic and the schematic calls for 1uf 100v capacitor.  When I ordered my parts I found the 1uf 100v electrolytic caps in Dougs cap listings and ordered them with out thinking twice about it.  Then I came across the assembly instructions for the actual PCB http://homepage.mac.com/calhoun/.Public/Firefly%20PCB%20Guide%208.pdf (be patient it takes a few seconds for it to come up and load the pdf) and it shows them as NP looking like metalized polyester type caps.  I searched Dougs parts and could not find it and actually found a local electronics store that actually had 2 1uf 100v yellow caps.  They look like a electrolytic type with the dimple in the top of the can but do say NP on them so I hope they are NP.  Could these just as well have been Sprague or Xicons?

I also notice you have (4) 4007 diodes instead of the (2) shown in the schematic.  Why?  Not questioning you, I am just curious as my knowledge really isn't quite there to understand exactly why yet.

I see you have a (1) 47uf 450v and (2) 33uf 450v instead of the (3) 47uf 400v shown in the schematic.  Again I ask why or reasoning out of curiosity.

I am using a 250p silver mica in C12 instead of the 220p called out in the schematic & you have shown.  Then again I have a 500p obtained for C6 instead of the 470p called out in the schematic & you have shown.  Do you think they will be ok and what will they do to the sound with what I have?

Sorry for being so lengthy but this is my first build am I am trying to obtain as much knowledge as I can as I go.

Steve

[m3moser]

Hi- Not sure you got your questions answered but I will take a stab:

You will be fine with the 1uf caps you have.  Those are the cathode caps and 50 watt or 100 watt (or even 25 watt) would be fine.  Non polarized are OK as well.

You can build the amp with 2 diodes or 4.  Some consider 4 a safety factor in the power supply.

You can build this amp with the 47 or the 33uf in the first postition.  Once again, its more of a personal choice in a low wattage amp like this one.

You 250 vs. 220pf and your 500 vs. 470pf silver mica caps will both be fine.  Maybe my dog could tell the difference thos will produce but probably not human hearing.

[kagliostro]

Tubenit

please, can you post newly the documentation about the layout (and other if you have)

the old link didn't work now

Thanks

Franco

EDIT: I performed a search and I've find a higher resolution image of your layout Tubenit, so, if you have some other documentation

it will be appreciated, if you haven't, anyway THANKS

[timm]

I am collecting parts for a Firefly as well. I have been going from this document...

http://vintageusaguitars.com/misc/Firefly%20PCB%20Guide%208.pdf

Tim

[kagliostro]

Thanks Timm


Franco

[Jack_Hester]

Franco -

Here's a complete layout by Paul Marossy, before he closed his DIYguitarist board. 

Jack

[shortfuse]

That is the same layout I used and it sounded very good.  But i did not like the 12AU7 for the power tube and switched it out for a NOS RCA 12BH7 and it sounded much better.  Also I switched out the standard 1UF Nichicion caps in the first stage to solen fast caps and it changed the whole dynamics, it seemed to open up the sound and did not seem as choked up as the nichicon caps did.

[kagliostro]

Thanks Jack

Franco