OT - Mistake in FireFly layout by Paul Marossy?

[sir Franc of SOSCASTOA]

Hi,
I am new to this forum and currently building a firefly using of course Doug H's site and the chassis layout picture of Paul Marossy.
I found no email addresses on their sites and found out they are regular posters on this forum so I decided to join, learn more about DIY and getting in contact with Doug and Paul.

First, I would like permission from both (or either) of them to place a link on my website to theirs (amps.soscastoa.com). In fact I already placed one to Doug's site  :oops: so Doug, if you have a problem with that, I'll take it off immediately...

Check my site for  pics of my firefly, I am actually almost done. Ceated a board, got all components and I am now making a chassis. This weekend I want to put it all together,  getting to maybe the most difficult part; the wiring.

This is where I have a problem with Paul's layout.
First, the heater filament wires seem to be connected to the tubes wrong?!
Paul connects them between pin 4 and 5, while there's only 6.3V to work with. Shouldn't this be between 4&5 and 9?
Second, it seems for the bottom half (in Doug's scheme) of the 12AU7, Paul swapped connections for kathode and plate. Kathodes of both triodes should be connected to R13 and the plates to the OT.
Paul connects kathode to plate and one kathode and the other plate to the OT.

It is confusing me a bit. Did Paul do this on purpose and did he actually build it like this? This can't be working, can it?

Sorry for this long post, I hope this hasn't been addresses before, I did do a search

Thanks,

Franc.

[jimmy]

well, i can help you out with the heaters!

paul may be running 12 volts two his heaters, thus only needing to use pins 4 and 5.

thats my 2 cents. ill check the site and maybe let you know if i discover anything else

cheers
Jim

[sir Franc of SOSCASTOA]

Thanks Jim.

I thought about that, but the layout also clearly mentions 6.3V for heaters and also a 6.3V indicator lamp.

Franc.

[Doug H]

I have not seen Paul's layout so I can't comment on it.

But here's the deal with the heaters:

If you are running them at 6.3V, short pins 4 and 5 together and use them and pin 9. If you are running them at 12v, use pin 4 and 5 and leave 9 disconnected.

No problem with linking my site. Eventually I'm going to link all the FF builders I am aware of to my site. Where's your site?

Doug

[RDV]

I No problem with linking my site. Eventually I'm going to link all the FF builders I am aware of to my site. Where's your site?

He's got it linked to the little WWW at the bottom of posts.

RDV

[sir Franc of SOSCASTOA]

Okay, thanks, combined with this post:
http://www.diystompboxes.com/sboxforum/viewtopic.php?t=21024&start=0&postdays=0&postorder=asc&highlight=
that explains the heater thing.

Still leaves the kathode/plate mixup...

[Paul Marossy]

sir Franc-

Yep, there is a mistake on my layout, my screw-up. That was brought to my attention about a week ago. I have the anode and cathode of one side of the 12AU7 mixed up. Mine is actually wired per this layout, and it seems to work just fine. (although I wonder if it is still in a self-split configuration like this...)
The other thing about that layout, which is something that I copied from a layout that someone else drew, is that the resonance control doesn't seem to do anything. I think it is not connected to the circuit properly. I'm not sure where it should actually be connected. Can anyone offer some assistance here?

I am currently running my tube heaters at 12.6 volts. It would probably work better on 6.3 volts, I imagine it would have less hum. I don't have a hum problem, per se, but I do get hum when the boost channel is on, and the volume and gain are cranked...

I am going to revise that layout this weekend sometime and upload it to my site. I'll let y'all know when it has been uploaded. Sorry for any inconveniences caused by this.  :oops:

BTW, you can link to my site I you would like. I have no problems with that.  

[sir Franc of SOSCASTOA]

Thanks Doug, Paul, I am going to update my site tonite and add the link(s).

If you are interested, have a look at my site:

http://amps.soscastoa.com

I am also working on a Marshall JTM45 clone.

Franc.

[Paul Marossy]

Cool page you have there, Franc.  
I think I am going to build a Matchless Spitfire clone sometime in the near future.

[dosmun]

A friend of mine builds Plexi clones and also sells parts and complete kits for a variety of Marshall type amps.  He makes some killer Marshall clones.  Here is his website.

www.metroamp.com

Here is also a link to a review of his JTM45 PTP board at Legendary Tones.

http://www.legendarytones.com/JTMPTP1.htm

[sir Franc of SOSCASTOA]

Thanks for the links. I know Metro Amps from the Plexi Palace forum.

I updated my website, if you're interested, have a look at:
http://amps.soscastoa.com