My first build has begun. - 5F2a from scratch

[jmardy]

Holes in the box so far.
That's a bare Dolby A noise reduction card (cut in half) that I'm going to use as a circuit board.

[echuta13]

I hope that's not the output transformer you were thinking of using. That one would be appropriate for a push-pull amp.

[jmardy]

Well shit, I guess that's what you get when you buy a box full of parts and don't know what the hell you're doing...
Thanks for the help:
So this one is the way to go?
40-18031

[guitician]

Sure you can use that one, but the Hammond would work too. Just connect the Brown wire on the primary to the B+ and the Blue to the plate and tape off the Red. Just because it was made for a Push Pull circuit doesn't mean you cant use it as a Single tube type by connecting it right.

[Chuck H]

That'll "work" but it's less than ideal. Of course I don't know how much idealizing went into the construction of the actual transformers used anyway. Aren't single ended transformer suppose to be built with a break in the lamination hoop?

[guitician]

I think that is in inductor cores. 8k ohms for a SE 6V6 is what they use I thought. Anyway, if jmardy has already got the part, he should hook it up and hear how it sounds, then buy another if it's not up to the job.

[echuta13]

SE amps usually have a "gapped" output transformer, so I think while this one might work... it's less than ideal. The other tranny you have a link to would be great (very flexible with output tube options and beefy)! 40-18031

[jmardy]

Thanks guys.
The Classictone 40-18031 is on its way.

[Chuck H]

Well... I know you've already drilled and punched some things, but what are the PT specs? A chassis should be about as affordable as a transformer. You may be able to change your plan to a push/pull design. At the very least you have a decent OT there for a Deluxe or 18W type of build for another project.

[guitician]

OK, I found this thread on PP vs SE....never that knew about the SE tranny. http://music-electronics-forum.com/t15200/

[jmardy]

Well... I know you've already drilled and punched some things, but what are the PT specs? A chassis should be about as affordable as a transformer. You may be able to change your plan to a push/pull design. At the very least you have a decent OT there for a Deluxe or 18W type of build for another project.

PT is an Allied 6K3VG
Allied - 6K3VG - Power Products - Transformers - Allied Electronics
650VCT @40DCMA, 5V@2A, 6.3A@2.0A,

Yeah, if this goes well, I'll do something bigger next.


Fortunately the Classictone is the same size as the Hammond.

[jmardy]

OK, I found this thread on PP vs SE....never that knew about the SE tranny. http://music-electronics-forum.com/t15200/

I have Sooooo much to learn...

[guitician]

Did you see the last post by MWJB? I have a Hammond 125A that is a small 3 watt PP transformer and recently used it as a 6aq5 SE and it functioned OK. It has a funky kind of tone, like a small old harp amp may get. I guess it's that saturation happening.

[Chuck H]

PT is an Allied 6K3VG

Well that IS too small for the normal small bottle tubes (6V6/EL84). You could do a push pull 6AK6 amp for about five watts. Just a thinking exercise really since it seems you've already ordered your proper OT for this project.

One nice thing about having the extra OT on hand is that it'll burn a hole in your brain until you build another amp

[jmardy]

Well, I'm 0 for 2 then.
eBay and ignorance can be an expensive combination...