want to build 5F1 amp

Hello. I've been lurking here for a while and decided to build my own amp. I can't seem to find a step by step process on this forum like....1. do this....2. do that.

I just got a vintage speaker cabinet (unknown year) when i switched it out for a newer one at my church. (it was a monitor for the sound guy who just passed away yesterday). I'm taking over the sound job now.

I was wondering, if anyone could give me a step by step instruction to building a clone Tweed Champ.

The weird thing about this cabinet is that there is a transformer attached to the speaker frame running to a pot that I have no idea what it does.


Thanks for looking. :mrgreen:

I don't think that speaker will work with your amp. I just finished a 5F1 kit from www.stf-electronics.com that has step by step instructions. If you want to source your own parts, you may be able to buy just the book from him. I would also sugest reading up theory and design of tube amps. And as always be very carefull because amps have lethal voltage in them even when turned off and unpluged

Solder joints are the weakest link in a first build!

I would totally use that cab and speaker -- the transformer is probably a 70-volt step-down transformer. Once you measure the DC resistance of the speaker, you can get the right transformer for your project.

If you're feeling adventurous, you could source a low-profile chassis and mount it in the bottom of that cabinet, sort of like a Gibson EH-150 amp.

- Scott

You can get a bill of materials at webers kit ordering webpage.

I think Marsh also has complete intructions.

The 5F1 kit from Tubedepot.com has a video and a 40 pages of instructions you can look at on their website http://www.tubedepot.com/kit-tweedchamp.html The kit is built using a PC board though which is different than other 5F1 kits I've seen. Not sure how you would incorporate those insctructions to use with the speaker you have, good thing Scott S had some input about that.

Can't get more step by step than that. I might go for it one of these days when I have the cash.

Ok so would that transformer work or do I have to remove it?

This is what the transformer says.


SECONDARY
Lafayette

99-6284

C 4 ohm 8 ohm 16 ohm


I downloaded that 40 page manual.

The speaker frame has the number 44-0103 and 328741.

The actual speaker cone has the number 1055362.

The speaker is 8 inches btw.


---------------
I also have this random transformer lying around that says...

MODEL: IBZ10G
INPUT: 120V AC 60 Hz(red-red)
OUTPUT: 16V 0 16V AC (yellow-black-yellow)
TRAN 125 C
NINGBO YINZHOU XIANYING HUAXING ELECTRIC APPLIANCE FACTORY


I assume it was made in Japan.

Your speaker looks like a public address unit from my junior high !
If you have a Harbor Freight near you go pick up their CEN-TECH digital multimeter for about $4 and clip the red wire on the speaker terminal and use the meter 200 ohm scale to measure from the two
terminals on the speaker . If it measures 3.? ohms it is an 4 ohm speaker and will work with most champ output transformers. The 70v transformer is used to distribute power among several PA speakers. You might could use it as an output, but it would not be easy for a beginner.
The meter will be invaluable in your build process.
Your other transformer is low voltage for solid state (transistor) use.
Good Luck !

Sorry to tell you all this but I've decided to hold off on this project when I have a little more free time. I just don't have the time or energy for it with school, trying to find a job, fixing sound system at my church, lawn care at various places, etc.

Sorry to get your hopes up. Maybe I'll tackle this in the near future when my life isn't so busy. Thanks for the help everyone!

in the mean time I'm going to build one, I'll start a new thread!

Wow! I love the shape and the grill cloth!

I would build a 5F2A or a Champ in it.
Or a SS amp with a TDA chip and a low power (12V) tube preamp, even with tube tremolo (as the vibracaster, just look through the threads) so you don't go to a high voltage tube amp the first time + you can run it with lead acid battery if you want to!

I'm also putting together an 5F1 Champ.
It was going to be a 100% scratch build.
But then I saw that 5E1/5F1 PCB board at Tube Depot ($17), and decided to make life a little easier on myself.
BTW: Edcor makes a very nice SE OPT, that is $30 cheaper, than a Hammond 125ESE.
Their power transformers are cheaper than Hammond too.


Steve