Hurray! New build worked first time! Now for the tremolo.

[Tyrannocaster]

Man, I was so nervous I didn't turn the amp on for a few days because I was sure it wouldn't work.  But I finally got my courage up and turned it on this morning and bada-bing, it works really well and there's very little hum at all - you have to put your ear down in front of the speaker to hear it.

This is the preamp from a 5D3 Deluxe (which is like all the other tweed Deluxes, of course) mated to the power amp of a 5E5 tweed Pro. I have a '55 5D3 Deluxe already, but it is worth enough that I don't like taking it out in the world and I wanted one that isn't almost 60 years old; it's kind of finicky even though it sounds like a million bucks. Anyway, the amp works well and sounds acceptable for now (I have crap tubes in it 'cause I was afraid they would redplate...if it even worked, I mean) as far as it goes. It has the bizarre, interactive volume controls just like I wanted, vor better or worse. But I learned from earlier failures and I decided to do this one in stages, starting with the base amp.

Now I want to add a tremolo to it. The tube socket is powered and there's a cap on the board for it with its own dropping resistor. I selected a preamp wiggler circuit for the tremolo, which may or may not be a good idea; I'm including the schematic for the amp below so anybody can comment on this and tell me what I may have overlooked. In the past I have had a lot of trouble with getting trems to work (and look at all the hassles Willabe had with his! Yikes!) so please take a look at this and let me know of any pitfalls you see before I do this. The trem will go on its own little circuit board in the amp.

Here's the schematic:


Thanks for any input.

[Willabe]

Man, I was so nervous I didn't turn the amp on for a few days because I was sure it wouldn't work.   But I finally got my courage up and turned it on this morning and bada-bing, it works really well and there's very little hum at all - you have to put your ear down in front of the speaker to hear it.

     Nice job! Quite as a church mouse to boot!

The 1'st amp I built (5E3) I used a long wooden stick to flip the power switch.   

One question, did you use a light bulb limiter on 1'st start up? Takes a lot of danger out of blowing something up on 1'st start up.

Here's a link to Sluckeys site with instructions on building/using one.

http://home.comcast.net/~seluckey/amps/misc/Amp_Scrapbook.pdf


                  Brad      

[Tyrannocaster]

No, I just plugged it in. I know about the light bulb limiter but all of the home made ones I have seen want a 100 watt bulb, which nobody sells anymore. Sluckey's document is the first one I've seen that uses a 60 watt bulb - I thought I had to have a 100 watter.

[Willabe]

Main thing is it _ worked fine _ from the get go. With, no volume problems, no bass/treble/tone problems and quite with no buzzing, no strange noises, no oscillations, no smoke.        

Good to gain some more faith in your own work? We all need that.      

You can use a 75w bulb too. IIRC the lower the w bulb the more the resistance = more protection?

On a small amp like a SE 5w to 10w, I think you could use a 40w, maybe even on a 15w to 20w?

On a big amp like a 180w SF TR or a Ampeg SVT or a big Sun amp, I think you might have to use a little bit bigger bulb?

I think there's a balance point were the amp under test pulls X current and if you use too small of a w bulb once the bulbs filament warms up the amp under test is still pulling enough current that it does not dim enough to tell if you have a short or not. OTOH if you use a bulb with too large a w you loss protection?

I bought a couple of 16 bulb packs in 60w and 100w from Home Depot not long ago, just to have some laying around.

Have you tried looking at the big box stores? Or are you in Cali?    

I believe you can also use the _ mini _ halogen flood/spot light type bulbs? You just need a different socket. They would take less space on the bench too.

Maybe one of the better math guys well chime in on this?  


                   Brad