Help with first build. 5F1 Champ

[pharmdawg]

Thats what I did and it worked perfectly after that. Its also normal for the tubes to glow a bluish violet color.

That was it...she sounds pretty when she growls...bugs me a little that I tore the whole thing down and re built it twice ..just to find out it was the ot ..never trust wiring diagrams and the color codes....my 5e3 took less time to build..not sure I could recommend a Mojotone kit ...im done

[Chuck H]

The OT leads being opposite of "correct" happens all the time. I build mostly prototype and custom orders. Often with new iron I've never used. Every time I fire up a new build I fully expect it to be wrong and even wire up my OT with a little extra lead so swapping will be easier. It's really not MOJO's fault you tore the amp down and rebuilt it twice. More experience would have made the diagnosis easy. A 5E3 has no NFB loop. So it's you can't have the NFB loop become a positive loop if the leads are incorrect in phase. That doesn't mean the amp may not perform better one way or the other. All the leads in the amp are "talking" to each other due to close proximity.

[pharmdawg]

I dont want to make this a Mojo bitch fest...thats why i didnt mention the missing parts in the kit and the very cheap tube sockets ...that i had to re-order from another vender... great fun for a 2nd build...and i will continue to build and no im not an expert at building but learning all the time like i said great fun but cant recommend MoJo ...thats just my opinion anyways she's growls real pretty...cheers

[Bruce / Mission Amps]

When I build an amp... at least one a week.... I always pull both the high voltage primary wires over to the furthest power tube socket and line them both up on the plate solder lug... that way if there is a phase issue, both wires can reach the furthest socket... it is just a simple matter to reverse the leads from the socket then.
So far, and only over the last 8-9 years. I've only had this happen a very few times with Mojotone's output transformers... possibly from different build schedules at their tranny winder... which for the most part is Heyboer.
And to be honest.... I think they were the 5F1 OTs and their replacement reverb driver OT, also a SE device!!
ha ha

[pharmdawg]

When I build an amp... at least one a week.... I always pull both the high voltage primary wires over to the furthest power tube socket and line them both up on the plate solder lug... that way if there is a phase issue, both wires can reach the furthest socket... it is just a simple matter to reverse the leads from the socket then.
So far, and only over the last 8-9 years. I've only had this happen a very few times with Mojotone's output transformers... possibly from different build schedules at their tranny winder... which for the most part is Heyboer.
And to be honest.... I think they were the 5F1 OTs and their replacement reverb driver OT, also a SE device!!
ha ha

Great to know,,,any advice on the hum im getting,,,,its not real bad but i wouldnt mind tweaking it a bit. volume at 10 you can really notice it. just for giggles i put an external attenuater on it and the hum is tamed but so is the treble.

[Bruce / Mission Amps]

Great to know,,,any advice on the hum im getting,,,,its not real bad but i wouldnt mind tweaking it a bit. volume at 10 you can really notice it. just for giggles i put an external attenuater on it and the hum is tamed but so is the treble.

Do you have the center tap of the 6.3v filament wires connected to chassis ground or "biased" with DC from the cathode of the 6V6?