This is my very first DIY guitar amp building. I'd like to share my experience with anyone who find it helpful.
As I said, It's my first try to build a tube guitar amplifier, I'd like to start something small but useful.Here’s a few from some companies sell small amp kits.
Probably the most well known amp kit seller.They are reasonable but it seems that quality of the components they use are not very good.
It looks their kit components are better than Weber ,such as Orange drop capasitors.Bit pricey though.
Afer long research,I dicided to go for Weber 6A14HP.It'a Fender Princeton Reverb clone with 6L6GC power tubes instead of 6V6. Slight more power 30~35W.
Before start working on your amp, I suggest to read through Weber Forum.There're tons of useful infomation. I added some mods to my amp which recomend on the forum.
Also, this website "Building an amp" made by a Coutry music player in the Netherlands is worth reading.He's made a 6A20.
First,I built equipments I need.
I also made the cabinet by myself. Plan is here. Dimentions are taken from Fender Princeton Reverb cabinet. It's bit small to fit a 12inch speaker.
When I checked layout, I discoverd the output transformer hit the speaker so I moved it off centre.
The chassis is pretty good quality. It's about 3mm thick, hard to drill halls without a proper drill press.Because I live in Japan, I chose a W025130INT PT.This transformer has wires exiting from both sides.You need 025130su endbells to convert to a stand up type.I had to drill extra holes to mount it & for wires.
I used Bus bar method, witch placed behind pots and only one side is grounded to near the input, as far away from PT. All grounds from the eyelet board and pots go here.AC ground goes to one of the PT mounting bolt or a welded bolt.The CE capcan automaticaly grounded when It's mounted. I didn't solder it for future replace. Isolated RCA jacks and reverb grounded V1 socket bolt.
Few things I changed after playing for a while.
Repalced first 12AX7 from Electro-Harmonix to Tung-sol after reading Anticue Electronic Supply comparison chart.
Replaced 12AT7 to 12AU7 to get better reverb control.
Replaced first cathode bypass capacitor from 25uF to 10uF to tighten up bass. I think Split-Load PI can't handle bass well.
Few days after it's completed,smoke came out. The pilot lamp holder just touched to the chassi and 6.3VAC line shorted.I burnt PT up.
We learn from mistakes,I isolated it with a bakelite board.
It arrived 2weeks after I orderd.B+ was a bit lower than W025130INT.Plate voltage became 420V.The sound didn't change much but less hum noise.
No more trouble please!