Amp Build: Brown Note 18Watt Lite IIB

[M29]

Beautiful work man: Any start up rituals? Gas masks, respirators, wet suits...

[Ch0jin]

Beautiful work man: Any start up rituals? Gas masks, respirators, wet suits...

Haha, yeah I'd like to know the answer to that also

Do you use a variac to run them up and monitor you rails as you wind it up?

When I fired up my home brew the first time thats what I did. I also thought it'd be a cool idea to run a separate heater supply for startup so all the tubes had the correct heater voltage even though the rail voltages were lower. (I just borrowed an old transformer someone had for this)

Anyway, we're all hanging out to see what happens

[M29]

[Kazz]

Looking good there Tung.....looking good

[tunghaichuan***]

IT LIVES!

Pix of the finished amp.

To tell the truth, I don't really have a start up ritual. I just check the wiring and hope for the best. I do make sure I have my safety glasses on and look away when I flip the on/off switch I really need to build a lightbulb current limiter to start up amps. I've been lucky so far, but eventually my luck will run out.

I spent about 15 minutes checking over the wiring this afternoon to make sure I didn't pull some boneheaded move and mis-wire something. Everything looked good so I plugged in a "hole filler" 5Y3 to check the voltages. Since there were no other tubes installed (and no current draw) the voltages were high, but about what I expected.

I have to tell you all, I was really sweating this build, my hands were shaking so bad I could barely plug the rest of the tubes in. I used a couple of Sovtek EL84s that I pulled from Valve Juniors. The two preamp tubes are low end Sovtek 12AX7WA tubes, nothing special. I call them hole fillers because if they short out or die in the circuit, then it is no big loss.

After I got the tubes installed and the amp warmed up, I checked the voltages. They looked a little low, but nothing outside of spec.

So I plugged my guitar in and turned it up a bit and got clean, glorious EL84 chime. The amp is very bright, especially with my single-coil equiped guitar. The tone knob doesn't have as much range as a Tweed Princeton's but it does make the amp slightly brighter or slightly darker.

Then I cranked it up all the way. Wow, tons of power tube grind. This circuit sounds very good, and I haven't even tweaked it yet. #I input is the single triode and it sounds good, the #II input is both triodes in parallel and is even better, more grind, more complexity.

The output transformer is only rated for 15 watts, so I was kind of concerned, but it didn't even get warm when playing the amp cranked up. I think it is up to the task. : The amp might benefit from a better OT, Heyboer, GDS, or Trinity. The Edcor sounds very good clean, very chimey so it might be a great choice for a Vox AC15 circuit.

Even though the voltages are low, the amp biased the power tubes to about 68% which is about where I want them for Class AB operation. I plan on using some different rectifiers: a 5V4, 5AR4, and a Groove Tubes SS plug in rectifier to see how different plate voltages change the tone of the amp.

Oh yeah, I did do one boneheaded thing: the on/off and standby switches are upside down so that the amp is on when they are in their off positions Doh! : Easy enough to fix, and it does't really affect anything.

Coming up next, some sound clips. Although it may take me a few days. This was my last day off for a few days, but hopefully I can get something recorded and posted to my web site.

This was a fun build, and now for some tweaking.

Thanks to DVM for a kick in the pants to get the project finished. :

tung

[M29]

Awesome Tung congrats I know the feeling!
If you look at different transformers I highly suggest the GDS (Vintage). I put the standard GDS in at first but upgraded to the vintage and what a difference!!! I love it. Much more intricate, musical and defined.

Again congrats on an enjoyable build for you and us too. I love this stuff and I really enjoy your way of presenting it to us:

M

[F_BSurfer]

looks good tung bet it sounds great to

[warren0728]

man that looks great! :

[Ch0jin]

Grats!! Good to read it fired up first go too

I'm not much of a fan of those spade connectors on the tranny though. They scream "accidental shock" to me. I guess once it's all inside an enclosure though it'll be fine.

Really nice looking build though. Very neat and tidy. Good job

[duhvoodooman***]

Excellent news! : Congrats & looking forward to those clips BIG TIME!

[tunghaichuan***]

Grats!! Good to read it fired up first go too

I'm not much of a fan of those spade connectors on the tranny though. They scream "accidental shock" to me. I guess once it's all inside an enclosure though it'll be fine.

Really nice looking build though. Very neat and tidy. Good job

Yeah, I'm not real keen on those quick disconnect spade connectors. I flipped the chassis over and almost made contact with one of the connectors. I think Edcor is really short sighted for not putting insulated flying leads on their transformers, but what do I know? The Edcor was only $20 so it nice to experiment with and easy on the wallet.

The power supply is still a rat's nest and needs to be cleaned up.

Also, it really needs a head cab.

tung

[tunghaichuan***]

Excellent news! : Congrats & looking forward to those clips BIG TIME!

I'm going to use the Triboost for one clip, I think it will sound good. I have high hopes for the new Green Screamer as well. It sounded pretty good into the EF86 amp I did.

The amp could benefit from some different tubes. The ones in it are marginal at best. I need to buy a couple more sets of JJs. I will definitely put in a couple of the used Mullard and/or Telefunkens I have. That should wake up the amp nicely.

tung

[Ch0jin]

... but what do I know?

tung

Haha true. I've shocked myself so many times on consumer electronics that had just plain dangerous component layouts, I guess I'm a little paranoid, but like u said, what would I know

Now go back and rock that thing!

[warren0728]

clips....clips....clips....clips....!

just sayin'....

[luvmyshiner]

Very nice Tung!!! Now, if you're finished trying to electrocute yourself, go grab an ice cold Shiner and celebrate.

Um, not this Shiner, one you buy from the store.

[Kazz]

Very nice Tung!!! Now, if you're finished trying to electrocute yourself, go grab an ice cold Shiner and celebrate.

Um, not this Shiner, one you buy from the store.

Ha.....You are Ice Cold......lmao......CB would say you are luke warm at best LMAO.

[tunghaichuan***]

I had the day off today, so I recorded some sound samples:

http://www.diycustomamps.com/mp3/BN_18W/

I finally got a chance to sort out some of the problems with the 18W. Namely, I fixed the wiring on the on/off and standby switches. I had them reversed so that the amp was on when the switches were in the off position and vice versa.

I also experimented with different rectifier tubes. The first one I tried was a 5Y3. I used a 150 ohm resistor on the EL84s to get the bias to about 70% plate dissipation. The plate voltage was fairly low at about 270, so I tried a Groove Tubes Solid State plug in. This is a tube base that has SS diodes in it to plug in in place of a tube rectifier. I had to use a 270 ohm cathode bias resistor to bias the amp to 70% again. The amp was louder and brighter, but more sterile sounding. I didn't like it either so I put in a 5V4GA tube rectifier and a 200 ohm cathode bias resistor. The plate dissipation was 72%, which is close enough for rock 'n roll. Now the amp was sounding pretty good, even with the Sovtek "hole filler" EL84 tubes.

Finally, I swapped out the Sovteks for a matched pair of JJ EL84 tubes. These made the amp considerably brighter, but not harsh or shrill. Since the amp is bright to begin with, I'm still kind of on the fence as to whether I like the JJs or the Sovteks better.

I recorded the sound samples with a different setup this time. I used a Sure PE52 Vagabond mike that I got from a friend over 20 years ago. I think it sounds better than the SM58 I was using. I recorded this into the mixer and panned it to the right. I then plugged a Behringer GI100 cabinet simulator into the mixer and panned it left. I recorded three samples using the BYOC Triboost on the germanium boost setting. I recorded three samples of the new Green Screamer I got from GC a few weeks ago. I then recorded the amp cranked all the way up with nothing pushing it. I recorded a clean sample to illustrate what the amp sounds like at low volumes. Finally I recorded some samples with a MI Audio Tube Zone that a friend sent to me. It was kind of a shock, this is a spendy boutique pedal that is basically a Marshall/Dual Rectifier in a pedal box. Very high gain, lots of tonal variation with a switch and a well voiced tone control.

Again, sorry for the bad playing, but I wanted to demonstrate how the amp sounded.

tung

[duhvoodooman***]

Very impressive sounding amp, Tung! The dimed crunch is very nice, and it obviously takes pedals well! I really like the sounds using that Triboost! They all sounded good, though.

Which guitar was it, BTW?

And no apologizing for one's playing allowed around here!

[sumitomo]

Very Very cool,I like the tones that amp puts out the tri boost sounds great,but that green screamer is no sloutch either and playing sounded good also.Sumi