Got the 18 watter working (Sound clip)

[Tyrannocaster]

I know this forum is about tweaking amps and technically this post is only about the results of a tweaked amp, so I hope it's okay to put it here. If not, maybe somebody can move it to an appropriate place.

It does have some hum at gale force volume, but it's coming from the first gain stage, not the one I added. It's so far below the roar of the guitar that I'm not going to worry about it.

I made a five minute clip of the amp today to see how it records, and I am pretty happy with it. I was interested in seeing how it handles loud to soft, and it's great at it. I didn't use any pedals or fx, just some reverb in the mix. The amp was set at about 12 o' clock volume with the tone all the way up for the whole clip, which I did straight through. I used my '94 Strat Special, its volume and tone controls, and that's it. I think the 18 Watt Marshall is a great amp, but its one drawback is not enough gain (IMO). This one certainly has enough. I tried different tubes in it and ended up using an old GE 5751 for the preamp tube.

Clip is here https://www.box.com/s/fae02ff11862bce0a99e.

Sorry about the funky playing, but I was more interested in the amp than leaving a record for posterity.  Anyway, I have a couple more questions about the amp but right now I'm having fun just playing it - there has to be some reward for all the head banging, and I intend to enjoy it for a bit. I'll come back with the specific questions later.

[HotBluePlates]

That sounds really good! What song are you playing the first 2 minutes, with the nice counterpoint/chord melody stuff?

Congrats after struggling with the weird issue on this amp.

[Tyrannocaster]

Thanks. That weird issue turned out to be (of all things) a BAD JACK that wasn't even related to the guitar input. The amp has a preamp out/power amp in and somehow, after I added the gain stage, that became problematic, but the issue seemed to move around and around. It was only when I realized that the jack's center was turning and its outside wasn't (when I tried to take it out) that I started to think - woah, I've never seen THIS before! I had a hell of a time getting the jack out! You could turn the nut and the center of the jack would spin but the rest of it stayed put. I've never experienced anything even remotely like this problem before. Well, it was (in retrospect) a crappy jack. Certainly not a Switchraft. I don't know where I got it, but it's history now. For now, the amp has no preamp/power amp insertion point, but it also has no weird buzz/crackle/shriek noises, either.

The song is an old British folk thing (from France, I believe, since the word "Sallie" comes from the French word "saule", which means "weeping willow") called "Down By The Sallie Gardens".

[HotBluePlates]

Sounds about right. I was gonna guess something celtic, but it reminded me more of this instead.

Jerry Reed did a lot of fun fingerpicking, but whoever arranged his take on the 15-16th century tune Barbara Allen did a fabulous job. Every verse has some slight change in instrumentation or rhythm that really keeps the song driving forward. If you listen with good headphones, you'll hear the bowed upright bass in the beginning, which I really love; it switches to plucked notes as the song progresses, then finishes with bowing the final bass note again.

[tubenit]

VERY NICE !!    

I would be pleased with an amp that sounded like that. Really great harmonics in the tone.  Bravo!

I enjoyed your laid back picking & playing too.  Good stuff.

Have you posted a schematic and voltages?  I'd like to take a look if you have.  I am typically not a fan of EL84 tubes, but I like the tone you have here.

In the first gain stage, is it a paralleled 12A_7 into Doug's gain stage into the LTPI?   Or did you follow Doug's design specifically and the first and second gain stage are single triodes not paralleled?  

With respect, Tubenit

[Ed_Chambley]

Sounds about right. I was gonna guess something celtic, but it reminded me more of this instead.

Jerry Reed did a lot of fun fingerpicking, but whoever arranged his take on the 15-16th century tune Barbara Allen did a fabulous job. Every verse has some slight change in instrumentation or rhythm that really keeps the song driving forward. If you listen with good headphones, you'll hear the bowed upright bass in the beginning, which I really love; it switches to plucked notes as the song progresses, then finishes with bowing the final bass note again.

Jerry Reed is my favorite.  Have you checked out his Nashville Underground Album.  Great

[Tyrannocaster]

Have you posted a schematic and voltages?  I'd like to take a look if you have.  I am typically not a fan of EL84 tubes, but I like the tone you have here.

In the first gain stage, is it a paralleled 12A_7 into Doug's gain stage into the LTPI?   Or did you follow Doug's design specifically and the first and second gain stage are single triodes not paralleled?  

I can post a schematic tomorrow. The amp uses a single triode (V1A) into a second triode (V1B), just as in Doug's schematic. Since I was starting with a pretty much stock 18 Watt Lite II already I just copied his changes to the second triode, removing the paralleled input and going into V1B, adding a separate cathode bypass, etc.

I think you should give the EL84s another chance. I have made several amps with them and I love their tone. They get used in "dirty" amps (like mine, LOL) a lot, but they make great clean amps, too. The first one I made was a Bruce Collins Voxy Lady several years ago and damned if that wasn't a great surf music amp (except for the lack of reverb, of course). I must have done something wrong, because Bruce said it shouldn't be all that clean, but mine sure was.

[HotBluePlates]

Jerry Reed is my favorite.  Have you checked out his Nashville Underground Album.  Great

I've heard most of his albums, pretty much everything before the mid-80's.

Jerry and Chet (with an honorable mention to Buster B Jones) have prompted me to pick up a thumbpick this past year and try to completely change up my playing style.

[tubenit]

I can post a schematic tomorrow. The amp uses a single triode (V1A) into a second triode (V1B), just as in Doug's schematic. Since I was starting with a pretty much stock 18 Watt Lite II already I just copied his changes to the second triode, removing the paralleled input and going into V1B, adding a separate cathode bypass, etc.

OK, here is an editable schematic that has Doug's preamp into a Lite IIb poweramp.

Can you modify this and show us exactly what you did with voltages, please?

With respect, Tubenit

[Tyrannocaster]

Okay, I will try to get voltages later today; I have been having so much fun playing it that I haven't wanted to take it over to the bench and turn it upside down, 'cause then I can't play it.  

Thanks for that schematic. I'd much rather work on one of those than in Photoshop. Still, I'm attaching a pretty accurate cut-and-paste of the amp. I think the only alteration I made from this schem was to use a 500k pot instead of the 470k resistor that references ground before the PI, but it was tunred all the way up for the recording, so that whshouldn't have made any difference. Whoops, I can't figure out how to do an attachment on this forum; I see them all the time, so I know it can be done. Well, let me put it in my Photobucket account:



The PT is a 275-0-275 from a guy who had a company called Handmade Transformers - everybody else had terrible experiences with him and he finally went out of business, but the PT and OT he sent me are great (they are both in this amp). I guess this one is the orphan amp, as the chassis came from another outfit that went bust, stiffing a lot of people: Tubegarden. Very nice expanded 5E3 head chassis.

Listening to the clip, I am especially intrigued by the short bit that starts at 4:25 - I don't usually associate percussive effects with the guitar's tone control turned all the way down. I'll have to play with that. The amp has a curious soft distortion that I couldn't hear on any recordings but which is quite plain in person - it's there at all volume levels, even the quietest, and it is most obvious when the guitar's tone control is turned all the way down. It's very pleasing, and not obvious right away. When you turn the tone control up it doesn't go away but it is masked by the amp's natural clean twang, although I believe it still contributes to the warmth of the sound. I wish I knew exactly where it came from so I could put it on a switch (or even add it to other amps!). This was not present at all before I added the gain stage so something I did introduced it.

How do you guys add attachments? I get really tired of Photobucket's processor intensive Javascript on my old computer; it takes me forever to do anything there.

[sluckey]

Here's how I do it...

[tubenit]

THANK you for sharing the schematic!  

I noted the large 150uf value for the EL84 cathode resistors.  That may be contributing to the "cleaner" tone as the larger values sometimes emulate fixed biased tone?  I was somewhat surprised to see the large 50uf on V1-3, but the amp certainly has great tone to it, so I would not change it.

I edited the SCH version and posted the GIF and sch here for others.

I added the passive effects loop since I am partial to those and using either a Boss digital delay or MXR analog delay (Carbon Copy) in those loops.

You did NOT indicate what node D is or the dropping resistor between those, so I borrowed from Doug's and made a guess with it?

What speaker did you use?

With respect, Tubenit

[Tyrannocaster]

Yes, I missed the correction on the schematic for the power supply; I don't have a node "D", and my schematic should read "C". The 18 Watt's power supply (and the power tubes' circuitry itself) is slightly different from Doug's, as you probably noticed; he has an extra cap in the line that I don't have. Copy and paste is not without its problems.   Perhaps that's why I have the hum I noticed at high volumes.

I use a variety of speakers but have settled on the Eminence Legend GB for live work, however I also put a variable level line out on every amp I make (just padded down from the OT - it's not on the schematic, but it's like the Matchless version or Gerald Weber's line out only with a pot) and I often record from that, which is what I did with this clip. It sounds better live in the room than with the line out, but an 18 watter is friggin' LOUD when it's turned up.

[Tyrannocaster]

Here's how I do it...

Ah, now I get it. Thanks!

[Tyrannocaster]

I got some voltages. I can't figure out Doug's page for storing them because it asks for voltages on pins 2 and 7 of V1 and I don't get any readings there - those are the inputs. Also for pin 2 of the EL84s and I don't get any reading there either.

Heaters are all at 3.42 v.

V1 (gain stages)
1. 172
3. 2.07
6. 172
8. 2.13

V2 (Phase inverter)
1. 194
2. 14.0
3. 20.0
6. 169
7. 14.5
8. 20.0

V3 & V4 (power tubes)
3. 12.2
7. 338
9. 292

I checked these several times; they varied a bit, but not by much at all. I hope it's of some use.