Sebego Sound Double Trouble. A take on #40

[Billion81]

Hey folks-

If you recall this thread https://tubeamparchive.com/viewtopic.ph ... 60&start=0

I offered an opinion of the clips and that some of them may not have put the amp in it's best light.. That began a discussion with Bill and I as I thought there was really something to his designs and wanted see if we could get a better demo that demonstrates what this amp is capable of.

In the interest of putting my money where my mouth is- Bill and I worked out a deal to get one here to put it through it's paces.

Now- This is by no stretch of the imagination a demo of all this amp can do, My style is my style but I must say that this is a really well designed amplifier that plays very well with a varied assortment of speakers-

The details of the amp are:

50 watt amp loaded with KT77s with the normal ODS layout with Bright, Mid, Rock/Jazz switches but you'll see in the note below from Bill

The clip attached was done with a 4X12, 40th anniv. JTM 45 reissue cab with the special Celestion Alnico silver speakers which are currently my favorite "reference" cab that I test all my amps with.

I did use a Mark Kane built 'lator. with a Boss RV5 through the loop. No other effects were used. Actually there is a section where i punch in a low gain setting AC Booster.

The recorder is a Sony PCM 10 handheld stereo recorder which brings in some ambient effects vs. a SM57 slammed up against the grill cloth.

I can say that what was captured is how this amp sounds. If you have decent set of speakers or headphones on your computer you will get the best results.

The guitar used is a '83 ES -335 '59 Dot RI with Shaw pickups (is there a better 'bucker for us mortals?)

here is a description of the circuit from Bill Dunham that describes some of the mods from the original # 40 circuit.

"Hi Ted, I finally had a chance to finish the 50W 70's amp (see the attached photo). I was playing around with a set of JJ KT77's and thought I would leave them in the amp. I did a lot of A/B with similar amp loaded with 6L6, and I thought the slightly more agressive tone of the KT77's suited this amp. The 70's circuit is a bit more raw sounding and the way it's currently set up it's downright nasty - a bit different than the later Skyliner amps. I wired the mid switch like the 70s "deep" switch, it's subtle but useful I think. I wire the rock/jazz so that "jazz" is really rock mode, and when you hit the "rock" position it's a raw boost somewhere between rock mode and full PAB, without as much EQ (mid) shift as full PAB. I do this since most never use the original Jazz mode position."

Alrighty then-

Here's the clip-
http://www.soundclick.com/bands/page_so ... D=10448621

[boldaslove6789]

Sounds Killer!

[ToneMerc]

Sounds Killer!

2X

TM

[CHIP]

Very nice .

[wjdunham]

A couple of notes on this amp - it's pretty much true to Tony's #40 layout, with a few exceptions:
Separate master for OD, 30pf bright cap on the clean master.
The Rock mode is sort of a half stack bypass, lifts the mid pot with a 220K and lifts the bass pot with a 100K. I wound up just sticking a couple of 250K pots in there and tweaked them until I got a boost that I liked without a lot of EQ (mid) shift. I find it much more useful on the cleans than full PAB, and works really well with the #40 circuit. I think Ted had that engaged for a good portion of the clip.
KT77's in stead of 6L6, and a 12AX7 in the PI, JJs all all around.
Otherwise she's all 70's - and Ted certainly make is sound it's best.
Bill

[CHIP]

"Tony's #40 layout", is that the 2nd generation layout in the files section?

[da Geezer]

"Tony's #40 layout", is that the 2nd generation layout in the files section?

I believe it is......Tony ref's #40 in that thread, 2nd post down (where the pic of Lukathers suede combo is).

https://tubeamparchive.com/viewtopic.php?t=12870

[tubedogsmith]

Very cool!! Another excellent demo Ted, and Bill's amp sounds killer!! Congrats. Ted, you're rapidly approaching "Master" status in regards to these dumbly deals!!

[wjdunham]

"Tony's #40 layout", is that the 2nd generation layout in the files section?

That's the one.

One more note on the amp, it's got a custom Heyboer Bassman OT with 4, 8 and 16 ohm taps. Anyone else have any experience using KT77 and a 4K Ohm OT - I really like the character of them with this amp.
Bill

[dogears]

Hi Bill,

Did you totally lift the clean master when in OD mode?? If not then you get a parallel loading effect and a treble bleed from the bright cap. I'd suggest a relay controlled 22M between the master and ground to preserve circuit integrity as designed.

A couple of notes on this amp - it's pretty much true to Tony's #40 layout, with a few exceptions:
Separate master for OD, 30pf bright cap on the clean master.
The Rock mode is sort of a half stack bypass, lifts the mid pot with a 220K and lifts the bass pot with a 100K. I wound up just sticking a couple of 250K pots in there and tweaked them until I got a boost that I liked without a lot of EQ (mid) shift. I find it much more useful on the cleans than full PAB, and works really well with the #40 circuit. I think Ted had that engaged for a good portion of the clip.
KT77's in stead of 6L6, and a 12AX7 in the PI, JJs all all around.
Otherwise she's all 70's - and Ted certainly make is sound it's best.
Bill

[talbany]

I personally like the character of the JJ KT77's especially the top end..Used them in several Bassman and MM output trans..
Note..You may need to tweak the NFB resistor vs the 6L's...Nice job Bill/Ted
If you like em use em..

Tony

[Billion81]

Very cool!! Another excellent demo Ted, and Bill's amp sounds killer!! Congrats. Ted, you're rapidly approaching "Master" status in regards to these dumbly deals!!

Thanks very much- I need to get to the next level and do some actual vids as the talking and wankery gets a bit numbing when only in Audio format. Some of the responses I got where like "dude, good demo but shut the F up" hahaha.

I do need to do some stuff like Scott does where it's with a track or something to that effect.

I must say that I am amazed at how "out front" the KT 77s are vs. the 6l6. I have a 100 watter that Mark Kane built that is close to this but with a bit Less spike on the mid vs. the KT 77 and pairs nicely with the 50 watt Double Trouble.

I also ran the Double Trouble along side the 100 watt 90s HRM EL34 amp and that was a killer combo. I must say that I am almost fully converted to Alnico speakers at this point.

The only Ceramics I'm sticking with (for now) are the Fane Studio 12 and the Scumback M75s.

Jelle is working a hybrid for me as well that will have a 4 KT88 tube set up.

[Structo]

I liked the amp and the playing as well.

The problem with talking when recording the amp is your voice is low volume so people turn up the speakers to hear what you are saying then you play something and WHHHHHHAAAAAAaaa.

So perhaps record the clip then dub in your description between riffs?

[wjdunham]

Hi Bill,

Did you totally lift the clean master when in OD mode?? If not then you get a parallel loading effect and a treble bleed from the bright cap. I'd suggest a relay controlled 22M between the master and ground to preserve circuit integrity as designed.

Scott, I did realize that leaving the clean master in the circuit would change the loading of the OD entrance, but after I had already built the amp. It sounded so good as it was though, I left it that way. I have changed the design to use the other side of the OD relay to take top of the clean master out of the circuit and send CL2 directly to the OD entrance (like the original). One side of the relay picks between the two masters, the other side sends CL2 out to either the clean master or OD entrance. I modified a 100W 2nd generation that I had and didn't notice a big difference, but I did not do a live A/B test so there may have been more change than I was able to perceive. Thanks for pointing that out though.
Bill


Bill

[dcribbs1412]

Really nice sounding amp grats
can I ask what PT was used?

Darin