"Dongbiter" 30 pics online

[M Fowler]

The SW30 is using the K60 ground scheme if you look infront of the so called tone board there are three ground tabs. 1st tab for input jack ground and V1 bias resistor/bypass cap ground. 2nd: below the volume pot for volume pot ground. 3rd infront of the PI for B+2 and PI grounding.

Mark

[DocJames]

Looking at some constellation pictures, the Trannies appear to be the same (OT transformer smaller then PT). Do we know what was used in the constellation?

[selloutrr]

You would need a better angle to see if the PT has a bevel bottom bell cover. The original Songwriter most likely used the same Pacific iron as the Liverpool or the Rockets Dynacor OT with a Heyboer (several Rockets), Pacific (most common PT after '92), or Ampeg PT (early). These Transformers don't match the typical Komet Iron I've seen, most Komet's have a Grey metallic bell cover.

Based on the test stamp in the picture it's a Pacific Transformer possible model - 2112

All searches come back as custom wound Komet transformers. The Constellation was custom wound to allow for a tube rectifier.

[M Fowler]

Mark,

Based on my pdf I posted earlier both versions by Ken used stock Constellation chassis and transformers.

There were two Songwriters made. Both were built onto Komet Constellation chassis I gave to Ken. The first one was an early Constellation prototype that I had put an octal tube in the PI position. Ken made use of that layout by employing a 6SU7 tube (similar to a 6SL7) for the phase inverter. This is "Inger", the amp pictured on the Trainwreck web site.

Then Ken requested and received a standard production Constellation he reworked into the second version of the Songwriter, named "Bree". This amp uses a standard 12AX7 phase inverter. It uses all current production parts used in other Komet amps, Komet transformers, etc.

Well at least the second version used stock connie transformers.

MF

[selloutrr]

Who manufactures Komet's Iron?

(removed as requested)

[RJ Guitars]

Does any one have good information or an intelligent guess otherwise what the switches on the front panel of the "Inger" amp are?

http://www.trainwreck.com/?page_id=19

Most of us will guess bright switch but I am curious about the 2nd switch which does not show up on the "Bree" build.

rj

[M Fowler]

Mark I believe Heyboer makes some of the iron not sure if they make all of them.

rj, maybe it is a NFB switch?

[selloutrr]

Does any one have good information or an intelligent guess otherwise what the switches on the front panel of the "Inger" amp are?

http://www.trainwreck.com/?page_id=19

Most of us will guess bright switch but I am curious about the 2nd switch which does not show up on the "Bree" build.

rj

earlier in a post it was suggest the toggles were independant SPST on/off allowing the user to blend capacitors

[rooster]

the rocket was simply an ac30 top boost ch with a couple of minor changes. this amp is an ac30 NON top boost type ch with a couple of changes. the bass pot just lets you go from the "treb" channel (500pf coupler) to the "normal" channel (.047uf coupler). he's got some series resistance after that which is bypassed by a bright cap, and the vol pot and some more series resistance after that then the pi coupler. all the pi couplers are the same value---.047uf. i'd guess the bright sw is the standard 3 way 100pf/off/500pf-----but you could do that to taste. and yes there does appear to be some nfb from one of the op trans taps----the tail resistor value could be divided up and inserted nfb inserted there, hence the 2 resistors there. this one let's komet use up some of the spare connie trannie sets rh

OK, I am thinking about this amp still. And here the pic is really a help. rhinson expresses what he thinks the bass control is - the only real mystery in the circuit - and looking at things, I agree with what he has said perhaps, but not with how he said it.

What I see is a static cap, probably 500pf (maybe slightly more?) (in red heatshrink), and then a simple parallel bridge of a larger cap controlled by a pot. Like rhinson, I can't imagine it is any larger than .022, but maybe .047 as rhinson says. Rhinson is saying something like this, yes, but he fails to state that the 500pf cap is always in the circuit, that the bass control is just adding capicitance to the 500pf coupling cap to create more bass. Also, this larger cap that joins in parallel to the 500pf cap seems to have some type of extra mass at the pot side exit. A resistor? Why heat shrink the length of wire that runs to the pot?

OK, everything else he presents, I agree with, BTW.

What confuses me about the pic is that the normal channel in a Vox TB circuit, having only one triode stage for gain, wouldn't have any usable volume if you replaced it's .047 coupling cap with a 500pf cap. I mean, it has gain because it is presenting a lot of bass. And I don't think I was hearing this when I heard the amp that I heard. It is possible that the bass control was never turned to '0' I suppose.

Lastly, the Volume pot is 500K, the Cut pot is 250K, but what is the value of the Bass pot? Here is where I think some magic might exist. For example, if you made it 3M, then the parallel cap would definitely be out of the circuit when the pot was on '0'. But what if it was a resistive value that let the bass cap bleed into the primary coupling cap? This may be why the amp I heard wasn't as thin as this circuit might be if the bass control was turned to '0'. See what I mean? It could very well be that the bass cap is also constantly 'in the circuit' but as you turn it to '10' it would be all in.

Well, something to think about.

[M Fowler]

The two 20uf caps B+3 and B+4 have their independent dropping resistors (probably 22k) feed by the B+2 cap to the single turret in front of the four EL84's feeding the 100R screen resistors.

[selloutrr]

Lastly, the Volume pot is 500K, the Cut pot is 250K, but what is the value of the Bass pot? Here is where I think some magic might exist. For example, if you made it 3M, then the parallel cap would definitely be out of the circuit when the pot was on '0'. But what if it was a resistive value that let the bass cap bleed into the primary coupling cap? This may be why the amp I heard wasn't as thin as this circuit might be if the bass control was turned to '0'. See what I mean? It could very well be that the bass cap is also constantly 'in the circuit' but as you turn it to '10' it would be all in.

Well, something to think about.

I see where you are going with this. If you consider the amp was made with parts on hand. We know ken had 1Meg pots.

[rooster]

selloutrr - Yeah, kinda different. I suspect there may be some old Selmer amp out there, something, that has something similar. The Zodiac Twin 50 and 30 have a 470pf cap bridged with two 220k resitors, a .01 cap, and a 1 meg pot affair - more moving parts and attached differently - but maybe there is some connection. I know Ken had an ear for tone and a fondness for things English. Eh, who knows? There could certainly be a cap and a resistor within the heat shrink, and there could be a resistor that exits the part, for that matter.

Hm. I don't want to get too crazy here and find out that there's a cigar butt in there...

At this point I would ask all readers here who are curious about this idea to see if they can find something somewhere that is similar. ???

[selloutrr]

I would bring your search closer to Ampeg influence.

To bad you don't know the exact end result. You could toss values around in a tone stack simulator and figure it out pretty quick.

[Reeltarded]

Does any one have good information or an intelligent guess otherwise what the switches on the front panel of the "Inger" amp are?


rj

AHA! I found you. STOP TURNING ON MY BATHROOM LIGHTS

Thanks, rj.. goodnight.. STOP!

omg really? You're so vindictive.

[rhinson]

the rocket was simply an ac30 top boost ch with a couple of minor changes. this amp is an ac30 NON top boost type ch with a couple of changes. the bass pot just lets you go from the "treb" channel (500pf coupler) to the "normal" channel (.047uf coupler). he's got some series resistance after that which is bypassed by a bright cap, and the vol pot and some more series resistance after that then the pi coupler. all the pi couplers are the same value---.047uf. i'd guess the bright sw is the standard 3 way 100pf/off/500pf-----but you could do that to taste. and yes there does appear to be some nfb from one of the op trans taps----the tail resistor value could be divided up and inserted nfb inserted there, hence the 2 resistors there. this one let's komet use up some of the spare connie trannie sets rh

What I see is a static cap, probably 500pf (maybe slightly more?) (in red heatshrink), and then a simple parallel bridge of a larger cap controlled by a pot. Like rhinson, I can't imagine it is any larger than .022, but maybe .047 as rhinson says. Rhinson is saying something like this, yes, but he fails to state that the 500pf cap is always in the circuit, that the bass control is just adding capicitance to the 500pf coupling cap to create more bass. Also, this larger cap that joins in parallel to the 500pf cap seems to have some type of extra mass at the pot side exit. A resistor? Why heat shrink the length of wire that runs to the pot?

i think the wire is heat shrinked simply to keep it from possibly touching the pot body. and i don't think there's a resistor there----he added (and heatshrinked) a bigger dia. piece of lead wire to the cap for stability and length, and the bulge is where he wrapped them and soldered them together.

you can tell the bass pot is diff from the other 2---- it's a clarostat. value is anyone's guess----smoothly adding and transitioning 2 capacitor values together with a pot is a bit of a trick in practice---it least (with off the shelf parts) it has been for me
you could always just do matchless, etc. rotary switch thing here with multiple caps---might be better in fact. rh