"Dongbiter" 30 pics online

[M Fowler]

V1 is parallel with 27k grids, 1k5/25uf/25v bias, and 220k plate.

3m bass pot, 500k volume pot and 250kL cut pot.

The rest appears to be all Rocket but has NFB tied to 16R tap.

You may need to play around with values.

Mark

[Reeltarded]

This amp is just exceedingly clean?

[Structo]

Man that chassis is heavy duty!

[andrew]

just for fun is there a way to add a mid cut pot to this tonestack? Thanks.

[passfan]

V1 is parallel with 27k grids, 1k5/25uf/25v bias, and 220k plate.

3m bass pot, 500k volume pot and 250kL cut pot.

The rest appears to be all Rocket but has NFB tied to 16R tap.

You may need to play around with values.

Mark

Is this what you wound up with at V1 through trial and error or your best guess. It appears differently on your sketch back on page 5 of this thread.

[M Fowler]

Everything is trial and error but Randal told me what some of the values are and others are still under wrap

My layout was guessing as was rj's.

[passfan]

Here is my prototype. I just caught an error in the cath resistor of V1 but I will post anyway. This amp just......... something, it's hard to describe. You play it and it just feels like it wants to take off (feedback and sustain) but it doesn't. It's like it's right on the edge but it doesn't break , it's the coolest thing. It's not chimey but you hear with clarity. I'll hold a note and it will just fade out feeling like it's going to feedback but doesn't. I have an 820 ohm on the v1 cathode so I need to go back and change that out. Might have something to do with the amp breaking up like mad at full volume. I'm pushing the preamp too hard. I also have the 250k bass pot which is wrong. The effect is minimal there so I need to change that. I like it better with humbuckers but I've yet to tweak it any yet so all I have are first impressions . And , I have a small signal buzz which is present anytime a cable is plugged into the input (I was scrounging for parts and such so a proper jack will eliminate that, no worries).
B+ is running at 365 and output tubes are running about 50 ma's apiece. Here it is without further ado

[passfan]

Got a small opportunity to do some voicing this a.m. I changed the v1 cathode resistor to 1k5 , changed the PI coupling caps from the .047 to .005 and .1 off Aikens site for the 6SL7. It now has backed off the earlier tendancy to break like all hell at full volume. The changes to the PI have cleaned up the mud in the bottom and made my 250 kb bass pot more responsive. I am understanding the crappy NY amp show demo after having played with this thing overnight. The only way to play this thing seems to be wide open with a light pick attack. That is where all the magic is. At lower volumes you get the NY amp demo.....nothing special. I went from a Sylvania 6SL7GT and an Amperex 12AX7 to a GE 6SL7 short plate and a Mullard (Blackburn). This combination makes me want to play this thing all day. I've swapped out the 6SL7 with an RCA 6SN7 short plate (black) with excellent results. The breakup almost disapeared and I was left with all the "good stuff" ( I was able to be a bit more aggressive with my pick attack at full bore while still avoiding all out breakup). I wouldn't hesitate to build this version out and perhaps someone will finish one up with some EL84's and report about it. As soon as I can get my recording rig back up I will see about posting a clip or two.

[roberto]

Hi, what about PT, OT and choke specs for the version with a quad of EL84?

[roberto]

Maybe 5k2 Raa for the quad of EL84 (à la Liverpool), something around 330-350V B+ and an hammond 194E choke?

[randalp3000]

But how does it sound?

The first time I used it at a gig my impression was eh. My #1 amp is an original RX on the edge of breakup with a Cusack Screamer for dirt through a Gold in a custom Thiele 1x12 cab. The SW comes stock with sovtec 12ax7lp's which I think are ok for a PI if you can find a good one but I don't care for them in a v1 position. I threw a Eh in v1 that tested at 80-90% of spec of all tests on a Amplitrex which seems to have helped.

Last night at a gig I swapped to the SW for the last set and was quite surprised. The amp is ridiculously responsive where it's almost weird. I could get the volume up to 12:00 where it just started to breakup with a Dimarzio PAF. If you've played an amp without a tone stack that's what it sounds like eq wise. The difference between the two bright settings on the bright switch are very subtle, I think they're 200 + 250pf. The cleans sounded very nice, pretty flat without too much mid scoop with nice bottom and a bit of sparkle on top but not harsh. With the screamer it gets pretty gnarly, very fat with tons of harmonics and feeds back very easily. You can really hear the power section breaking up and for my taste I would have liked it to be a bit tighter on the bottom end. I would think with a SS recto it would stay tighter but the OP trans and choke seem a bit on the small size so maybe that could play a part in it.

It's an interesting amp, not sure yet if it will get my #1 spot. Sometimes I'm blown away by it and other times I wish I was using the RX or Zwreck. I'm ok with the ridiculous purchase because it only cost me 2 guitars and now it's out of my system. The build quality is very impressive but that shrink wrap is an annoyance.

hope this helps
rp

Wow did I screw up. I was doing some tube testing and decided to test the output tubes and the PI in this amp and discovered I put a 12AY7 in V1. I replaced both V1 and V2 with EH 12 ax7's that tested within 10% and some older JJ EL 84's that were about 30%(Amplitrex). This became a whole new amp, a lot more balls and it doesn't compress and flub out near as much when hitting it hard with my overdrive. Now it has a wicked snarl and will tear your head off.

This has become my favorite amp with the exception of not having enough clean volume. I like it really clean when I want clean and I want it to cut your face off. I run it with the bass and treble around 3:00 and volume between 9-11:00. This amp still has a weird feel, very dynamic even when it starts to clip. You have to really think about your pick attack when playing.

I think now I'm going to mess around with some different phase inverters to see if I can get just a touch more headroom.

[M Fowler]

Randal, that is great your enjoying the SW30. For clean you need to run two amps the other amp being a Dr Z Stangry, great clean powerful amp worth the price of admission.

Mark

[randalp3000]

Randal, that is great your enjoying the SW30. For clean you need to run two amps the other amp being a Dr Z Stangry, great clean powerful amp worth the price of admission.

Mark

I used one for about a year and still have one, a bit too scooped and now I find the top end a bit obnoxious and I like bright amps. The original Rx does pretty good and I've been wanting to use my Zwreck some more but I'm waiting to get it back from the shop. Looks like the power trans might have had some issues. I did score a Komet 60 and I'm hoping that will give me some more volume for the out door gigs where I seem to be lacking. Should be here tomorrow I'm also on the lookout for an AC50 at the moment to see if that will give me the clean Vox volume I'm looking for.

One of my favorite clean sounds is the DrZ Galaxie/tweed super but it get's too loose for my taste and not enough headroom. I have an Express chassis and I might do a Super pre into El34's. The 6L6's seem a bit slow to me and don't have the bite that I like. The El34's have a much higher transconductance which I think would make them more responsive like El84's.

thanks Mark
rp

[Lauchie]

I know the thread is old but the question fits: Is there any "most complete" schematic of the Songwriter around, with all the values being pretty zeroed in on?