50w highgain mod

[dukeamps]

Hi Guys, here's an amp i have modded, its was originally a trainwreck express amp. Here is a couple of clips of how the amp sounds.

http://soundclick.com/share.cfm?id=9934173

http://soundclick.com/share.cfm?id=9646821

http://soundclick.com/share.cfm?id=9937439

So if you are interested in doing this follow this.

First mod your amp to a 2203 or 2204,

The input resistor is 33k, & do the shield trick on the input, instead of the shield going to ground connect it to the anode, then put a 500pf over the second plate resistor, .1uf over the 10k, .68uf over the 820r, 1000pf bright cap, 500pf sounds also nice, the tone stack is 33k/500pf, & the most important thing is you have to lower the b+ down to 390v, then bias the el34s at 31.5ma, then you get the brown sound in the mix.
NFB is 47k/.1uf/.68uf what ever you like best, 4ohm tap. Fizz cap is 100pf

The transformers are originally from a trainwreck express amp, bought from marstran, the pt already has the lower b+ so you don’t have to use any zener diodes to drop the b+ down. I also bought the choke there too, but you could also try it on any amp & see how it sounds, just make sure that if it’s a 50w jmp drop the b+ from 440v down to 390v & if it’s a 100w jmp drop the b+ from 480v down to 430v.

Cheers

Nigel

Ps only try this if you know what you are doing

[Richie]

Cool clips Nigel.
Mark has alot of clips of modded 2203 pre, and has a wreck version too. And about all the other mods.
you can listen to what they sound like with different changes made. Great place to check out if you haven't been there.
http://www.soundclick.com/bands/default ... tent=music

[dukeamps]

Cool clips Nigel.
Mark has alot of clips of modded 2203 pre, and has a wreck version too. And about all the other mods.
you can listen to what they sound like with different changes made. Great place to check out if you haven't been there.
http://www.soundclick.com/bands/default ... tent=music

Hi Richie, thanks for the feedback & the link, I'm going to check that out.

Cheers

Nigel

[Decko]

Hi Nigel,

I liked what I heard there! Heavy...

Can you further explain what is happening in the amp sections that gives you that sizzle?

Regards,
Danny

[dukeamps]

Hi Nigel,

I liked what I heard there! Heavy...

Can you further explain what is happening in the amp sections that gives you that sizzle?

Regards,
Danny

Hi Danny thanks for the feedback What is it you would like to know exactly?

Cheers

Nigel

[M Fowler]

Finally had a chance to listen to the clips and they are good love the high gain.

Mark

[dukeamps]

Finally had a chance to listen to the clips and they are good love the high gain.

Mark

Hi Mark, thanks for the feedback

Cheers

Nigel

[gldtp99]

Cool Tone !!
Here's a clip of some similar amps i've modded/built lately---the solo tracks are the white 14 watter in the pic, with a Wha pedal. This preamp is similar to the mods you've described--- EL84 x 2, cathode biased--- lo-budget PT from MPS (PT190), OT pulled from old EL84 x 2 PA head, 125C3A-type choke from Magnetic Components--- V1 plate resistors 82k-- V1 coupling caps are .015/630V (? brand--- blue film caps from West Florida Components)---all=lo buck build.
I let my two friends loose in the studio to make amp demos and this is what they came up with. James brought the drums/bass backing track he made up on his computer. James did all the guitars except the shorter solo (panned left). This was Bobby.
It's hard to tell, but there are three different amps used in the clip----two 50 watters used for rhythm tracks----- a 4010 Marshall 1x12 combo with similar mods and a 4 gain stage version head using 6L6GC's (this one has Magnetic Components Bassman-type 4/8/16 ohm OT p/n 40-18001 w/M6 steel used).
http://soundclick.com/share.cfm?id=9924119

I've build or modded five different amps lately that are all using similar mods---- 3 and 4 gain stages--- 14, 25, and 50 watters----some have Lar/Mar PPIMV, some have Resonance control---different approaches on preamps, etc---- the 14 watter also has a Pentode/Triode switch for even less overall power---fun stuff......................gldtp99

[dukeamps]

Cool Tone !!
Here's a clip of some similar amps i've modded/built lately---the solo tracks are the white 14 watter in the pic, with a Wha pedal. This preamp is similar to the mods you've described--- EL84 x 2, cathode biased--- lo-budget PT from MPS (PT190), OT pulled from old EL84 x 2 PA head, 125C3A-type choke from Magnetic Components--- V1 plate resistors 82k-- V1 coupling caps are .015/630V (? brand--- blue film caps from West Florida Components)---all=lo buck build.
I let my two friends loose in the studio to make amp demos and this is what they came up with. James brought the drums/bass backing track he made up on his computer. James did all the guitars except the shorter solo (panned left). This was Bobby.
It's hard to tell, but there are three different amps used in the clip----two 50 watters used for rhythm tracks----- a 4010 Marshall 1x12 combo with similar mods and a 4 gain stage version head using 6L6GC's (this one has Magnetic Components Bassman-type 4/8/16 ohm OT p/n 40-18001 w/M6 steel used).
http://soundclick.com/share.cfm?id=9924119

I've build or modded five different amps lately that are all using similar mods---- 3 and 4 gain stages--- 14, 25, and 50 watters----some have Lar/Mar PPIMV, some have Resonance control---different approaches on preamps, etc---- the 14 watter also has a Pentode/Triode switch for even less overall power---fun stuff......................gldtp99

Hi gldtp99, your mods sound really good what way have you modded them exactly?

Cheers

Nigel

[M Fowler]

gldtp99,

Yes another good sounding high gain amp, well done guys.

Mark

[Decko]

Hi Nigel,

I liked what I heard there! Heavy...

Can you further explain what is happening in the amp sections that gives you that sizzle?

Regards,
Danny

Hi Danny thanks for the feedback What is it you would like to know exactly?

Cheers

Nigel

Hi Nigel,

I built a 4 watt Trainwreck Express and I would like to experiment with the preamp to create the tones that I heard but at low volumes. The amp is non master volume. I can modify the preamp to emulate the 2203 and 2204 preamp. What needs to happen at the PI and Power Section? I am using dual 6SN7's for power tubes. 4 triodes.

Regards,
Danny

[Decko]

Cool Tone !!
Here's a clip of some similar amps i've modded/built lately---the solo tracks are the white 14 watter in the pic, with a Wha pedal. This preamp is similar to the mods you've described--- EL84 x 2, cathode biased--- lo-budget PT from MPS (PT190), OT pulled from old EL84 x 2 PA head, 125C3A-type choke from Magnetic Components--- V1 plate resistors 82k-- V1 coupling caps are .015/630V (? brand--- blue film caps from West Florida Components)---all=lo buck build.
I let my two friends loose in the studio to make amp demos and this is what they came up with. James brought the drums/bass backing track he made up on his computer. James did all the guitars except the shorter solo (panned left). This was Bobby.
It's hard to tell, but there are three different amps used in the clip----two 50 watters used for rhythm tracks----- a 4010 Marshall 1x12 combo with similar mods and a 4 gain stage version head using 6L6GC's (this one has Magnetic Components Bassman-type 4/8/16 ohm OT p/n 40-18001 w/M6 steel used).
http://soundclick.com/share.cfm?id=9924119

I've build or modded five different amps lately that are all using similar mods---- 3 and 4 gain stages--- 14, 25, and 50 watters----some have Lar/Mar PPIMV, some have Resonance control---different approaches on preamps, etc---- the 14 watter also has a Pentode/Triode switch for even less overall power---fun stuff......................gldtp99

Killer tones!!! Wow!

[dukeamps]

Hi Nigel,

I liked what I heard there! Heavy...

Can you further explain what is happening in the amp sections that gives you that sizzle?

Regards,
Danny

Hi Danny thanks for the feedback What is it you would like to know exactly?

Cheers

Nigel

Hi Nigel,

I built a 4 watt Trainwreck Express and I would like to experiment with the preamp to create the tones that I heard but at low volumes. The amp is non master volume. I can modify the preamp to emulate the 2203 and 2204 preamp. What needs to happen at the PI and Power Section? I am using dual 6SN7's for power tubes. 4 triodes.

Regards,
Danny

Hi Danny, I would like to be able to help you but I have never used those tubes before that you have mentioned. Sure just mod your preamp & see what comes out.

Cheers

Nigel

[gldtp99]

Hi gldtp99, your mods sound really good what way have you modded them exactly?

Cheers

Nigel

Thanks for the kind words, guys---- i only have the 25 watter here at home---all the others are at my workshop across town.
25 Watter:
1) Heyboer 18 watt Marshall PT/OT, 125C1A-type choke from Magnetic Components
2) ss Rec-- UF4007 x 2 (each leg)
3) fixed bias--- Marshall style bias circuit-- 220k input res---- 56k resistor/20k bias pot in series
Preamp:
1)V1a--- 68k grid---- 2.7k/.68uF cath--- 82k/470pF plate--- .015uF coupler (blue marked "Full PPD" and ".015J630" sourced from West Florida Components, probably surplus)--- 47k to gain pot, no bright cap
2)V1b--- 10k/.1uF cathode---- grid is shielded cable with shield grounded--82k plate and .015uF coupler--- 470k/470k voltage divider, no bypass cap
3) V2a--- 1k/.68uF cathode--100k plate res (on tube socket)
4) tone stack--- 500pF silver mica/33k slope res/.022 Sozo Mid/Bass caps
5) 680pF/1000V ceramic cap to ground after MV pot and before .022 PI input cap (Sozo)
6) .047uF PI/Output coupling caps, Mallory 150's--- Lar/Mar PPIMV----25k Pres pot/.1 uF Pres cap
7) 82k NFB resistor connected to 8 ohm OT tap
8] Power Supply filtering is 40uF plates--- 20uF screens/22k dropper--- 20uF PI/10k dropper--- 20uF V2/10k dropper----- 20uF V1.
Filtering caps are a JJ 40/20/20/20uF 500V can and a seperate 20uF/450 axial mounted on the turret board
9) JJ 6V6S output tubes---- i've used many different 12ax7/ecc83 preamp tubes---now a Blackburn Mullard is in V1, GE short plate 12ax7a in V2, Sylvania long plate 12ax7 in PI

So it's a pretty generic 3 gain stage AFD-modded Marshall circuit in a 25-ish watt package------ the main reason i'm using the .015uF V1 couplers and 82k V1 plate resistors was to cut a little of the gain/bass out of the early part of the preamp (and i bought a bag of 25 of these caps for $6.89)---i orig had a 470pF bypass cap on the 470k/470k voltage divider but i found the amp way too bright, removing the 470pF bypass cap and adding the 680pF "treble dump" cap before the PI input cap (.022uF) made this one much smoother in overall tone response.
I tried a 250kA Gain pot early on to try and get rid of some of the hiss resulting from the added gain mods---- didn't like the sound of the 250kA pot so i tried a 1MegA with a 150k on wiper to ground----- didn't really like this either so i went with a 1MegA Gain pot and used the 680pF "treble dump" cap just before the .022uF PI input cap.
One of the players, Bobby, on the new demo clips likes this 25 watter the best out of the five different amps---he says that it sounds very much like his 50 watt Marshall Silver Jub head that he usually plays.
This 25 watter is the smoothest sounding of the five modded AFD-type amps ---- the others are a bit "on the edge"---all the amps have different mods, none are identical--- what's the fun in that ?............gldtp99
Pics:
http://s46.photobucket.com/albums/f112/ ... FD%20Guts/

This amp isn't the most photogenic, i know--- it's a test bed/prototype for mods----if i was to build another today, many things would be tighter looking---- it does sound good, though !!!...................gldtp99

[dukeamps]

Hi gldtp99, Thanks for the great info, that 25w amp sounds really good.
Would it be possible to tell me a bit more on the AFD Prototype Assembly amp, i really like that sound.

Just for a bit of fun here's a 18watt amp i have modded, it's not highgain but good for blues rock.

http://soundclick.com/share.cfm?id=9921659

Cheers

Nigel