Fourth preamp tube

Discuss our latest amp kit.

Moderator: VelvetGeorge

SDM
Senior Member
Posts: 1644
Joined: Sun Feb 26, 2006 6:24 am
Just the numbers in order: 13492
Location: MI
Contact:

Re: Fourth preamp tube

Post by SDM » Wed Dec 02, 2009 1:13 am

That layout came about when years ago some simply asked how an extra stage could be added to the front end of a 2203 amp in general. So it started as just a rather "generic" extra stage up front on a stock 2203 which he was then going to tweak to his liking.

As I recall he did just that, tweaked things to his liking and the layout reflects his changes, at least at some point. So just decided to throw the layout up on the site years ago, unclassified and with no descriptions, for the heck of it. Still only really meant as a general base for how a stage could be physically added to the front end for those that happened to stumble across it. Tweak as desired, take and leave bits as desired.

So anyway, it's not something I have ever built, just a layout I helped someone with years ago. Thought the base layout and some things in there could be of use to others for ideas, so decided to throw it on the site somewhere.

User avatar
LP Freak
Senior Member
Posts: 162
Joined: Sun Mar 08, 2009 6:42 pm
Just the numbers in order: 7

Re: Fourth preamp tube

Post by LP Freak » Wed Dec 02, 2009 11:19 am

As far as dialing in my own values, I'm new to this so I was looking for some help. I was wanting to experiment a little with the tone of the amp but I don't know my way around the board too well yet. Can you give me some advice on what to change and what to change them to?

RagnarMarGunn
Senior Member
Posts: 237
Joined: Tue Sep 09, 2008 4:05 am
Just the numbers in order: 7
Location: Iceland

Re: Fourth preamp tube

Post by RagnarMarGunn » Sat Jan 16, 2010 5:53 am

LP freak,

I used SMD´s layout to add an extra tube to my Metro 50W kit which I had converted from 1987 to 2204 (also SDM´s layout) and it´s simply great, at least to my ears. Did some clips:
http://soundclick.com/share?songid=8318163
Regards
Ragnar Már

'67 JMP 50W
'82 JCM 800 1959
'83 JCM 800 2203
'87 2554
'09 Metro JMP 2204
'10 SDM 2550X
'10 Metro JMP 2203

User avatar
LP Freak
Senior Member
Posts: 162
Joined: Sun Mar 08, 2009 6:42 pm
Just the numbers in order: 7

Re: Fourth preamp tube

Post by LP Freak » Sat Jan 16, 2010 6:03 pm

Wow, impressive!

User avatar
Kramer
Senior Member
Posts: 154
Joined: Sat Jun 13, 2009 11:23 am
Just the numbers in order: 7
Location: Pittsburgh

Re: Fourth preamp tube

Post by Kramer » Tue Jan 19, 2010 11:31 am

That's a great cover right there

joepete
Senior Member
Posts: 100
Joined: Sun Jan 14, 2007 4:05 pm

Re: Fourth preamp tube

Post by joepete » Sat Jan 30, 2010 10:42 pm

I had a 77 2203 modded with the extra tube and 2nd master volume and it was one of the best sounding Marshalls I have ever owned! IT was a bit noisy when the gain was cranked high but other then that it sounded awesome. I will try to find the layout 4 u

trubasser6778
New Member
Posts: 7
Joined: Sat Jan 23, 2010 1:22 am
Just the numbers in order: 7

Re: Fourth preamp tube

Post by trubasser6778 » Sun Jan 31, 2010 12:32 pm

Hey guys, I'm a complete newbie to all of this. I'm going to be building my first kit this spring and was looking to maybe add a 4th pre-amp tube myself. What I really wanted to be able to do is put in a second pre-amp gain control and a switch to be able to have essentially two channels one being the stock 2203 and one with the added gain stage each with their own gain control. Would this be possible or am I all wet?
Thanks,
Kyle

niksa
New Member
Posts: 8
Joined: Sun Feb 07, 2010 7:10 pm
Just the numbers in order: 7

Re: Fourth preamp tube

Post by niksa » Mon Feb 08, 2010 7:20 am

Hello guys I've just found this great forum.
I have question about this mod. When using 6550s after changing 3 resistors to another value, do I also need to connect negative feedback wire (with 1.5nF capacitor) to 4 ohm tap? It seems logical for me to do this. Thanks

Roe
Senior Member
Posts: 5008
Joined: Thu Apr 13, 2006 1:36 pm
Just the numbers in order: 7
Location: Drontheim. Norwegen
Contact:

Re: Fourth preamp tube

Post by Roe » Mon Feb 08, 2010 7:29 am

changing nfb with 6550s isn't necessary but it gives a tad more breakup and warmth
http://www.myspace.com/20bonesband" onclick="window.open(this.href);return false;
http://www.myspace.com/prostitutes" onclick="window.open(this.href);return false;
Super 100 amps: 1202-119 & 1202-84
JTM45 RS OT JTM50 JMP50 1959/2203/34/39

User avatar
jerrydyer
Senior Member
Posts: 3346
Joined: Fri Oct 15, 2004 6:13 pm
Location: Westminster, CA
Contact:

Re: Fourth preamp tube

Post by jerrydyer » Wed Mar 24, 2010 2:53 pm

that Landry sounds great.
vids.
http://www.youtube.com/user/jerrydyer?feature=mhw4" onclick="window.open(this.href);return false;
http://www.dui-specialist.com" onclick="window.open(this.href);return false;

erigm
Senior Member
Posts: 736
Joined: Wed Feb 01, 2006 11:29 am
Contact:

Re: Fourth preamp tube

Post by erigm » Tue May 04, 2010 3:26 pm

RagnarMarGunn wrote:LP freak,

I used SMD´s layout to add an extra tube to my Metro 50W kit which I had converted from 1987 to 2204 (also SDM´s layout) and it´s simply great, at least to my ears. Did some clips:
http://soundclick.com/share?songid=8318163
Just to clarify the layout that Ragnar used is different than the one posted earlier in this thread. The one posted earlier adds the gain stage in front of the standard 2204 circuit.
erigm

fusionbear
Senior Member
Posts: 93
Joined: Sun Dec 27, 2009 9:29 pm
Just the numbers in order: 7
Location: Southern California

Re: Fourth preamp tube

Post by fusionbear » Sat Dec 25, 2010 10:59 pm

Any reason you can't parallel the added gain stage tube? Hate to leave that other triode unused... :help:
Amps: diy JTM45/100, Trip-R, BV120H
Cabs: Scumback, Rockit, CA
Speakers: Scumback, EV12L
Guitars: Suhr,Epiphone, Ibanez

joshwilson3
Senior Member
Posts: 765
Joined: Fri Jun 17, 2005 4:48 am

Re: Fourth preamp tube

Post by joshwilson3 » Sat Jan 22, 2011 8:05 pm

What about adding an extra gain stage like whats on the Soldano Slo?

User avatar
rockstah
Senior Member
Posts: 12481
Joined: Thu Sep 15, 2005 12:28 pm
Just the numbers in order: 7
Location: Austin Texas

Re: Fourth preamp tube

Post by rockstah » Wed Feb 02, 2011 11:05 am

here is the clip i did with the rocco mod.
http://www.soundclick.com/bands/page_so ... ID=3877112" onclick="window.open(this.href);return false;
Mark

MaximumGtr
Senior Member
Posts: 83
Joined: Wed Sep 08, 2010 12:46 pm
Just the numbers in order: 7

Re: Fourth preamp tube

Post by MaximumGtr » Wed Feb 02, 2011 12:46 pm

Pretty freakin' sweet!
:toast:

Post Reply