18Watt.com

I Just built my first amp, a Richie TMB 18 watt head. My local amp tech (a good friend) looked it over and fired it up for me so I didn't fry myself. It worked on the first try (Beginners Luck), but I had to correct a couple of small things. Here are the details:

Board: Nik from Ceriatone (Great guy, great board, excellent service)
Chassis, Plexi Panels, and Trannies: Graydon
Misc Parts: Mouser & my local amp tech

Total Cost: Roughly $450-$500

Background:
I play in classic rock/soul/r&b cover band. I currently use an 81 Marshall 2204 EL34 100 watt MV head, with no effects or pedals (TONE KILLERS!). I play an 81 Les Paul Standard with Lindy fralin 59's. My cabinet is a close back Jenkins Sound 2x12 w/ celestion greenbacks (Jenkins no longer makes this awesome cab). Anyway, I use my volume controls to go from clean to dirty, but my 2204 head doesn't really sound great unless its on 5, which is usually too loud for most clubs/bars I play.

When I discovered the legend of the 18 watt, I knew I had to have one, but $1800 was way out of my price range. Also, the 18watt tremolo channel seemed like an incredible waste, so I decided to build my own and go with the Richie TMB design. I would have went with a "lite", but being that the graydon chassis has all those holes, I figured, what the hell..

Unfortunately, it doesn't seem like anybody else had built the Richie TMB except for Richie himself. Also, the Richie TMB layout is WOEFULLY incomplete, so I had to figure out how to read the schematic and piece together a complete layout from others layouts of the "Normal" 18.

Here are some of the problems I encountered:

1. V2 and V3 are reversed on the TMB layout.

2. The TMB layout does not show the V1 pins in numerical order.

3. The TMB layout does not show the second filter stage.

4. Input #1 on the TMB layout refers to the Master Volume Channel, Input #2 is the Normal Channel.

Power Tubes:
EI EL84s

Output Tranny:
Running at 4ohms to match the cab.

SOUND
First Impression - Is this thing on? This amp is UNBELIEVEABLY QUIET!! I made sure to keep all my wires in the "right" places. I also used shielded wire for my inputs with one side of the shield going to ground on the jack.

Normal Channel on 1-4: What a tremendously Clean, brillant and bright sound, but with nice warm bass! LOUD. LOUD. LOUD. Such clarity. No Marshall I ever played sounded this good clean. It shamed the famous "Fender Clean" tone. I could swear it was an Ampeg.

Normal Channel on 5-10: Woah. Did someone switch amps on me? Hello Plexi crunch. Gain City. On "10" its got plenty of full, crispy gain.

Tone Control: This seems to add warmth and bass when its down low, and it acts more like a PRESENCE control when its up higher, it adds sizzle, not ice-picky high-end.

The Master Volume Channel:
This channel doesn't sound as good as the normal channel, not as much clarity. The TMB controls work *somewhat* but they don't have a wide sweep like a normal marshall. The master volume doesn't really work too well, it still needs to be loud to get a good sound.

Overall:
This amp has so much more high-end than my 2204, it seems to detail every nuance of the sound of my les paul so much clearer. I'm using a 22.5uf filter cap for the second filter stage - What would this amp sound like without it? This amp is LOUD as HELL. Don't even THINK this sucker is suitable for an apartment. This amp is perfect for a stage volume rig, but definately louder than a sound man would like.

Anyway, I will be uploading some clips tonight, so you can hear what it sounds like. The pics have been uploaded to Pattersongray, so hopefully Gabi will make an album for me.

Jersey Aaron

jersey_aaron wrote: Unfortunately, it doesn't seem like anybody else had built the Richie TMB except for Richie himself. Also, the Richie TMB layout is WOEFULLY incomplete, so I had to figure out how to read the schematic and piece together a complete layout from others layouts of the "Normal" 18.
Jersey Aaron

I have a drawing done up for a Richie TMB. I am not sure if it matches anything on this board as I got input straight from Richie. I have the board built but I still haven't finish punching the chassis as I am working on a stock trem head at the moment. With Richie's permission I could post the drawing that I have.

Norm

If you look in the TROUBLESHOOTING gallery, I have an ammended version of the TMB layout, which has alot more information, but its still incomplete. I could create a complete layout based on my proven build of the Ritchie TMB, but it would take a while to do in photoshop..

Well that was a pretty good write up, and if Norm doesn't have a copy of the layout drawing,i think i still have a copy. the pic of the black amp uses the TMB ..And the channel with the MV should have tons of gain. I used the MV more of a balance between the 2 channel volumes. It is, or will be a nastier sounding channel,with sustain and over driven. So if its not doing this, something must be not quite right. And everyone that has heard it seems they can't believe its as loud as it is. As for the controls,I useally set them on the TMB..treble and middle maxed..and bass on 2..
and depending if you want a little less nids,roll it back some. But useually treble on this channel is on 10.. And this amp,as i explained to Norm, is wide open to many tweaks. But you have my permission to post or pass it around. Maybe even remove the one posted,and replace it with the one Norm drew up.

Richie

Hey Aaron!

I created an album for you... Check it out...

Congrats! it looks good! If you record mp3s we'll post them too...


gab.

Gabi,

Here is a link to a pdf of my drawing. I couldn't put in in the troubleshooting gallery because it won't allow pdfs. Could you put it somewhere?

Norm

http://webpages.charter.net/normanfrech ... MB%202.pdf

Gab - Thanks!

Rich - You are totally right about the Master Volume Channel! I had to put the bass on 0 and the Treble and Mids on 7 to get a sound I liked.

It seems to me that the Master Volume Channel has too much bass, maybe cutting that 25uf bypass cap on the cathode resistor would help.

Also, what are your thoughts on adding a 100pf-470pf cap across pins 1&6 on V2 going to the phase splitter to cut treble?

Excuse me if none of this makes sense, I'm still learning the terminology.

Well, like i said,this circut can be tweaked to more what your after..
Its basicly a plexi type marshall,the channel with the MV.. And this one is set up to be somewhat more like the bass amp circut.

If you wanted the lead circut,change the 56K tone slope..or resistor before your tone caps. to 33k or 47K 33K will give more treble,and a little bit of a boost.

And if you used the values in the old layout,looks like you have the .1 and .047 change these to .022 both of them..and the mica treble cap to a 330pf or 470pf

If you need more treble,you can also add a 470pf cap across the 470K resistor going to the input of the tube{think you put yours in the V3 spot}

A Small cap across the volume pot will also work..kinda like a bright cap.
You can look at the traynor tweak page..or about any marshall mod pages..and see the tweaks. everyone has done these for a long time.

The cathode resistor can also be changed on this tube to 1.5k or 2.7k to lessen the gain..then add a .68 cap for a mid boost.

These are all for the channel with the MV.. you can even change the coupling cap going to the volume control from the .022 to a .01 or .0022
I never liked the .022 much..makes the marshall amps too bright sounding.

You can try just the changes in the tone caps first. Then add or change the others one at a time and see if you like them. Theres just alot you can do. But its all simple stuff.. Try to use something besides the Orange drops.

Richie

"""100pf-470pf cap across pins 1&6 on V2 going to the phase splitter to cut treble? """
well that would effect both channels in that position..

If the normal channel is bright,just roll back the tone control..

When the circut is like this,you can change it to more of a 5F3 tone control for the normal channel.. But you seem to like it.. But its maybe a 5 min job to change things to try..

Richie

I must say if I were building this amp, I would feel sorely tempted to reduce V1a's cathode cap to around 1uF, and to also place a similar cap at V2a's cathode, to both increase gain and tighten up the low end when cranked....

Richie, I took your advice. I changed the:

1. The .1 and .047 tone caps to 22uf

2. The 56k slope resistor to 47k

3. The treble cap from 250pf to 330pf

MUCH BETTER! *Now* the Master Volume Channel is kicking ass and taking names. However, my only peeve is that the Master Volume's pot sweep stinks. A LARGE portion of the volume changes occur between 1 and 2 on the knob, this is where I need to expand that sweep. Is there a cap or something that I can add across the pot to fix this??

Richie, one other thing, all of the .01uf caps on the TMB layout are listed as 100n on the schematic.

Also, the 10n bass cap on the schematic is listed as .1 on the layout.

If my math is correct, both of these are decimal point/conversion errors.

jersey_aaron wrote: 1. The .1 and .047 tone caps to 22uf

And a 22uF tone cap isn't a decimal point/conversion error?

DOH! Seriously though, someone should revise the schematic!

"""caps to 22uf """ should be .022 which you probably did.

As for the taper of the MV.. are you useing an Audio pot or linear?
Should be Audio.. Try a 500K Auido MV Pot

"""I would feel sorely tempted to reduce V1a's cathode cap to around 1uF,""

The way its set up is too add a bit more bass.. see below.


Also the schematic is wrong{i don't draw schematics}.. the V1a and B sides are swapped..

If you went by the layout..the Normal channel has a 50uf bypass cap and 820 resistor..

And the side for the TMB ..cathode is 820/25 And if the TMB side has a bit too much gain..change the resistor to a 1.5k or 2.2K or 2.7K You should still have plenty of gain, but you'll have a bit more use of volume control.. Meaning You can have more clean room,and then it start to break up at more the end of the pot control setting..

Norm and I both have a couple better layouts.. i could send them to you.

Gabi is off camping,so maybe when he returns,he can pull the schematic..and Put in the better layouts..

Richie

Thanks guys. Richie, definately upload the new layouts to Gabi!

I'm relatively happy with the Normal channel. I tried putting a 220pf cap across the grids on the phase invertor tube and it DID take away some of the highs, but I kind of liked the "sparkle" I was getting without it. The only time it really gets "edgy" is when I roll my volume knob off on my guitar to get clean sounds (I tweaked the treble bleed caps on my paul for my MV head, so I guess I will have to try some lower values if I'm going to use this amp).

The Normal Channel stays clean up to 5. From 5-7 is the sweet spot for distortion. By this time, its the same loudness as my 100watt 2204 head at gig level. From 7-8 its Eddie Van Halen, Randy Rhodes-type distortion. but it starts to lose a wee bit of "tightness". From 9-10 you can tell that the Power Tubes are crushing the highs and lows.

I think that adding more gain at lower volume is only going to reduce the flexibility of this channel, and it sounds pretty damn good the way it is now! I would rather tweak the MV channel and make that my lower volume "rehearsal space" channel.

The MV channel sounds close to the Normal Channel, but it has less "high end" and more bass. I'd like to get rid of some of that bass so I don't have to keep that knob on zero. I will try adding different value resistors to its cathode to knock the gain down a bit, and try a few of your other suggestions to recapture some treble. I will post some sound clips of that channel when I get it right!!

Jersey Aaron

jersey_aaron wrote:The MV channel sounds close to the Normal Channel, but it has less "high end" and more bass. I'd like to get rid of some of that bass so I don't have to keep that knob on zero.

Just reduce the cathode bypass cap on the MV channel to around 1uF...

Hi Aaron,

Go with what your ears tell you, I guess.

The guys have given much advice on the tweaks.

But, isnt this kind of familiar? We didnt have the original schematic until Ian's amp. Now the work for "original" TMB is on the way

Richie, hope to be able to see the actual circuit soon. I dont even know what I messed up Hehe.. seriously, thanks for the TMB...


Nik

Zaphod Phil is THE MAN. I went to go reduce the cap on my MV channel, when I noticed the 50uf cap on my Normal Channel cathode was hooked up BACKWARDS all along!! (Rookie mistake). So, when I hooked the cap up the right way, the Normal Channel lost all of its high end and started breaking up at about 4-5. Sounded like somebody put a blanket on the amp. Its beautiful clean tone went down the crapper. Anyway, I put a 1uf cap on that channel (to replicate the 50uf not being hooked up right) and it was back to the way I liked it!

So then I figured out why I don't like my MV channel. I immedately removed its 25uf cathode cap and replaced it with a 1uf. Whooahh! Awesome sound. More Bass. Guess which channel is my favorite *NOW*..

Thanks Zaphod Phil.

You're welcome! No one expects that by reducing the value of a cap you can sometimes get more bass - or least what sounds like it. Two heads are better than one, they say...