Mesa Boogie DIY!

[Gabster]

Hi,

I recently found schematics for many mesa boogie guitar amplifiers (here) . The one I'm the most interested in is the dual rectifier solo head (one of my friends has one and it is amazing). All the schematics seem there, the goal is to build a replica.

I have two major concerns:

1) Is that kind of project doable? The guy on the site seems pretty sure it's not a good idea (read comment in red at the top). I think it's just a comment to avoid to receive 100's of emails about this. Using the schematics we can do a lot!

2) Is it possible to find the transformers? Is it easy to get these as replacement parts from mesa boogie?

The bottom line:
Is it people out there who ever succeeced in that kind of project and/or would be interested to invest time to give it a try? I'm seeking for people who have knowledge and would be active members of the thread "The DIY Mesa/Boogie project".

regards,
Gabriel

 

[wasp]

Hi Gabster,
1) Yes is possible to build a clone: I built several
2) The parts are widely available. And also not as direct replacement.
Ask me more informations if required.

 

[tschrama]

Hi,

Would like indeed. I'm busy for more than a week now on a high-gain SE EL83 guitar amp but I keep having problems with hums, buzzes and crackles... Do you have a website?



gr,
Thijs.

 

[dice45]

...high-gain SE EL83 guitar...

Are you sure it is not EL84 or EL86 ?
EL83 is an odd number and would have non-linear, regulating-purpose transfer characteristics.

 

[Gabster]

I'm happy there's some interest.

wasp, what was your tactics when building clones? Did you only used the schematics? What did you build?

I had the idea to find a cheap non working dual rectifier (I hope I can find one), use the original PCB as a reference for the layout, built the clone, fix the amp and sell it to repay what I've built.

With the schematics and the original PCB it should be easy to end up with a good replica. Furthermore, I would also try to build a box like the real thing...shouldn't be hard, simple design.

tschrama, sorry no website. I'll update this thread as soon I have something.

now, let's see if I can find what I need...

regards,
Gabriel

 

[wasp]

Hi Gabster,
I have built 4 JTM 45 Marsciall, 2 Showma Fonder, and various little SE guitar amp.
The layouts are drawn by myself or, for the Showma, using the original one.
If You gain experience with tubes all the amplifier are laid out the same way.
The hard thing in building amplifiers isn't the layout but: the cabinet, the finish, the chassis, the covering and last but not least the sound.
To acquire knowledge I think it's better to start building little things: small preamplifiers o little se, with low gain.
Wasp.

 

[tschrama]

Oops...

I mean EL84 (not EL83), a small 12watt penthode, used alot in small guitar amplifiers. I got rid of the hums and buzzzis.. today I learned:

(1) allways give the heater connections a reference to ground (like the schematic dammit).
(2) Used non-microphonic tubes.

These two rules make life alot easier.

gr,
thijs

 

[Gabster]

hey wasp, what about the transformers on the clone you built? Were they standard or did you acquire replacement parts from Marshall?

 

[wasp]

Hi Gabster,
I tried transformers from various makers and "replacement".
I quote them becasue theyr'nt original from marzhall but clones from MagicParts.
The results were very good with both.
I upgraded the trafos on marzhall heads with one from MP and the sound became "more wide".
The result is obvious: the original trafos had a narrower bandwidth.
Even if you can read that the reduced bandwidth smooth the harness of sound I prefer to use wide band trafos and shape the tone in the preamp.
I found that to obtain a good design I have to follow some rules:
1) Define what's a good sound. For me, heavy metal fan, is a deep distortion, articulated and aggressive.
2) The mix of preamp and power stage is important: in the preamp I shape the tone, the output must be more linear and fast (dinamic) as possible: ultralinear topology.
3) In the preamp I cut away the bass part of sound, distort, and then emphasize the bass. In pratice this "little trick" gives me a distortion very Zoldano but with the plus that the UL output stage preserve the detail of sound even if very overdriven.
Now I'll go on holyday till the 5th of August, cu all later.

 

[wasp]

Back to reality

Hi Gabster,
I'm back.
In these days I'm designing a 3 channnel guitar preamplifier, only tubes inside.
The 3 channels are :clean,crunch and distortion.
The 2 tone stacks, a classic 1 res, 3 caps, 3 pots is after the gain stages.
In each channel there is a boost.
In the clean channel there are: deep,mid and bright switch.
In the rush and distortion only mid and bright.
In the rectification of the anodic current I use diodes, paralled with caps.
Other infos available on request.
I know that You are interested in a Meza Boogee clone but my time is very limited and I could only help with the project of the 3ch preamp.
If You want we could start a "open project".
Hope to hear soon.
Wasp

 

[Wyatt Turk]

Boy is this an old subject I have only sean one company that claim to sell Mesa Boogie output transformers. Most people use Marshall traniers as replacement ones.

I have emailed Mesa direct myself and they do sell ther transformers to the public but they come at a price I was quoted $530.00 AUD for one. So I would stick to the Tried method and mix a marshall out but with a Mesa front end you should get a similar tone.


Wyatt

 

[Naigenoir]

I build a mesa boogie clone.
I searched for drawings of the chassis ... but nothing Where I can find them?
I need at least dimensions of the Mesa head.

Thanks.

 

[szabogabor]

help

Hi, I'm from Hungary. I want to make an Boogie Mark III. Have you maybe a PCB and/or a part list? Thank you so much! Gabor

 

[aletheian]

I built a Bogie Recto clone (just the red channel) for a recording project once, because I thougt the project would benefit from the tone, but there were a few things about the sound of the stock head that i really hated (noise being one of them, and the cold bias of the output tubes). It worked out fine and sounded 10x better -- in my opinion -- than the real Recto. So go ahead and do it if you want. Just becareful about lead dress and layout or you will have a noisy oscillatng mess.

 

[peterpan73]

HOw much will this cost

How much will it cost in parts to complete the Mesa Boogie Dual Rect Clone Project?? Ballpark will do.

 

[foul_owl]

Four quick questions about dual rect clone

I am attempting to build this clone:

http://www.freeinfosociety.com/electronics/schemview.php?id=507

Four quick questions:

1. For the caps that aren't labeled, what voltage rating should they be?

2. Can I bump this sucker up to 150 watts by adding two more 6L6's, two more 1K/2W resistors, 2 more 1.5 K resistors, and bumping the wattage rating of the output transformer up to 150?

3. Any guidelines for component layout to avoid noise?

4. What wattage should the pots be? I'm going with 1/2 watt for all the other resistors, should the pots be 1/2 watt or is 1/4 watt ok?

Thanks!!

 

[marginwalker]

Hi guys, any news? i'm very interested with the boogie... is there a genuine schematic laying around? aletheian, would you share yours?

I'm currently building the OD channel of a bogner xtc, you can find the thread on sloclone forum, but it's just time to start building another preamp and the recto will be the one

 

[gingertube]

Gingertubes Guitar Amp Opinions

I've built a heap of guitar and HiFi Tube Amps.

Reading between the lines I can see several fairly smart fellows in the posts above.

Taking out the essential details for the benefit and learning of others.

The heavy overdrive sound of the Mesa's (and others) are developed in the preamp and you need to run a fairly fast and clean output stage to preserve that sound (see above someone is using an ultralinear output stage - checked back it was "wasp", he obviously knows what he's doing).

With that sort (clean) of output stage tube rectifiers will do absolutely nothing. Save money and complication and vastly improve reliability by using Solid State rectifiers. The Dual and Triple Rectifier stuff is pure marketing BS (something for which Mesa is renown). A tube rectifier will give some advantages in a vintage low gain blues amp, it makes zero difference to the sound in high gain amps where 95% of the sound is developed in the preamp. In fact tube rectifiers can only make high gain guitar amps sound worse not better.

The secrets (common sense) to a good high gain preamps:
- 3 stages with solid state diode soft signal level bounding or 4 stages without the diode bounding.
5 stage things like Peavey 5150 are just too noisey
- Interstage attenuators such that each stage can not overdrive the next stage by more than say 9dB
- tone / frequency shaping done primarily in those interstage attenuators (capacitor bypasses on the top arm of the attenuator to emphasize the harmonics)
- restrict the amount of deep bass by using small coupling caps and small or no cathode bypass caps.
- in the final couple of stages where overdrive is largest use big (100K or even 220K) grid stop resistors to limit grid current and intermodulation distortion and roll off higher order harmonics.
- adequately bypass the High Voltage rail for EVERY stage.

If using reverb on a high gain amp then the 3 spring, full length long delay tank is what you need. The medium delay tanks just get too sonically messy and I've never heard a decent reberb sound out of any sort of amp (high or low gain) using the short tanks.

In my view Mesa falls down on a couple of these points.

Buy Kevin O'Connor's TUT3 from London Power Press for some well thought out DIY Guitar Amp designs (and possibly TUT 5 as well).

Cheers,
Ian

 

[marginwalker]

Ian, very interesting tips! but what's the diode bounding?

 

[marginwalker]

Re: Four quick questions about dual rect clone

1. For the caps that aren't labeled, what voltage rating should they be?

2. Can I bump this sucker up to 150 watts by adding two more 6L6's, two more 1K/2W resistors, 2 more 1.5 K resistors, and bumping the wattage rating of the output transformer up to 150?

3. Any guidelines for component layout to avoid noise?

4. What wattage should the pots be? I'm going with 1/2 watt for all the other resistors, should the pots be 1/2 watt or is 1/4 watt ok?

1. 220u caps in the psu MUST be rated for 300V or above (they see only half of the full secondary voltage), 47u for 500V. In the preamp section go for 600V polyester and silver mica in the range of pF.

2. i don't know exactly but i don't think this would be that easy.

3. run heaters with DC supply

4. i suggest 2W resistor in the psu section, on tube's anodes and that 100k on the cathode follower.
1/2W for all other resistors is ok.
as pots, standard alpha pots will be just fine.

hope it helps!

marco