Does anyone know about mods for the Haze?

[light_n_roses]

Hi all !

I'm new in the forum so hi to everyone !

I'm writing here because I have just brouch a used marshall haze 40 combo and I'm searching for some mod !
I actually like the amp it's very versatile and I like the effect, but I use it inside my room so I canno't turn the volume too high. In particolary I would like to obtain a more vintage sound from the overdrive channel, is there any mod to do this ?! ?

I have seen that has been reported this mod here :

I got a few.... The Haze, in its stock form, is a bit mellow sounding. The amp has basically the gain structure of a 2203 preamp, the boost circuit tweaks the cathode resistor and cap values of V2A to get more gain out of the circuit. We all know the 2203 is a very bright sounding amp, but Marshall has tweaked some of the highs out of the Haze. Since Marshall tone lives in the mids and highs, I wasn't too happy with this.

To get the overdrive channel a bit brighter, here's what you do:

1. C73 is a 220pF cap placed in parallel with the element of the overdrive volume pot. Change this cap to 68pF for a huge increase in treble quality in the overdrive stage. The cap needs to be there as with the cap totally removed there is a bit too much treble and the channel switching starts to pop a little. BTW, the volume pot is a dual 1M pot with one stage changing gain in the preamp, and the other as a standard master volume.

2. C72 is a 47pF treble bleed cap on the overdrive gain control (the famous bright cap). Parallel this cap with a 820pF cap to get more Marshally highs at low/mid gain settings.

These two simple mods make a big difference in the overdrive tone. They don't affect much else though. I am very happy with the amp with just these mods. The biggest benefit is you don't need the bright switch for overdrive to sound good with these mods; if you engage this switch it can also make the clean channel too bright.

but this is regarding bright I was intersted in vintage sound !!

 

[light_n_roses]

it seems that this guy obtain a better sound by just changing all the tube with the groove tube. here the video [ame=http://www.youtube.com/watch?v=SHMDWNexo2I]Marshall Haze40c mod - YouTube[/ame]

 

[Nikkep]

Do the caps mentioned have to be of a particular power rating (such as the replacement for c73 would be 50v) or will any cap labeled as 68pf suffice?

question base on this thread which has the haze 40 diagram:
http://music-electronics-forum.com/t16936/

 

[40-haze-tone]

ive seen a few mods for getting the amp less muddy, which is great, and i think i might even try some of them... but has anyone heard of getting a bit more gain? even with the boost switch, it's a bit low on gain. especially for something like a guns n roses lead sound, i can tell the amp has the tone in it. but the gain just isnt there... i found the "bainzy mod", which might give reasonable amounts of gain as long as i dont engage the boost switch although im a bit of a tube noob and so im not sure if i could do that mod on my amp, because as far as i can tell it was made for vintage marshall heads. does anyone more experienced know if it would be possible? if not, any ideas for other mods that might increase the gain???

 

[Denis]

The fix in the CATS-00163 document from Marshall does fix the problem completely (it did in mine at least). If you get an older one it can be fixed. You can tell if one has the fix if you pull the back off and check the following parts and values:

R90 = 1M

R100 = 220K

R101 = 1M

There are caps to change as well, but the resistors are the easiest to spot on the board. This assumes the caps (C33, C60, C68 and C71) were changed when the resistors were.

Hello!
This information is valid for haze Haze15?
Where can I find the source of this information, or a schematic?

 

[Denis]

Guys, help me!

 

[Nicodonald]

For the haze 15 I dit this :
remove c58 (47pF bright cap)
remove c59 and replace with 47pF bright cap (from c58)
Replace c12 by 2.2nF (v1a bypass cap)
Put a 1nF cap in c37 socket (v1b bypass cap)

It's a lot better but still a bit much of bass, especially for the OD channel,
I will change r15 (v1a cathode resistor) to 1.5k and c12 to 1nF

 

[flametop]

does anyone have a schmatic, or instructions to add a presence control to a haze 15.? I dont like the "bright" control...its either on or off....no in between. Thats really all I can find to fault the amp with. I like it fine otherwise. It sounds great through a 4/12. Thanx, ron.

 

[Jonathan Wilder]

One thing I highly recommend modding on these is the standby circuit. In stock form, the bias supply goes dead when switching to standby. I rewire the bias circuit input to the line side of the standby switch as opposed to the load side of the standby switch.

Requires minor PCB surgery to make it happen but anyone who can read a schematic can easily figure out how to do it.

 

[Medronio]

Hello.
I want to do the bright mod for od channel on my haze 15 head but i am new to pcb soldering. I soldered an effect pedal that ist working as it should and learned something about soldering, temperature etc. But i am quite concerned i may burn the pcb layers or something that will make the amp unusable cause the pcb is damaged.
Can you please give me some advice on how to desolder the caps c58 and c59 and some general info on pre mounted pcb soldering?
Regards and greetings from coalarea in germany (we have beautiful weather here right now, full sun and blue sky all over the place )

 

[Ken]

Hello.
I want to do the bright mod for od channel on my haze 15 head but i am new to pcb soldering. I soldered an effect pedal that ist working as it should and learned something about soldering, temperature etc. But i am quite concerned i may burn the pcb layers or something that will make the amp unusable cause the pcb is damaged.
Can you please give me some advice on how to desolder the caps c58 and c59 and some general info on pre mounted pcb soldering?
Regards and greetings from coalarea in germany (we have beautiful weather here right now, full sun and blue sky all over the place )

Just a few thoughts:

Get a proper soldering iron and a solder sucker, and a big magnifying glass is helpful. Also a good directional light.

Practice on junk pcb's to get some technique down. Be aware not to use more heat than you need, especially around transistors, diodes and IC's as they can fry. If you are working next to an IC connection and it can be pulled out of a holder, by all means do so.

It's not rocket science but neat soldering takes practice. I'm not nearly as skilled as the builders here but anyone can do a decent job with practice.

Ken

 

[Medronio]

Thanx so far.
i am asking myself if i can Touch the pcb with the soldering Iron, or if i better just heat the metal wires from the caps directly and try Not to Touch the Board.
i guess the pcb copper lines are very sensitive and a little too much heat or Else will destroy the lines.
Also should i, as i saw at a technician, put a little of my soldering silver (dont know the english translation) First on the melting point to make the fabric One liquid faster, so i Do Not need so much heat?
and what temperature can be a good starting point?
i almost everytime use a temperature between 350-400 degrees Celsius when i am soldering cause it makes the solder process fast and easy.
greetings from supersunny coalarea Germany (we have such a beautiful weather for days now, unbelievable and Not typic to Germany :-D )

 

[Ghostman]

One trick I use when desoldering is to add some solder to the joint before I remove. The added solder flux helps the flow and makes it much easier to remove the solder completely. If I get a small amount on the pad that just won't come out, I'll resolder the joint with new solder and then remove the new stuff. Again, it's the flux that aids to the flow of the solder.

This works especially well on mass manufactured boards as the solder used by a lot of manufacturers do not have flux to aid in the flow of the solder. Very common in solder bath type manufacturing facilities which is pretty much all of them. lol.

I've spent thousands of hours doing soldering and rework soldering for my jobs.

 

[Medronio]

Thanx! Thats what i saw too and what i will keep in mind and do.
What temperature do you use and do you touch the board soldering joint directly with the iron?

 

[Ghostman]

For most of my amp work in the DSL and the Haze I was using around 650F and a fine tip soldering pen. And yes, I touch the pad and the leg of the device I'm soldering or desoldering.

 

[Medronio]

Thank you so much Ghostman!
Now i can go on and give my best.
Do you have a recommendation for type of caps to use?
I guess they should be 630V capable, but what type of cap -> metal film, etc?
Regards

 

[Joska]

Yes, londonpower

 

[Joska]

would anybody know a mod that helps with the clarity (as in note separation) in the overdrive channel? overdrive 2 is so muddy that it's unusable. od 1 is ok but still needs improvement.

I just used 2 x 12 Vintage 30 from my Blues Juniors oversized cab at 2 days old Haze 40 and is sounding brighter-better. But I`m to new at Haze and vill make update how is going forward. Love this amp very much, it got that fantastic vintage sound that remains me a lott of second Zepp album. It is Mesa Boogie El 34 inside, don`t know what is in preamp, i have some TAD 7025 and have feeling they vill improve sound placed in V1

 

[Joska]

Does anyone have any ideas on how to add an effects loop to the Haze 15? I have emailed
http://www.skipzcircuits.com/Contact.html to see if their effects loop kit would work, I will post any findings.

http://www.londonpower.com/effects-loops theirs kits are very good

 

[jack daniels]

Or Marshall could have just addressed these issues before they released the Haze to the market. Mantra of business, "get your product out there first before anyone else does." Of course this doesn't address issues with bugs or design flaws.