MAX Forty "Devil"

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Re: MAX Forty "Devil"

Postby Kuli on Mon Feb 09, 2015 8:48 am

Racing wrote:Cool as snot!! :excited:

Thing is,i presume them cabs and the amp of yours is somewhat later versions? Seing the advent of greenbacks vs the older Celestions in that 312 of the Devil.?

Now,please don´t take this the wrong way but...i´m REALLY excited about taking delivery of the rig! Point being that i do the occasional tuber ´n...takes a bit to get me to tip toe these days :mrgreen: .
This MAX tho..does. You know the old saying,"the biggest nationalist there are..are people living abroad" :lol:

Thanx for the link. Pouls story is really sweet... :D

In turn we got a fella around town here,Gothenburg,that has the exact same amp you do. Have owned it since -69. Spoke to him the other day,told him i got a hold of one too,and he got about as excited as i am.
From what i gather there IS a difference between the "MAX Forty" and the "MAX 40". The former an amp that,from what i read in the original pamphlet,developed to cater to all sorts of instrument really. However,they were marketed with a guitar next to it?

What´s more i´ve come to understand that the two models differ quite extensively both in hardparts and topology? Anything you happen to know more of?


Yes I think they are really cool amps too and being Danish, I guess these Max amps are some of the only legacy we danes have regarding guitar tubes amps from the golden years of guitar amps during the 60's...
I too think the "MAX 40" is a later model than your "MAX Forty" - how do your friend like his "Max 40"?
'66 JTM 45
'66 JTM 45/100
'68 1959T Super Tremolo
'69 1987 Lead
'69 Royal Purple 1960B basketweave
'70 4x12" Park blue basketweave
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Re: MAX Forty "Devil"

Postby Racing on Mon Feb 09, 2015 10:23 am

Tommy..basically has had his refined over the yrs. Very close to stock if my info is correct,however even hardpts like OT asf has been replaced,out of pure necessity. The man handling the service of it is none less then Mr Niemand himself.

Michael in turn..i believe his is stock,and that he basically doesn´t use it all that much. Michael is a bit in the know from a tech POW and his biggest concern has been the real odd values of the James network.
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Re: MAX Forty "Devil"

Postby Racing on Wed Feb 11, 2015 11:28 am

Got to install a PPIMV and indeed..that made the volume out of this thing bearable.

Seems i´ve got a cold solderjoint or something tho..cause as the amp REALLY gets hot sound comes n goes...need to look into that.

Tone out of the amp tho is bar none. As stated imagine a GOOD JMP/Plexi just with more "air n open-ess" in the sound. REALLY good sounding amp.
Giving thought to repinning the preamp for 6n2p-EV´s tho. Them are REALLY good tubes and cheap to boot..and i´ve got a bundle of them laying around. Very close to the ECC-808´s in how they perform and repinning in this case is a matter of moving one wire really. Heaters go for pin 4 n 5...

YT clip coming up.

That said,time for phase 2.
Idea of mine is a minor 12VDC PSU unit to run a series of relays. I guess i could work with optos too but relays hand ya a definite "cut" in the signal. In turn i´m going to install a bracket inside the chassis,on existing fasteners,that holds an additional preamp tube. Non intrusive mods does it..and relays,PSU´s,brackets and what have you not can always be scrapped at will and the amp thus returned to stock. This is imperative to me and sort of the red line though it all.

Further i´m giving thought to an external loop too. Just install one of Tubetowns silicon powered loops in a separate,shielded,box and glue or bolt that thing to the cab "roof". Wiring in n out won´t present a problem as there´s several holes punched in the chassis top that ain´t used. A simple rubber grommet..and you can lead wires through there to hearts desire.

PPIMV i installed in the one stock cutout for speaker out. Don´t use more then one cab a time anyways so..
What´s more the amp is so INSANELY loud in its new guise that a PPIMV is a def must. The ooze from it last night as i really leaned into it together with our drummer Bjoern...let´s just agree that the amp hasn´t developed that kind of power in a loooooooooong time..cause the smell was one of tubes getting REALLY hot..and in turn heating up cab asf as well. :jam: :mrgreen: :mrgreen:
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Re: MAX Forty "Devil"

Postby Racing on Wed Feb 11, 2015 11:06 pm

Doh!!
Just...
DOH!!!
Had an issue in that sound came and went right. Of course someone like me instantly thinks i´ve done something wrong. Doh! It sure helps to use a wire between the guitar and amp that is A ok! DOH!!! :mrgreen: :mrgreen:
Touched the wires at each end with the soldering pen for a second..and we were all in business again and the amp roared along like noones business.

Image

Anyways. PPIMV. Right. Installed into one of the holes that stock sports speaker out. Works like a charm and is EXACTLY what the Dr ordered in this case.

Amp truly sounds amazing. It really does,but as noted above...ANYTHING can be improved upon right.

Image

Image

So that there will hold an EF-86. The perfect "solo tube" in my opinion. That bracket there in turn is to be installed INSIDE the amp chassis. Ie;upside down,and to some of the existing fasteners. Again..seing how scarse the amp is..mods are ok to me as long as they do NOT entail drilling into whatever.. That also brings that i´ll have to fab yet another bracket for some sort of volume control,and i´m thinking along the lines of pulling off a "depth" control while at it. IOW two pots to the same bracket.
That there in the pic will bring the need for relays tho..and such a breadboard will be put together and installed inside the chassis as well. Where to put the switch tho..no idea as of yet. It needs to be accessible one way or another after all..

This far tho. That there is one SERIOUSLY old school roaring viking amp by now! :jam: :cheers: . REAL happy with the tone and attitude of it.
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Re: MAX Forty "Devil"

Postby Racing on Thu Feb 12, 2015 11:06 pm

https://www.youtube.com/watch?v=Gg_dNJ770gY&feature=youtu.be

Then for a viking amp modded to smithereens by yet another viking.
Leddies n gentlemen...the MAX Forty Devil...Racing edition,101. Ie; a work in progress.
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Re: MAX Forty "Devil"

Postby Racing on Fri Feb 13, 2015 12:29 am

Oh.
Btw.
That little "cry" at the end. Nah..ain´t the amp.

Image

That Diezel. 11 weeks old by now...
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Re: MAX Forty "Devil"

Postby Happy Face on Fri Feb 13, 2015 2:06 am

Racing wrote:https://www.youtube.com/watch?v=Gg_dNJ770gY&feature=youtu.be

Then for a viking amp modded to smithereens by yet another viking.
Leddies n gentlemen...the MAX Forty Devil...Racing edition,101. Ie; a work in progress.


Thanks for the sound clip. That thing rocks. Nicely done!!
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Re: MAX Forty "Devil"

Postby Racing on Fri Feb 13, 2015 12:18 pm

Thanx!

Now for phase 2. To implement a couple of relays,a PSU for them..and in turn them brackets with novals... :mrgreen:
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Re: MAX Forty "Devil"

Postby Kuli on Fri Feb 13, 2015 2:08 pm

Nice sounding amp!!
'66 JTM 45
'66 JTM 45/100
'68 1959T Super Tremolo
'69 1987 Lead
'69 Royal Purple 1960B basketweave
'70 4x12" Park blue basketweave
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Re: MAX Forty "Devil"

Postby Racing on Fri Feb 13, 2015 5:40 pm

Thanx Kuli :D

The MAX amps lend themselves to sounding...different :mrgreen: ,when so modified. Part of it of course being the trafos and how they react. IOW...they did ´em right the first time out.
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Re: MAX Forty "Devil"

Postby Racing on Sat Feb 14, 2015 6:12 pm

That wonderful MAX Forty... Hm.

First up,a "repair". Turns out that one of the inputjacks had lost its tension. To the degree where it has come to affect signal,presto...time for a swap. Now,the jack for "line in" isn´t used anymore so...just swapped jacks and that was the end of that.

Second up. Version 1.2 i guess...

Image

Seing the behavior of the 6n2p tubes in that Geloso 218 i just did...this was a no-brainer really. The 6n2p carries with it a higher value for transconductance ...and atop that simply has a more thought through layout of the heater.
What that brings is a tube that omits less hiss..and less hum. So..a no-brainer. From most aspects the 6n2p can really be regarded as a sort of russian take on the ECC-808 as i´ve touched on before,and...they´re good preamp tubes. That simple.

Image

The difference in pinout between ECC-83 and 6n2p comes down to the wiring for the heaters. Needs to be moved to pin 4&5 only...and pin 9 in turn is to be run for ground,as it is an internal shield.
Doing so i opted to replace the entire wiring. First of all for the sake of multistrand wires...and in turn to twist the whole thing way tighter,and in turn to get better control of lead dress.
Result..is obvious i´d say. It simply turned cleaner yet...

Image

Then for version 1.3 right off the bat. Played around for a while with positioning of the bracket with the extra noval and all said n done...i ended up bolting it to the outside. There´s various reasons for this,but suffice it to say for now that the idea here is room for growth.
Of course that brings an added volume pot...

Within the chassis in turn there will be a PSU for relays. The same type of PSU you´ve seen me put together a number of times by now...and the idea is for several relays.
First up to be able to switch that EF-86 in n out...second of all to be able to separate the signals entirely. Ie;jump the mixerresistors. Idea behind that is one of a "different" distortion palette,obviously.

In turn these amps use 220k plate resistors throughout stock for the 4 triodes. This particular amp had been modded to use a 100k for one of the entry triodes... (for the one channel),and i´m now giving thought to replacing them all with 100k.
What that´ll bring is a more snappy and cleartoned preamp. Distortion will still be ample,and the thing here is that what i´ll get rid of is a certain degree of compression,that i TBH can do without.
Or..i´ll put it this way,i´m going to try 100k-ers out for fit.

..and as before...to be continued... :mrgreen:
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Re: MAX Forty "Devil"

Postby Racing on Mon Feb 16, 2015 8:21 pm

Image

Image

The setup is up and running since yesterday..albeit in "hardwired" mode. Ie;the relays and PSU are still missing,and hence the one jack for the one channel has simply been rerouted. Unorthodox placement...but it sure works,and works like a million bux.

The thing simply works,what can i say? The EF-86 truly brings something to the table,as i´ve written before,and the more i get to use them in various amps the better i find them. Seing that they in turn are the entry stages...actual amplification factor becomes secondary,which the EF-86 has in abundance already as is.

I even recorded a couple of clips buuuuuuuut...at to high a volume for my cellphone camera to keep up so i need to readress that asap i guess.

No matter. I´m this far REAL happy with the outcome. To the point where the only real "need" for the relays is one of practical circumstance. Ie; it IS after all worth the bother to be able to swap channel midflight on a stagefloor. So..relays it is.

In turn. Installed one of Tubetowns loops into a ´59 Bassman RI today,that i´ve modded as for the base amplifier too,and...it sure does work. Now..TBH i don´t really use pedals and effects...and indeed this MAX of mine is here to stay. However..a loop that WORKS is still an asset. Food for thought. It´s just that in cab space is getting cramped... :mrgreen:
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Re: MAX Forty "Devil"

Postby Racing on Wed Feb 18, 2015 10:51 pm

Image

Got to spend a little more time with that MAX. First up...there in the pic you´ve got the rather small PSU for relaycontrol..and in turn a tubetown loop.
However.
I got to reset a few cathode resistor values and to play around with what node got voltage,and the thing is...FTW. What emerged was that really sweet distorted tone that is about "metallic" to the sound. What i´m saying is that i´m kind of having second thoughts on the whole concept of relays and a loop.
Now please have in mind that one of the groundrules in the case of this amp is to keep any and all alterations to the chassis to a bare minimum. Before cutting into it...that will be preceded by some serious afterthought,and thus far..i´ve kept that in check.
The few holes i HAVE added are all 3mm ones..which has been out of pure necessity. Like the separation of the bridge negative vs grounding of first e-lyte vs the rest of the chassis grounds for instance.

The point i´m trying to make here is..this is "my" amp from now on out. It thereby needs to fit MY needs. Noone elses,and the point is that i rarely use effects onstage...and i rarely swap channels.
Channels..that could be handled with a simple AB-Y box....and well. The only real "need" i´ve got for a loop is for timebased effects,and as stated i very very rarely use that. Delay on a few songs,out of hundreds and hundreds....iow i CAN survive without too.

Amp,as is now,works and sounds killer. It really does. The EF-86 brings clarity and attitude no doubt and i´ve come to cherish the small signal pentodes for that,no matter if EF-86...or EF-40 or whatever.
They DO however need to be first in chain as the do NOT take kindly to overdriven signal. When placed first tho..they DO work wonders. Or,like an old friend dubbed it..."the EF-86 is one great solotube". Yes. Yes,that´s exactly what it is.

If i opt to go relay tho that frees up the entire serve. Doing so i really don´t need more then 2 inputjacks,and that leaves that one of the 5 can be used for relay control..and in turn yet two of them for the loop. That would save drilling into the chassis in any form really,and..IF i´m to do it..that is how.

If i take a step back...i in such a case would add a relay for channel select. Then one for putting the EF into action. In turn,to widen the amp,it MIGHT be an idea to install yet another relay,this time a DPDT one,to separate the channels entirely.

Worth it?
Right now,i dunno. I really dunno..
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Re: MAX Forty "Devil"

Postby Happy Face on Thu Feb 19, 2015 2:46 am

No. Leave it be. :!:
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Re: MAX Forty "Devil"

Postby Racing on Thu Feb 19, 2015 9:58 am

I hear ya.
ATM tho..still undecided. Will hopefully get a little time to play around even more during the day.

That said. Forgot to mention that i reset the centertap for the heaters to the 39VDC negative of the bias circuitry yesterday,and the net effect of that was negligible. Really.
So what i´ll do is replace them two 100 Ohm resistors that make up for an artificial centertap with a 500 Ohm 1/4w trimpot and reset that to chassis ground instead.

However.
"Wide" amps with an attitude is always nice and..i started thinking. Seing the preamp topology..i´m ATM happy with what it provides. Over the yrs tho it has struck me many a time the impact the choice of cathode resistor of the phaseinverter has on sound.
We see the common 470 Ohms in various Fenders and Marshalls and what have you not...we see 820 Ohms in Oranges asf...and in turn 1.2k i various Vox´s and their syblings.
The alteration of cathode resistor value truly DOES impact how an amp comes across,and that got me thinking... We´re accustomed to that a pot should never see DC voltage.
Ok. Buuuuuuuuut...heading limitied DC voltage for a pot would most certainly be doable,so what IF i were to route that voltage of the cathode conn for a 1k pot..routed in series with a 330 Ohm to 470 Ohm resistor?
That would bring,hopefully,that you could alter the characteristics of the PI on the fly. Or...you could set attitude of the amp to hearts desire with a regular pot that would reside by the PPIMV pot out back.

First up that extra hole there was intended to keep a feedback control or similar,but seing the PPIMV..that brings a hell of a lot of adjusting seing how feedback needs alteration vs PPIMV setting. What´s more the actual effect of it...is limited. That brought me to the thought above. ´N..why not? DC voltage at the pot would be limited,let´s say a max of 50VDC or so,and the actual voltage drop and thereby load on the pot would also be very limited.
Sure...you´d get "scratch sounds" out of the amp as you adjust it,but i seriously doubt that you´d be doing so on the fly mid set. The idea here being able to alter amp attitude in a rather simple manner.
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