Massive Passive...solid state output

[crm0922]

Ok. Anyone have any theory on how I might bypass the tube-makeup and transformer output stage of a Massive Passive? Sorta like the new Mini Massive, except I don't necessarily care about using the "Rapture" output amps.

As I understand it, the EQ is a parallel design. So I assume there are two tube stages, a summing stage to "mix" the individually eq'd bands together and an output driver.

I'd be fine with leaving the tube summing amp as-is, and just replace the output amps with a solid state solution.

Thoughts anyone? Perhaps someone has done some digging inside one of these and might be able to shed some light on the feasibilty of something like this.

Thanks,

Chris

 

[gyraf]

iirc, it is already solid-state to some extent?

 

[clintrubber]

[quote author="gyraf"]iirc, it is already solid-state to some extent?[/quote]
Jakob's right, see for instance:
http://www.groupdiy.com/index.php?topic=11520

 

[crm0922]

That thread seems to be about the solid-state input stage and driver to the EQ section.

I'm talking about trying to bypass the output transformers and making the ouput buffer solid state.

Chris

 

[clintrubber]

[quote author="crm0922"]That thread seems to be about the solid-state input stage and driver to the EQ section.

I'm talking about trying to bypass the output transformers and making the ouput buffer solid state.

Chris[/quote]
That's correct, it is the input-stage - I added that to illustrate the remark that Jakob made, so wasn't addressing the output-buffer. OK, back to your actual topic.

 

[CJ]

Ask M-ley.
They are pretty good about tech emails.
Especially since you bought one.

 

[crm0922]

I could ask Manley but I wonder if they won't just tell me to forget it because it is too much work. When, in reality, it might just be more work than they are willing to put into helping some dude one-off a mod.

Paul is good at tech support, but I'm not sure he is the guy to talk to about this project.

Ultimately, I'd like to make the output switchable so I could assign the outputs to the tube/iron section or to a solid state (maybe pseudo-balanced) output from something like JLM hybrid as an output driver.

Anyone actually take an in-depth look at the output section like the above thread does to the input section?

Thanks to all for the responses,

Chris

 

[CJ]

well, thats kind of a protected schematic.
anyone with that on their site had better watch it.
arhh Matey!

looking.....

ooops! ..new OS,scrubbed the reader, no Adobe on my machine.

Yes!

but how to read pdf now?

why go here, for a non bloated, non adobe free reader:

http://www.foxitsoftware.com/pdf/rd_intro.php

 

[CJ]

ok, first off, you already have a jack that bypasses the OT.
are you aware of this?

 

[CJ]

ok, thats a common cathode into a semi follower type thang.
so you need about 24 db mmakeup from transistors.
but how?

API!

slap one of those little black boxes in that big chassis and you are done!
except for the pwr supply, that is.
its unbalanced so you don't need an input tranny. :twisted:

there goes your warranty.

 

[Kev]

:grin:
it's funny when CJ starts talking amongst ... himselves ....

 

[SSLtech]

KEV!!!

Good ta see ya, mate!

Stroll on, no worries, good on yer, etc...

Keef

:thumb:

 

[PRR]

> how to read pdf now?

Uh, on Windows.... Adobe.com, wait, "Get Reader", wait, pick "OTHER Versions", find 6.0x. (7 and 8 add bugs but not features.) Run it (or save then run), wait, wait, recompose.....zzzzz...

Launch it, Help, Update, re-start Reader and Help, Update again (the first time didn't count). Take the most recent version of 6. There are real nasty vulnerabilities in the older six-point-oh versions, and surely more to come, so keep your 6.0? up to date.

Reader and even Windows may want to re-start, and Windows tends to bink after any Adobe change. It does settle down.

When you got it up again, Preferences has a lot of options, including one to kill the splash screen, default to 100% and page-mode, and the dummy update frequency setting.

With Reader fully closed, go to Control Panel, Add/Remove Programs, and remove the Acrobat Updater (if present).

It is almost quicker to do than to describe (though a slow CPU will take a loooong time recompositing for no apparent reason). Reader 6 is a good solid tool.

> go here, for a non bloated, non adobe free reader:

Yeah, another option is cool. FWIW, the beta Linux version does work on Puppy Linux 2.17.

 

[crm0922]

Older Acrobat versions have issues with certain features of new PDF's, some of which can be handy...like filling in forms, etc. So I just use V8 and put up with the bugs. I don't recall 6 being all that great either, all of them are resource pigs.

But I digress...

CJ, you have totally lost me. Are you looking at a schematic?

Are you suggesting the 1/4" output jacks are something other than the TRS version of the XLR? I haven't disassembled the EQ yet, it is actually loaned out at the moment (long story).

What do you mean by "slapping" an API in the chassis. Are you talking about using a 2520 or something as the makeup gain amp/output amp? I'd prefer to use something else, removing the coloration of the output transformer to replace it with API coloration is not quite what I am looking for.

Is there a summing section followed by the makeup gain section? If that is the case, can the output of the summing section be branched to a separate makeup gain circuit,even if it has to have separate knobs?

The warranty has already expired.

Thanks again,
'
Chris

 

[rotation]

what summing are you talking about? There is output amp and no summing. See Gyraf's Pultec...

 

[crm0922]

Since the bands are passive filters operating in parallel, how are the results "paralelled" if not through summing? That was my thinking anyways.

Chris

 

[CJ]

yes, the 1/4 inch jack is just an unbalance output.
should be in your manual, or go to Maley site.

I spoke too soon (working on that) about the API.
Of course you have other black boxes out there.
Forrsell, Hardy, and the others.
An API output xfmr is the most transparent OT out there, so don't worry about that.

yes on those back reved Adobe programs.
the 3.0 ver has a built in distiller, if you can find it.
but who would want to make a pdf doc anyway?

 

[crm0922]

[quote author="CJ"]yes, the 1/4 inch jack is just an unbalance output.
should be in your manual, or go to Maley site.

I spoke too soon (working on that) about the API.
Of course you have other black boxes out there.
Forrsell, Hardy, and the others.
An API output xfmr is the most transparent OT out there, so don't worry about that.

yes on those back reved Adobe programs.
the 3.0 ver has a built in distiller, if you can find it.
but who would want to make a pdf doc anyway?[/quote]

Thanks CJ. I'm still not sure I am understanding your suggestions, though.

Are you saying to use the unbalanced output or to replace the makeup gain amp? I would prefer to replace the makeup gain amp completely, and avoid an output transformer. API's are pretty colored, that is pretty much the opposite of what I am looking for.

I'd use an IC output or something like the JLM hybrid in class A if possible. However, I still am not sure if you have the information I am seeking. Essentially, whether or not it is possible (and relatively easy) to intercept the signal before the makeup amp and route it to a solid state gain cell.

Thanks again,

Chris

 

[SonsOfThunder]

Sorry for the hijack...

Older versions of Acrobat

HTH!
Charlie

 

[JLM Audio]

HI Chris
The Massive Passive has a Solid State balanced input amp that drives the 4 paralleled boost controls + filters into a Intermediate valve makeup amp which drives the 4 cut controls and then a final valve makeup amp that drive the output transformer. Both valve amp stages are inverting and very similar.

You are right that the Massive Passive are very coloured sounding. If you do a 1k tone alignment for the in/out switch and then play music the music level jumps about 2 dB with the EQ flat just because of the extra THD.

We have a mastering client who has asked us to make his Massive switchable between normal and fully solid state super low THD so it can be used better for his mastering which I will have a look at doing when I get back from New York AES. The strange thing about the Mastering version is that the stepped cut and boost control is still actually a pot not a switch and the clicks are made by the 2 piece knob used on the mastering version. So if you are trusting your left / right balance to the cut/boost detents think again.