1176 Mnats Rev D finished!

[rick]

just like the link cable loop on a original 1176

actually maybe it would be better to DIY something that worked ....

[Alistair]

I think that maybe the point behind the stereo link boards Hairball makes. I've never tried linking two original 1176's, but the write ups on these DIY versions seem to suggest it was a little bit less than perfect....


I think I'm going to do the only sensible thing here. Buy one, build it, and then if I love it build a stereo one after! Having 3 can't hurt....

[prequalizer]

He also doesn't like pot nuts on the outside which means a hidden layer behind the front panel. While aesthetically nice, they are a bit of a pain to get together.

cya
Geoff

Are you talking about the silver panel behind the front? Are you saying the the pot nuts are after the silver panel and behind the front case?

eg.
pot --> silver panel --> nut --> front case --> knob

If this is the case, then wouldn't the rest of the parts connected to the silver panel like the push buttons, VU, etc, be out of alignment?

I think you have that wrong, the silver panel is flush against the front case, and thats why people complain that they can not get the pot nuts on and have to make a cut out on the silver panel so that the pots are up against the front case and not the silver panel. The silver panel is only there to hold the push button poles which mount the push buttons.

Correct me if I am wrong, but I have not seen anyone build the DIY 1176 with purushas case with the pot nut elsewhere. The holes for the pots on his case arent even big enough to allow the nuts through.

Has he redesigned them?

[ghengis]

He also doesn't like pot nuts on the outside which means a hidden layer behind the front panel. While aesthetically nice, they are a bit of a pain to get together.

cya
Geoff

Are you talking about the silver panel behind the front? Are you saying the the pot nuts are after the silver panel and behind the front case?

eg.
pot --> silver panel --> nut --> front case --> knob

If this is the case, then wouldn't the rest of the parts connected to the silver panel like the push buttons, VU, etc, be out of alignment?

I think you have that wrong, the silver panel is flush against the front case, and thats why people complain that they can not get the pot nuts on and have to make a cut out on the silver panel so that the pots are up against the front case and not the silver panel. The silver panel is only there to hold the push button poles which mount the push buttons.

Correct me if I am wrong, but I have not seen anyone build the DIY 1176 with purushas case with the pot nut elsewhere. The holes for the pots on his case arent even big enough to allow the nuts through.

Has he redesigned them?

It's been a while since I assembled one, but with my nite EQ there was no way to space the front panel to the sub panel behind it. The sub panel is threaded so you have to manually space it by incrementally screwing in the front hex screws. Once it is in place it is fine, but a pain to get right. If you need to remove or change a pot it is such a PITA, you have to disassemble the whole case. The 1176 may be different, but I'm talking generally about his aesthetics which on one hand I applaud, but on the other hand aren't necessarily implemented the best/easiest way. I do quite like the way that switches look cut through the front panel fwiw.

With regard to everything mounting, I know that the push buttons would have 5mm of leaway so should be able to easily sit behind the sub panel without too much of a worry. I would imagine that there would be a VU cutout of the subpanel so that it can sit flush and mount on the front panel.

cya
Geoff

[prequalizer]

Purusha's 1176 case is different to his other case that you have dealt with it seems. The silver panel (sub panel) is too flexible to place a gap with the front face of the case. Otherwise, when you go to push the buttons on the push buttons or push the knobs, they would sink in and bounce back up.

I think the silver panel method that Purusha uses for the 1176 is primitive and awkward. Hairballs approach seems more solid and makes building easier. Purusha should really try to improve on his casing according to the build, since that is his business. His approach seems to be using a standard case, and just setting up holes and painting it, not really catering for the build like the wiring, parts used, positioning of the things inside, etc.

You know, like if a ford manufacturer makes new models by simply painting the car different colours.
eg,
This is the new Ford laser 2010 model - which is just a red laser
This is the new Ford Festiva 2010 model - which is just a blue laser

[Alistair]

Well,
I'm gonna follow in Mac and Futureman's footsteps and give it a shot. Placed an order with Hairball for the Rev D kit last night. I'll let you know how it turns out in a month or so!

[Futureman]

Make sure you spend a long time reading the REV D thread in Prodigy Pro Forum... it's frigging huge, but you'll be better off at the end after you have read all the common mistakes people made..

http://www.prodigy-pro.com/diy/index.php?topic=20058.0

Also, feel free to ask away here or there if you have any questions.

Have you ordered the other components? get more of the transistors than you need.. (So you can potentially match them)

I'm not sure if mouser still have the 'free postage if your order is over $200' but if they do, it may pay to bump your order up to $200 to save on the expensive postage.

Regards
mike

[Alistair]

Hi Mike-

Yep Mouser still has free shipping over $200. I was gonna order 2x the transistors etc needed, and then maybe some parts for other prodigy DIY projects for the future- the G9 dual tube preamp looks pretty cool! I figure reading the thread is a good way to spend the time before the kit arrives, so by the time it gets here I know what I'm doing.

Thanks for the offer of advice, hopefully I won't need it! (but I'm sure something will confuse me).


Speaking of the Mouser stuff, do you guys ever do group buys on this board? Another board I'm on did a redco group buy from Mogami cable the other month, and it worked out pretty well. Cheap and easy for everyone involved.

[EvLoutonian]

Your units look very cool, Mike.
I just got some of the MNATS Rev J boards .. designed for the Lundahl transformers..
Do you think this board would also work with the parts kit from Hairball, if I mounted the I+O transformers off the board?
(I think it's compatible with the RevF version, not orig A thru D versions).

[Futureman]

Your units look very cool, Mike.
I just got some of the MNATS Rev J boards .. designed for the Lundahl transformers..
Do you think this board would also work with the parts kit from Hairball, if I mounted the I+O transformers off the board?
(I think it's compatible with the RevF version, not orig A thru D versions).

I'm not that familiar with the Rev J, but a quick google shows me that it's based around the Gyraf 1176.

I'm sure the case and VU and knobs would all be good.. and I'm sure you will be able to somehow mount the transformers.

Does the Rev J use a 'T pad' attenuator for it's input.. (My memory says 'no' , and also 'no' to input transformer)

Regards
Mike

[EvLoutonian]

Hi Mike!

I'm a bit confused by all the different revisions involved with researching this project
[there's not just the original 1176 revision lettering system, but also the further multitudinous DIY build revisions on top of this from the various DIY offerings around currently]
.. but I think I've boiled it down thus, as far as the particulars of the Rev J. boards that I have, and options / differences from earlier versions as per your points above:

The "Rev J." PCB from MNATS does offer the option of using an input transformer, but yes - you are totally correct - the actual revision of the 1176 that this board is based on [Rev G.] I'm pretty sure was the last of the original 1176 model revisions. Each was getting cleaner sounding, and I suppose this would have been a significant objective of each revision. By Rev G. they had done away with the input transformer altogether at that stage, as outlined succinctly here: (copied below)

http://masonaudio.manaservice.com/masonaudio/comp1176

* Revision F.
In this unit the class A 1108 preamp is replaced by a "push-pull" amplifier based on 1109 style class AB preamp with an output transformer that gives more output gain and a slightly different sonic character. Rev. F switches from discrete to opamp based metering circuit.

* Revision G.
This revision removes the input transformer in favor of an IC differential amplifier. The output is class A/B and it uses a B11148 output transformer. F and G are the cleanest revisions as they measure the lowest harmonic distortion resulting in a less colored sound, although preserving the 1176-style compression.


Hmm, kinda makes me wonder if I might end up with a somehow more nicely 'charactered' limiter if I went for the Rev A, or other early version, but I guess they can all sound excellent..

So, anyway, you can use the IC-based input on my Rev J. PCB, or replace it with either the Lundahl or OEP input transformer also provided for on the PCB. Just depends if I want the input transformer sound, more like the older rev's, or not. Nice to have the option, though I'm not sure this alone would make a massive difference on this model.

Likewise, there are two output transformer options offered on the pcb, & it's class A/B output, as opposed to the earlier revisions' class A output. This later design had the least harmonic distortion apparently.

I didn't really research it up before getting these PCB's..
The 1176 was just something I'd been thinking would be a good DIY build, & someone offered me some surplus pcb's they had for sale, which happened to be Rev J. He built one and said it's great, so I thought, why not!?

I wondered about even using some old Trimax 150/600:600 ohm transformers that I have sitting around -> for both input & output stages, even!
Do you think they should be suitable?

They're kinda large - definately larger than required, but not ludicrous. They're prob around 10cm tall. Ok to fit in a 2RU case, I think. Just not sure if the spec is exactly right. They don't indicate frequency response on them.

Here's some info on this revision:
http://mnats.net/1176.html

Being not all that far along yet, it is tempting to look at the Rev A or Rev D complete hardware kit from Hairball and maybe go from there.

- maybe save these Rev J. boards for a slightly more homebrew style project..

Hmmm.. Did you notice much difference between your two Rev D builds in the end?

[Futureman]

I didn't notice a huge difference between the two output transformers TBH.

Going by the Group DIY site.. There was a thread about favorite and most disappointing DIY projects... It seemed the 1176 Rev D came up as being a common favourite while the SSL comp came up often as biggest disappointment.
(I'm summing up that thread, as it's not all black and white)

I think the Rev A is also highly rated.. And if it was around when I bought my PCB's I would have made one along with my D.

Don't forget Bluzzies Neve 1084 EQ.. Pricey as everything uses in it is top of the line.. $40 rotary switches etc.
But damn that sounds good. I think the total bill for be was around $700.
Transformer in and out EQ with inductors all throughout.
The easy 1084EQ is truely an easy build and is very well documented..

On I side note.. These posts reminded me to investigate making a side chain input on my 1176's... Did some quick experimenting and pretty much got it sorted. I want to tweak a few values, but it's very straight forward.

[EvLoutonian]

Ooooh, nice - keep me posted on the sidecháin results..
Are you documenting as you go?

[Futureman]

Finances dictate I sell some stuff.

I'm probably going to sell the blue faced rev D.

I love it, but I've got 2 and I can always build another at a later date.

$780 and it's yours. Buyer pays postage.

(Sydney)

[andygriffiths]

Mike, I'd consider it if it was a revA

[Futureman]

Mike, I'd consider it if it was a revA

Sadly that won't change.

I'm umm-ing and ah-ing about selling that.. Really on the fence.