[BUILD] 1176LN Rev D DIY

[edanderson]

those mallory t600s will work; i found some surplus a few years ago and a few people built purple units with them, SSLtech for one. they are wirewound and pretty stiff feeling, but good quality. new i think they go for around $100 the last i checked.

ed

 

[kazper]

I had a quote for them from the only place that popped up on google with them and it was like $105 each a few weeks ago before I found a few on the bay.

 

[kato]

for anyone using my parts list -
capacitor C22 is too large to fit in the footprint. It bumps into resistor R4.

Not major - you can offset R4 a bit to make it fit. Or use a smaller replacement for C22 if you don't want to de-solder R4 and replace it. (this is assuming you solder resistors first.)

I apologize for the error. I chose the polyprop wima without noticing it's excessive wideness. My parts list has been updated with the polyester wima for that value.

http://nimbleswitch.com/diy/1176_revD_parts.html

 

[nerd]

I just can't bring myself to spend $100+ on an attenuator. I think I am going to use a 12 position 2 pole switch and do a bridged T with ~4.5db steps. I know that that is probably too coarse of an adjustment, but most things I will be using it with will have some sort of output level adjustment.

I was going to use finer steps (2db 12 positions) figuring I would only attenuate the signal within a limited range anyway, but it doesn't seem like you can start at zero attenuation +2db +2db... It looks like there is almost always some attenuation going on.. So the question here would be, well... where to start? It looks like you calibrate the meter with the input set to 24db. So, 14db +2db +2db... up to 34db seems like it would work, but I am not confident enough with this assumption to run with it.

Any thoughts?

 

[ap123]

Kato, I just went with the flow... :thumb:

 

[kato]

[quote author="ap123"]Kato, I just went with the flow... :thumb:

[/quote]

Thanks for being flexible! I had no idea how honkin' big those were going to be.

The experience has taught me to check the width column in the catalog even on parts I think I know...

 

[ap123]

nerd, I found this the other night and thought about emailing these guys: http://www.marchandelec.com/att.html Maybe they could whip up a T600 kit or something.

 

[timmygrimm]

[quote author="ap123"]nerd, I found this the other night and thought about emailing these guys: http://www.marchandelec.com/att.html Maybe they could whip up a T600 kit or something.[/quote]

I was thinking this might be cool for a group buy, but I guess they only do stepped? I can't decide how I feel about that.

Tim

 

[nerd]

nerd, I found this the other night and thought about emailing these guys: http://www.marchandelec.com/att.html Maybe they could whip up a T600 kit or something.

I only looked briefly, so I may be wrong, but I don't think those are constant impedance attenuators. I think they are just stepped potentiometers.

For less than the $50 it costs for the 24 position attenuator they have posted, you could build one. Electroswitch has a DP24T switch for around $36 from mouser. If you are the one building this into a 1u rack, I don't think that switch will fit though. I think it was more than 2 inches across. That is my problem too. I am (attempting to) building a dual in a 2u.

I think I am going to go with my earlier idea with large steps. Rotary switches make a big jump in price and size after 12 positions. That is, unless someone makes a good argument that it only really needs to work in a smaller 24db range, then I would use the 2db steps across that small range, or someone finds a source for an inexpensive attenuator or switches.

FYI: I am a noob, so don't take my posts too seriously. This is my first DIY since some paia kits in the 80s.

 

[kazper]

maby a group buy for a tpad style unit or switches. I will again at the local surplus stores for something and see if there is a inexpensive fix to help keep the projects price point low. Also keep a eye out for ebay, I got my T-pads there.

 

[Stagefright13]

Hey I built and cloned my own PAIA kits also in the 80's they were fun I believe I still have an "Axe Grinder" laying around somewhere for guitar

 

[ap123]

Are there any other options for the input attenuator beside the ever elusive T600? Can you have, say, no attenuator? For instance, what is happening here under the section "Input Wiring Option B (transformer balanced input)?" That doesn't look like a big fancy $100 bridged attenuator.

 

[kazper]

NY Dave's switch setup about the best lo cost option next to finding one on ebay.

or read this thread
http://groupdiy.com/index.php?topic=10593&start=30&sid=1ab9426da227a8425f56e7fc18df79e5

 

[enthalpystudios]

i know this is diy, and i know that we all have short wallets at times, i know i do, but if you indeed want to build a *rev D* clone 1176, that 100 bucks (tops, probably more like 60-70), is not really that big of a deal when you factor in the money you save doing it yourself. if your time is valuable in a the sense of real dollars and cents, it'll be cheaper to buy one.

plus surplus they can be found for 5-10 bucks if you aren't pressed for time, and keep you eyes open and the swap meets and ham fests and surplus joints, whatever.


stepped is of course a fine alternative.... but running the signal straight into a tx, ESPECIALLY if its a utc o-12 or clone of an 'ouncer' unit, is NOT a good idea.... Especially, again, if you are recording in a modern, bridging, electronically balanced world where impedances can run high.

they didnt use the attenuator just to off put cloners, they had a very good reason to do so. the electronically balanced input or a stepped or variable bridged tee are the only options available in my book, otherwise i'll build a different compressor, with a different design.

 

[tommypiper]

Guys, if you need your 600 ohm bridged T, there are Clarostats here that match one of the two Purple solutions on the Purple schematic. They're only $30. This was mentioned back around page 8 or 9 in this thread. http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&ih=013&sspagename=STRK%3AMEWN%3AIT&viewitem=&item=230002096428&rd=1&rd=1
(Edit: this sale is apparently closed.)

Or are you looking for something different?

 

[tommypiper]

[quote author="ap123"]Are there any other options for the input attenuator beside the ever elusive T600? Can you have, say, no attenuator? For instance, what is happening here under the section "Input Wiring Option B (transformer balanced input)?" That doesn't look like a big fancy $100 bridged attenuator.[/quote]

That's a different circuit.

Look at my previous post for a 600 ohm solution. (EDIT: Sorry, my error, the sale is apparently closed.)

Otherwise, I think using a modern transformer with a pot will work. I plan to try that route myself.

I beleive Mnats has also said you can go straight in unbalanced without a transformer.

We'll need to experiment but it should work with several options.

 

[ap123]

There is also a Clarostat CIT 600 that Leed's has mentioned as an alternative to the Mallory T600. It is three gang. This will work, too, I think. Is this clarostat the closest thing to what UA is having PEC mfg now?

Yeah I saw that auction the last time I was on page 8 or 9...it was ended early but gee I can't imagine why. :?

I agree completely on the price issue. Spending $500 on a DIY 1176 is good fun.

 

[tommypiper]

Edited: The ebay item is closed, my mistake. I had posted that it was still open.

 

[ap123]

We must be looking at different auctions. This one has said "The seller ended this listing early because the item is no longer available for sale" since I found it days ago. I get the feeling (loud and clear) that discussing options and availability for the T600 has become an inconvenience for some of you. Please realize that some of the threads on this topic are a year old and contain broken links and incomplete discussions (or link to auctions that have long since ended or links to threads that have been mysteriously deleted altogether like the one that contained a pic of the PEC T pad).

NewYorkDave was kind enough to re-post his schematic for his switched attenuator and I appreciate that greatly. His posts were over 2 YEARS old and I'm sorry I couldn't find them using my many search queries.

Does anyone agree that these would be appropriate additions to the 1176 meta?

http://www.groupdiy.com/index.php?topic=4825

 

[tommypiper]

Oh, you're right about it closed, my mistake, I'm sorry. I would contact the seller anyway and ask if he has the parts available.

It doesn't bother me to discuss the 600 ohm stuff, I just thought the parts were still available.

However, I also think it makes sense to consider that the original 600 ohm implementation is not the only way to skin the cat. And one shouldn't lock oneself into just one idea, particularly if parts availability is an issue. Cloning may not be your best solution.

This is DIY, not CIY. Celebrate your freedom to try something new.