1081 Project Errata

[matthias]

I was just looking for some switches for the 1081...

is it a problem, when the switches are shorting...???


in the part list from tommy are all switches (without the treble sw2) mentioned as non-shorting ...


???


thanks,
mat

 

[Family Hoof]

Matthias,

Here's a DIY answer. Think about what shorting means - make before break - meaning while the switch is in between positions both are making contact. Think about what audible effect this will have based on the circuit it's controlling. For example, if it's switching different shunt resistors for gain boost and shorting then the shorted in between position will have the two resistors in parallel, making a lower value, and causing a jump up in gain. If the switch was non shorting there would be no shunt resistor connected at all in between positions so you'd have the opposite - the gain would quickly fall to its basic level.

That's just one example. Got it? I don't think there are many situations where one or the other type of switch is a problem per say, it's just going to have differing audible effects. And if your switch changes contacts quickly enough you may not hear a difference.

Just my two cents.

 

[matthias]

Hi Jens,

thanks for your answer...

 

[Val_r]

Hi all!

Just reading this thread I noticed many of you are interested in the 1081 clone. I was one of the first to complete the clone more than 1yearago and I must say that it took several months to get the parts together, especially for the windings and the custom switches.

But it was all repaid when I heard the unit (one of the best sunding)!!!

Bass and treble switches: it's not simple as shorting or non-shorting but:
treble is cumulatively shorting!!!! this means that, starting from CCW to CW position, as long as you go CW it is shorting 1 pole more, so in position 1 the contact made is only pin 1, in position 2 the short is in 1 and 2 together, in position 3 the short is 1, 2 and 3 together and so on until the full CW position, where ALL the contacts are shorted!

Bass switch works exactly the opposite way: ALL shorted in the CCW position, and only 1 pin in the CW pos.


I had to build these switches by myself, but at last they worked!

Hope to have been of any help to someone out there!

Respect,

Val

:wink:

 

[ToroRojo]

I'm working on sourcing parts for the B338 boards. Accoring to all of the 1081 docs I have found, there is suppossed to be a 100pF capacitor (C4 on Neve schematics) between Q5 and R4 (on the TommyTones boards). This part is absent from the parts list. If this part is purposefully removed, could someone explain why to me?

I think it would be very helpful to this project to have some very high resolution images of an authentic 1081 and the removed daughter cards. Would anyone be willing to supply those? I have some high bandwidth server space available...

 

[Kev]

[quote author="Infernal_Death"] ... I am really surprised that there is so little interest in this project. After all, all the group orders should be reaching the end and people should have all the parts so i think there should be some new talk about the 1081 project ? But seems like i am wrong ?[/quote]

there is interest
but as was said right from the off
Some of us are insanely busy and this is a BIG and costly project.
I for one will not be starting this for some time as it is not even near my top twenty things to do list.

sorry
just one of those things

 

[tommypiper]

[quote author="Val_r"]Hi all!
I was one of the first to complete the clone more than 1yearago and I must say that it took several months to get the parts together, especially for the windings and the custom switches.

But it was all repaid when I heard the unit (one of the best sunding)!!!
[/quote]

Val, congrats! Did you use Tommytone's boards? Could you send us some photos?

Once I get time I will volunteer (try) to summarize all the mentioned changes/updates into one of these threads, unless someone else does it first. Will help us to have all the changes and notes listed on one page.

Like everyone, I'm swamped by life and pressing things. But there is definitely an interest. Still collecting parts...

Quadwould was recently saying he's putting a BOM (parts list) together here: http://www.groupdiy.com/FORUM/viewtopic.php?t=115&start=75&sid=bbe446a4f24c83000fc0cb95a70305b8

 

[thestudio]

Yep, very interested in 1081 project but still collecting parts........

Would also like to know if Val built units with "tommytone" pcb sets because I'm finding that pins are not lining up :roll:

Is Gustav still going to produce some 1081 sets closer to the original without missing traces :?:

 

[Infernal_Death]

Hi Kev

Yes i also set new priorities although my 1081 is nearly completely stuffed. I am just missing some parts.
Anyway i also got some other projects to do (well there are always other projects, right ? :green: )
It's just that it seems everyone is waiting for somebody to finish this and i fear that this "somebody" won't surface. Oh well we see :thumb:
I also think that i will go the Neve 1290/1073 before trying to complete the 1081.

Flo

 

[ToroRojo]

For those who have stuffed, or partially stuffed boards:

On the B312 motherboard, there are 8 silver mica capacitors listed on the parts list. The values range from 22nF to .1uF. As far as I can tell, these values are way too high for silver mica capacitors. The closest values I've been able to find have been 2.2nF (and lower).

What have your guys been using for these capacitors? If you are using silver mica, where did you get them?

These capacitors are used in the filter sections, so I imagine that their makeup and values are pretty important for that authentic 1081 sound.

Thanks for the help.

 

[Family Hoof]

You're right. WAY too high for mica. AFAIK, Neve used various types of poly film caps in the EQ (usually either Mullard or Suflex would've been specified), not mica. The values you listed are also too high for styrene so I would assume the Mullard polys, which are propylene?? Can't remember right now. I believe AM*S-Neve uses those yellow axial CDE polypropylenes in the reissue.

 

[ToroRojo]

I found the 22nF and 33nf (but no .1uF, yet) at RS Components.

Problems: These parts are between 7 and 9 pounds each. Converted to US dollars, that's over $100 per channel for the silvered mica capacitors. :shock:

I haven't found a US distributor with anything yet.

Any suggestions for good substitutes?

 

[rascalseven]

If anyone is needing the Elma gain switches for this or other Neve projects, I've got four of the gold contact version (04-3133, I believe) that I don't need. I bought four originally in the group buy, and then thought that my wife had thrown them out accidentally for a few weeks, during which time I bought replacements from Elma. I just found the four originals, so now I don't need the new ones.

:roll:

There's a 20% restock fee for returns to Elma, so I'd like to sell them instead. Cost on these was $76.35 each, so if someone wants killer switches for this project, or any other Neve preamp model, I'd love to move these and get my money back. They are unopened.

PM me or email at r7fm (at) integrity (dot) com if interested.

I'm very sorry for the intrusion. Please carry on.

Thanks,

JC

 

[ToroRojo]

WARNING: Be very careful as you work on this project. I've been wiring up the PSU and noticed that the silk screen didn't quite reflect the parts I was putting in. i.e. Really big cap on really small circle and vice versa. Before I got to far into it, I figured out that the Tommy Tones board I am using isn't the latest revision, while the parts list is. Apparently, Mr. Tones decided to throw out the numbering scheme he was using earlier and redo everyting with new designations. :roll:

I wish he would put old versions on his website, instead of just the latest revision.

I think I've got it sorted out, but what a pain in the ass.

 

[tommypiper]

Well, there are two versions of the PSU boards. I know because I have one of each. The first one had an error in the 48v section, but the 24v and 6v sections were fine. And there was a simple jumper and trace cut fix for the 48v, so those boards are still usable. I know he corrected the mistake and made a second batch of PSU boards. That may be the confusion you're having if he updated the layouts for the new PSU board but you are stuffing the original one.

I belived Tommytones posted a correction here somewhere - I haven't searched for it, maybe someone can find it.

I found a silver mica source with Digi-key last year but can't seem to find my notes... EDIT: Here it is. Digi-key # 338-1068-ND. It's a 10pf/250v.

 

[Tekay]

Here's the Rev1 & Rev 2 of the partlists!
http://www.vintagedesign.se/diy/index.htm

Goodluck!

 

[ToroRojo]

[quote author="Tekay"]Here's the Rev1 & Rev 2 of the partlists!
http://www.vintagedesign.se/diy/index.htm

Goodluck![/quote]

It looks to me that rev. 1, rev. 2, and rev. 3 are all the same, just different file names. At least the power supply sections are the same. They all list 15 capacitors and 7 resistors. The Tommytones board I have only has 14 caps, but 10 resistors.

I did a lot of searching on the forums and was unable to find references to the different psu boards other than the message in this thread. It is obvious that the layout on the diy81 website is different than the actual board I have in hand.

 

[tommypiper]

Toro, if you PM me your email address I can send you the PDF file that Tommytones sent out at the time to everyone. It shows the corrections. In any case, he said the 24v section was fine, so you can at least use the PSU board for that in the meantime. I think many/most of us here got the first version of the PSU boards which need these corrections. I haven't built mine yet so can't help further.

cheers,
tommypiper

 

[fuzzbox]

I don't know if this is of any importance to anyone, but I was having trouble finding parts for this project and fell upon this site.

www.dalbani.co.uk

They sell bax13 and aa144 diodes. also they have bc461's they said they had bc441's but those turned out to be 2n5320's.
as i said I don't know if this helps anyone, just thought I'd let you guys know.