8 Channel, 3U NEVE 1073 completed

[danjpiscina]

Hey guys, just read through this post today and I have to try this. I've done a couple small DIY projects but was looking for a pre to sink my teeth into. I think I'd like to try a 2 ch. My question is what has been the experience with the PSU inside the enclosure vs outside?

I noticed Martin prefers outside. Has anyone installed it inside? Pros/Cons?

Also what about 2U vs 1U regarding a 2ch?

for what is costs to make an external PSU, it's worth it. it's like an extra $20-25 for the case/XLR's/cable etc. It's more reliable and simpler to build. Plus you can build a pair in a 1RU enclosure this way. Martin designed the boards and does it this way so I'd take his word for it. I recommend a separate PSU.

This is a great project!

 

[adam1176]

thanks guys. so you didn't need to bend any parts to fit in a 1U? Did you mount anything funny? Is it possible to see pictures of your work? Thanks for the help.

 

[danjpiscina]

thanks guys. so you didn't need to bend any parts to fit in a 1U? Did you mount anything funny? Is it possible to see pictures of your work? Thanks for the help.

Here are some picture of the first pair I built.
http://www.groupdiy.com/index.php?topic=20152.msg419581#msg419581

I didn't have to bend anything except for the heatsinks. This was really easy to do and I'm sure if you look around and take some measurements you could find some that fit without bending. You also have to get the "narrow board version" o/p transformer:
http://www.audiomaintenance.com/acatalog/CA-18-VTB1148_extended_info.html

Also, make sure you get a decent case.

Dan P.

 

[Whoops]

thanks guys. so you didn't need to bend any parts to fit in a 1U? Did you mount anything funny? Is it possible to see pictures of your work? Thanks for the help.

Like Dan said, maybe you have to slightly bend the 2N3055 heatsinks, nothing special.

And you have to get the narrow board version of the Carnhill output transformer.

I can't find any pictures now, but i will search for them tomorrow

 

[adam1176]

I already know the answer to this I'm sure but is there a place in the states to order the carnhill transformers from? Looking to save on shipping. I'm sure it would have already been posted but before I order I'll try my luck.

 

[Whoops]

thanks guys. so you didn't need to bend any parts to fit in a 1U? Did you mount anything funny? Is it possible to see pictures of your work? Thanks for the help.

here is he way I mounted everything in a 1unit rack case,
I still need to redo some stuff in the wiring and tidy up a bit, but the placement of parts will be the same.

 

[danjpiscina]

I already know the answer to this I'm sure but is there a place in the states to order the carnhill transformers from? Looking to save on shipping. I'm sure it would have already been posted but before I order I'll try my luck.

I haven't found a reasonably price US dealer. I got mine from Audio Maintenance (in England) and considering they're English transformers I doubt you can get them cheaper in the US. Shipping from AML was pretty reasonable.

 

[Neil]

I'm trying to finish up the power supply for a 2-ch version, but Digikey is backordered on the TE62085-ND toroid until November!  :'(

Can I sub the TE62075-ND since I'm only running 2 ch? It's only 35 VA, and 22 @ 1.590 parallel, 44 @ .795 series instead of 50 VA, 22 @ 2.272 parallel and  44 @ 1.136 CT series.

If that won't work does anyone have a good substitute? I've already got the ACDC and everything else on the power supply built per Martin's excellent assembly guide.

Thanks!
Neil

 

[Whoops]

To be honest I don't really know which capacitors are in Martin's BOM.

Are you refering to the Styroflex (Polysterene) capacitors? 
(white and transparent ones)


As far as I know those are the type of capacitors used in the original Neve modules,
you only find them in pf Values.
They are much expensive than Ceramic capacitors.

Don't know the sound differences because I never compared it to any other module.
I can just tell you that my 2 channels sound really good.

 

[SIXTYNINER]

To be honest I don't really know which capacitors are in Martin's BOM.
Are you refering to the Styroflex (Polysterene) capacitors? 
(white and transparent ones)

yes whoops
the white and transparent ones
martin bom have ceramic
cheers...

 

[briomusic]

whoops, I see you used an SSL9k board for the PSU, which I am planing to to as well.
Did you just replace the 7818 with a 7824? and the transformer with 2*24 Volts?

BTW, I accidentally ordered WIMA's for all the PF and NF capacitors, which involved a lot of bending into shape but does work. Is this going to sound different to Styroflexes? I guess the tolerances are higher for starters...

 

[pedroplanet]

as far as I know these wima are inductive, styroflex and ceramic-multilayer are non-inductive design

on the smaller values 100pf and 220pf I even used silver mica

 

[Whoops]

whoops, I see you used an SSL9k board for the PSU, which I am planing to to as well.
Did you just replace the 7818 with a 7824? and the transformer with 2*24 Volts?

BTW, I accidentally ordered WIMA's for all the PF and NF capacitors, which involved a lot of bending into shape but does work. Is this going to sound different to Styroflexes? I guess the tolerances are higher for starters...

Yes I used the SSL9K PSU. You're right I just replaced the 7818 with a 7824, it's as simple as that.
2 x 24V transf. Left the negative side empty since you only need the positive rail.

I'm sure the Caps will sound different than the Styroflex ones, don't know in what way.
People seem to describe Styroflex as more "hi-fi" sounding, but I don't really Know.
Maybe someone can help here.

As I said I just used them because those were the type used by Neve.

 

[zachs]

Thanks so much for this awesome project madriaanse!

You can see my 4 channel version here: http://www.groupdiy.com/index.php?topic=35124.0

 

[promixe]

Hi All,

Just ran into an issue with my 4-channel 2U rack. I use a single 50VA 2x22V toroid to power all four boards through two separate PSUs (FiveFish PSU-2448 for Phantom and two EZ1290 & Igor's 33609 PSU for the remaining two EZ1290s). It worked fine for a while until today I powered it up and started calibrating the bias. The toroid started buzzing after 5 minutes of being powered on, then it started overheating, so I had to power everything down. Beside powering 4x EZ1290s there are 7 total LEDs in the unit (4 of them were off at the time of toroid saturation).

Any suggestions as to how to troubleshoot this issue?

Basically, I run the secondaries with the center tap to the FiveFish PSU as suggested in its manual. Then I also run one of the secondary 22V (the black wire) and the center tap into Igor's single 24V PSU to derive 24V for the additional two channels. Both PSUs spit out correct +24V (+/- 0.10V). FiveFish also gets me exact 48V.

Could it be a defective toroid? Or am I maxing it out with 4x channels? 50VA @110VAC should be enough for peak 500mA per channel x4, right?

Thanks for the input!

UPD: After waiting awhile to cool down the trafo I powered the unit again and the toroid is buzzing immediately from the start now, so it seems to be permanently damaged. =( Everything still powers up though, I'm just not able to run it past 10 seconds due to overheating again. Thoughts?

 

[pedroplanet]

is your transformer an Antek AN-0525?

 

[promixe]

is your transformer an Antek AN-0525?

No, it's Avel Lindberg Y236205 - http://avellindberg.com/transformers/y23_range_specs.htm . It's 1.14A per 22V winding.

After thinking a bit more about the issue I realized that I might have overloaded the first secondary winding. Correct me if I'm wrong but wouldn't it work if I fed the yellow wire into Igor's PSU (a single +24V PSU) instead of the black one? That would load the 2nd trafo winding with Igor's PSU and the 1st winding with the FiveFish PSU, since I'm not using the negative rail on it? Does that make sense at all? Or do I still have to pretty much double the VA rating of the toroid for this scenario?

THanks

 

[briomusic]

Didn't want to start a new thread with my humble little EZ1290 build, so here goes:

I decided against the go-between for two reasons:
1. I don't think I need a pad with the level switching (none of the commercial 1073 clones seem to have one)
2. I wanted to put the phase swap on the output (instead of the input) to avoid the popping sounds you get when switching phase with phantom power engaged.

I accidentally ordered wima caps for all the polys, but so far it sounds ok to me (only tried speech sofar). If anything a little brighter than the Ch*ndler LTD-1 I used to compare.

I am using the Ch*ndler PSU for the time being but plan to stick a transformer in there eventually. If I use the outer windings of a 2*12 will this work as a 24v psu? can the SSL PSU still derive 48 Volt phantom or are modifications needed?

Thanks to the group and especially madriaanse for the PCB.

 

[mitsos]

is your transformer an Antek AN-0525?

No, it's Avel Lindberg Y236205 - http://avellindberg.com/transformers/y23_range_specs.htm . It's 1.14A per 22V winding.

After thinking a bit more about the issue I realized that I might have overloaded the first secondary winding. Correct me if I'm wrong but wouldn't it work if I fed the yellow wire into Igor's PSU (a single +24V PSU) instead of the black one? That would load the 2nd trafo winding with Igor's PSU and the 1st winding with the FiveFish PSU, since I'm not using the negative rail on it? Does that make sense at all? Or do I still have to pretty much double the VA rating of the toroid for this scenario?

THanks

Pedro, have you had problems with the Antek? I'm using a couple with no issues...

Promixe:  I don't know either of those PSUs (can't find anything on Igor's) but I would have connected both secondaries to both PSUs.

 

[pedroplanet]

No, I've bought an antek 50VA for 4 channels, just wondering if it could handle...