8 Channel, 3U NEVE 1073 completed

[mattmartin831]

I notice the PCBs for this build are currently out of stock. Anyone have an idea when they might be selling more?

 

[TillM]

That was fast
I get an E-Mail a week ago, that they back in stock.
Holy cow ... i'm sure that in the next weeks new PCBs will arrive.

 

[mattmartin831]

So I've been thinking about the best way to efficiently power my 8 channel 1290 preamps and right now I'm thinking about buying one of these switching mode power supplies (http://www.ebay.com/itm/292065772914), then adding some linear voltage regulators to bring it down to 24VDC and decoupling capacitors to reduce the ripple in the ouput voltage. Has anyone tried using this type of power supply? Are there any other problems or drawbacks that I should be aware of?

 

[useme2305]

what do you mean " bring it down to 24VDC"?  it's already 24VDC as far as i can see.

i'm using a 48VDC switching power supply in conjunction with a JLM TREX (little PCB that puts out 24VDC from an 48VDC input) for my two channel unit. works fine and sounds great!

in an 8 channel unit this would mean ALOT of heat though! i don't think it's possible without alot of venting and at least one fan.

 

[mattmartin831]

what do you mean " bring it down to 24VDC"?  it's already 24VDC as far as i can see.

i'm using a 48VDC switching power supply in conjunction with a JLM TREX (little PCB that puts out 24VDC from an 48VDC input) for my two channel unit. works fine and sounds great!

in an 8 channel unit this would mean ALOT of heat though! i don't think it's possible without alot of venting and at least one fan.

The power supply I ordered has 28VDC output with up to 5A of current with around 120mV of ripple. I would think most the heat in your situation comes from  the 48V to 24V voltage drop across the linear regulators, so since I will only be dropping 4VDC across them, and I also plan to limit the current going across each regullator to about 500mA, hopefully that will minimize the heat coming off of them.

 

[useme2305]

my bad. i thought you wanted to use a 48VDC PSU and i didn't see that the one you wanna buy has 28VDC but i instead read 24VDC and thought you probably wanna go the 48V to 24V route.

EDIT:
why didn't you just go with a 24VDC external PSU? why the hassle of regulating the 28VDC to 24VDC?

 

[mattmartin831]

my bad. i thought you wanted to use a 48VDC PSU and i didn't see that the one you wanna buy has 28VDC but i instead read 24VDC and thought you probably wanna go the 48V to 24V route.

No problem man, I'm glad to hear from someone who has made it work. Makes me feel more confident in my plan, so thanks!

EDIT: I chose the 28V psu because I realize there is a lot of ripple voltage coming out of the switching mode power supply. I wanted to minimize this ripple voltage so I decided to use LM317's to regulate the voltage and turn the expected 120mV of ripple into something in the scale of micro or nanovolts.

 

[Glutamatjunkie]

Hey Guys, maybe someone can help:

can I use 630Volt Polystyrenes instead of 50Volt?

Thanks.

 

[Whoops]

Hey Guys, maybe someone can help:

can I use 630Volt Polystyrenes instead of 50Volt?

Thanks.

Yes, it just means the capacitor can whitstand an higher voltage without burning.

But it would be bigger, might not fit the pcb and it will be much more expensive also

 

[Glutamatjunkie]

Thanks Whoops!

 

[Whoops]

Hey Guys, maybe someone can help:

can I use 630Volt Polystyrenes instead of 50Volt?

Thanks.

why do you want to use 630v caps?

Where are you located?

 

[Glutamatjunkie]

why do you want to use 630v caps?

Where are you located?

Have some laying around here.
Just ordered a bunch at Banzai.  8)


PS: I'm from Bremen

 

[Whoops]

Have some laying around here.
Just ordered a bunch at Banzai.  8)


PS: I'm from Bremen

Banzai, Farnel and Mouser
all of them have those

I think Mouser is cheaper

 

[tomnyhbees]

Hi,
Is it possible that B and C deck for the Grayhill switch on the EZ1290 PCB are reversed?  The common for deck B on the EZ1290 schematic and wiring diagram connects to U on the BA183 schematic,  and the common for deck C connects to T on BA183 schematic, but on the EZ1290 PCB the pin for deck B would connect to the 1k8 (which is T on the schematic) and deck C would connect to the 120k (which is U on the schematic). 
Thanks

 

[sr1200]

The grayhills are only switches.  Which deck goes to which component is a matter of design and kind of irrelevant.

 

[Spencerleehorton]

Quite excited, building some original spec Lo1166 output transformers and have tested against the carnhills, carnhills spec isn't half as good! Quite surprising! Testing in Neve channels next week once first batch finished!

 

[vdr20]

I'm currently building this on stripboard and so far it seems to be going well. I've currently made the BA183/NV board as well as half of the BA183/AV board and they seem to be working well.

It looks like I'm going to run out of room on the rest of the BA183/AV board so I was wondering if the heatsink is completely necessary. Would it be okay for me to build it without the heatsink?

 

[Whoops]

I'm currently building this on stripboard and so far it seems to be going well. I've currently made the BA183/NV board as well as half of the BA183/AV board and they seem to be working well.

It looks like I'm going to run out of room on the rest of the BA183/AV board so I was wondering if the heatsink is completely necessary. Would it be okay for me to build it without the heatsink?

I guess if the heatsink was not needed companies would just skip it save costs

 

[madriaanse]

EDIT: I chose the 28V psu because I realize there is a lot of ripple voltage coming out of the switching mode power supply. I wanted to minimize this ripple voltage so I decided to use LM317's to regulate the voltage and turn the expected 120mV of ripple into something in the scale of micro or nanovolts.

Don’t use a switching power supply. Just don’t do it! You end up putting band aids on things that didn’t need to be wounded in the first place. Use a good linear 24/48V as specified.

Also, 2N3055 will wants its heatsink.

M.

 

[Potato Cakes]

I just finished another reincarnation using the ez1290. 2065 inductor based HPF/LPF, JLM Audio MAC Opto compressor with modded ratios, Whistle Rock ML12 PSU. Very quiet and clean. Sounds really great!

The bad news is I have to P-Touch over the LPF selections as I made the panel with the wrong frequencies and direction of the switch. It adds to the DIY spirit of things I guess.

Thanks!

Paul