Neve out layout here.

[Bauman]

Maybe this is useful for someone else... gonna use it on several things, like after a ssl9k micpre...

(i have changed the layout a little bit around Q7...)

here are the files:

sch
http://www.thediypill.phx.com.br/forumfiles/neveout_sch.pdf

parts layout
http://www.thediypill.phx.com.br/forumfiles/neveout_parts.pdf

ready to transfer solder side
http://www.thediypill.phx.com.br/forumfiles/neveout_solder.pdf


:guinness:
Fabio

 

[giobinein]

:shock:
Thanks for the sharing Fabio !!
:razz:

 

[amorris]

thanks as well.

 

[Guest]

Time to resurrect this one
A few questions...

Do we have a value for RV1?
Do we have a explanation of RGx .. possibly in connection with using this as a Pultec make up gain.

 

[matta]

Hi UK,

This board is the output section of the BA283AV, the same parts and components as the orginial and RV1 there is 5K, so I assume it is the same for this board. If I recall it adjusts the DC onto Q4 (not looking at the schemo, doing this from memory).

RE RGx, the explaination is on the Schematic, RGx sets the gain for board.

If you wanted to be clever, jumper RGX and then wire up a Lorlin with the resistors to the RG and GAIN pads, that would allow you to increase or decrease the gain...

Or if you want a fixed gain, jumper RG GAIN and set the gain using RGx.

Hope that helps.

Matt

 

[Guest]

Thanks Matt
Starting a new thread...

 

[BR]

Yeah..
RV1 is a 5K trimmer and the matta makes total sense with the RG, RGx and Gain theory..
I'm getting a bunch of these pretty soon.
I'll be putting at the end of my SSL clone using some Lynx traffos. It will be a while, but I'll post pics and sound files when done.

take care
Gil

 

[matthias]

thank you, that's really useful for some of my future projects (pultec...)

but, does the 2n3055 really need a heatsink?
and if yes, I've never seen such a small heatsink that would fit on the board...

mat

 

[dissonantstring]

hey matthias,
i was thinking the same thing - about to build fabio's BA283 boards.
i found this at digikey:
http://rocky.digikey.com/WebLib/IERC/Web Data/7-423,7-438.pdf
model: 7-423BA. seems like the heatsink fits right over without taking up any real estate. only 2W dissapation though, so i was wondering if they would sink enough heat from the 2N3055. they are pretty pricey - $4.60 each (more for the EU crew).
regards,
grant

 

[rascalseven]

Yes, the big 2N3055 needs a heatsink... it gets pretty hot. The heatsink doesn't have to be very large (the one's Neve used back in the day were essentially just a stout piece of aluminum just large enough to cover the rectangle below the thing).

I buy short, black, finned heatsinks for these (not more than a half-inch high) from my local surplus store for 29-cents each, and they work great. After the circuit is well warmed up the top of the 3055 is lightly warm to the touch... not hot at all. You could get the super tall / high dissipation versions as well, but that's way overkill IMO.

Without a heatsink it's to hot to comfortably touch, however.

JC

 

[dissonantstring]

thanks for the info JC!
do you think that the 2W dissapation would be sufficient? most of the TO-3 heatsinks available dissapate about 5W-20W. hmmm, maybe i'll just have to try it and see. again thanks JC!
-grant

 

[clintrubber]

[quote author="dissonantstring"]hey matthias,
i was thinking the same thing - about to build fabio's BA283 boards.
i found this at digikey:
http://rocky.digikey.com/WebLib/IERC/Web Data/7-423,7-438.pdf
model: 7-423BA. seems like the heatsink fits right over without taking up any real estate. only 2W dissapation though, so i was wondering if they would sink enough heat from the 2N3055. they are pretty pricey - $4.60 each (more for the EU crew).
regards,
grant[/quote]
I'll be using that 'over the top'-thing as well. FWIW, some more on that 7-423BA-style here:
http://www.groupdiy.com/index.php?topic=11992&start=0&postdays=0&postorder=asc

 

[dissonantstring]

hi peter,
thanks for the link! i should have done a search for it earlier. after reading the post you referenced i'm still wondering if i need more heatsinking? :?
will you be using just the 'over the top' heatsink or are you still planning on using something below as well (but then that would kind of just make the 'over the top' heatsink redundant.) :? hmmm... what to do?
that huge square platform heatsink on the original neves makes me wonder how much heat really is being dissipated?
-grant

 

[clintrubber]

[quote author="dissonantstring"]hi peter,
thanks for the link! i should have done a search for it earlier. after reading the post you referenced i'm still wondering if i need more heatsinking? :?
will you be using just the 'over the top' heatsink or are you still planning on using something below as well (but then that would kind of just make the 'over the top' heatsink redundant.) :? hmmm... what to do?
[/quote]
I see your point and I think we're in fact 'struggling' (biiiig words...) with the same. What to lose...? I just be trying that over-the-top thing and if things get too hot then I know I have to add more. In fact, those coolers I have are part of a complete cooling thing, there's also a bigger thing underneath. But if I want to mount the TO-3 low that won't fit.

So the plan: first try the top-section, and if that gets too hot I'll desolder the '3055 and mount it higher above the PCB, now with the thing underneath as well. (I won't cut the E & B pins so I can still do that). This should be enough for sure now. And by now the top-thing will be redundant, but OK. Note that I got that combo thrown in at another sale, so I can just try. New they're indeed relatively expensive.

But even degraded to account for Bcarco's valid arguments (see the other thread), I don't excpect that the top-only will get a very hot '3055.

that huge square platform heatsink on the original neves makes me wonder how much heat really is being dissipated?
-grant

Less than 2W I expect: Voltage drop across '3055 times 80mA.

Bye,

Peter

 

[EEMO1]

how does one implement this to existing stuff?

i'd like to try one with a g1176 comp and a pulteq, both gustavs boards.

thanks,

eero

 

[Greg]

My plan is to eventually implement these as makeup gain after some type of passive summing network. But this project is a little bit off. I have built and tested these boards and they're great.

Not sure about your specific question, though...

 

[EEMO1]

the thought i had that these could be used in place of a output transformer? or with the pultec that has a passive output...

are these only for a summing makeup gain?

 

[guavatone]

These may be a perfect fit for the @udix modules that I was complaining about. without a proper output section they don't have enough signal to drive some inputs. Anyone?

Are the part values listed in the BA283 parts list the same?

 

[Greg]

[quote author="EEMO1"]the thought i had that these could be used in place of a output transformer? or with the pultec that has a passive output...

are these only for a summing makeup gain?[/quote]
Well you still need an output transformer with this output stage, and I think the output transformer for the 1176 can be wired 2:1, 1:1, or 1:2. If you wanted to keep the gain structure the same (which you don't have to), then the most gain you'll be getting from AM stage is 6dB. I don't know if it will be happy with that small of gain... but you'd have to try it to see. Also, it'd probably be better to replace the entire output stage of the 1176, not just the output transformer... I don't know for sure but the AM stage might not load the output transistor pair properly.

And these can be used for more than just makeup in summing amps.

 

[EEMO1]

thanks greg.

i have one 1176 that has oep out. engineer friend of mine tested it out and he said that the output was low. i noticed that the output also distorts/oscillates after 1-2 o'clock at the output. it good for my needs, but now im building another one and started thinking about it. guess im going to test things out, so i'll know better... :thumb: