Hotrod Build Thread

[clintrubber]

[quote author="Greg"]I think I see what you're saying... just to be sure, are you saying the 12-pin connectors (one for BA283 and one for the switch) are hitting one another. Which part number are you using?[/quote]

Yes, those two 12-pin 'headers'. No problem though, lots of other ways to do it.

W.r.t. part-#, I don't know, just some I came across. Maybe these are 'wider' than other Molexes.

In general, I myself am fond of Stocko's, mainly for their easy & quick assembly (no special tools). But they're bigger of course, that will give problems on crowded PCBs.

Bye,

Peter

 

[Greg]

I put the part number that fits the footprint on the hookup instructions/BOM. There's a link in the first post.

 

[soundguy]

[quote author="kato"]Do these perform approximately the same function as glide-on-fade's awesome switch?[/quote]

the switch we made was simply taking the design for the neve switch and laying it out for a compact pcb that will accomodate a sealed greyhill switch and fit easily inside an existing 1272 module. We didnt make any real changes to the neve spec for the 283AV. It is my experience that the 283 is particularly sensitive to how much gain you pull out of it, so I wanted to come up with a solution which followed exactly what neve did, and thats what our switch does. The primary advantage is that our switch can be configured to accept a line input using either a single 10468 input transformer, like the 1063 does, or it will switch to a 31267 for the line input section like a 1073 does, depending upon how you set it up.

I believe joe just took the mic section and spread it out over 12 positions so you have a finer resolution. 5 positions on our switch is line input, just like a neve EQ would have. I havent built the hotrod so can really only comment on our thing with any kind of authority. Hopefully that will answer some questions. If you dont need a line input, dont want to use a greyhill, dont need the compact pcb, I would imagine joe's arrangement will work out well, his stuff always does. Again, I havent built it to know if it sounds any different. If anyone finishes the hot rod board and wants to make a comparison Id be happy to send out a switch for listening comparisons so long as it gets returned. here's a photo of the switches installed on a pair of 1272 amps I finished up last year, racked with 3126's.

dave

 

[Greg]

Dave:

I should have my Hotrods finished in 2-4 weeks. I'm waiting on some engraving right now. I've never used an original 1272, but have used 1064s on a few sessions in the past... the 1064 usage is the extent of my Neve experience. I can send you my Hotrods when I'm finished if you'd like to give them a whirl. I'm sure you have more experience with Neve modules in general than I do, so maybe you'd be interested in doing the compare. And the BA283AV I'm using are DIY as well...

 

[kato]

Wow, impressively clean layout for all that's in there.

Where did you get the divider for the interior of your case? If you don't mind my asking.

 

[soundguy]

hey greg-

thanks for the offer but Im swamped with too many things, namely getting the mixer together that I designed the switch for.

the divider comes with the par metal 12 series chasis.

dave

 

[crm0922]

Greg, do those 4700uF caps on the hotrod board need to be so big? It is going to take a lot of power to charge those things at powerup.

The ones on Joe's schemo are significantly smaller.

What was the reasoning for making them 4700uF? I'm sure I am missing something.

Thanks,

Chris

 

[clintrubber]

[quote author="crm0922"]Greg, do those 4700uF caps on the hotrod board need to be so big? It is going to take a lot of power to charge those things at powerup.

The ones on Joe's schemo are significantly smaller.

What was the reasoning for making them 4700uF? I'm sure I am missing something.

Thanks,

Chris[/quote]

Interesting this comes up - I'll likely be using smaller than 4700 as well since it won't hurt to use those value of course (more=better, but diminishing returns), but if it means additional hassle to get types that fit the board I better use something more readily available.
As it happens I've been browsing the RS-catalogue yesterday and to my surprise the combination of 7.5mm pin spacing & <13mm diam. is a difficult one. I usually get my stuff there and will have an upcoming order - placing another one somewhere else for these will be overdoing things.

 

[Greg]

[quote author="crm0922"]What was the reasoning for making them 4700uF? I'm sure I am missing something.[/quote]
This improves low frequency response. From the mouth (or should I say fingers) of Geoff Tanner. 2200u should be fine a well.

Nichicon PW Series caps fit the board perfectly.

 

[matta]

Hey Greg,

Firstly just wanted to say the boards arrived and are super nice. I've already stuffed the resistors, caps and wiring to the edge connector... trying to be motivated to do the switch now, but waiting on my panel.

Clint, I shop at RS alot myself. I've used the Rubycon YXF Series, 105 degree, low ESR caps, which I'm a fan of. You can get them in 4700uF/25V. The RS part number is 191-7820 and I know they fit cause I've already stuffed them on my PCB :thumb:

Hope it helps.

Cheers

Matt

 

[Greg]

I'm waiting on my panel as well.

 

[crm0922]

[quote author="Greg"][quote author="crm0922"]What was the reasoning for making them 4700uF? I'm sure I am missing something.[/quote]
This improves low frequency response. From the mouth (or should I say fingers) of Geoff Tanner. 2200u should be fine a well.

Nichicon PW Series caps fit the board perfectly.[/quote]

I got the 4700's, same as on your parts list I think. I was just pondering why I'm putting 4700uF caps in the PSU decouple type of duty when there is only 2200x2 in the PSU itself....seemed strange is all. And I was thinking about turn-on draw to charge those bigguns when it fires up.

If you guys say it is good to go, I'll assume if I build a PSU for +24V 1.5A, that should more than cover it!

Thanks,

Chris

 

[clintrubber]

[quote author="matta"]

Clint, I shop at RS alot myself. I've used the Rubycon YXF Series, 105 degree, low ESR caps, which I'm a fan of. You can get them in 4700uF/25V. The RS part number is 191-7820 and I know they fit cause I've already stuffed them on my PCB :thumb:

Hope it helps.

Cheers

Matt[/quote]

Hey Mat, thanks for the info :thumb:
I did see those types but skipped them at first since I saw a 18mm diameter, possibly pushing away the other components. So thanks for the info, will add those 191-7820 to my list.

Thanks,

Peter

 

[clintrubber]

[quote author="Greg"]This improves low frequency response. From the mouth (or should I say fingers) of Geoff Tanner. 2200u should be fine a well.

Nichicon PW Series caps fit the board perfectly.[/quote]

The thought just struck me that we're actually doing a bit of a strange combination here. :wink:

I mean, most of us will be using Fabio's 'BA283-recreation' that mimics the original board as much as possible. This to stay as close as possible 'to the truth and only truth' - no chances taken - use the same layout.
Then it gets HotRodded and bigger caps :twisted:
Perfect clone ? :roll:

Just a thought - it's all about a nice preamp of course so when things can be improved let's do it. It's just that I recalled one of the reasons for the BA283-card-layout... I mean, Fabio's 1272 daughterboard & motherboard can do HotRod also already, right ? :wink:

End of rant - here's to nice preamps ! :guinness: :sam:

Nichicon PW Series caps fit the board perfectly.

:thumb:

 

[Greg]

This is definitely not a perfect clone of the 1272, nor was it really intended to be. We're also adding and output control, which is unlike the original. soundguy Dave has a nice writeup about the two caps in question here, as well additional info on the 1272. He also recommends changing these caps. I know he uses 4700u for one and something else for the other. Can't remember what exactly. He mentions that Neve was limited to the size of caps because caps were physically bigger back then, so they had to use what would give in the 1272 module. Now we can cram lots of capacitance into small spaces.

 

[clintrubber]

[quote author="Greg"]This is definitely not a perfect clone of the 1272, nor was it really intended to be. We're also adding and output control, which is unlike the original. soundguy Dave has a nice writeup about the two caps in question here, as well additional info on the 1272. He also recommends changing these caps. I know he uses 4700u for one and something else for the other. Can't remember what exactly. He mentions that Neve was limited to the side of caps because caps were physically bigger back then, so they had to use what would give in the 1272 module. Now we can cram lots of capacitance into small spaces.[/quote]
Thanks for adding - and it all makes perfect sense of course.
As said, the thought just struck me. :thumb: :wink:

 

[Milkmansound]

I will be using original cards - I can not see what the huge difference will be though, Fabios seem to be precisely the same right?

 

[clintrubber]

[quote author="Milkmansound"]I will be using original cards - I can not see what the huge difference will be though, Fabios seem to be precisely the same right?[/quote]
If this is w.r.t. my 'aside remark' then that's not what I was saying. Fabio's boards are most likely 200% spot on, so no differences from that - if it all to significantly noticable amounts, but don't let me trigger a PCB-layout-influences discussion.

Bye,

Peter

 

[Milkmansound]

my B283 boards just arrived today, and the ********* who sold them to me did not specify that they were missing the input section! So I have only output...

I assume that the BOM and layout on fabios board can be used for an original card too right? I just need to add in the 20 or so missing parts to get the output section going... this dude who sold them to me... well, I do not want to curse here.

 

[Greg]

Look at my first post, #3. In that spreadsheet, I have a parts list for the BA283AV with the part number that corresponds to the board. That'll get you started... :thumb: