Warwick Hellborg preamp transformer question
- Thread starter LukeFRC
- Start date
vigilante398
Authorized Vendor
Looks to me like those are the letter O and not the number 0. So possibly an abbreviation for positive and negative Output voltage?
Reasonable to assume that's the rail voltages for the NE5532
Also have a 40Hz LPF on each rail going on. 100R shouldn't alter the V but will current limit protection to some extent. Well. After 150mA or so. That's when you'll see V drop.
vigilante398
Authorized Vendor
It had been a while since I heard back from Haufe, but they emailed me today informing me that upon further investigation it turns out ST 8161 is a customer-specific item and they are not allowed to sell it to anyone else. They offered to try to find me a similar unit, but I already have a few hundred similar units on a shelf so I don't really need theirs.
Feral Feline
Well-known member
Me thinks they found the thread!
Well, almost...
Well, almost...
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Well - first of all thank you Nathan
Even if they can't sell something with you, what you managed to find out from them means we can work out what the design decisions would have been....
Its specs as you found are very very close a Neve line input transformer, wired backwards. So either that's chance or they were trying to get close to a Neve line input transformer - which sounds like something Jonas Hellborg might have asked for...
So that's enough to recreate the preamp section.
The EQ section, was good but no so great, and inductors are a) expensive and b) a wee bit beyond my capabilities/undersanding at the moment
and the DI transformer is a custom transformer, (possibly neve flavoured), but essentially any DI transformer that will work from the output of a NE5532 will be fine ...
My plan then is to make a thing.
Transformer- preamp stage - output and DI out
- omit the EQ, mute and effects loop.
I'll use it end of my pedal board chain - though I'm tempted for pedalboard use put it in a box with an Input buffer of some kind into switchable loop infront of it. Still working out if that's a good idea!
vigilante398
Authorized Vendor
I mean realistically получилось enough for me, it was just a curiosity thing on my end.Me thinks they found the thread!
Well, almost...
