Re: Warm Audio 251
« Reply #1 on: January 04, 2019, 12:44:33 AM »

gyraf

Re: Warm Audio 251
« Reply #2 on: January 04, 2019, 03:12:50 AM »
I hope all those relays are not in the high-impedance path. Been there, tried that... ::)

Jakob E.
..note to self: don't let Harman run your company..

Re: Warm Audio 251
« Reply #3 on: January 04, 2019, 03:32:25 AM »
they are in the hiZ, for polarity switching  :(
specific reed relays would be more suitable imho, with ultra high insulation and very low capacitance...
mechanical switch is the best option off course, but costs more...
« Last Edit: January 04, 2019, 04:31:35 AM by granger.frederic »

gyraf

Re: Warm Audio 251
« Reply #4 on: January 04, 2019, 04:28:57 AM »
exactly. normal small-signal relays won't do here...

..note to self: don't let Harman run your company..

JessJackson

Re: Warm Audio 251
« Reply #5 on: January 04, 2019, 12:59:41 PM »
Did Warm copy someone's circuit or something?

Without a doubt! well in fact myself and Eric Racy from black box audio originally came up with the idea of using the relays in that configuration, we copied Oliver's custom 251. Bless his heart. but we procrastinated on printing the boards so Dany tweaked and executed it.

My original Sketch on an envelope:

https://groupdiy.com/index.php?topic=52727.0

Danys Release:

https://groupdiy.com/index.php?topic=55010.0
« Last Edit: January 04, 2019, 01:07:12 PM by JessJackson »

Spencerleehorton

Re: Warm Audio 251
« Reply #6 on: January 05, 2019, 02:56:51 AM »
Cheeky buggers!!! That’s clearly a rip off.
website: www.mohawkstudios.co.uk
email: [email protected]

If it hisses its probably the wrong impedance!!!

Re: Warm Audio 251
« Reply #7 on: January 05, 2019, 07:55:36 AM »
I'd like to hear from poctop before casting any stones. It's quite possible that he has entered into some agreement with Warm granting them rights to use the design. Also, we're talking about a design based on someone else's design based on a 60 year old design. So it's not exactly the exclusive intellectual property of Dany.

On the tangent involving switches in high-z: so understood that it's normally a bad thing, but can anyone with first hand experience with Dany's kit chime in? Any issues with noise or hum, or have the issues been adequately resolved? A (very) quick scan through the build thread suggests the latter...

Re: Warm Audio 251
« Reply #8 on: January 05, 2019, 11:53:00 AM »
Poctop ripped off the relay solution from an active design used by Blackspade. Didn't matter though, since the commercial products were terminated shortly after. Once it was part of a discontinued circuit, the relay solution became everyone's property. Including Warm's  8)

Breaking it down further, that massive hole in the board to allow for a bigger capacitor? Matador's solution.

imo it's a bit of a sh*t product released by Warm. They're not bringing anything to the market except for another round of 'race to the bottom'. Also a lack of consistency in their designs – they made their U47 a multi-pattern mic, but then use a relay solution on their 251 to remain 'authentic'? Doesn't really add up.

shabtek

Re: Warm Audio 251
« Reply #9 on: January 05, 2019, 01:58:36 PM »
relays and space for bigger capacitors is protected technology?

does calling it 251 make it so?
"really fine players do not use stomp boxes or master volume, they match the amp to the room and turn it up to 11.  Stevie Ray, BB King, Albert King, Duane Allman, Dicky Betts, Louis Armstrong"
   -CJ


Gus

Re: Warm Audio 251
« Reply #10 on: January 05, 2019, 02:11:59 PM »
Does it have a UL listing etc?

In a microphone like this the high Z might not matter as much if the board is clean because the grid to ground is a lower value.

Off Topic a little
Is there any interest in a solid state circuit to use instead of a tube in a microphone like this?
I have not released this because I would need to check the liability issues.
It has been built in a microphone.


RuudNL

Re: Warm Audio 251
« Reply #11 on: January 05, 2019, 02:32:46 PM »
relays and space for bigger capacitors is protected technology?

does calling it 251 make it so?

It is funny that most '251 clones' have only one thing in common with an original 251: the type number!
(This specific one looks like an Alctron HT-11a/Apex 460 with a different headbasket. And even the shape of the headbasket is different than a 251.)
« Last Edit: January 05, 2019, 02:39:40 PM by RuudNL »
There is a solution for every problem!

http://www.vansteenisaudio.nl

Re: Warm Audio 251
« Reply #12 on: January 05, 2019, 04:25:45 PM »
Does it have a UL listing etc?

In a microphone like this the high Z might not matter as much if the board is clean because the grid to ground is a lower value.

Off Topic a little
Is there any interest in a solid state circuit to use instead of a tube in a microphone like this?
I have not released this because I would need to check the liability issues.
It has been built in a microphone.
I think a solid state circuit would be interesting.

Re: Warm Audio 251
« Reply #13 on: January 06, 2019, 10:07:10 AM »

Off Topic a little
Is there any interest in a solid state circuit to use instead of a tube in a microphone like this?
I have not released this because I would need to check the liability issues.
It has been built in a microphone.


Sure!

RuudNL

Re: Warm Audio 251
« Reply #14 on: January 08, 2019, 06:41:36 AM »
I have had the opportunity to exchange some ideas with Gus, but his 'solid state tube' looks very promising!
You could compare his 'solid state tube' more or less with the product Phaedrus is offering. (AC701, VK14)
There is a solution for every problem!

http://www.vansteenisaudio.nl

e.oelberg

Re: Warm Audio 251
« Reply #15 on: January 08, 2019, 10:27:03 AM »
solid state tube circuits could be very interesting to mod a gefell 691 with m58

analogguru

Re: Warm Audio 251
« Reply #16 on: January 08, 2019, 08:05:35 PM »
How cool, can't wait to see a FET-based plug-in replacement for the VF14.  Are we talking about something like this:
https://vintage-radio.net/forum/attachment.php?s=3837375a4887c04e107e6c866e80baa8&attachmentid=129303&d=1472384060

or are we talking about something like Danyuk's triode emulator ?


 

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