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Re: Darkglass - Vintage Microtubes

PostPosted: 12 Apr 2017, 05:05
by johnk
i drew up an etchable pcb for it, but i want to test it first before i post it, but i'm pretty sure that i got it right.
i used own the original and i remember well how it sounded so i should be able to tell if it sounds like the orig.

Re: Darkglass - Vintage Microtubes

PostPosted: 13 Apr 2017, 00:37
by johnk
okay. i built and tested it and it works perfect except the 'era' control is nowhere near as effective as on the original. IMO, there must be something amiss in the schematic.
i i tried it both ways as per these schematics and neither way is like the original pedal.:

Re: Darkglass - Vintage Microtubes

PostPosted: 13 Apr 2017, 07:00
by johnk
hmmmm. Darkglass describes that the era interacts with the Drive knob to shape the character of the pedal, but i don't really see how it can, being that it's located post the drive/distortion part of the circuit as per the posted schematic.

Re: Darkglass - Vintage Microtubes

PostPosted: 13 Apr 2017, 18:01
by Frank_NH
johnk wrote:hmmmm. Darkglass describes that the era interacts with the Drive knob to shape the character of the pedal, but i don't really see how it can, being that it's located post the drive/distortion part of the circuit as per the posted schematic.


Just perusing this on my lunch hour. It looks to me that the Era control is just a variation on the BMP tone control. But...it's missing a resistor to ground at the junction of lug 3 and C21 in the first schematic. That resistor would form a HPF with the 1 nF cap when the Era control was all the way up. I don't know if there is a gut shot somewhere, but you could look for a resistor near the 1 nF. Otherwise experiment (start with something like 100K to ground, and go up from there to retain more lows).

The last two op amps are Sallen-Key filters to chop off the high end somewhat, probably a good thing since this is being used for bass...

Re: Darkglass - Vintage Microtubes

PostPosted: 13 Apr 2017, 18:10
by johnk
yeah, i was going to try adding a resistor to it.
i also just ordered a GUMA antique overdrive which is supposed to be an accurate clone of the VMT and i intend to trace it to see if it matches the posted schematics.

Re: Darkglass - Vintage Microtubes

PostPosted: 13 Apr 2017, 18:17
by Silver Blues
It was actually from pictures of that board that I determined the missing capacitor values. I was just looking at it again to see if I could figure out the connectivity, but there's only so much I can do without having the physical board in front of me. As far as I can tell right now Era 2 and Era 3 are actually connected to each other, don't know if that helps.

Re: Darkglass - Vintage Microtubes

PostPosted: 13 Apr 2017, 19:19
by johnk
i think that ERA 2&3 are connected together too. it may be wrong cap values but the GUMA antique appears to have the same values in the BOM.

Re: Darkglass - Vintage Microtubes

PostPosted: 13 Apr 2017, 19:21
by johnk
i think that ERA 2&3 are connected together too. and yes the GUMA antique has those values in the BOM.

Re: Darkglass - Vintage Microtubes

PostPosted: 20 Apr 2017, 09:03
by stangwarrior
Just completed ksenanekro's version and it works ok.Two of the pot as reversed - you should swap blend 1 and blend 3, and drive 1&2 should go to volume 1.ERA works as it should i think, tho i don't own the original and can't compare...

Re: Darkglass - Vintage Microtubes

PostPosted: 21 Apr 2017, 19:29
by miguelmoita
Here is the my schematic based by the ones the johnk did with the values of Guma Antique. There are very few adjustments. I have it in my breadboards and it sounds awesome but I do not have the original to compare. I own the B7k, and it definitely sounds like a Darkglass.
I am going to make a tone transfer image in the next days, I will post here.
Regards,
Miguel

Re: Darkglass - Vintage Microtubes

PostPosted: 02 Jun 2017, 05:39
by miguelmoita
Just finished Mine :)

Sounds awesome!
Just needs the decals now.

Re: Darkglass - Vintage Microtubes

PostPosted: 22 Jul 2017, 06:55
by fersynes
miguelmoita wrote:Just finished Mine :)

Sounds awesome!
Just needs the decals now.


wow! it looks so good! and the board is very similar to you b3k. could you please upload the layout and pcb?

Re: Darkglass - Vintage Microtubes

PostPosted: 04 Aug 2017, 12:51
by vadgrek
miguelmoita wrote:Just finished Mine :)

Sounds awesome!
Just needs the decals now.

Psb!.. Psb!..Psb!.., :applause: :applause: :applause:

Re: Darkglass - Vintage Microtubes

PostPosted: 25 Aug 2017, 17:33
by horacemap
Just finished mine too.

Sounds really great. Super bassy with a touch of growl :D

Thanks for sharing the layout !!

d00137fc-94fc-4068-85f8-ead0759a04c8.jpg

Re: Darkglass - Vintage Microtubes

PostPosted: 26 Aug 2017, 00:15
by bajaman
I just built the B3K which is very similar to the VMT :wink:
I have some boards available if anyone is interested - pm me :secret:
cheers
bajaman
IMG_3249s.JPG
IMG_3249bs.JPG
IMG_3248s.JPG
IMG_3248bs.JPG
IMG_3239s.JPG
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IMG_3237s.JPG

Re: Darkglass - Vintage Microtubes

PostPosted: 23 Oct 2017, 10:13
by stangwarrior
Hi,
anyone have issues with this build?I have two problems - one is the gain, which squeeks and cuts the sound after 80-90%, the other is whatever i do, it sounds dephased in a wierd way, very artificial...The only difference in my build is i use j113 transistors instead of j201 and the unused inputs of the CD4049 are not grounded

Re: Darkglass - Vintage Microtubes

PostPosted: 25 Oct 2017, 09:31
by stangwarrior
Anyone? 3 builds allready and always the same problem - it sounds like high pitched shit, especially when you play on the hight strings...
Are you sure some of the opamps stages should invert the signal?Isnt the signal inverted after the CD4049 and the out of phase with the clean signal?