Page 1 of 2

Darkglass - Vintage Microtubes

PostPosted: 28 Dec 2014, 14:57
by Bernardduur
Got one it becase it had some huge issues; all sounds were horrible distorted and gating, only the gain potmeter did something.......

I found the problem to be the TL074 which were all shot. Replaced it with a new one and it again works like a charm!!

DSCF3958.jpg
DSCF3957.jpg


And some schematic; it doesn't state the capacitor values and my DMM that can read em is broken

Darkglass - Microtubes Vintage.JPG

Re: Darkglass - Vintage Microtubes

PostPosted: 02 Jan 2015, 04:22
by thoglette
Bernardduur wrote:I found the problem to be the TL074 which were all shot.


Wonder what killed it - you've usually got to try really hard to kill one of them. Any ideas?

Re: Darkglass - Vintage Microtubes

PostPosted: 05 Jan 2015, 16:05
by olejason
Thanks for the schem!

Re: Darkglass - Vintage Microtubes

PostPosted: 05 Jan 2015, 21:19
by Bernardduur
thoglette wrote:
Bernardduur wrote:I found the problem to be the TL074 which were all shot.


Wonder what killed it - you've usually got to try really hard to kill one of them. Any ideas?


No idea! The owner got it second handed with these errors and hoped he could fix it! It was never resolved how it ended up being this way!

Re: Darkglass - Vintage Microtubes

PostPosted: 09 Jan 2015, 02:23
by Bill_Mountain
C19 looks way high???

Re: Darkglass - Vintage Microtubes

PostPosted: 09 Jan 2015, 18:22
by Bernardduur
Bill_Mountain wrote:C19 looks way high???


F***; typo! I'll upload a new version later!

Re: Darkglass - Vintage Microtubes  [schematic]

PostPosted: 09 Jan 2015, 21:36
by Bernardduur
Darkglass - Microtubes Vintage.JPG

Re: Darkglass - Vintage Microtubes

PostPosted: 10 Jan 2015, 00:00
by Bill_Mountain
I really like this design. It's clean simple and it allows you to scoop your mids and run it direct because of the LPF. I knew this was good pedal but seeing this really shows how much Doug gets bass players and their needs.

Re: Darkglass - Vintage Microtubes

PostPosted: 18 Jan 2015, 17:39
by Silver Blues
Yeah nope FML. Guys I apologize profusely. This is what I get for doing such a complicated layout so late at night. I've double-checked this version, it's a little ugly again but I THINK EVERYTHING IS CONNECTED WHERE IT SHOULD BE :shock:

Re: Darkglass - Vintage Microtubes

PostPosted: 22 Jan 2015, 19:42
by OnTheTundra
Where are we at with the cap values? I will build one from the last vero once those are posted.

Re: Darkglass - Vintage Microtubes

PostPosted: 22 Jan 2015, 21:21
by Silver Blues
OnTheTundra wrote:Where are we at with the cap values? I will build one from the last vero once those are posted.


Be sure to give it a once-over before you build it so I can fix any last-minute mistakes if they appear. Wouldn't want you to build something this big from an incorrect layout :mrgreen:

Re: Darkglass - Vintage Microtubes

PostPosted: 23 Jan 2015, 05:28
by Silver Blues
What I'd like to do, if you don't mind, is refer you here for the future. This is easier to keep updated without me taking up posts on this thread.

Re: Darkglass - Vintage Microtubes

PostPosted: 21 Feb 2016, 12:08
by vorokha
In the circuit there is a manifest error.
The frequency characteristic in this regard is far from the original.
R24 = 100k

Re: Darkglass - Vintage Microtubes

PostPosted: 01 Mar 2016, 20:38
by Bigwan
Sorry to dredge this up, but can anyone explain what the Era control is doing. My first thought was it was like a modified muff tonestack but I know it acts quite a lot on the midrange. Anyone?

Re: Darkglass - Vintage Microtubes

PostPosted: 02 Mar 2016, 08:00
by Bigwan
Further to my previous question, is it a fixed low pass filter (R27 and C20) and variable high pass filter (VR2, R28 and C21)?

Re: Darkglass - Vintage Microtubes

PostPosted: 02 Mar 2016, 08:48
by Bernardduur
Bigwan wrote:Sorry to dredge this up, but can anyone explain what the Era control is doing. My first thought was it was like a modified muff tonestack but I know it acts quite a lot on the midrange. Anyone?


It is a simple mid filter (as can be found here)

Re: Darkglass - Vintage Microtubes

PostPosted: 10 May 2016, 23:13
by rocket8810
i know it's been awhile since anything moved on figuring this one out, but if your dmm is still broken and want/can send it out, i'd gladly test it to figure out the missing caps. would be real nice to get this one right man. btw, great work so far.

Re: Darkglass - Vintage Microtubes

PostPosted: 17 Dec 2016, 14:12
by ksenanekro
do we have any news on this one? i've breadboarded this and got nothing really.... i've used the values i thought that would be ok, but the only thing i got is a working blend control.any guesses maybe about the caps??
thanks
Savvas

Re: Darkglass - Vintage Microtubes

PostPosted: 11 Jan 2017, 17:24
by Silver Blues
Ladies and gentlemen! I present to you, a complete, fixed and verified layout for the Darkglass Vintage Microtubes!

Darkglass VMT f.png


I have used three TL072 instead of a TL072 and TL074 because the latter arrangement was basically impossible to make a reasonable layout with. I have also added a 100K pulldown to the output per Savvas' recommendations.

The missing capacitor values, referencing the newest schematic in this thread, are as follows:

C18 @ JFET = 22nF
C18 in the filter network = 22nF
C16 = 22nF
C17 = 22nF
C8 = 220pF
C28 = 220pF
C24 = 1uF
C23 = 1uF
C20 @ last op-amp stage = 2.2nF
C20 @ Era control = 4.7nF
C25 = 1nF
C22 = 1nF
C27 = 1nF
C21 = 1nF
C10 = 220pF

Enjoy!

Re: Darkglass - Vintage Microtubes

PostPosted: 06 Apr 2017, 10:26
by ksenanekro
attention! there is a mistake on this schematic, so there is a mistake on the layout too...
the circuit round tone control, should be like a big muff's tone control..from c21 we should go to era pin3 and from era pin2 to the 10k resistor.

i've build the Silver Blues's layout above, and it worked, but didn't sound as good as in the demos. my friend that i build it for sent it back to me to see if i can make it bassier, and then i saw that the tone control part was similar to a B.M.'s. i immediately made the changes i suggested above and boom! sounds great! after that, i've build 2 more boards with an other layout i drew that allows a 1590b. So here is my layout. Verified