TTSH Ver.3 (rev.8) General build thread

From circuitbending to homebrew stompboxes & synths, keep the DIY spirit alive!

Moderators: Joe., lisa, luketeaford, Kent

Post Reply
amir
Common Wiggler
Posts: 140
Joined: Thu Dec 15, 2016 12:59 pm

Re: TTSH Ver.3 (rev.8) General build thread

Post by amir » Thu Mar 05, 2020 11:08 am

I posted pics a long time ago but I will get some new ones later today. Everything is in the right place. Out of insanity I started probing every diode on the main board last night and found two that were flowing in both directions. They are in the vca section. I am assuming these wont fix the current problem but I wonder if they were bad to begin with before i even put them on the board. it takes a lot to damage a diode to make it open up like this.

A board this big really needs some reference points. The original arp schematics are also a lot more helpful than the ttsh schematics which are purposefully made confusing. I don't understand why the builders think they've created something new and unique here and need to be so protective of the design. it is literally copying an old design. There is no intellectual property here, just post the trace.
You do not have the required permissions to view the files attached to this post.

amir
Common Wiggler
Posts: 140
Joined: Thu Dec 15, 2016 12:59 pm

Re: TTSH Ver.3 (rev.8) General build thread

Post by amir » Thu Mar 05, 2020 2:53 pm

The replaced diodes in the vca section display same behavior which points to the open circuit in them as being part of the larger circuit in that section (not a fault).

Pictures of 4012 card attached.
You do not have the required permissions to view the files attached to this post.

amir
Common Wiggler
Posts: 140
Joined: Thu Dec 15, 2016 12:59 pm

Re: TTSH Ver.3 (rev.8) General build thread

Post by amir » Fri Mar 06, 2020 12:52 am

So after a lot more probing... A few of the fine tune slider pins were shorting out. I followed it on the front of the board and my red wire for the -15v missing trace was sitting on top of one of its traces. Just sitting not making any contact that would allow a connection to be made. I lifted the wire up in the air and that short resolved itself.

The only other weird part in this section is the 3.3M resistor that sits right under the filter card. Every other resistor in this section came up as the correct value on the DMM but the 3.3M comes up as 187k with the filter card removed. I checked the colors and it is an actual 3.3M resistor. Is this normal based on where it is in the circuit and other components around it or is it bad? It is connected directly to the slider (pic attached).
You do not have the required permissions to view the files attached to this post.

User avatar
fuzzbass
Super Deluxe Wiggler
Posts: 2052
Joined: Thu Feb 06, 2014 6:08 pm
Location: Florida, USA

Re: TTSH Ver.3 (rev.8) General build thread

Post by fuzzbass » Fri Mar 06, 2020 8:14 am

amir wrote:
Fri Mar 06, 2020 12:52 am
So after a lot more probing... A few of the fine tune slider pins were shorting out. I followed it on the front of the board and my red wire for the -15v missing trace was sitting on top of one of its traces. Just sitting not making any contact that would allow a connection to be made. I lifted the wire up in the air and that short resolved itself.

The only other weird part in this section is the 3.3M resistor that sits right under the filter card. Every other resistor in this section came up as the correct value on the DMM but the 3.3M comes up as 187k with the filter card removed. I checked the colors and it is an actual 3.3M resistor. Is this normal based on where it is in the circuit and other components around it or is it bad? It is connected directly to the slider (pic attached).
There is no point in measuring component values in-circuit; you are measuring the combined value of every adjacent component. Is your filter problem resolved?
Wired for weird

amir
Common Wiggler
Posts: 140
Joined: Thu Dec 15, 2016 12:59 pm

Re: TTSH Ver.3 (rev.8) General build thread

Post by amir » Fri Mar 06, 2020 11:02 am

Not yet, it has improved a bit but something in the circuit is still not functioning correctly.

I am not getting any kind of signal on the inverted input line (vcf2?) either. The gain trimmer crackles as it’s being adjusted and the offset has to be maxed clockwise before any sound comes out. the resonance at zero produces a very faint sound but increased about halfway, the volume exponentially grows. I am focusing on this part of the circuit right now unless you guys have any other ideas.

amir
Common Wiggler
Posts: 140
Joined: Thu Dec 15, 2016 12:59 pm

Re: TTSH Ver.3 (rev.8) General build thread

Post by amir » Wed Mar 11, 2020 9:00 pm

Delete.

amir
Common Wiggler
Posts: 140
Joined: Thu Dec 15, 2016 12:59 pm

Re: TTSH Ver.3 (rev.8) General build thread

Post by amir » Thu Mar 12, 2020 5:22 pm

Does anyone on here have the trace file for the filter cards?

The 2n3904 shown in the attached schematic are supposed to be thermally coupled and were on version 1 & 2 of the TTSH. For some reason they were not oriented in this format on the cards.

I want to make sure one is not supposed to be flipped around like many other things on this board. My signal gets very faint at this point in the circuit, which makes sense since this is what feeds the feedback part of the circuit. Looking at the board alone would makes me think that they are not making the correct connections.


That aside, has anyone tried these caps yet? I got some of the slow fade leds and they look really cool but want to dim down a bit with caps not resistors to keep the cool pwm looking color change. link: https://www.ebay.com/itm/NEW-10-FADER-k ... Sw7NVeS6ij

Led video:


thanks
You do not have the required permissions to view the files attached to this post.

amir
Common Wiggler
Posts: 140
Joined: Thu Dec 15, 2016 12:59 pm

Re: TTSH Ver.3 (rev.8) General build thread

Post by amir » Sat Mar 21, 2020 2:18 pm

Few updates:

1) filter is still not working.

2) I’ve measured the incoming signal with and without the filter card in. The signal is getting reduced to ~2vpp on the pin where it enters the filter card. At the osc it is 10vpp and patched directly into vca yields same 10vpp. Something is happening in the filter section.

3) there aren’t many components in the main board part of the filter section. So I thought maybe something weird was happening in the led rails and bleeding into the sliders causing them to short the signal?

4) So next I checked the led rails with all power disconnected. I am getting some resistance between the -15v and ground rails but when I connect between 15v and ground or across -15v and 15v... I get no movement on the meter. It sticks at the default 1 value on the screen at all resistance ranges. Does this seem normal?

5) not sure what else to check. Any ideas would be greatly appreciated. Thanks

Post Reply

Return to “Music Tech DIY”