madbeanpedals::forum

Projects => VFE Projects => Topic started by: madbean on August 12, 2017, 06:15:01 PM

Title: Tractor Beam update
Post by: madbean on August 12, 2017, 06:15:01 PM
Progress has been made on the Tractor Beam (phaser) and is on schedule for release probably in 7-10 days. I got the audio board populated after waiting on a couple parts from Mouser. The Tractor Beam was originally called the Enterprise and is built on the same board. There are a few value tweaks from the Enterprise so the pot values here are not all accurate.

This will be a difficult build, but if you have done one of the VFE already it shouldn't be too bad. There is on electro that has to be soldered in parallel with a Zener (top right). There are three resistor networks (two 10k and one 22k). It also requires four matched 2n5952 FETs. I actually had a set I previously matched for a different project and was no longer using. The doc will have instructions on how to match FETs (I think I may have already covered this in the Phase 90 doc). The "B10k" is actually 1k now, and only having 2k on-hand I soldered in another 2k resistor in parallel with it.

Also, I have a FET matching board I may just put up on OSH Park. It was supposed to be part of a small batch of utility boards I was going to offer for sale but I never got around to it.

Anyway, to do: build the switching board and test it out. My prototypes for the re-designs of the VFE switching board will be here in a few days so I think I will wait and test one of those out with this build.
Title: Re: Tractor Beam update
Post by: Zigcat on August 12, 2017, 06:45:19 PM
Decent!
Title: Re: Tractor Beam update
Post by: BrianS on August 13, 2017, 03:33:46 PM
Brian,
Anyway you might beable to post the board page with all the parts like you did with the Choral Reef? If you can't it's no big deal. Thanks.  (http://)
Title: Re: Tractor Beam update
Post by: lego4040 on August 13, 2017, 06:04:12 PM
awesome, will keep watch
Title: Re: Tractor Beam update
Post by: Ralfg on August 13, 2017, 07:49:28 PM
What Function F(x) board is that in the background?
Title: Re: Tractor Beam update
Post by: m-Kresol on August 14, 2017, 01:53:57 AM
What Function F(x) board is that in the background?

should be the clusterfuzz.

that phaser layout is really closely packed...
Title: Re: Tractor Beam update
Post by: dan.schumaker on August 14, 2017, 06:50:02 AM
That looks really cool.  Never used resistor array's before.  Looks like a really smart way to save a lot of space on a really packed board.
Title: Re: Tractor Beam update
Post by: madbean on September 12, 2017, 08:50:01 AM
Here is the draft of the Tractor Beam BOM/Shopping list. I have a bit of debugging to do on my build but I believe this list is accurate.

Title: Re: Tractor Beam update
Post by: dan.schumaker on September 12, 2017, 08:52:34 AM
As always, thanks Brian!
Title: Re: Tractor Beam update
Post by: Hirti on September 12, 2017, 09:17:55 AM
Thank you!
Title: Re: Tractor Beam update
Post by: hasanova on September 13, 2017, 06:17:58 PM
Cheers!
Title: Re: Tractor Beam update
Post by: tcpoint on September 14, 2017, 04:44:43 PM
The 1.43K resistor that you link to mouser is way too big.  It's a Vishay Dale that's the same size as a 1/2 watt Xicon.   I did a quick search but couldn't find anything suitable.  I'll probably get some smd resistors of that value and make them work.  After all, it's diy.
Title: Re: Tractor Beam update
Post by: madbean on September 14, 2017, 05:46:39 PM
Huh - 8mm. That is a bit long (though they could be made standing). Here are two 6mm ones (still a bit long):

http://www.mouser.com/ProductDetail/Vishay-Dale/RN55D1431FRE6/?qs=sGAEpiMZZMu61qfTUdNhGzQiLrTi4xBWc4N7jZ0yHC0%3d
http://www.mouser.com/ProductDetail/Vishay-Dale/RN55D1431FB14/?qs=sGAEpiMZZMu61qfTUdNhG3gu04FpCMicro03p17NpK8%3d

Thanks for posting that. I forget which one I used...I'll have to look.
Title: Re: Tractor Beam update
Post by: Jules on October 07, 2017, 03:47:55 AM
Have you made any progress with the debugging of your build Brian?
Just in case you read this, thanks.
I have been really enjoying these VFE builds.
Title: Re: Tractor Beam update
Post by: madbean on October 10, 2017, 06:33:43 PM
Have you made any progress with the debugging of your build Brian?
Just in case you read this, thanks.
I have been really enjoying these VFE builds.

Yeah, it's pretty much done. Should be releasing later this week. Turns out it was user error. I'm the user.
Title: Re: Tractor Beam update
Post by: jimilee on October 10, 2017, 07:40:25 PM
That's a sexy phaser
Title: Re: Tractor Beam update
Post by: Jules on October 10, 2017, 10:12:41 PM
Great! Thanks a lot.
Title: Re: Tractor Beam update
Post by: Netnnk on October 26, 2017, 04:16:00 PM
Is this how to assemble your own resistor arrays for the Tractor Beam?

*edit* Updated. Thanks, WormBoy!

(https://i.imgur.com/pp9VHAU.jpg)
Title: Re: Tractor Beam update
Post by: WormBoy on October 27, 2017, 01:13:13 AM
Isolated looks good. For bussed, the bus needs to be directly connected to pin 1, so basically you would replace one of the outer most resistors with a jumper. As Brian explained in another thread: it does not matter whether thatís the first or the last (quirk of the tractor beam design: both the first and the last pin of the bussed array are connected to ground, so one resistor is in fact unused). I would always quickly check the board with a DMM, just to make double sure  ;D.
Title: Re: Tractor Beam update
Post by: greenskull on November 06, 2017, 08:41:26 PM
Many thanks, I just received my boards today!
I didn't notice the Tractor Beam listed on the switching board doc..... what voltage zener do I need?
Also want to double check I need the charge pump chip. Thank you very much.
Title: Re: Tractor Beam update
Post by: WormBoy on November 07, 2017, 01:59:47 AM
The Tractor Beam is on the last page of the switching board doc, in the schematic. States a 16v zener, but if you only run it on 9v, you can easily use something lower (it is only there to protect against overvoltage). The charge pump is in the photo in the TB build doc, and if you look at the opamp voltages, it is indeed used  8).
Title: Re: Tractor Beam update
Post by: greenskull on November 07, 2017, 01:50:52 PM
Thanks, Wormboy! I might need glasses.
Title: Re: Tractor Beam update
Post by: mark123 on November 11, 2017, 07:22:26 AM
When I'm matching the JFETs, what is the tolerance? How close do they have to be?
Title: Re: Tractor Beam update
Post by: 287m on November 11, 2017, 08:20:49 AM
When I'm matching the JFETs, what is the tolerance? How close do they have to be?
as close as possible
while we waiting Brian project jfet matcher, you can view NomNom docs
Title: Re: Tractor Beam update
Post by: mark123 on November 11, 2017, 10:34:14 AM
... you can view NomNom docs
I saw that mentioned but didn't know what it meant. I Binged it and figured it. Thanks.

From the Nomnom doc:
Quote
You want to find the closest matching voltage readings on these transistors. At least within 5% of one another, although I generally shoot for 1% or less. So, if a device reads ≠0.75vDC, I would look for another one that measures ≠0.74 to ≠0.76v.
Exactly what I was looking for.  Since we're looking at Vgs I'm just thinking of picking up a semiconductor analyzer.
Title: Re: Tractor Beam update
Post by: mark123 on November 18, 2017, 12:29:26 PM
The Tractor Beam uses the TC7662B and the low ESR Electrolytics, correct?  It's not listed in the switching board "Used With" column but it is in the picture of the doc.
Title: Re: Tractor Beam update
Post by: madbean on November 18, 2017, 02:22:14 PM
Correct.