DIY Audio Projects Forum
 NEW  Matt presents bias and operation data for the 6V6 tube in SE operation - 6V6 Single-Ended (SE) Ultra Linear (UL) Bias Optimization.

DIY Audio Projects Forum

Welcome to the DIY Audio Projects Message Forum. Use these forums to discuss Hi-Fi audio and to share your DIY Audio Projects. Registration is free and required to post messages and view the file attachments. Registration will only take a minute and registered users do not see any advertisements. After you have completed the online registration process, check your email (including spam/junk folder) for the verification email to activate your account. New members are under moderation - so your posts will not be visible until approved by a moderator. See the Read Me 1st, Forum RULES and Forum FAQ to get started on the forum.

It is currently 23 Jul 2019, 14:18

All times are UTC - 6 hours [ DST ]




Post new topic Reply to topic  [ 47 posts ]  Go to page Previous  1, 2, 3, 4, 5  Next
Author Message
PostPosted: 28 Oct 2008, 11:54 
Offline

Joined: 10 Sep 2008, 19:54
Posts: 22
Location: Boston
I've just been using a little speaker and .5W resistor to test the units out.

One of them (the second unit I built) seems to be working great. With an input from my laptop on all 4 inputs there is significant amplification with an AC power supply at 14V. The other one seems to be dead.

I made a few mistakes whiele soldering (actually i sorta screwed both up... I got some solder on the chip holes for number 2 and bent some of the pins)

I think the connections in the first one are fine but i might have blown the chip with ESD... Is there an easy way to test for this?


Top
 Profile  
 
PostPosted: 28 Oct 2008, 12:02 
Offline
Project Author
User avatar

Joined: 06 Jun 2008, 20:12
Posts: 972
Location: Houston, TX
I doubt you had an ESD problem. These are not low power little computer ICs. I dont know how to test for it though.
Did you get the solder cleaned up or could it be shorting a few legs of your IC together?
Ri

_________________
DIY Lightspeed Passive Attenuator


Top
 Profile  
 
PostPosted: 28 Oct 2008, 15:12 
Offline

Joined: 10 Sep 2008, 19:54
Posts: 22
Location: Boston
I can't visibly tell if any of the leads are shorted; it all looks fine to me. I'll double-check though.

I only say it might be ESD because the chip (and a few odd diodes, etc) came in an ESD-safe bag and I had to carry the kits (and built units) back and forth a few times to the engineering building from my dorm room. and they got a little man-handled.

I also had a problem when soldering the SMT diodes in (problem being: I soldered them in backwards at first) so I had to pull out a capacitor to reach them and then put it back.

Also while poking around checking continuity I bridged one of the diodes near the chip and it glowed and started to smoke... Basically there are quite a few potential problem spots and from what I've discovered it's quite difficult to re-do any soldering work. Am I wrong? Could I potentailly salvage this by replacing some parts?


Top
 Profile  
 
PostPosted: 28 Oct 2008, 15:18 
Offline
Project Author
User avatar

Joined: 06 Jun 2008, 20:12
Posts: 972
Location: Houston, TX
Absolutely. Replace parts. If you smoked something like that you may have other failed components. If anything smoked at all replace it. You might find yourself replacing several parts.
Ri

_________________
DIY Lightspeed Passive Attenuator


Top
 Profile  
 
PostPosted: 05 Nov 2008, 16:44 
Offline

Joined: 10 Sep 2008, 19:54
Posts: 22
Location: Boston
So the newest update is as follows:

I went to a local electronics store (well, not too local, It was a 30 minute train ride and a 15 minute walk...) and bough a project box, fuse holder, power jack, power switch, mute switch (gonna have to get a new one because it was a momentary! :x ) wires, 3.5mm stereo input jacks, RCA output jacks (banana plug jacks were about $5 a pair, which would be $30 in plugs, no thanks!), and some nuts, bolts, etc.

I cut holes for the power parts (jack, switch, fuse holder) with a dremel. It kind of got away from me for the fuse hole and it looks a little ugly, but in any case, they're mounted. hoorah.

I also soldered (22 AWG) hookup wires to the holes in J10 and (18 AWG) wires to the speker outputs, and the AC 1/2 in to the secondaries of the transformer. To be sure, I want to make sure I'm not dumb and the thinner, red and black, wires from the transformer should be the secondaries and the thicker, blue and green wires should be the primaries.

I have an issue: i *always* blow a fuse when I power the amp on. I tried some 5A quick-blow and 6.3A (don't know why they're 6.3, but thats what radioshack had) slow-blow type, and both make a blue spark from one of the leads on the fuse holder and blow the fuse when i flip the power switch.

The toroid has 2 sets of blue/green wires (which i assume should go to the 120VAC) and 2 sets of red/black wires. I'm not near the box right now so a description will have to do.

Currently this is what I have:

Code:
      _____
    /   3   \             <-- power jack
    |_1___2_|

wire 2 on the power connects to one lead of the fuse holder. The other lead of the fuse holder connects to one lead of the switch (it's an on/off so has only 2 leads). The other lead of the switch connects to one of the green wires on the transformer. The blue wire (right next to the green) connects directly to wire 1 on the power.

Wire 3 on the power connects directly to the GND hole on the board. One pair of red/black wires from the transformer is connected to AC1/AC2 on the board.

Is any of this wrong? Do i need to do anything with the extra wires on the transformer? I'll try to get a picture up soon.


Top
 Profile  
 
PostPosted: 05 Nov 2008, 17:00 
Offline
Project Author
User avatar

Joined: 06 Jun 2008, 20:12
Posts: 972
Location: Houston, TX
Hi,
Your wires from power are +/- and GND. Put + on the switch and the - just comes right through and is not switched (although you can switch both of them if you want if your switch allows for it) So, we have GND and one straight AC wire and one switched AC wire. Take both AC wires and connect them to the two input wires on your transformer. Its unlikely that you have more than two input wires, but its possible to happen. More than likely you have 2 in and 2 out. Sometimes you have 2 in and 4 out.
It didnt sound like you have both of the AC wires hooked to the transformer.
Either confirm that or take a pic for me.
Do you have a part number or a datasheet/schematic of your transformer?
Ri

_________________
DIY Lightspeed Passive Attenuator


Top
 Profile  
 
PostPosted: 06 Nov 2008, 19:12 
Offline

Joined: 10 Sep 2008, 19:54
Posts: 22
Location: Boston
aha. i'm an idiot it seems :)

its an antek toroid... http://antekinc.com/AN-6218.pdf

turns out the red/black are for the 115V in and blue/green are for 18V out...

Good thing I had the fuses...


Top
 Profile  
 
PostPosted: 06 Nov 2008, 19:38 
Offline
Project Author
User avatar

Joined: 06 Jun 2008, 20:12
Posts: 972
Location: Houston, TX
Very nice thing you had those fuses :)
Ri

_________________
DIY Lightspeed Passive Attenuator


Top
 Profile  
 
PostPosted: 07 Nov 2008, 18:11 
Offline

Joined: 10 Sep 2008, 19:54
Posts: 22
Location: Boston
Hoorah! Success! Eureka!

I've hooked it all up in the project box and it works! Now its just a matter of cutting the holes for the inputs/outputs and tying everything down. I'm very happy with how it all turned out.

When i'm finished I'll take some pictures and put them up here


Top
 Profile  
 
PostPosted: 07 Nov 2008, 18:25 
Offline
Project Author
User avatar

Joined: 06 Jun 2008, 20:12
Posts: 972
Location: Houston, TX
Awesome!! Doesnt it sound great?!
Ri

_________________
DIY Lightspeed Passive Attenuator


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 47 posts ]  Go to page Previous  1, 2, 3, 4, 5  Next

All times are UTC - 6 hours [ DST ]


Who is online

Users browsing this forum: No registered users and 7 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Jump to:  
DIY Tube Projects :: DIY Tube Amp Kits :: DIY Speaker Projects :: DIY Solid State Projects :: DIY IC / Op-amp Projects :: DIY Phono Projects :: DIY Cable Projects :: Hi-Fi Audio Schematics
© diyAudioProjects.com - Terms of Service - Privacy Policy