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 18 Oct 2019, 00:15

All times are UTC - 6 hours [ DST ]




Post new topic Reply to topic  [ 39 posts ]  Go to page Previous  1, 2, 3, 4  Next
Author Message
PostPosted: 26 May 2011, 13:24 
Offline
User avatar

Joined: 19 May 2011, 16:20
Posts: 17
Location: Somewhere over the rainbow, Cali
Hey Gio,

Meant the wiring for the output to speakers :)

I had to re-solder the 3 10w resistors to the bottom of the board because I'm an idiot and didn't think that it would give me problems come time of putting everything into a box... ooops! All fixed though. Along with this, rest of the .22uF caps are all installed, board is mounted in a box, and transformers are bolted down.

Getting REALLY close to finishing it up :)

Ended up buying a pair of old GE speakers from the thrift store for $3.99 and using that as a box. Looks nice, cheap, and overall size is just right. Planning on mounting a little 120vac fan where the speaker would normally reside in order to get a bit of airflow through the box to cool off those transformers. Currently contemplating where to mount the volume pot, amongst speaker in/out.

No pictures as of yet- at work until 6pm, then a family related gathering until who-knows-when.

-AJ

_________________
She was a punisher... a punisher of eyes.

If it's not broken... break it.


Top
 Profile  
 
PostPosted: 27 May 2011, 12:15 
Offline
Editor
User avatar

Joined: 28 May 2008, 21:53
Posts: 4579
Location: Winnipeg, CANADA
22 ga for the speaker wire is fine.

Cheers

_________________
[ DIY Mains AC Power Cable Cord ] - [ Gobo LM1875 Amp Kit ] - [ Tang Band D4-1 Horn Speaker Kit ] - [ Monoblock Push-Pull KT88 Tube Amp Kit ]


Top
 Profile  
 
PostPosted: 27 May 2011, 21:06 
Offline
Project Author
User avatar

Joined: 04 Jun 2008, 20:59
Posts: 4031
Location: Arizona, USA
Hi, I have a fond spot for the K-12. Mine still works well although it has been eclipsed by some of my own designs. For the pot, I have had good results with one that Radio Shack still carries. It is a dual 100k (with a loudness tap that you can ignore) made by Alps. They run about $5. Not as good as an Alps Blue or Black, but still quite suitable for the K-12. The mods I found best with mine were replacing 4 of the coupling caps with Auricaps and leaving out the two on the inputs. Power supply improvements were next then better output transformers. Welcome to the forum. The K-12 is a nice place to start.

Good listening
Bruce

_________________
Some of my DIY Tube Amplifier Projects:


Top
 Profile  
 
 Post subject:
PostPosted: 28 May 2011, 12:26 
Offline
User avatar

Joined: 19 May 2011, 16:20
Posts: 17
Location: Somewhere over the rainbow, Cali
Awesome! I'll need to check that out. I already wired up the stock pot, which is fine as I'm wanting to do a comparison between a complete stock K-12 to whatever modifications follow, just so that I can enjoy the upgrades (and money is tight anyways!!!).

I had a bit of a dilemma though- my original idea of using a speaker box as a case has fallen through- I canned that idea just because of issues that I know would arise with grounding everything out, spacing inside of the box, mounting the audio ins/outs on crappy 30 year old MDF that's flaking away, and so on. Luckily I had some leftover 20 gauge aluminum sheets that were godsend last night. 28x18cm (roughly) with 8cm wooden dowel legs and rubber base pegs- still mounted the transformers/board on the underside, tubes up top- speaker out is bolted through the chassis straight onto the board (grounding out - and insulating + obviously). Ohmed everything out to make sure my grounds are in check, and tested all the caps to make sure they're within range, along with checking the resistors.

VERY close to finishing the initial stages of the amp up- MAINS plugs came in- how do people cut out the opening? That's pretty much where I left off at last night just because I wasn't sure how to cut out the opening and I was already a couple of drinks in ;).

REALLY need to get some of the pictures off my camera. Once I test the amp and get to listen to it a bit, the whole thing will come apart once more so that I can HAND polish the aluminum face. Other plans are to build a 2cm thick oak board surround so I can get some VU meters installed :D - Ahhh, need to get cracking on all this fun stuff!

-AJ

_________________
She was a punisher... a punisher of eyes.

If it's not broken... break it.


Top
 Profile  
 
PostPosted: 04 Jun 2011, 21:25 
Offline
User avatar

Joined: 19 May 2011, 16:20
Posts: 17
Location: Somewhere over the rainbow, Cali
It works!!! :D
It has quite the hum... :worried:
It didn't blow up~ :smoking:
The louder I turn the volume, the more noise is present (with no signal in) :confused:

Maybe I grounded everything too much?
Attachment:
Glow.JPG

-AJ


This post has a file attachment. Please login or register to access it. Only Registered Members may view attached files.


_________________
She was a punisher... a punisher of eyes.

If it's not broken... break it.


Top
 Profile  
 
PostPosted: 05 Jun 2011, 07:37 
Offline
User avatar

Joined: 14 Feb 2010, 13:13
Posts: 663
Location: Lisbon, Portugal
Congratulations!

As for the HUM, i´ll check the potentiometer wiring and input cables shielding. Did you avoid ground loops? Star grounding is generally easier to deal with.

Cheers,
Miguel


Top
 Profile  
 
PostPosted: 06 Jun 2011, 14:32 
Offline
Project Author
User avatar

Joined: 04 Jun 2008, 20:59
Posts: 4031
Location: Arizona, USA
Hi, If you don't find any bad connections or such PM me and I get you an email to send some photos of the wiring and I 'll see if I can spot the problem. There is a small amount of hum in these amps, but it should not be excessive.

Good listening
Bruce

_________________
Some of my DIY Tube Amplifier Projects:


Top
 Profile  
 
PostPosted: 06 Jun 2011, 21:37 
Offline
Editor
User avatar

Joined: 28 May 2008, 21:53
Posts: 4579
Location: Winnipeg, CANADA
As noted there is a little inherent hum with the amp but that should be rather quiet. If you have excessive hum it may be a layout issue. Feel free to post the photos and we will take a peak.

Cheers

_________________
[ DIY Mains AC Power Cable Cord ] - [ Gobo LM1875 Amp Kit ] - [ Tang Band D4-1 Horn Speaker Kit ] - [ Monoblock Push-Pull KT88 Tube Amp Kit ]


Top
 Profile  
 
PostPosted: 08 Jun 2011, 14:06 
Offline
User avatar

Joined: 19 May 2011, 16:20
Posts: 17
Location: Somewhere over the rainbow, Cali
Yep, I screwed up somewhere. Just hooked it up to my system and WOW, this little amp is STRONG and literally transformed my DIY speaker that I built... but on the -right- channel only :(

Left Channel is not functioning properly- changed leads and checked wiring to the amp and to the speakers. All I get is a FAINT sound that is controllable via the POT. After about 10 minutes of usage, the left channel started crackling intermittently... then I turned the amp of in fear of any potential damage that could happen.

My ground is the upper chassis itself. Just to note, I am using only the pieces parts supplied in the kit, including the power cable.

Here is a shot of the lower chassis- note that the ground leads between left and right are connected via the chassis (did not use the little isolation washers). I double checked everything when I put it together, and Just did a once-over visual and can not see anything out of place. Hohummmm.... :worried:
Attachment:
board.JPG

-AJ


This post has a file attachment. Please login or register to access it. Only Registered Members may view attached files.


_________________
She was a punisher... a punisher of eyes.

If it's not broken... break it.


Top
 Profile  
 
PostPosted: 08 Jun 2011, 22:44 
Offline
User avatar

Joined: 19 May 2011, 16:20
Posts: 17
Location: Somewhere over the rainbow, Cali
Nevermind! Found out one of the 22gauge wires running to the POT decided to snap on me....? Fixed it real quick, and everything works right as rain :)

I'm honestly blown away by this little beast. Comparing it to my Pioneer VSX-816 makes me cringe that I even bought the pioneer to begin with! Running it straight off of my (still not completed) bookshelf speakers totally impressed me off the bat- smooth bass, crisp highs... it sounds so very flat yet so VERY full. Next up are my DCM's for a nice listen, hehe. I may need to buy a couple of these afterall!

Now that I know things are A-OK and functioning properly, I'll be focusing a bit more on finishing up the chassis!

-AJ

_________________
She was a punisher... a punisher of eyes.

If it's not broken... break it.


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 39 posts ]  Go to page Previous  1, 2, 3, 4  Next

All times are UTC - 6 hours [ DST ]


Who is online

Users browsing this forum: Google Adsense [Bot], Majestic-12 [Bot] and 9 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