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 22 Nov 2019, 11:46

All times are UTC - 6 hours [ DST ]




Post new topic Reply to topic  [ 156 posts ]  Go to page Previous  1 ... 6, 7, 8, 9, 10, 11, 12 ... 16  Next
Author Message
PostPosted: 02 Aug 2009, 12:20 
Offline
Editor
User avatar

Joined: 28 May 2008, 21:53
Posts: 4580
Location: Winnipeg, CANADA
Bluesman wrote:
Whipped up a small bracket for the Altronics. But, if I use the bracket as is, the transformer case will be connected to the chassis. Is this OK?
Hi Greg, the bracket looks good and I think I will take the same route as you. As for the connection, that will depend on how the chassis is grounded. If you want to follow Pete's schematic, you would isolate the transformer from the chassis and connect the transformer case (which I am assuming is attached to the core of the transformer) to #2 on the PCB. You would likely have to use plastic or wood for the bracket to do this. Otherwise, what you have is probably going to be fine but in addition, I would connect the transformer case to #2.

Bluesman wrote:
Drilled for the transformer mounting and holes for the wires to pass through the chassis plate. Finally peeled the protective film off the Hammonds, and they don't look too bad. There's something kinda neat about the raw, brushed aluminum finish. Too bad the finish doesn't stay that way.

I feel the same way and have left a number of the Hammond aluminum enclosures in a raw state. It is an ok look. I've had good look finishing them with one thick coat of Tremclad rust paint. Just one coat and lay it on thick with a brush. The brush (hair or foam) will leave lines while you are painting, but don't touch them up as they close up when they dry and make a pretty decent finish for the cost and effort involved. It is when you try touch up a spot that has started to become "tacky" that the finish gets ruined.

What did you use to do the chassis drilling?

_________________
[ 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: 02 Aug 2009, 16:01 
Offline

Joined: 04 Oct 2008, 11:29
Posts: 375
Location: Chillicothe, Ohio
I have a Greenlee step bit that is undoubtedly one of the handiest tools ever made. I can drill any hole from 3/16" to 7/8". Don't even need a pilot hole.

For the tube socket holes I have a Greenlee knockout punch. It's generally made for electricians to use on conduit. I only have the one, which punches a perfect 1 1/8" hole. The punch is sold as 3/4" because that's the size conduit that takes a 1 1/8" hole. 1 1/8" is a common size for octal sockets, so I make it a point to buy that size socket since I have this particular punch. I have to drill a 3/4" hole with my step bit and then use the punch for the 1 1/8" size.

The Greenlee tools are not cheap, in terms of initial cost, but you get what you pay for. You can buy an entire set of punches on ebay for $29.99 or so, but they are complete junk. Will not hold an edge, thus giving you really bad looking holes. We have Greenlee punches at work that dozens of electricians have abused for years. Still work great.

I'm going to isolate the Altronics bracket from the chassis with a teflon pad and some nylon screws.


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



Top
 Profile  
 
PostPosted: 08 Aug 2009, 13:37 
Offline

Joined: 04 Oct 2008, 11:29
Posts: 375
Location: Chillicothe, Ohio
Anyone care to weigh in on if they're using a preamp with the UniAmp, or planning to use a volume pot and run a source directly to the input?

What value pot should I use if I plan to use solely my CD player as the source? Output impedance is not listed in the manual. 50K alright?

Thanks, Greg


Top
 Profile  
 
PostPosted: 16 Aug 2009, 06:00 
Offline

Joined: 04 Oct 2008, 11:29
Posts: 375
Location: Chillicothe, Ohio
Slowly making progress. I'm being patient and not taking any shortcuts that I know I'll repret later. When I find myself getting impatient, I walk away. That is the one upside of having limited time for projects.

Anyway, some shots of my chassis work thus far. I mounted the Edcors on one chassis to see what it looks like. I'm extremely happy with the results. I need to move the OPT about 1/4" closer to the edge so it's lined up with the power tranny. Originally I planned to put the curly maple panels on the short sides and use the long sides as the front and back. So I focused on centering the OPT between the tubes in front of it, and wasn't concerned with how it lined up with the power tranny. Now that's changed. Not a big deal as I can drill new holes and they will still be hidden under the OPT mounting tabs. I'm going to have to add some kind of support to the top plate, as the trannies are heavy enough to cause an issue there. Plan is to run a leg of sorts from the top plate completely through the bottom plate to the shelf below the amp. I'll fabricate it out of threaded rod, making a spike on the bottom. It will have lock nuts above and below both the top and bottom plates of the amp, and will support both when adjusted properly.

For those who have not seen the Edcor blue powdercoat, the color is not accurate in the pictures. The pics do not do justice. The Hammond is painted dark grey hammertone. Looks fantastic up close. Pics also do not do justice to the curly maple. I put a simple clear poly on the panels because I wanted them to look natural.


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



Top
 Profile  
 
PostPosted: 16 Aug 2009, 06:59 
Offline
User avatar

Joined: 08 Aug 2009, 03:11
Posts: 2229
Location: Chilliwack, BC
Gorgeous! Love the Maple :D

Bluesman wrote:
The Greenlee tools are not cheap, in terms of initial cost, but you get what you pay for. You can buy an entire set of punches on ebay for $29.99 or so, but they are complete junk.

Agreed.

Though I do have a pair of Pioneer punches in with my Greenlee lot... they did pretty good on this ship-deck-plete-tempered-aluminium I got surplus :blush:

Cheers!

_________________
-= Gregg =-
* Ratings are for transistors - tubes have guidelines*
Home: GeeK ZonE
Work: Classic Valve Design


Top
 Profile  
 
PostPosted: 16 Aug 2009, 07:12 
Offline

Joined: 04 Oct 2008, 11:29
Posts: 375
Location: Chillicothe, Ohio
Thanks, Geek!

Yes, the curly maple is really cool, I think. I also picked up some awesome looking birdseye maple for future use.

Cheers, Greg


Top
 Profile  
 
PostPosted: 16 Aug 2009, 10:26 
Offline
Editor
User avatar

Joined: 28 May 2008, 21:53
Posts: 4580
Location: Winnipeg, CANADA
Bluesman wrote:
Anyone care to weigh in on if they're using a preamp with the UniAmp, or planning to use a volume pot and run a source directly to the input?

Hi Greg, Looking at the specs, Vin is <270mV for full output so preamp should not be a necessity. I am thinking 100k may be more suitable.

Gregg (Geek), have you built a uniamp?

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: 18 Aug 2009, 20:05 
Offline

Joined: 04 Aug 2009, 20:14
Posts: 5
Very nice! When are the next set of boards coming out? 8-) (Nudge nudge)
Enjoying the build thread...post some more, guys!


Top
 Profile  
 
PostPosted: 21 Aug 2009, 21:42 
Offline

Joined: 06 Jun 2008, 14:03
Posts: 272
Location: Tulsa, Oklahoma
Well I am getting the parts real slow lol, I just got the 6 octal sockets for the boards this last week, now to save for the caps and the two little trannys for the boards, than it will be to save for the power tubes as I got all the other tubes and trannys sitting here.


Top
 Profile  
 
PostPosted: 25 Aug 2009, 19:08 
Offline

Joined: 04 Oct 2008, 11:29
Posts: 375
Location: Chillicothe, Ohio
I've made a bit more progress with my build. Other than a different volume knob and some kind of cone shaped feet, pics are dead on what it will look like. No wiring is done yet, but cosmetically it is how it will be when finished. I'm very happy so far with the way it's shaping up. I decided to change sockets after I had already drilled mounting screw holes. That's a bit annoying. The first sockets were of the convertible variety in that they could be top or bottom mounted. I was most disappointed in how high above the chassis plate they were after they were installed. Looked pretty corny with tubes installed, so I opted for some nice strictly bottom mount versions from Angela Instruments. Slightly different spacing on the mounting holes, but a little persuasion on the new sockets with a small rat tail file, and all is good. Sockets sit barely above the chassis and look great. As luck would have it, 2 of my 4 Sovtek KT66 bottles are crooked in the base. Oh well.

Cheers, Greg


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



Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 156 posts ]  Go to page Previous  1 ... 6, 7, 8, 9, 10, 11, 12 ... 16  Next

All times are UTC - 6 hours [ DST ]


Who is online

Users browsing this forum: No registered users and 32 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