DIY Audio Projects Forum
 NEW  Bruce Heran outlines the details and construction of his simple DIY 6DJ8 (ECC88) Tube Hi-Fi Headphone Amplifier Project.

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 17 Sep 2014, 22:35

All times are UTC - 6 hours [ DST ]




Post new topic Reply to topic  [ 108 posts ]  Go to page Previous  1, 2, 3, 4, 5 ... 11  Next
Author Message
PostPosted: 13 Jan 2009, 15:19 
Offline

Joined: 13 Jan 2009, 15:14
Posts: 1
I'd like to build this preamp. It's exactly what I'm looking for, the parts cost is very low. I'd like to just buy the boards from RCS in Australia including the power supply board, but the SMPS transformer's got me stumped. Where would I get such a beast? The internet is NOT my friend sourcing the part number provided (ETD29-3C90) I've never forayed into winding transformers but have got about 20 odd SMPS's in various states of disrepair with lots of transformers evident in each. Are they re-windable and, if so, how critical is the actual core properties? Would it work is what I am asking if I were able to find a frame with the right pin spacing. Or where can I buy a Philips ETD29-3C90?

If I get past the power supply, I'd also like to sub maybe 6n1P or 6SN7 or 6DJ8 as I've got all those tubes. Anybody done up a chart of resistor changes necessary?

Thanks

Dave


Top
 Profile  
 
PostPosted: 13 Jan 2009, 18:00 
Offline
Project Author
User avatar

Joined: 04 Jun 2008, 20:59
Posts: 2377
Location: Arizona, USA
Hi Dave, This has been an ongoing problem since the kits were discontinued. The actual core is not that critical. It needs to be big enough to hold the right number of turns. Many will do. Since you have several. I would pick one and try it. The very worst that will happen is that it won't work. I would prototype it before incorporating it in the final project. Test it under load. One problem that some diyers have had is that the coil "sings". If yours does, let us know as there are some fixes. Keep us posted on the results.

Good listening
Bruce

_________________
Some of my DIY Tube Amplifier Projects:


Top
 Profile  
 
PostPosted: 13 Jan 2009, 20:40 
Offline
Moderator
User avatar

Joined: 02 Sep 2008, 14:34
Posts: 514
Location: Rochester, NY
Hi Dave,

Welcome to the Forum.

Have you purchased the boards yet or are you still doing the grunt work? I wish I could help you out with your question, but I can't. I was one of the many(?) who didn't purchase the kit and now wished I had. Good luck, I am watching because if you can get done so can I.

Cheers,

Alan

_________________
Cheers, Alan
.
Allied 935 Integrated | Integra CDC 3.1 | SOTA Sapphire-RG301-Grado Gold 1 | Soundwave Soliloquy Series I


Top
 Profile  
 
PostPosted: 15 Jan 2009, 17:12 
Offline
Moderator
User avatar

Joined: 02 Sep 2008, 14:34
Posts: 514
Location: Rochester, NY
Hi all,

Seems to me, and mind you I am new to all this, that this power supply would work very nicely to power the pre-amp itself. According to the web site this little regulator can put out up to 2.5A and it can deliver an output voltage that ranges from +5V to +25V.

Please let me know if I am on target or not.

Alan

_________________
Cheers, Alan
.
Allied 935 Integrated | Integra CDC 3.1 | SOTA Sapphire-RG301-Grado Gold 1 | Soundwave Soliloquy Series I


Top
 Profile  
 
PostPosted: 15 Jan 2009, 18:03 
Offline
Editor
User avatar

Joined: 28 May 2008, 21:53
Posts: 4265
Location: Winnipeg, CANADA
Hi Alan,
That won't be suitable for this 12AX7 tube preamp as it requires 260 and 12 volts.
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: 15 Jan 2009, 18:57 
Offline
Moderator
User avatar

Joined: 02 Sep 2008, 14:34
Posts: 514
Location: Rochester, NY
gmilitano wrote:
That won't be suitable for this 12AX7 tube preamp as it requires 260 and 12 volts.

Gio,
Thanks, I missed that little specification. :confused: So, I am thinking that this one is a better choice. Looks a bit pricey though.

Alan

_________________
Cheers, Alan
.
Allied 935 Integrated | Integra CDC 3.1 | SOTA Sapphire-RG301-Grado Gold 1 | Soundwave Soliloquy Series I


Top
 Profile  
 
PostPosted: 18 Jan 2009, 23:03 
Offline
Project Author
User avatar

Joined: 04 Jun 2008, 20:59
Posts: 2377
Location: Arizona, USA
Hi , The more costly one would certainly work. It looks like it could power several preamps as the current requirement is fairly small.

Good listening
bruce

_________________
Some of my DIY Tube Amplifier Projects:


Top
 Profile  
 
PostPosted: 24 Mar 2009, 21:24 
Offline

Joined: 24 Mar 2009, 21:07
Posts: 2
Hey All,
I have recently found one of these kits and built it up for use as a guitar preamp. I am very impressed with the sound although it has an issue where it sounds like the notes seem to cut short prematurely. I was wondering if this could be the "coil singing" mentioned above , any remedies or ideas on this would be greatly appreciated.
Thanks,
Tim


Top
 Profile  
 
PostPosted: 24 Mar 2009, 22:00 
Offline
Editor
User avatar

Joined: 28 May 2008, 21:53
Posts: 4265
Location: Winnipeg, CANADA
Hi Tim, welcome to the forum.
The problem that they were referring to was power supply related.

Do you get that problem at all volumes or just when it is turned up?

_________________
[ 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 Mar 2009, 02:05 
Offline

Joined: 24 Mar 2009, 21:07
Posts: 2
Yes this only happens with the volume cranked. The power supply I am currently using is one of those switchable ones that goes from 5 - 23 volts. At the 15 volt setting you get about 450mA.
Are there any power supplies you could suggest to remedy this?
I want to iron out this little problem and get onto my next project, I think i'm addicted!
Thanks


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 108 posts ]  Go to page Previous  1, 2, 3, 4, 5 ... 11  Next

All times are UTC - 6 hours [ DST ]


Who is online

Users browsing this forum: Google [Bot] and 4 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 / Opamp Projects :: DIY Phono Projects :: DIY Cable Projects :: HI-Fi Audio Schematics
© diyAudioProjects.com - Terms of Service - Privacy Policy