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 20 Feb 2018, 04:37

All times are UTC - 6 hours [ DST ]




Post new topic Reply to topic  [ 61 posts ]  Go to page Previous  1 ... 3, 4, 5, 6, 7  Next
Author Message
PostPosted: 29 Nov 2015, 16:18 
Offline

Joined: 11 Nov 2015, 15:13
Posts: 3
Location: Bristol, UK
Quote:
Do you have the FETs in the right way?


Was thinking of that... So I turned them round. But same thing. Is it likely I damaged the FETs by having them in the wrong way?


Top
 Profile  
 
PostPosted: 29 Nov 2015, 21:54 
Offline
User avatar

Joined: 08 Aug 2009, 03:11
Posts: 2159
Location: Chilliwack, BC
Some depletion FET's don't care if the S and D are reversed (MPF102, 2N3819,21 and ilk)

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


Top
 Profile  
 
PostPosted: 30 Nov 2015, 04:21 
Offline
Project Author
User avatar

Joined: 06 Jun 2008, 18:23
Posts: 4833
Location: Australia
Geek wrote:
Some depletion FET's don't care if the S and D are reversed (MPF102, 2N3819,21 and ilk)

Would therapy help?

_________________
Projects: "Sanctum" - 12AU7 and 6AS7 direct coupled headphone amp | "retro-Oatley 6J6" - 6J6 push-pull headphone amp with OPTs | "Mimic Carbon" - carbon resistors and PIO caps. MM phono preamp
Website: retro-thermionic


Top
 Profile  
 
PostPosted: 30 Nov 2015, 05:24 
Offline
User avatar

Joined: 08 Aug 2009, 03:11
Posts: 2159
Location: Chilliwack, BC
*snicker*

Both the FET and I are beyond redemption :P

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


Top
 Profile  
 
PostPosted: 30 Nov 2015, 05:45 
Offline
Project Author
User avatar

Joined: 06 Jun 2008, 18:23
Posts: 4833
Location: Australia
You will hate me for saying this but guessing your pos and neg rails they looked like they were in the right way.

_________________
Projects: "Sanctum" - 12AU7 and 6AS7 direct coupled headphone amp | "retro-Oatley 6J6" - 6J6 push-pull headphone amp with OPTs | "Mimic Carbon" - carbon resistors and PIO caps. MM phono preamp
Website: retro-thermionic


Top
 Profile  
 
PostPosted: 01 Dec 2015, 16:23 
Offline

Joined: 11 Nov 2015, 15:13
Posts: 3
Location: Bristol, UK
The other thing I was thinking of was the capacitors I used instead of the 99.3 stated in the diagram. I used actually 4 different capacitors in parallel to make up the value. Would that have an influence on the sound?
I've attached a diagram for reference.


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



Top
 Profile  
 
PostPosted: 01 Dec 2015, 20:26 
Offline
Project Author
User avatar

Joined: 06 Jun 2008, 18:23
Posts: 4833
Location: Australia
Fewer caps the better but in this case exact values are critical.

As a suggestion put 50ohm resistors in the source leg.

_________________
Projects: "Sanctum" - 12AU7 and 6AS7 direct coupled headphone amp | "retro-Oatley 6J6" - 6J6 push-pull headphone amp with OPTs | "Mimic Carbon" - carbon resistors and PIO caps. MM phono preamp
Website: retro-thermionic


Top
 Profile  
 
PostPosted: 11 Feb 2016, 05:34 
Offline
User avatar

Joined: 03 May 2011, 15:16
Posts: 178
Location: Romania,Iasi City
andreidaniel wrote:
A similar, mostly the same design on that kind of PCB like yours I made. Also, I get a small hum, I don't know why. If I try to power the entire bloc from a DC source the hum is higher, so I power it from 3 x 9V battery but they don't last so much. I also placed a 220uF/50V capacitor between + and - for reducing a little the hum.

Image
Image

The boozhound website recommands a unique power supply for eliminating the hum. http://boozhoundlabs.com/collections/all/products/power-supply-kit
Image


Hello guys!
I bought yesterday this metal case for the preamplifier. Should be good a shielded metal case.
Image

Also, I thought at some things when constructing it:
1st: I recovered a transformer from a stereo system which included radio, 2xtapes + cd and also had a phono input!! The transformer doesn't make any noise and I think that also the fact the it is shielded itself with another perpendicular cover and with the copper tape on the coils would not perturb the good functioning of the preamplifier.
Image

2nd: As it seems in the original power supply the author usess schottky diodes, and between those two caps of 4700uF there is a 1 ohm resistor. I am thinking that a good result could be in replacing that resistor with a small coil on the ferrite ring linke those from the PCs or notebooks power supply because the resistor has a low value and also could take the noise after. My question here is if I can replace that LD1085 with a LM317? Or LM150, 350? On the internet I saw different designs which used either LM317 or even zenner+transistors for the regulated power supply.

3rd: I'll redesing the entire board on a PCB. This is only "educational" but works fine. Something like this should appear finally:
Image

For the rear pannel I was thinking to put 2 x RCA + 1 x 5 pin DIN for the older devices, and for the front pannel the same as rear.


Top
 Profile  
 
PostPosted: 12 Feb 2016, 09:57 
Offline
User avatar

Joined: 04 Nov 2013, 21:18
Posts: 89
Location: Florida
This thread has so much win...

_________________
Are we not men?


Top
 Profile  
 
PostPosted: 19 Feb 2016, 20:33 
Offline
User avatar

Joined: 03 May 2011, 15:16
Posts: 178
Location: Romania,Iasi City
Another similar design of passive RIAA correction.

Source: http://6p3s.com/forum/viewthread.php?forum_id=9&thread_id=32&rowstart=0


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  [ 61 posts ]  Go to page Previous  1 ... 3, 4, 5, 6, 7  Next

All times are UTC - 6 hours [ DST ]


Who is online

Users browsing this forum: No registered users 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 / Op-amp Projects :: DIY Phono Projects :: DIY Cable Projects :: Hi-Fi Audio Schematics
© diyAudioProjects.com - Terms of Service - Privacy Policy