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 30 Mar 2020, 11:48

All times are UTC - 6 hours [ DST ]




Post new topic Reply to topic  [ 231 posts ]  Go to page Previous  1 ... 14, 15, 16, 17, 18, 19, 20 ... 24  Next
Author Message
PostPosted: 16 May 2013, 10:33 
Offline

Joined: 12 Apr 2013, 05:28
Posts: 15
Location: Boise, Idaho, USA
Thank you all for nice advises.
1. All my wires are tightly twisted. I used hand drill to to that work.
2. Yes, I use +15V and -15V symmetric (adjusted to exact 14 VDC) Lambda PSU and the sound is good. I did not try 24 VDC PSU with +24V and 0V.
3. I have that small hum even when I connect 18V batteries pack instead of my PSU.
4. I do not have a full enclosure yet (it still in machine shop) and all circuses are assailable on its bottom panel. No walls, no sides and no top is attached yet. I got my enclosure (please see attached picture) from: http://www.ebay.com/itm/New-Enclosure-c ... 2a2c6dbdb9
As you see, that enclosure has wood made sides. Should I add aluminum foil to these sides in order to create fully closed box as "Faraday cage"?
5. I like an idea to move out AC circuit to a separate box. Please link me to the some location where I can purchase good quality and very well filtered PSU for my tandem (MC and MM).
Thank you in advance.


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



Top
 Profile  
 
PostPosted: 16 May 2013, 11:31 
Offline

Joined: 10 Feb 2011, 14:01
Posts: 30
Re: your questions and points:
1. Good.
2. So are you saying you're using a dual supply but only drawing on the +15V?
3. Sounds like either ground loop or induced hum. Separating the PS is not a bad idea and should be easy enough to try out. I'd do that first. But I'd definitely look at your grounding system if separating the PS doesn't work.
4. Can't hurt to line the box with aluminum foil, but from what I've read, it'll only help with high frequencies and not the 60 or 120Hz hum that is typical (and sounds like what you have).
5. You might look through tubecad's site for a PS. http://glass-ware.stores.yahoo.net/vore.html


Top
 Profile  
 
PostPosted: 16 May 2013, 15:04 
Offline

Joined: 12 Apr 2013, 05:28
Posts: 15
Location: Boise, Idaho, USA
Hi Carlp,
2. So are you saying you're using a dual supply but only drawing on the +15V?
A: No, I use +15V -> "+" and -15V -> "0".
5. You might look through tubecad's site for a PS. http://glass-ware.stores.yahoo.net/vore.html
A: Which particular unit would you recommend? They all looks good for me beside I do not need bipolar. Right?
In addition, do I need any additional filtering after it?

I forgot to mention that I do not use original resistors for MC and MM. I used Vishay Z-Foil Naked for MC and Kiwame for MM.
All these should have very low noise and very musical.
All Cup are Mundorf MKP (on MM) and Zn (0.22 uF on MC) and all matched, beside 0.033 and 0.001 on MM is still Russian original from the kit.

Thank you.


Top
 Profile  
 
PostPosted: 16 May 2013, 15:49 
Offline

Joined: 10 Feb 2011, 14:01
Posts: 30
Hmmm. So amp ground is at -15V potential relative to mains ground? That seems like a big problem to me but I can't wrap my head around how it would affect things just now. Note that RCA grounds are connected to the ground plane which is connected to the PS -15V. Which means the cartridge ground pins are at -15V. Unless you've somehow isolated and floated that system. I don't really get what you've done.

Re: the Tubecad gear, looking a little closer I'm not sure his will do what you want. This one http://glass-ware.stores.yahoo.net/hps1.html has potential. Other than that, Elliot Sound Products has nice dual/bipolar PSU boards but no single units.

I tend to build my own PS, and am currently using a simple supply SS rectified 24vct with an LM317 set to about 23V (fixed), smoothing caps and maybe a few 4700uF reservoir caps. VERY quiet with the MM amp, but I don't know what would happen with an MC step-up.


Top
 Profile  
 
PostPosted: 17 May 2013, 20:36 
Offline

Joined: 12 Apr 2013, 05:28
Posts: 15
Location: Boise, Idaho, USA
Yep, you're right and my ground is -15V. I asked Joe from Boozhound Labs and he tald that both MC and MM can use a symmetrical PSU with + and - 15V. To be honest, I'm not sure by myself what is done there, but I just used PSUs which I had ready in my home. I have two Lambda units and both symmetrical (+/- 15 VDC and +/- 24 VDC). Both noisy for audio...

So, I used your advise and I connected 18V batteries (3 packs of 4 batteries which gave me about 19V) instead of PSU and all grounds connected to the chassis. Hum is gone, but it still hear a little shshshshshsh when volume is high.

Next step, I'll build PSU and I'll add "shunt" capacitor to kill that shshshshshs...
As well as I'll use 6 Rubicon Electrolyte caps for smoothing. It is 10.000 uF total.
Also, I still did not enclosed everything into my box. I'll post pictures soon when everything will be intact.

Thank you.


Top
 Profile  
 
PostPosted: 18 May 2013, 21:51 
Offline

Joined: 10 Feb 2011, 14:01
Posts: 30
Despite most people's wishes, batteries are not silent. Quiet yes, but not silent. The Shshshshsh sounds to me like battery noise from a system with so much gain, but maybe others want to weigh in. Try the DIY PSU as it may do the trick, but let us know if you do.


Top
 Profile  
 
PostPosted: 18 May 2013, 22:26 
Offline
Project Author
User avatar

Joined: 06 Jun 2008, 18:23
Posts: 5189
Location: Australia
Carlp wrote:
Despite most people's wishes, batteries are not silent. Quiet yes, but not silent. The Shshshshsh sounds to me like battery noise from a system with so much gain, but maybe others want to weigh in. Try the DIY PSU as it may do the trick, but let us know if you do.

Agree. When I use battery powered devices I always add a small cap (e.g.0.1uf) and a storage cap (220uf), often low ESR to help suppress the internal chemical noise and slight voltage changes. These I place directly across the battery supply.

_________________
Projects:”Image” - Low Profile 100W Class D amp | ”fiih” - 150W Holton inpsired power amp | "Precision" - 300W Class AB Holton power amp | ”Gothic” - FET Push-Pull headphone amp


Top
 Profile  
 
PostPosted: 18 May 2013, 22:34 
Offline

Joined: 10 Feb 2011, 14:01
Posts: 30
Ah, good suggestions.


Top
 Profile  
 
PostPosted: 18 May 2013, 23:11 
Offline

Joined: 12 Apr 2013, 05:28
Posts: 15
Location: Boise, Idaho, USA
Can you guys send me your PSU schematic.
I have nice Military 12 V or 24 V (depend to setup) transformer which I can use and may be some parts which I can find in local RadioShack. Thank you very much.


Top
 Profile  
 
PostPosted: 19 May 2013, 19:18 
Offline

Joined: 10 Feb 2011, 14:01
Posts: 30
OK, will try to do that ASAP.


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 231 posts ]  Go to page Previous  1 ... 14, 15, 16, 17, 18, 19, 20 ... 24  Next

All times are UTC - 6 hours [ DST ]


Who is online

Users browsing this forum: Google Adsense [Bot] and 11 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