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 Oct 2018, 04:49

All times are UTC - 6 hours [ DST ]




Post new topic Reply to topic  [ 634 posts ]  Go to page Previous  1, 2, 3, 4, 5, 6 ... 64  Next
Author Message
PostPosted: 23 Dec 2011, 10:49 
Offline
Project Author
User avatar

Joined: 04 Jun 2008, 20:59
Posts: 3814
Location: Arizona, USA
Hi, Only the one on the upper anode. The lower one would shunt all the signal to the ground.

Good listening
Bruce

_________________
Some of my DIY Tube Amplifier Projects:


Top
 Profile  
 
PostPosted: 23 Dec 2011, 11:12 
Offline

Joined: 29 Nov 2009, 13:17
Posts: 29
Showing you everything I know about audio circuit design... :blush:

So just on pin 6... I've changed the image (above) so that nobody mistakenly implements my bad advice.

Also, this is all OT and should maybe be moved to the Forewatt thread?


Top
 Profile  
 
PostPosted: 23 Dec 2011, 11:28 
Offline
Project Author
User avatar

Joined: 04 Jun 2008, 20:59
Posts: 3814
Location: Arizona, USA
Hi, A little OT, but since it relates, probably no harm in leaving it here. The basic thought is regarding the use of remotely located power supplies on audio gear and really applies to pretty much any project.

Good listening
Bruce

_________________
Some of my DIY Tube Amplifier Projects:


Top
 Profile  
 
PostPosted: 08 Jan 2012, 14:31 
Offline

Joined: 01 Feb 2011, 06:57
Posts: 18
Location: Aalborg, Denmark
I have just ordered most of the parts for this build (Edcor transformer should take 1-2 months to get to Denmark :( ). Since this is my first build, I decided to go for the JJ ECC83S and ECC81 (not the Gold plated, super stuff) just to save the money should I burn them somehow. Then I can upgrade them when (if) it all works, and if I see fit.

It is going to be running on a Beogram 4000 turntable with a SP15 / Soundsmith MMC20EN pickup (http://www.sound-smith.com/cartridges/bosmmc20en.html). The input resistance should be >47k and capacitance >400pF - I might include some switching in order to be able to change this and figure out what sounds the best. Anyone has some preferences?

The "audio-grade" capacitors I have ordered so far, is some SCR / Solen Fast (5%). However I want some more precise for the RIAA filter - anyone knows a good brand and place to get them in Europe?

_________________
Daniel
Luck tends to favor the prepared.


Top
 Profile  
 
PostPosted: 08 Jan 2012, 16:04 
Offline
User avatar

Joined: 02 Mar 2009, 12:41
Posts: 1063
Location: Vänersborg, Sweden
Among the VERY best caps for analoge filters ever made are RIFA's PFE225 (I think they were called). They were housed in small white plastic boxes (http://www.wellgainelectronics.com/rifa ... 100v2.aspx) and were originalled developed ofr Ericsons analogue telephone exchange systems.
They may be very hard to find but are extremely precise and stable, much more than so called "audio grade" caps are. (Don't expect an "audio grade" cap to be anything more than a standard cap with golden print och the can and an exclusive price tag).

_________________
Magnus

“If you don't know where you are going, any road will get you there.”
―Lewis Carroll


Top
 Profile  
 
PostPosted: 08 Jan 2012, 17:29 
Offline
Project Author
User avatar

Joined: 04 Jun 2008, 20:59
Posts: 3814
Location: Arizona, USA
Hi, I checked the specs on the cartridge and it appears to be a low output moving coil. The Groovewatt has more gain than most at 45 db, but it is designed for high output moving coil and MM cartridges. You may have enough gain in your preamp to get it up to the level you need. Hard to say.

Good listening
Bruce

_________________
Some of my DIY Tube Amplifier Projects:


Top
 Profile  
 
PostPosted: 09 Jan 2012, 01:23 
Offline

Joined: 01 Feb 2011, 06:57
Posts: 18
Location: Aalborg, Denmark
My current RIAA is the Cambridge 640P (set to MM) and the pickup is the original SP15, this works just fine. According to the Cambridge datasheet the nominal sensitivity is 3.35 mV, so it will work with the SP15. The question is then if the Soundsmith is "the same" as the SP15.

Edit: The SP15 renamed the MMC4000 (and later renamed MMC20EN) is specified to have Output mV/cm/sec.: 0,6mV/47kOhms - which is equivalent to the SMMC20EN. Also the gain of the Cambridge (MM) is 39dB. so everything looks like it is in the clear.

_________________
Daniel
Luck tends to favor the prepared.


Top
 Profile  
 
PostPosted: 09 Jan 2012, 01:59 
Offline
Project Author
User avatar

Joined: 06 Jun 2008, 18:23
Posts: 4945
Location: Australia
If you don't get sufficient gain try the Le Pacific MC preamp. Adjust the input impedance resistor to suit the cartridge. But after building three they simply appear to do a good job.
http://www.diyaudioprojects.com/Forum/viewtopic.php?f=10&t=3046#p22908

_________________
Projects: "Lagoon" - tube preamp with cathode follower | "retro-Oatley 6J6" - 6J6 push-pull headphone amp with OPTs | "retro-Hiraga" - Jean Hiraga Le Monster
Website: retro-thermionic


Top
 Profile  
 
PostPosted: 10 Jan 2012, 11:15 
Offline
Project Author
User avatar

Joined: 04 Jun 2008, 20:59
Posts: 3814
Location: Arizona, USA
Hi, If it works with the Cambridge with its gain, then there should be no issues. :)

If I recall correctly...not all cartridges are measured / spec'ed the same way and some use output (millivolts/cm) at different groove modulation levels. This could well be such an instance.

Good listening
Bruce

_________________
Some of my DIY Tube Amplifier Projects:


Top
 Profile  
 
PostPosted: 24 Jan 2012, 22:04 
Offline
Project Author
User avatar

Joined: 04 Jun 2008, 20:59
Posts: 3814
Location: Arizona, USA
Hi Everyone, An update and some info on what comes next. I incorporated a Groove and Forewatt into one chassis with a digital wireless remote (that part is not my design and is modular and could be replaced with an Alps 100K). The results are excellent and and I will post a project on it in the not too distant future. Now for some details, I used all Jantzen Silver Z coupling caps (both electrically and physically large) to replace the Auricaps and PIOs in the photos. Auricaps are very very nice, IMHO the Zs are better. I have to "break them in" a bit yet before I can do any measurements but the sound is really special now. The next step is .... (fanfare) making it able to do low output moving coil cartridges. Initial tests are that a simple mod will achieve this and still retain nearly all of the 90 dbv S/N. With a 1.6mv output MC it will easily drive my Oddblocks directly to full output in the passive preamp mode. I suspect that the extra 5 db I can get easily will make it just fine with low (0.5mv) cartridges. Stay tuned for further progress.
Attachment:
Pre In system.jpg

Attachment:
Pre inisde with covers2.jpg

Attachment:
Pre inside no covers view 2.jpg

Good listening
Bruce


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


_________________
Some of my DIY Tube Amplifier Projects:


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 634 posts ]  Go to page Previous  1, 2, 3, 4, 5, 6 ... 64  Next

All times are UTC - 6 hours [ DST ]


Who is online

Users browsing this forum: No registered users and 22 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