Go Back   Home > Forums > Commercial Sector > Vendor Forums > DIY HiFi Supply

DIY HiFi Supply Parts and Kits from Diy HiFi Supply

Reply
 
Thread Tools Search this Thread
Old 26th February 2012, 01:47 PM   #21
Desmo is offline Desmo  Denmark
diyAudio Member
 
Join Date: Jan 2007
Location: Aarhus
Quote:
Originally Posted by ThorstenL View Post
Hi,



Seems you only use the MC input.

Have a look if the MC inputs float or are grounded (100R//100nF will usually do this nicely).

Ciao T
Yes, I have two MC cartriges so I only use the MC input on The Vinyl Song.

Yes, the input is floating since it's the primary winding of the MC transformer. Or maybe you are referring to something else?

100R in parallel with 100nF..! Do you mean on the input of The Vinyl Song, on the primary side of the MC transformer? (sounds a bit strange..!!!)

Last edited by Desmo; 26th February 2012 at 01:50 PM.
  Reply With Quote
Old 26th February 2012, 01:52 PM   #22
Previously: Kuei Yang Wang
 
Join Date: Nov 2002
Hi,

Quote:
Originally Posted by Desmo View Post
100R in parallel with 100nF..! Do you mean on the input of The Vinyl Song, on the primary side of the MC transformer? (sounds a bit strange..!!!)
It looks to me like your wiring floats the primary completely, this can lead to hum.

Essentially Shell of MC RCA Input to the UTS Input ground via 100R/100nF (I call that "soft" ground), if this reduces hum but does not kill a direct wire may be needed.

Ciao T
  Reply With Quote
Old 26th February 2012, 02:16 PM   #23
Desmo is offline Desmo  Denmark
diyAudio Member
 
Join Date: Jan 2007
Location: Aarhus
OK, now I understand what you mean... You're suggesting either a ''soft'' or a ''hard'' ground between the input signal ground, and output signal ground on the mc transformer. Right?

My wiring is done like this, from the build manual... The primary winding is indeed floating, and the screen (black wire) and housing (white wire) from the mc step-ups are connected to the ground post, as shown in the build manual.

I'm out of time working on this now, but next time I get some time I will try the ''soft'' ground, or even a direct connection. Thanks for these suggestions. I will get back with an update on the effect...

Click the image to open in full size.

Last edited by Desmo; 26th February 2012 at 02:18 PM.
  Reply With Quote
Old 26th February 2012, 04:04 PM   #24
Previously: Kuei Yang Wang
 
Join Date: Nov 2002
Hi,

Quote:
Originally Posted by Desmo View Post
OK, now I understand what you mean... You're suggesting either a ''soft'' or a ''hard'' ground between the input signal ground, and output signal ground on the mc transformer. Right?
Right.

Quote:
Originally Posted by Desmo View Post
My wiring is done like this, from the build manual... The primary winding is indeed floating, and the screen (black wire) and housing (white wire) from the mc step-ups are connected to the ground post, as shown in the build manual.
Seeing this you can make the connections directly to the grounding post.

I also notice another chance for noise to get in. It looks like the Earth goes straight to the chassis. This I do not like.

Connect mains transformers screens directly to the IEC Earth, but connect a diode bridge (rated for the same current as the mains fuse or more) with +/- shorted together and using the AC pins between the IEC Earth connector and the Chassis.

The Diode bridge clamps any voltage between earth and chassis to around 2V. It may not pass on some "PAT" Testers, but it retains the electrical safety. Also connect 100R//100n between IEC Earth and chassis.

I normally prefer to connect bridge and RC between signal ground and chassis and have the chassis earthed, but that would mean isolating a lot of stuff from the chassis in the Vinyl Song and so cannot be done.

Ciao T
  Reply With Quote
Old 11th April 2012, 10:43 AM   #25
Desmo is offline Desmo  Denmark
diyAudio Member
 
Join Date: Jan 2007
Location: Aarhus
OK, time for an update on The Vinyl Song... During the Easter holidays I finally had the time to work on the hum issues, and I have found a solution that works.

I have tried both ''soft ground'' and ''hard ground'' between the input ground and output ground for the mc step ups, the soft ground did not work here, but the hard ground did. The best way to implement this hard ground is to make a connection on the back plate switches as shown with the white lines on the attached picture. This way the ground is as close to the mc step-ups as possible and as far from the dirty chassis ground as possible. With this, there is just a slight bit of hum left, but barely audible. Maybe I'll try some of your other suggestions Thorsten to check if I can get rid of that also. But for now, this level of hum is more than acceptably low.

Also, when building this phono stage, please notice that the green/red and the blue/orange wires must be swapped for the switch to work as described in the manual.

Finally I recommend to have an individual screen on each wire pair, that way the screen can follow the wires all the way to the soldering points on the switches and connectors, this gives the lowest noise/hum level.

I'm running in the phono stage now. The first impression is, that the treble is quite splashy and forward, but I think that's normal for brand new step up transformers and LCR circuits.

Click the image to open in full size.

Last edited by Desmo; 11th April 2012 at 10:48 AM.
  Reply With Quote
Old 3rd May 2012, 07:54 AM   #26
Desmo is offline Desmo  Denmark
diyAudio Member
 
Join Date: Jan 2007
Location: Aarhus
Questions for you Thorsten, thanks for helping

After sorting the grounds my Vinyl Song is now singing without hum, and it sounds great. However it's also singing very quietly, there is not much gain..! As a comparison, I have the volume control on my Tram II at around 2 - 3 o clock when listening at loud levels with my cd player (2 volt output). I use the middle - 3dB output on the Tram. However, when listening to vinyl I can only get moderate levels even when turning the volume all the way up.

My cartridge is a Sumiko Pearwood Celebration II with 0,5mV output, so there is plenty of signal feeding The Vinyl Song, and I have of course tried both the ''hi'' and ''low'' gain settings.

I use a pair of NOS RCA ECC88 tubes.

So what is the gain actually in this phono stage? And is there a way to increase it?

When looking in The Vinyl Song build manual these specs are mentioned, with these jumper settings:

Click the image to open in full size.

Click the image to open in full size.


But when I then look in the specs mentioned for the Universal Tubestage used in The Vinyl Song the gain with this jumper setting is mentioned as 30dB. If this is the case, then the total gain in The Vinyl Song will be around 30dB in the MM setting and around 50dB in MC setting, meaning that I need around 10dB of gain. This makes sense compared to the low gain I have...

Here the specs from the Universal Tubestage:

Click the image to open in full size.

Click the image to open in full size.

Can you please advise how to get the right gain (as mentioned in The Vinyl Song specs)?

Another question... Regarding the cartridge load.

I would like to implement a 24 position selector, located on the back panel, to give me more load options for the cartridge. This means that I need to increase the 47K input load resistor on the module to -lets say- 470K and then have one of the resistors on the 24 position selector in parallel with that resistor. This way I can get high resolution on the load of MC cartridges.

My question is: Can you help locate the 47K input resistors on the tube module that I need to replace?

Thanks again Thorsten!
Morten
  Reply With Quote
Old 3rd May 2012, 01:03 PM   #27
rtsang is offline rtsang  Hong Kong
diyAudio Member
 
Join Date: Aug 2005
Quote:
Originally Posted by Desmo View Post

My cartridge is a Sumiko Pearwood Celebration II with 0,5mV output, so there is plenty of signal feeding The Vinyl Song, and I have of course tried both the ''hi'' and ''low'' gain settings.

I will try to help.
Are you using a step up transformer?
0,5mV output is not a high output MC cartridge and usually need a step up transformer.
The sumiko blue point special is a high output MC with 2.5mV of output.
BTW, if you need a step up transformer, you get a a nice one from Brian.

Raymond.
  Reply With Quote
Old 3rd May 2012, 01:07 PM   #28
Desmo is offline Desmo  Denmark
diyAudio Member
 
Join Date: Jan 2007
Location: Aarhus
Thanks for your reply If you look back in this thread you will notice that I have the ''fully loaded'' Vinyl Song with the LCR modules and the MC step-ups.

For a low output MC the Sumiko Pearwood Celebration II output on 0,5mV is amongst the highest from any low output MC, but still the gain from this phonostage is very low...

Last edited by Desmo; 3rd May 2012 at 01:11 PM.
  Reply With Quote
Old 23rd June 2012, 10:21 PM   #29
Desmo is offline Desmo  Denmark
diyAudio Member
 
Join Date: Jan 2007
Location: Aarhus
A few updates...

The mc step up transformers replaced with a pair of Hashimoto HM-3, the polystyrene caps after the LCR modules replaced with 220nF Duelund VSF, the output caps are now Mundorf silver/gold and the wiring to/from step up's and LCR's is silver in silk. Also I did a bit more work on shielding with mu-metal inside the transformer box, and the result is, that the phono stage is really quiet...

Click the image to open in full size.

Click the image to open in full size.

Click the image to open in full size.
  Reply With Quote
Old 24th June 2012, 08:52 AM   #30
diyAudio Member
 
QSerraTico_Tico's Avatar
 
Join Date: Oct 2004
Default sound of Hashimotos

Hi, how does the sound of the Hashimoto HM-3s compare with the Cinemags?
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Windows MP3/song player that caches whole song in RAM before playing Daveis Digital Source 10 2nd October 2007 03:37 AM
vinyl v cd differences - phono pre and cd-player cbutterworth Tubes / Valves 28 16th August 2007 04:24 PM
Most depressing song? Wombat Music 173 25th June 2007 05:21 PM
mm only 'el cheappo vinyl addicts'phono schematic fergs1 Analogue Source 6 25th May 2006 09:55 AM
do you know this song? kinser Music 3 16th June 2004 12:57 PM


New To Site? Need Help?

All times are GMT. The time now is 08:41 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright ©1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2