Topics Topics Edit Profile Profile Help/Instructions Help Member List Member List  
Search Last 1|3|7 Days Search Search Tree View Tree View  

Computer Audio Problem

:: EPE Chat Zone ­:: ­Radio Bygones Message Board :: » EPE Forum Archives 2010 - » Archive through 04 September, 2011 » Computer Audio Problem « Previous Next »

  Thread Last Poster Posts Pages Last Post
  ClosedClosed: New threads not accepted on this page        

Author Message
Top of pagePrevious messageNext messageBottom of page Link to this message

bruce
Frequent Contributor
Username: bruce

Post Number: 666
Registered: 04-2008

Rating: N/A
Votes: 0 (Vote!)

Posted on Tuesday, 19 July, 2011 - 06:01 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Hi guys,
This may be one for the audiophiles.
I was given a record deck recently, but without any amp. I think it's probably good quality, but quite old/obsolete. I want to record my stash of vinyls, which have been languishing in the loft for 17 years, and then bin them ( shortly before they become collector's items and I realise I have thrown away a priceless collection. Where is Fiona Bruce when you need her? ).

The output from the deck is a screened cable with 2 plugs: these are the old RCA audio connectors ( red and white ) still used for composite video, I believe. Now, my guess is that these 2 connections go straight to the needle without amplification. What I want to do is to record these vinyls on the computer, but I dont have an amp.
On the front panel of the computer is a bank of 3 RCA sockets ( I assume for composite video ). I used the 2 audio connections, but the computer doesnt see them, I dont think.
The first thing I have to establish is whether the output from the record deck is big enough to be recorded on the computer.

Where should I start with this one?

bruce
Top of pagePrevious messageNext messageBottom of page Link to this message

gajjer
Frequent Contributor
Username: gajjer

Post Number: 355
Registered: 05-2007

Rating: N/A
Votes: 0 (Vote!)

Posted on Tuesday, 19 July, 2011 - 06:30 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Bruce
has her indoors gone off and left you to play.!
I'm guessing you have a magnetic pick-up on the deck. If so you need a RIAA equalisation preamp - being a magnetic sensor the output increases with frequency - so it needs compensation.
Have a look here
http://sound.westhost.com/project25.htm

Now get back to washing the dishes and then finish that dolls house!

cheers
gaj
Top of pagePrevious messageNext messageBottom of page Link to this message

twintub
Frequent Contributor
Username: twintub

Post Number: 194
Registered: 02-2007

Rating: N/A
Votes: 0 (Vote!)

Posted on Tuesday, 19 July, 2011 - 10:32 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

...or there's this one in EPE's project archive:
09-2002 - Vinyl to CD Preamplifier

...or just buy a cheapo unit from Maplin!

...or search the internet for a simple (op-amp) based circuit.
Top of pagePrevious messageNext messageBottom of page Link to this message

quintus
Valued Member
Username: quintus

Post Number: 20
Registered: 07-2007

Rating: N/A
Votes: 0 (Vote!)

Posted on Wednesday, 20 July, 2011 - 12:05 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Bruce

I have a vellerman stereo RIAA preamp kit no K2573 which I bought about 5 years ago but then got a USB turntable. I am very happy to post it to you. (We are on the move so I have been told to clear out some of my "junk)

David
Top of pagePrevious messageNext messageBottom of page Link to this message

bruce
Frequent Contributor
Username: bruce

Post Number: 671
Registered: 04-2008

Rating: N/A
Votes: 0 (Vote!)

Posted on Thursday, 21 July, 2011 - 05:13 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Hello David,
Thanks for the offer ( I guess you mean Velleman? although I still have no idea how it's pronounced ).
Can you email me privately?

Regards
bruce
Top of pagePrevious messageNext messageBottom of page Link to this message

bruce
Frequent Contributor
Username: bruce

Post Number: 672
Registered: 04-2008

Rating: N/A
Votes: 0 (Vote!)

Posted on Thursday, 21 July, 2011 - 06:29 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Hello Gaj,
Thanks for that, but how can you tell what sort of pick-up is on the deck? I was given this by a friend ( ex-friend ), probably because it dates from the 1970s! It's a Goodmans delta 800P, but I found nothing to help on Google.

bruce
Top of pagePrevious messageNext messageBottom of page Link to this message

alec_t
Frequent Contributor
Username: alec_t

Post Number: 702
Registered: 03-2009

Rating: N/A
Votes: 0 (Vote!)

Posted on Thursday, 21 July, 2011 - 07:44 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

"how can you tell what sort of pick-up is on the deck?"

Scope the pickup voltage when playing a record.
If it's only a few mV than you've probably got a moving-coil pickup. If it's tens/hundreds of mV then you've almost certainly got a ceramic/xtal pickup. I'd bet on the latter for a Goodmans deck.
Top of pagePrevious messageNext messageBottom of page Link to this message

dave_g
Frequent Contributor
Username: dave_g

Post Number: 693
Registered: 05-2005

Rating: N/A
Votes: 0 (Vote!)

Posted on Thursday, 21 July, 2011 - 08:26 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

In either case you need to provide some kind of preamplification.

Ceramic pickups are considered inferior to magnetic; the big advantages are a) cost and b) you only really need a high impedance follower. In my experience the characteristics of a ceramic pickup are such you can "get away" with feeding the pickup into an op-amp, or maybe an bipolar emitter follower amplifier. Not as good as RIAA equalisation which is really required.

Magnetic needs some significant amplification as well as RIAA. There are lots of op-amp designs about but make sure you use a low noise op-amp, eg NE5534.

Better still, if you have magnetic, go on E bay, buy an Integrated Amplifier with a Phono stage or just a Preamplifer. Arcam are brilliant, look for an Alpha model. You can use the preamp/tape monitor out to your PC. Almost certainly you can buy that cheaper than anything you can build and they are excellent for a computer sound system! There is no point "digitising" these records if the results are rubbish, might as well do a decent job IMHO.
Top of pagePrevious messageNext messageBottom of page Link to this message

alec_t
Frequent Contributor
Username: alec_t

Post Number: 704
Registered: 03-2009

Rating: N/A
Votes: 0 (Vote!)

Posted on Friday, 22 July, 2011 - 10:42 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

You might get lucky and pick up a half decent hifi amp with the necessary inputs for next to nothing at a charity shop or car boot sale.
Top of pagePrevious messageNext messageBottom of page Link to this message

quintus
Regular Contributor
Username: quintus

Post Number: 21
Registered: 07-2007

Rating: N/A
Votes: 0 (Vote!)

Posted on Saturday, 23 July, 2011 - 03:13 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Hello Bruce

Did you get my email re the Velleman?

David
Top of pagePrevious messageNext messageBottom of page Link to this message

ant
Frequent Contributor
Username: ant

Post Number: 806
Registered: 05-2006

Rating: N/A
Votes: 0 (Vote!)

Posted on Sunday, 24 July, 2011 - 12:10 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Hello all,

"RadioCommunication", the RSGB's magazine, has a useful-looking little stereo-USB board with an absolute minimum of components and a huge dynamic range. It uses a PCM2900 and it must have some sort of range-compression going on, I've not looked any more deeply into it than you see here but it may be a quick and easy way out of the problem.

Unless the Golden Ears are in use, any advantage of equalisation will quite possibly be lost in your choice of loudspeakers and listening acoustics. Many people adjust their tone controls or whatever to give them the most pleasing sound!

Regards Ant
Top of pagePrevious messageNext messageBottom of page Link to this message

externet
Frequent Contributor
Username: externet

Post Number: 154
Registered: 05-2005


Rating: N/A
Votes: 0 (Vote!)

Posted on Wednesday, 03 August, 2011 - 05:59 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Likely your record player has no preamplifier/RIAA equalizer in it; was meant to use a 'Phono' input on the amplifiers of that era.
It is better to find/borrow an amplifier with such input and feed its L,R outputs for tape recorder to a PC audio card.
There is many programs to record -now they call it burn- audio onto CD; (I use Audacity) they will preserve your collection on better media.

Miguel
Abolish the deciBel !

Administration Administration Log Out Log Out   Previous Page Previous Page Next Page Next Page