Malefoda said:
http://www.hndme.com/
http://www.welbornelabs.com/
http://www.partsconnexion.com/
http://www.diyparadiso.com/
http://www.schuro.de/
Have a look at the Dale/Vishay resistors, they're very good (non-inductive and low tolerance). Don't go over the top for capacitors, Elna RJH are good. Black Gate are indeed high quality but you best use them where appropriate. One has to have some knowledge of circuits to descide where to make most out of them.
Jaap
rowemeister said:
Brent,
The ones I use are 4uF low inductance Multicaps. Got 'm from Partsconnection Canada.
Why don't you try these 15mm caps:
http://uk.farnell.com/jsp/endecaSearch/partDetail.jsp?SKU=3891082&N=401
Regards, Jaap
PS My (valve)amplifier has highish input impedance so I can settle for a lower value coupling cap.
Simon,SimontY said:Hi guys!
My maths is rather poor and I couldn't quite work this out
Could you help me choose a minimum cap value please? My pre-amps input impedance is 100K.
I hope to be using this discrete output in a couple of weeks or so lol (with FETs)
Thanks!
Simon
Good choice, the fet buffer
Maths come down to this simple eqation.
Take the outcome of the division of 1 by the result of the input impedance of your amp (in ohm) multiplied by the coupling cap (in Farad) multiplied by 6.28
So, f=1/(6.28 x 100000 x 0.0000033) = 0.48 Hz, which is low enough.
And, f=1/(6.28 x 50000 x 0.0000022) = 1.45 Hz, which is also low enough for 50kHz input and 2.2uF cap.
Regards, Jaap
Hello
I did some more mods I replace all the resistors around the opamps with 1% PRP and Vishay/dale metal film, silver mica cap, and black gates in C611-614. First impressions huge improvement in the high frequency much more detail nice deep bass. Also the sound stage seems wider. I will have to give it some time to burn but all in all very happy
Regards,
Dave
I did some more mods I replace all the resistors around the opamps with 1% PRP and Vishay/dale metal film, silver mica cap, and black gates in C611-614. First impressions huge improvement in the high frequency much more detail nice deep bass. Also the sound stage seems wider. I will have to give it some time to burn but all in all very happy
Regards,
Dave
disco said:
These are my caps
http://www.maplin.co.uk/Module.aspx?ModuleNo=393&criteria=Polypropylene&doy=7m6
Brent
6h5c said:
???
The 20k would be an example of the input impedance of the next stage (eg. your (pre-) amp). With a 3u3 cap that would lead to 2.4Hz roll-off frequency. Most of the times the impedance is higher, so no problems are to be expected
Ray.
Sorry Ray i completely got the wrong end of the stick
Brent
rowemeister said:
Specs look good to me. Maybe you can fit one above and the other below the board? The Evox Rifa are selected for 2.5% I noticed (not carried by Farnell): http://www.evoxrifa.com/cap_catalog/generalp/smr.pdf
Jaap
Gooch said:Hello
I did some more mods I replace all the resistors around the opamps with 1% PRP and Vishay/dale metal film, silver mica cap, and black gates in C611-614. First impressions huge improvement in the high frequency much more detail nice deep bass. Also the sound stage seems wider. I will have to give it some time to burn but all in all very happy
Regards,
Dave
Hi Dave,
Good to hear you like the results. Matching the filter components brings clarity to the soundstage. Metalfilm resistors are very good for exact values. I like the old carbon composits better for sound but they are hard to obtain in europe. If you can find me some vintage 1/8W Allen Bradley I would be very greatful.
Solid bass notes come from new low esr caps. Black Gate standard series are very good indeed. In my opinion one might settle for smaller capacity than originally applied as they do an excellent job keeping up the voltage and delivering the current with very short delay.
Regards, Jaap
disco said:
Simon,
Good choice, the fet buffer
Maths come down to this simple eqation.
Take the outcome of the division of 1 by the result of the input impedance of your amp (in ohm) multiplied by the coupling cap (in Farad) multiplied by 6.28
So, f=1/(6.28 x 100000 x 0.0000033) = 0.48 Hz, which is low enough.
And, f=1/(6.28 x 50000 x 0.0000022) = 1.45 Hz, which is also low enough for 50kHz input and 2.2uF cap.
Regards, Jaap
Hi Jaap,
Many thanks for helping me with that. I'll clearly be very safe with a 2.2uF cap, and that would be OK for other typical amps it could be connected to aswell. Excellent.
In a x-over the LCR cap sounded vastly superior - cleaner with less glare and louder and fuller with bigger imaging and more detail - than a standard Intertechnik metalised film cap.
I have also used them in my preamp for coupling and found them significantly better than the standard recommended metalised box cap that was in there. But I'm starting to wonder if I need any caps in there at all... Hmm, maybe I could have a cap-free input just for the CD player...
Simon (dreams of hearing his CD63 again...)
disco said:
Interesting... When I "upgraded" to all 1% metal film around the op-amps I found the sound was better and worse at the same time. I eventually put this down to the sound of metal film resistors, which I suspect sound shut-in and not as enjoyable as carbon. Something I need to test more I think. My output resistors are 33R carbon
disco said:
Interesting insights Jaap. Do you think I have ruined mine by using 3300uF caps around parts? It did sound better, but maybe it would be better still if I'd used smaller ones
If I do another player I'll use small Black Gates, as the low values (Standards) aren't all that expensive really.
Si