Phono 3 with 5751 valves

[Shian7]

I'm a bit intrigued by the "lower noise than metal film" claim of the Kiwame's though...

I think it's actually got Tyco's in there at the moment!

[bearded fiddler]

I ordered three GE 5751 valves from Watford Valves. C17 of my Phono 3S is a Vishay (supplied with WDPSU3XL). What is missing to bring the Phono 3S up to full XL specs? Polypropylenes for C11/12? Anything else?

Jan

[Shian7]

Originally Posted by bearded fiddler

I ordered three GE 5751 valves from Watford Valves. C17 of my Phono 3S is a Vishay (supplied with WDPSU3XL). What is missing to bring the Phono 3S up to full XL specs? Polypropylenes for C11/12? Anything else?

It says...

"As an option an XL version of this kit is available which includes high performance HT smoothing capacitors, NOS 5751 JG valves and SONIQS polypropylene output capacitors for those who desire the ultimate in performance from this outstanding Phono preamplifier."

...but no further details!

[colin.hepburn]

Well I am still in the process of upgrading my phono 2 clone to the 3S
For the PSU 2 HT.
I used schottky diodes for the bridge and mills wire wound for R1/R6 100uf Ruycon’s for C1/2/4 all bypassed with 0.1uf polypropylene
At a later date I would like to change these Rubycons for ether 100uf polypropylene or ASC OIL Caps but these are expensive in those values for the LT Heater again I used schottky diodes for the bridge and a bigger better first Cap for C6 changed from 4700uf to 10.000uf See this thread for PSU changes
http://www.wduk.worldomain.net/forum/showthread.php?t=4131&highlight=phono2&page=2
The Phono2
R15/16 Takman Carbon all others are Holco Resistors Capacitors’ C12/13/ Are 0.1 uf WD 'SONIQS' SAX and C 22/23 2.2uf 'SONIQS' SAX C14/15 were change out for 10uf solen poly Caps added C17 as for the 3S I used 20uf solen Cap C16/17 are 8.2nf silver mica C20/21 also silver mica but changed from 220pf down to 200pf
Added 220uf Oscon bypass Caps to first stage cathode I still have to do the 3.18uS correction and add R31/32 plus C15/17 as per the 3S to 10uf solen polyps but so far its sounding very good indeed

[Richard]

I ordered three GE 5751 valves from Watford Valves. C17 of my Phono 3S is a Vishay (supplied with WDPSU3XL). What is missing to bring the Phono 3S up to full XL specs? Polypropylenes for C11/12? Anything else?

Originally Posted by Shian7

It says...

"As an option an XL version of this kit is available which includes high performance HT smoothing capacitors, NOS 5751 JG valves and SONIQS polypropylene output capacitors for those who desire the ultimate in performance from this outstanding Phono preamplifier."

...but no further details!

Ah, that's new, when I built mine there wasn't an XL Phono as I recall. So just those parts if you want that XL spec

You can tweak whatever you want though. I use those valves with Soniqs coupling caps on the ouput at C11/12, lowered the bass roll-off first coupling C1/2 with 0.1uF Soniqs, and fitted Oscon 220uF to the first stage cathode bypass position across R7/8. Of everything the bypass caps make the biggest difference. Drawing in post 1 of this thread.

[bearded fiddler]

Thanks everyone. Richard, if I understand this right, you removed the switch for C1/C2 - C3/C4 - C5/C6 and replaced the caps by one 0.1 uF cap. Isn't this value higher than the combined value of the three original caps? Could you tell me something about the way capacitors raise or lower the bass roll-off frequency? Does one need more or less capacity for lowering the bass roll-off frequency? Excuse my ignorance but, although I can follow instructions and build kits, I have hardly any theoretical background. I'd like to read more about the basics, but I don't know where to begin. I bought Owen Bishop's Electronics A First Course, and it's ok, but I need something more focussed on valves and kit building, without getting swamped in mathematics and formulas. I bought a book on valves, but it's full of mind-boggling graphs. I hope you don't mind this rant.

Jan

[colin.hepburn]

Originally Posted by bearded fiddler

Thanks everyone. Richard, if I understand this right, you removed the switch for C1/C2 - C3/C4 - C5/C6 and replaced the caps by one 0.1 uF cap. Isn't this value higher than the combined value of the three original caps? Could you tell me something about the way capacitors raise or lower the bass roll-off frequency? Does one need more or less capacity for lowering the bass roll-off frequency? Excuse my ignorance but, although I can follow instructions and build kits, I have hardly any theoretical background. I'd like to read more about the basics, but I don't know where to begin. I bought Owen Bishop's Electronics A First Course, and it's ok, but I need something more focussed on valves and kit building, without getting swamped in mathematics and formulas. I bought a book on valves, but it's full of mind-boggling graphs. I hope you don't mind this rant.

Jan

Hi Jan
You will have seen on here many referrals to MJs valve amp books
pretty much all of us will have a copy of both his books I would start with the third edition Valve amps the yellow one and then get the blue one http://www.google.co.uk/products?hl=en&rls=com.microsoft:en-gb:IE-SearchBox&rlz=1I7GGLJ_en&q=morgan+jones+valve+amp+ books&oq=&um=1&ie=UTF-8&ei=LaOeS4TZJZXNjAfNjqjGCA&sa=X&oi=product_result _group&ct=title&resnum=3&ved=0CCAQrQQwAg

[bearded fiddler]

Thanks Colin. I ordered them this morning.

Jan

[Richard]

Originally Posted by bearded fiddler

Thanks everyone. Richard, if I understand this right, you removed the switch for C1/C2 - C3/C4 - C5/C6 and replaced the caps by one 0.1 uF cap. Isn't this value higher than the combined value of the three original caps? Could you tell me something about the way capacitors raise or lower the bass roll-off frequency? Does one need more or less capacity for lowering the bass roll-off frequency? Excuse my ignorance but, although I can follow instructions and build kits, I have hardly any theoretical background. I'd like to read more about the basics, but I don't know where to begin. I bought Owen Bishop's Electronics A First Course, and it's ok, but I need something more focussed on valves and kit building, without getting swamped in mathematics and formulas. I bought a book on valves, but it's full of mind-boggling graphs. I hope you don't mind this rant.

Jan

Hi Jan,

Keep reading, familiarity is half the battle, it will all drop into place. Bruce Rozenblit is good too,
http://www.amazon.com/Beginners-Guid.../dp/1882580133

That coupling is a cap into an impedance, known as a high pass filter. It has a slope of 6dB/Octave and its "corner frequency" is expressed halfway round at -3dB point.

The bigger the cap value the lower AC f it will pass into a given impedance (AC resistance of path to ground).

In our case C1/2 0.015uF into R9/10 1M

We can use a formula or a calculator,
http://www.muzique.com/schem/filter.htm

Enter the values and see it is 10.6Hz. You can work out the others.

Play with the calc, double and halve values and you'll see the ohms and cap are equally important.

Here's the PhonoII design article covering exactly this, hope Peter doesn't mind, only part of it and a good advert for other articles on the WD archive CD from the shop so you can check those through too against the designer's text,

[bearded fiddler]

Thanks Richard. I ordered the Rozenblit too. Enough to keep me busy for quite a while

At the moment I'm running two Philips 5751 with blue print on the valve and one with green print (all US made) in my Phono 3S. Are these exactly the same valves? The one with the green print is a JAN type; for the other two I don't know. I've been using the blue ones in my "Phonodude" phono stage (a Dutch design) and they have a very rich, smooth and detailed sound.

Jan