[jimbo900custom]

Has anyone tried one of these in place of the 5AR4? Is it compatible?
I have the Cornet 2 Jim auctioned on A'gon last year.

[poty]

In my opinion - the tube should work. The only concern is the pulse current capabilities: all datasheets mention only 4uF in place of the first capacitor in the filter (in the Cornet 2 there is 47uF), but as far as the current consumption of the Cornet 2 is very low comparing to the max current of the tube - I don't think this limitation ever occurs.

[jimbo900custom]

Thank you for the response. Poty. I think I will order one and try it out!

[hagtech]

No problem with pulse currents.  The CORNET2 has extra 220 ohm resistors added in series with the rectifier plates - which totally changes the way that specification is read.  It's about maximum energy dissipation.  The C2 ends up being very low and rather gentle on rectifier tubes.

jh

[poty]

Yes, I completely agree with the second part, but for every rectifier there is the effective plate resistance specified, so I doubt you can change the way the specification should read.

[hagtech]

The effective plate resistance is the spec of the tube at that operating point - as if it were a resistor in series with a perfect diode.  I add the 220 ohm on top of that, which makes a huge difference.

jh

[thorman]

Not sure if it helps or not but I just used the same tube ( from Upscale audio ) in my Modwright / Oppo 105 Power supply .. I subbed it for a Vintage Mullard 5ar4 and it works very well. A neutral tube with excellent pace and nice quick/tight and punchy bass attack..To me if you wish to go more neutral and lively ( as opposed to Mullard ) this is a good tube to try..........

       

[poty]

The effective plate resistance is the spec of the tube at that operating point - as if it were a resistor in series with a perfect diode.I add the 220 ohm on top of that, which makes a huge difference.
jh

Sorry, my fault to not be specific. I meant the parameter "Total Effective Plate-Supply Impedance per Plate" which includes beside effective plate resistance also the serial resistance "on top of that". I wanted to point out that datasheets have already had the information and carefully reading them already reveal the way of use the serial resistors. There are no "other way of reading the datasheets" or some incentives about that.
Specifically for the tube there is a note: "Indicated values for conditions shown will limit peak plate current to max. rated value. When a filter-input capacitor larger than 4uF is used, it may be necessary to use more plate-supply impedance than the value shown to limit the peak plate current to the rated value." This phrase just must be read rightly, that is all.

[contium]

Damn that is a sexy Cornet 2!

[jimbo900custom]

Well, I got the Philips tube 2 weeks ago and my impression so far is that the Philips 5R4GYS tube works just fine in the Cornet2.
It seems to bring the midrange a little more forward, compared to the Sovtek 5AR4. Particularly the vocal and especially female voice.
The bass is more pronounced but still tight, and to my ears very musical. Hard to say if it is an improvement or just a little different flavor.
So far I would say I like how it sounds. It has not made a major change in the sound, the Cornet2 character remains the same, it just puts a little
different spin on things.
If you are curious about this tube, I would say it is worth the $$. It's not a "game changer", but is very pleasant to listen to.
It is a large tube and the shape of it puts the tube about 2mm from the transformer.
And Contium, it is a sexy looking phono pre, thanks to Jim for building it and offering for sale. I was glad to win the auction. Jim thought it was too much silver, but it looks great in my system.

[david62]

I tried a 5R4GY in my Clarinet and didn't like it.I made it a bit more forward and harsh around the edges...

[hagtech]

On a side note, the 2mm spacing should be no problem.

jh

[sebrof]

I sub'd a Philips in for a Potato Masher 5R4WGB and I think I like the Philips better. I like the looks a lot better as well.

But - If you change any 5R4 for any 5AR4 that will be a much bigger difference than the Philips brand will give, no? IOW it's not the Philips, it's the 5R4 vs. 5AR4.