CV2799
- pre65
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#1 CV2799
I got some CV2799 valves ages ago by mistake thinking they were substitutes for 832a.
Now, could they be used for A2 experiments similar to what I am trying with 1626 ?
Where do I start ?
http://www.tubecollector.org/cv2799.htm
200-230v HT would be nice, just need a rough idea of how to calculate a cathode resistor then I can experiment.
I'd double up the anodes and grid 1 and triode connect for simplicity and possibly (shared) cathode current around 50ma.
OR could I just ground the cathode ?
Now, could they be used for A2 experiments similar to what I am trying with 1626 ?
Where do I start ?
http://www.tubecollector.org/cv2799.htm
200-230v HT would be nice, just need a rough idea of how to calculate a cathode resistor then I can experiment.
I'd double up the anodes and grid 1 and triode connect for simplicity and possibly (shared) cathode current around 50ma.
OR could I just ground the cathode ?
The only thing necessary for the triumph of evil is for good men to do nothing.
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
- pre65
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#2
The madness continues.
I've gutted the old 300b chassis, and it now sports a pair of B9a sockets to suit the CV2799.
The chassis is rigged up to feed from the 450v dual mono PSU, so that is one less job to sort out.
I will draw out some sort of plan before too long.
Any help with how to bias the cathode, or pointers to info which would guide me would be appreciated.
IDEA ? If I wanted to get (for example) 50ma would it be easier to have a 50ma CCS on the cathode ?
I've gutted the old 300b chassis, and it now sports a pair of B9a sockets to suit the CV2799.
The chassis is rigged up to feed from the 450v dual mono PSU, so that is one less job to sort out.
I will draw out some sort of plan before too long.
Any help with how to bias the cathode, or pointers to info which would guide me would be appreciated.
IDEA ? If I wanted to get (for example) 50ma would it be easier to have a 50ma CCS on the cathode ?
The only thing necessary for the triumph of evil is for good men to do nothing.
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
- Paul Barker
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#3
that's one way to skin this particular cat, which has often been recommended but I haven't tried it.pre65 wrote:
IDEA ? If I wanted to get (for example) 50ma would it be easier to have a 50ma CCS on the cathode ?
- pre65
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#4
It works very well on the push pull 832a amp.Paul Barker wrote:that's one way to skin this particular cat, which has often been recommended but I haven't tried it.pre65 wrote:
IDEA ? If I wanted to get (for example) 50ma would it be easier to have a 50ma CCS on the cathode ?
There is a voltage and current limit on G2, so I'm allowing for that when connecting up in triode mode.
The only thing necessary for the triumph of evil is for good men to do nothing.
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
- pre65
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#5
After a morning of cobblering things together, I switch on and get no sound.
So, after a lot of checking and head scratching, I decide to ground the CV2799 grid.
Now it works.
It's only been on a few moments, but I'm impressed
A) because it actually works.
B) it sounds very full and dynamic.
More listening me thinks.
PS Who needs 300b ?
So, after a lot of checking and head scratching, I decide to ground the CV2799 grid.
Now it works.
It's only been on a few moments, but I'm impressed
A) because it actually works.
B) it sounds very full and dynamic.
More listening me thinks.
PS Who needs 300b ?
The only thing necessary for the triumph of evil is for good men to do nothing.
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
- pre65
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#6
Must say I'm astounded how good this lash up sounds.
If I can get this good without really knowing what I'm doing just imagine how good things could be if I was edumucated like wot some of you others are.
If I can get this good without really knowing what I'm doing just imagine how good things could be if I was edumucated like wot some of you others are.
The only thing necessary for the triumph of evil is for good men to do nothing.
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
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#7
You are a star Phil.
So is that the HT supply at the front, the preamp at the back and the output stage between the two?
So is that the HT supply at the front, the preamp at the back and the output stage between the two?
- pre65
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#8
Dual mono choke input HT PSU at the front, the TDA2050 driving stage at the back and the CV2799 bit in the middle. Now it works I will integrate the middle and back bits somehow.
I resistored the HT down a bit cos it was about 470v and I was looking for about 440v.
The only bits I had to buy were 4 Kiwames from HFC, and I ended up not using them.
I need a hum pot on the AC heaters but I have the pots to hand.
I resistored the HT down a bit cos it was about 470v and I was looking for about 440v.
The only bits I had to buy were 4 Kiwames from HFC, and I ended up not using them.
I need a hum pot on the AC heaters but I have the pots to hand.
The only thing necessary for the triumph of evil is for good men to do nothing.
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
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#9
As a project to learn from you could instead, starting on one monoblock build a shunt reg to get the voltage where you want it.pre65 wrote: I resistored the HT down a bit cos it was about 470v and I was looking for about 440v.
- pre65
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#10
Hum pot has made no difference.pre65 wrote:
I need a hum pot on the AC heaters but I have the pots to hand.
The wires are a bit long in places, I'll wait till it's been tidied up before I worry too much.
Regulated power supply.
I need a member of my listening panel to hear it as is first to make sure it's not just my euphoria.
The only thing necessary for the triumph of evil is for good men to do nothing.
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
- pre65
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#11
It's still amazing me with the way it sounds.
And it's so simple really.
The bass is particularly good, firm and tuneful. Best bass of any amp I've ever heard with my speakers.
And it's so simple really.
The bass is particularly good, firm and tuneful. Best bass of any amp I've ever heard with my speakers.
The only thing necessary for the triumph of evil is for good men to do nothing.
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
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#12
that is a worthy recommendation. I am pleased your amp chip didn't work out as good.
- pre65
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#13
The amp chip is still driving the CV2799.Paul Barker wrote:that is a worthy recommendation. I am pleased your amp chip didn't work out as good.
The only thing necessary for the triumph of evil is for good men to do nothing.
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
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#14
Shock horror!
It must be therefore that the amp chip you chose isn't capable of driving far into A2 but is fine with this load.
So now you tell me that effectively a hybrid amp is your best to date?
somebody help me my world is sinking beneath my feat.
Oh well nothing else for it, like smokers pooh pooh the evidence that smoking is bad for you, I will regress back into my own little world of valves alone, and pooh pooh this evidence.
It is not good for my sanity to accept this paradigm shift. I will pretend I never heard this.
It must be therefore that the amp chip you chose isn't capable of driving far into A2 but is fine with this load.
So now you tell me that effectively a hybrid amp is your best to date?
somebody help me my world is sinking beneath my feat.
Oh well nothing else for it, like smokers pooh pooh the evidence that smoking is bad for you, I will regress back into my own little world of valves alone, and pooh pooh this evidence.
It is not good for my sanity to accept this paradigm shift. I will pretend I never heard this.
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#15
The amp chip -> A2 worked fine, just wouldn't do treble at the "away match" (tried at someone else's house)
"No matter how fast light travels it finds that the darkness has always got there first, and is waiting for it."