Just didn't want to say "lemon"
Passive is less worse than active. (Overload/distortion/feedback considerations)
You're excused anything if they're salvage.
Why on earth do you want to hear Windoze alerts? I added loudspeakers to my computer for ten minutes before binning them. My old computer had a top-notch soundcard (for loudspeaker measurement) but no loudspeakers...
Passive is less worse than active. (Overload/distortion/feedback considerations)
You're excused anything if they're salvage.
Why on earth do you want to hear Windoze alerts? I added loudspeakers to my computer for ten minutes before binning them. My old computer had a top-notch soundcard (for loudspeaker measurement) but no loudspeakers...
Ladies and gentlemen!!!!!!
See!!!
The SRPP is a controversial circuit. Even its name is not set in stone, as it is called the SRPP, the SEPP, the mu follower, the mu amplifier, the cascoded cathode follower, and the totem-pole amplifier. Interestingly, the name given in the 1940 patent (US 2,310,342) for the circuit is seldom used: a "balanced direct and alternating current amplifier.
For more interesting reeding:
http://www.tubecad.com/articles_2002/SRPP_Deconstructed/index.html
I never trust in a lady!
cheers
jorge
See!!!
The SRPP is a controversial circuit. Even its name is not set in stone, as it is called the SRPP, the SEPP, the mu follower, the mu amplifier, the cascoded cathode follower, and the totem-pole amplifier. Interestingly, the name given in the 1940 patent (US 2,310,342) for the circuit is seldom used: a "balanced direct and alternating current amplifier.
For more interesting reeding:
http://www.tubecad.com/articles_2002/SRPP_Deconstructed/index.html
I never trust in a lady!
cheers
jorge
Pre-amp
Tim,
I realised the 3.3meg resistor was there for bias in conjunction with the 1meg resistor, I just wondered whether it was really necessary in practice - I've never used this method even when I've had the resistor on the cathode follower up to 47k. The heavily negative bias this gives the grid obviously will affect gain, but as fdegrove comments the gain overall might be rather high, and this can help reduce it. Why not try the circuit both with and without the resistor and see which is best suited for you?
Bunville?????!!!!!
Tim,
I realised the 3.3meg resistor was there for bias in conjunction with the 1meg resistor, I just wondered whether it was really necessary in practice - I've never used this method even when I've had the resistor on the cathode follower up to 47k. The heavily negative bias this gives the grid obviously will affect gain, but as fdegrove comments the gain overall might be rather high, and this can help reduce it. Why not try the circuit both with and without the resistor and see which is best suited for you?
Tube_Dude said:
Bunville?????!!!!!
Actually, Bunville sounds like a nice place. Bun = bread (as 'hotdog buns') and also the buttocks 
, and ville is often used with city names (Janesville), so BUTT TOWN HERE I COME!!
Cough ahem, anyway.
I don't see how the CF would work, really at all, without the 3.3M. Without, the grid would be at 0V, and for a reasonable amount of current, say 2-5mA, the load resistor would have to be smaller by at least 10 times! This also loads down the tube, increasing distortion and reducing headroom. As-is, current would be miniscule if biased in this way.
By obtaining grid bias from a voltage divider instead, the extra cathode voltage is subtracted, allowing more headroom, a higher load resistance, and sufficient bias current.
Tim
, and ville is often used with city names (Janesville), so BUTT TOWN HERE I COME!! Cough ahem, anyway.
I don't see how the CF would work, really at all, without the 3.3M. Without, the grid would be at 0V, and for a reasonable amount of current, say 2-5mA, the load resistor would have to be smaller by at least 10 times! This also loads down the tube, increasing distortion and reducing headroom. As-is, current would be miniscule if biased in this way.
By obtaining grid bias from a voltage divider instead, the extra cathode voltage is subtracted, allowing more headroom, a higher load resistance, and sufficient bias current.
Tim
Re: Ladies and gentlemen!!!!!!
Tube_Dude said:
See!!!
The SRPP is a controversial circuit. Even its name is not set in stone, as it is called the SRPP, the SEPP, the mu follower, the mu amplifier, the cascoded cathode follower, and the totem-pole amplifier. Interestingly, the name given in the 1940 patent (US 2,310,342) for the circuit is seldom used: a "balanced direct and alternating current amplifier.
For more interesting reeding:
http://www.tubecad.com/articles_2002/SRPP_Deconstructed/index.html
I never trust in a lady!
A SRPP is not a mu-follower; the circuits are quite different.
7N7
cheers
jorge
Re: Ladies and gentlemen!
Well if you look at the circuits, you will see that the mu-follower has an anode load resistor for the lower valve. It follows therefore, that the mu-follower will offer lower distortion. The (lower) anode output is coupled to the upper grid via a small capacitor. These components are not used in a SRPP stage.
The mu follower is a better voltage stage (lower output resistance) but requires higher HT (because of the load resistor).
The SRPP is economical in terms of HT, and, I understand, makes a better driver stage.
I know nothing of Totem Poles, buckskins, warpaint, wampum and suchlike.
7N7
Tube_Dude said:Hi 7N7!
well ...who must i believe...7N7 or Tubecad .com...
By the way we were talking about of Totem pole!!!
Jorge
Well if you look at the circuits, you will see that the mu-follower has an anode load resistor for the lower valve. It follows therefore, that the mu-follower will offer lower distortion. The (lower) anode output is coupled to the upper grid via a small capacitor. These components are not used in a SRPP stage.
The mu follower is a better voltage stage (lower output resistance) but requires higher HT (because of the load resistor).
The SRPP is economical in terms of HT, and, I understand, makes a better driver stage.
I know nothing of Totem Poles, buckskins, warpaint, wampum and suchlike.
7N7
Tim,
I'm not familiar with the characteristics of the 8514 tube, but I've used cathode followers with a range of tubes from 6J5s to the ECCxx series, without needing to provide positive bias from the HT line (or anywhere else, for that matter) to overcome excessive negative bias. Anyway, try it both ways - I'd be interested in hearing your results.
Are you sure you'd want to live in a place called Bunville? Sounds like a place for refugees from Bugs Bunny cartoons...
I'm not familiar with the characteristics of the 8514 tube, but I've used cathode followers with a range of tubes from 6J5s to the ECCxx series, without needing to provide positive bias from the HT line (or anywhere else, for that matter) to overcome excessive negative bias. Anyway, try it both ways - I'd be interested in hearing your results.
Are you sure you'd want to live in a place called Bunville? Sounds like a place for refugees from Bugs Bunny cartoons...
Absolutely .. not!
Patents/Search/Patent Number, you get scans of the documents themselves. IE doesn't do TIF internally, so you have to go to http://www.alternatiff.com for the plugin to view them.
If that still doesn't work I can upload them as .GIF.
Tim
Patents/Search/Patent Number, you get scans of the documents themselves. IE doesn't do TIF internally, so you have to go to http://www.alternatiff.com for the plugin to view them.
If that still doesn't work I can upload them as .GIF.
Tim
PATENTS OR NOT.
Hi,
Regardless of patents, the so called SRPP does not shunt, it does not regulate and it is not really push-pull either.
What interests me more though is that it can sound good, offer quite a few advantages and when used correctly can beat a few other compromised circuits.
Cheers,
Hi,
Regardless of patents, the so called SRPP does not shunt, it does not regulate and it is not really push-pull either.
What interests me more though is that it can sound good, offer quite a few advantages and when used correctly can beat a few other compromised circuits.
Cheers,
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