Can this be done without a major overhaul and just some parts swapping?
This is an existing circuit on a PCB, and I don't want to totally reengineer it, hopefully just swap some part values to reduce the overall gain.
yaquin 845 pre schem by Barry, on Flickr
Thank you
This is an existing circuit on a PCB, and I don't want to totally reengineer it, hopefully just swap some part values to reduce the overall gain.
yaquin 845 pre schem by Barry, on Flickr
Thank you
Looking at that schematic, I am guessing one of three things:
1. It does not work properly. Forget about too much gain, or too little gain, that is not the fundamental issue.
2. It is not drawn properly.
3. Both 1. and 2. above
Where does the input tube's plate get its current and voltage from?
Look closely at the circuit, please.
I see the path of the input tube plate as:
input stage plate to a grid, and then to a grid to cathode resistor, and that cathode resistor and cathode connects to a second grid.
Wow!
1. It does not work properly. Forget about too much gain, or too little gain, that is not the fundamental issue.
2. It is not drawn properly.
3. Both 1. and 2. above
Where does the input tube's plate get its current and voltage from?
Look closely at the circuit, please.
I see the path of the input tube plate as:
input stage plate to a grid, and then to a grid to cathode resistor, and that cathode resistor and cathode connects to a second grid.
Wow!
No anode load, no cathode load, no grid leak resistor ... who penned the diagram?
It cannot work as the schematic shows. Yaquin, the same people who made the FU49 amplifier and didn't know how to wire the IEC mains connector!
Many went through my workshop, sent in from all parts of the UK for suspected mains transformer issues. Turned out the mains inputs had all been wired Live to Live. Neutral to Earth and no Mains Earth!
It cannot work as the schematic shows. Yaquin, the same people who made the FU49 amplifier and didn't know how to wire the IEC mains connector!
Many went through my workshop, sent in from all parts of the UK for suspected mains transformer issues. Turned out the mains inputs had all been wired Live to Live. Neutral to Earth and no Mains Earth!
Well, it does work, as I had it plugged into my system last night, it's just that when in use, the volume knob is barely cracked open to get to normal listening levels. I believe it was designed to drive a dedicated amplifier that needs a high input signal. The amplifier I'm trying to pair it with needs less.
Oh my....
Why would anyone want an ecc83 srpp as a preamp!!!!
The gain is ridiculous.
Why would anyone want an ecc83 srpp as a preamp!!!!
The gain is ridiculous.
This is a line stage? Unless you use a turntable and phono stage, all that gain is simply unnecessary.
Try plugging your source directly into your amplifier, which seems to have a volume control.
Don't compound mistakes, keep it simple. Sell that to someone else if you don't need the gain.
Try plugging your source directly into your amplifier, which seems to have a volume control.
Don't compound mistakes, keep it simple. Sell that to someone else if you don't need the gain.
I don't really understand this stuff, but it was designed to drive a 845 power stage(?)
pdf of the full schematic is here
pdf of the full schematic is here
This seems to be a driver stage for the power tube, and so is not suitable for a line stage.
Where is the volume control located, if not in the amplifier?
Again, if you do not use LPs, you likely don't need any line stage gain at all.
Where is the volume control located, if not in the amplifier?
Again, if you do not use LPs, you likely don't need any line stage gain at all.
On the front of the preamplifier. If you look at the link of the full schematic you'll see it in the bottom left corner
This is still not clear.
Are you taking an integrated amplifier, and trying to use it as a line stage preamplifier,
and connecting it to an external power amplifier?
Or are you just trying to get the complete integrated amplifier to work with your speakers?
Are you taking an integrated amplifier, and trying to use it as a line stage preamplifier,
and connecting it to an external power amplifier?
Or are you just trying to get the complete integrated amplifier to work with your speakers?
No, this is a preamplifier, in a stand alone chassis, with 4 stereo line level inputs, and one stereo line level output.
https://www.aliexpress.us/item/2251832622191204.html?gatewayAdapt=glo2usa4itemAdapt&_randl_shipto=US
I purchased it used, and wasn't aware of its extraordinary gain characteristics.
You cannot just swap tubes around. That won't work, and can cause damage.
What audio sources do you have: turntable, CD, tape, FM, etc?
What audio sources do you have: turntable, CD, tape, FM, etc?
Mostly CD, also a turntable with an outboard phono stage. I suppose I could connect the turntable directly...
No, I know there would be no RIAA correction 😉
The only volume control in my system is in the preamplifier.
No, I know there would be no RIAA correction 😉
The only volume control in my system is in the preamplifier.