Grundig Tk145'i Amplifikatöre Dönüştürme
I want to use Grundig Tk145 as an Amplifier, can you help me with what I need or need to eliminate in the circuit? I'm having a hard time because there is no external audio input. Can you help me by drawing?
I want to use Grundig Tk145 as an Amplifier, can you help me with what I need or need to eliminate in the circuit? I'm having a hard time because there is no external audio input. Can you help me by drawing?
Splitting it where the red line is would be OK I think, but that capacitor and resistor make a high pass filter, and you would proibably need a grid leak resistor and a volume control.
The complication is the switching for the different biases required for the different tape speeds. I would recommend getting familiar with LTSpice and drawing the circuit excluding the switching. LT Spice is very useful for creating schematics, and that part of it is not a very steep learning curve. If you have that then you could get some help to get it to run, and then you would be able to get a good picture of expected voltages and component values.
Looking at it again maybe you need another stage before that, depending on what source you are using.
The complication is the switching for the different biases required for the different tape speeds. I would recommend getting familiar with LTSpice and drawing the circuit excluding the switching. LT Spice is very useful for creating schematics, and that part of it is not a very steep learning curve. If you have that then you could get some help to get it to run, and then you would be able to get a good picture of expected voltages and component values.
Looking at it again maybe you need another stage before that, depending on what source you are using.
What's the desired input sensitivity? If it is line level, follow Old Hector's advice, leave only the ECL86/6GW8 triode pentode combo and build a textbook two stage AF amplifier with some mere 4 watts output power. Ground C30, connect C11 to R55, put a 1M grid leak from this connection to ground, disconnect C23, insert some carefully designed GNFB from the output to the triode cathode (pin 2), that's it.
Anything else can be omitted (besides the PSU, of course).
Best regards!
Anything else can be omitted (besides the PSU, of course).
Best regards!
Thank you yes the input will be line level, I was just thinking like old Hector said. I wasn't sure what material I should add or remove. This is my first time working with a lamp device.What does gnfb mean?
Are you planning on isolation the circuit in the tape recorder, or do you plan to salvage the parts from the tape recorder and build it like the schematic you posted? Is your tape recorder using PCB circuits, or a metal chassis and point to point wiring?
A picture would be interesting. I just cannibalized a Tandberg 64 thinking it might make a useful phono RIAA preamp, but it is so integrated with different switches for different functions it would take a lot of work to retain just that function. The components probably need checking as well, so will probably not happen.
A picture would be interesting. I just cannibalized a Tandberg 64 thinking it might make a useful phono RIAA preamp, but it is so integrated with different switches for different functions it would take a lot of work to retain just that function. The components probably need checking as well, so will probably not happen.
If it will be of better quality, I want to protect the stock circuit by dividing it from the red line.
Only the switches, capacitor, supply and output transformer are connected to each other with metal chassis and cabling.
But if the circuit in the next picture I share is better, I can do that too,
or if you have any other suggestion.
Only the switches, capacitor, supply and output transformer are connected to each other with metal chassis and cabling.
But if the circuit in the next picture I share is better, I can do that too,
or if you have any other suggestion.
The circuit you shared is beautifully simple. It can be a bit tricky doing all the wiring on a triode-pentode like an ECL86, so it would make it easier. There are a lot of connections to 9 pins in a small a small space and it pays to think about the layout before diving in. (This is a good tool for layouts, DIY Layout Creator).
What sort of presentation are you hoping for at the end of this project? Tubes on display, or everything in a box?
If you want something safe that can be used daily and left on display, then in my experience 90% of the work at least is planning the layout, drilling holes, adding all the connectors, switches and potentiometers. Or alternatively just screw the bits to a wood panel, if this is solely a learning exercise.
If you try and adapt the circuit you have in the reel-to-reel, then you will also learn of lot of good practice from the designers of that circuit and its construction.
At the end of the day, depends on what you want to achieve.
What sort of presentation are you hoping for at the end of this project? Tubes on display, or everything in a box?
If you want something safe that can be used daily and left on display, then in my experience 90% of the work at least is planning the layout, drilling holes, adding all the connectors, switches and potentiometers. Or alternatively just screw the bits to a wood panel, if this is solely a learning exercise.
If you try and adapt the circuit you have in the reel-to-reel, then you will also learn of lot of good practice from the designers of that circuit and its construction.
At the end of the day, depends on what you want to achieve.
Metal plate, metal chassis or wooden enclosure? Do you have hole punches or equivalent?
Anything you can harvest from the old reel-to-reel, apart from tubes, sockets and transformers?
Do you have a stereo reel-to-reel, or will you build a mono amplifier?
Anything you can harvest from the old reel-to-reel, apart from tubes, sockets and transformers?
Do you have a stereo reel-to-reel, or will you build a mono amplifier?
Btw, not untypical for old Grundig R2R appliances, this TK 147 doesn't have a dedicated power transformer. The motor acts as transformer here. Do you really want that? And if you want to build a stereo amp, be aware that you need a second identical output transformer and a second ECL86, which is a scarce and expensive tube nowadays.
Best regards!
Best regards!
I have 2 TK147 deluxe. I have an external supply transformer.
I have metal plates and many materials.
I want to turn this into a stereo hi-fi amplifier with only line level input.
I have metal plates and many materials.
I want to turn this into a stereo hi-fi amplifier with only line level input.