Hey diyAudio community. This is my first post here so I apologize for any noobness.
Background: I recently got a transistor tape recorder that I fixed up and I think it sounds awesome when I use it to record drums. It's certainly textured and lofi in an exciting way. But the best part is the wow and flutter is terrible (lol) so long sounds like my cymbal come out super drunken and wavy while short sounds aren't noticeably changed. I think it's a cool effect that I want to be able to explore more, but the recorder only has a built in speaker so I can't record the tape to digital to work with it. The speaker in the recorder is labeled 8ohm 0.1w and I think it's powered by a 9v battery. There's also 3 C batteries in there but I think they power the motors and the record and erase heads.
Questions: can I use an audio transformer to convert the signal being sent to the 8ohm speaker to 600ohms and connect that to an 1/8" output jack to connect to a daw? Would using a transformer even make sense to try to load match the output to line level or is there an easier way? I want to use a switching jack connected to line and speaker level before the transformer so the speaker can be engaged for monitoring when there's nothing plugged into the output jack.
Thanks in advance for any help you can offer!
Background: I recently got a transistor tape recorder that I fixed up and I think it sounds awesome when I use it to record drums. It's certainly textured and lofi in an exciting way. But the best part is the wow and flutter is terrible (lol) so long sounds like my cymbal come out super drunken and wavy while short sounds aren't noticeably changed. I think it's a cool effect that I want to be able to explore more, but the recorder only has a built in speaker so I can't record the tape to digital to work with it. The speaker in the recorder is labeled 8ohm 0.1w and I think it's powered by a 9v battery. There's also 3 C batteries in there but I think they power the motors and the record and erase heads.
Questions: can I use an audio transformer to convert the signal being sent to the 8ohm speaker to 600ohms and connect that to an 1/8" output jack to connect to a daw? Would using a transformer even make sense to try to load match the output to line level or is there an easier way? I want to use a switching jack connected to line and speaker level before the transformer so the speaker can be engaged for monitoring when there's nothing plugged into the output jack.
Thanks in advance for any help you can offer!
All you need is a jack connected across the speaker. Or just clip-leads. "Matching" is totally moot since you have more than 100X more power than a studio line input needs. The signal level at "reasonable" speaker volume will be 0.1V to 1.0V which is in-line with what studio gear needs. Since it is battery power you don't even need ground isolation. Since I assume the tape player will be right next to the digi-gear you don't need balanced lines or other tomfoolery.
FWIW: back when home tape decks were new (1950s) a standard accessory was a plug with clips on the end to connect to anything with a speaker.
FWIW: back when home tape decks were new (1950s) a standard accessory was a plug with clips on the end to connect to anything with a speaker.
Thank you for your response PPR! And thanks for the historical note! I love getting context for how these things work.
So I can just solder the jack so the signal to the speaker is broken when the cable is inserted and not even worry about it.
Would there be any advantages like improved bass frequencies or an amplitude gain if I did put a transformer in there?
So I can just solder the jack so the signal to the speaker is broken when the cable is inserted and not even worry about it.
Would there be any advantages like improved bass frequencies or an amplitude gain if I did put a transformer in there?
May I suggest adding a resistor in series, between speaker "hot" terminal and jack? This is purely as a safety measure; if the jack you add becomes accidentally shorted, the series resistor will protect the power amplifier inside the tape recorder. Old vintage transistor power amps have a nasty habit of frying themselves if you short the output, and you don't want that to happen!
The value of the resistor is not critical at all. Anything between ten ohms and one thousand ohms would work just fine.
Not really. You are more likely to lose some bass, if anything. And you already have all the signal amplitude you need - no need to increase it through a transformer.
Back when cassette players were common, I loathed the huge amount of wow and flutter. 😀
-Gnobuddy
Woah great info thank you Gnobuddy! I'll be way more careful with this when I'm modding the speaker output. I've been pretty cavalier up to this point. No transformer and one resistor it is!
😊 There's so many reasons this unit sounds trash but the lack of a flywheel really stands out haha. It's good trash though cuz it's my trash!
😊 There's so many reasons this unit sounds trash but the lack of a flywheel really stands out haha. It's good trash though cuz it's my trash!
I just realized I misread your earlier post; you wanted to insert the jack "so the signal to the speaker is broken when the cable is inserted". This makes perfect sense, but if you put a resistor in series, it will reduce power to the speaker all the time. That may not be what you want.
I had been envisioning your new line-out jack simply being wired in parallel with the speaker. That way, you can put a resistor in series with the jack, without affecting the signal to the speaker in any way. However, the speaker is always on if you do it this way.
That said, if you do use a series resistance with the same value as the speaker resistance, output power is only reduced by 3 dB, which may be acceptable?
That is to say, use a series resistor of 3.9 ohms, 8.2 ohms, or 15 ohms depending on whether you have a 4 ohm, 8 ohm, or 16-ohm speaker in the cassette player. This would guarantee that the amplifier in the cassette player always sees a load no lower than it was designed to handle.
No flywheel? Now that, I have never seen before! 🙂
-Gnobuddy
I had been envisioning your new line-out jack simply being wired in parallel with the speaker. That way, you can put a resistor in series with the jack, without affecting the signal to the speaker in any way. However, the speaker is always on if you do it this way.
That said, if you do use a series resistance with the same value as the speaker resistance, output power is only reduced by 3 dB, which may be acceptable?
That is to say, use a series resistor of 3.9 ohms, 8.2 ohms, or 15 ohms depending on whether you have a 4 ohm, 8 ohm, or 16-ohm speaker in the cassette player. This would guarantee that the amplifier in the cassette player always sees a load no lower than it was designed to handle.
No flywheel? Now that, I have never seen before! 🙂
-Gnobuddy