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Vintage Tape (Audio), Cassette, Wire and Magnetic Disc Recorders and Players Open-reel tape recorders, cassette recorders, 8-track players etc.

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Old 21st Mar 2021, 10:34 pm   #1
reeltoreelrob
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Default Recording from DAB

Hi all,
I have been trying to record from digital radio the sound is really tinny I have used different leads radios and recorders.
The best results tend to be with valve recorders.
Any advice, could a little circuit be made to block the treble.
Works perfectly when plugged into an old yacht boy.

Thanks in advance.
Rob.
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Old 21st Mar 2021, 10:52 pm   #2
TIMTAPE
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Default Re: Recording from DAB

DAB should not sound tinny any more than does a CD. How are you trying to record it?
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Old 21st Mar 2021, 11:17 pm   #3
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Default Re: Recording from DAB

Hi,
I did forget to say it's onto vintage reel to reels, using the 3.5mm line out into the tape recorder Din socket. Even using the tape recorder as an amp while recording it sounds bad so obviously the recording is poor too.
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Old 21st Mar 2021, 11:36 pm   #4
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Default Re: Recording from DAB

The 3.5mm socket (earphones?) will be stereo so you need a 3-way lead. For recording in mono you will have to choose one channel or mix them together with a resistor in each feed, say 1k
Try plugging the PC monitor system into the radio - should sound sweet
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Old 22nd Mar 2021, 10:50 am   #5
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Default Re: Recording from DAB

DAB broadcasts often have very low bit rates so lots of stations can be crammed into the multiplex. The resulting sound is likely to be on the poor side to say the least.
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Old 22nd Mar 2021, 11:31 am   #6
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Default Re: Recording from DAB

I use the headphone socket of an old Roberts RD60 to drive a cheap FM microtransmitter, mainly to listen to Times Radio on FM sets around the house. The sound quality is very good, though this is a speech based station so the low bitrates have less impact.

What may be causing confusion is that the audio outputs of a DAB radio are likely to be flat. Old FM radios did a lot of frequency shaping to improve the sound or produce a distinctive 'corporate sound' - old Grundigs are notorious for this.
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Old 22nd Mar 2021, 2:34 pm   #7
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Default Re: Recording from DAB

Quote:
Originally Posted by reeltoreelrob View Post
Hi all,
Works perfectly when plugged into an old yacht boy.
Quote:
Originally Posted by reeltoreelrob View Post
Hi,
using the 3.5mm line out into the tape recorder Din socket.
This could be your problem.

If you're taking the output of a Yacht Boy from the 3.5mm headphone socket, then you'll be used to the sound of a Yacht Boy.

In case you're not aware, the Yacht Boy includes an absolutely massive bass boost in the equalisation. So anything else will sound tinny by comparison. But it's likely* not the DAB radio that's at fault - rather, it's your expectations based on your experience of the Yacht Boy's built in equalisation.

* Of course, it's likely that the headphone socket of your DAB radio is also subject to unwanted equalisation - especially if the unit has small speakers - but in my experience, headphone sockets on DAB radios tend to be fed from separate amplifiers and have a nominally flat response (op-amps are cheap!). Of course, nothing that happens in the MPEG coding affects the bass end, but other parts of the spectrum can be affected, as we know.

Back to the Yacht Boy - if you take the output from the 5 pin DIN socket, then that is prior to the equalisation, and won't have the extreme EQ that the headphone socket has. Quite apart from that, it's best practice to do that so that your recordings won't be affected by the volume and tone control settings of the radio. Forgive me if you already know all this, and if that's what you're already doing, but you did specifically mention the 3.5mm lead, so that's why I had this thought...
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Old 22nd Mar 2021, 3:10 pm   #8
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Default Re: Recording from DAB

The other possibility here is the input socket on the tape recorder, if the microphone or phono input is used the sound may sound tinny where as a line input (may be called Radio) should be flat response and should sound ok.
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Old 22nd Mar 2021, 4:16 pm   #9
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Default Re: Recording from DAB

You try plugging the radio into your computer line in, set up the input and level in the software and then plugging your tape recorder into the line out of the computer.
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Old 22nd Mar 2021, 7:07 pm   #10
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Default Re: Recording from DAB

Am I missing something?

We are told that the DAB output is being fed into an old reel to reel recorder DIN input which could be either a mic or radio input. Either which be expecting a low audio signal from a high impedance load. Not a low impedance high level audio which I suggest it is getting.

So, may I suggest, the first question is, just what make and model tape recorder is being used and the input chosen.

Next, which DAB receiver is being used so that we no longer need to guess how to match the two.

All agree?

Chris
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Old 22nd Mar 2021, 8:19 pm   #11
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Default Re: Recording from DAB

No, I don't agree - not yet, at least. We first need an answer to points I raised earlier regarding the comparison between a DAB radio and a Grundig Yacht Boy.

If the OP is taking the audio signal from the headphone socket of the Yacht Boy, then he will be accustomed to the extreme bass boost (about 25dB!) that Yacht Boys are famous for (https://www.vintage-radio.net/forum/...554#post371554). Anything else will most definitely sound "tinny" be comparison.

But if he is taking the signal from the Yacht Boy via its DIN socket, then that is prior to the amplifier EQ, so is nice and flat. If the DAB radio sounds "tinny" compared to that, then yes, we do have an interesting problem to chase. At which point makes and model numbers might well help us.

To the OP: What socket are you using on the Yacht Boy?

Mark
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Old 22nd Mar 2021, 9:03 pm   #12
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Default Re: Recording from DAB

Radio Four is often in mono on DAB. What's going on there?
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Old 22nd Mar 2021, 9:28 pm   #13
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Default Re: Recording from DAB

I think R4 goes to mono when R5Xtra is on. There are only a limited number of bits to go round.

No general discussion of DAB in this thread please.
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Old 22nd Mar 2021, 10:53 pm   #14
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Default Re: Recording from DAB

Hi all and a big thank you for all of the replies,
When I record from the Grundig I use the 5 pin din, when I try to use the DAB radio I use a 5pin din to 3.5mm adapter, it's not a home made one its part of a kit, so far I have tried the line out and headphone sockets on the DAB and both sound bad, even compared to the recordings I did on reel to reel years ago, I will have another experiment and see if I can get better results.
All the best Rob.
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Old 22nd Mar 2021, 10:56 pm   #15
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Default Re: Recording from DAB

In that case, something is wrong. Possibly your adapter isn't wired appropriately for this application. The sound quality from the Grundig DIN socket and DAB radio line out jack should be very similar - in some respects, the DAB output will be better.
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Old 22nd Mar 2021, 10:57 pm   #16
reeltoreelrob
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Default Re: Recording from DAB

The radio is a pure Evoke-1 and the tape recorder is a stellaphone st454.
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Old 23rd Mar 2021, 1:45 am   #17
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Default Re: Recording from DAB

I thought the Evoke-1 was mono only, and doesn't it also have a line output socket?
What does it sound like on headphones in the appropriate socket?
Do you have a PC with separate monitor speakers?
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Old 23rd Mar 2021, 8:53 am   #18
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Default Re: Recording from DAB

If the Evoke is giving a stereo output and you are commoning this to feed a mono machine, it would be better to use a couple of buffer resistors in each feed - 10k would be enough. What you want to avoid is loading one output with the output impedance of the other, which will cause distortion.
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Old 23rd Mar 2021, 10:04 am   #19
mhennessy
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Default Re: Recording from DAB

Quote:
Originally Posted by reeltoreelrob View Post
The radio is a pure Evoke-1 and the tape recorder is a stellaphone st454.
Quote:
Originally Posted by reeltoreelrob View Post
When I record from the Grundig I use the 5 pin din, when I try to use the DAB radio I use a 5pin din to 3.5mm adapter, it's not a home made one its part of a kit, so far I have tried the line out and headphone sockets on the DAB and both sound bad
Hi Rob,

Thanks for confirming that you're using the DIN output of the Grundig - while it might have seemed like a daft question, it was important to clear that up (in my mind, at least ).

The line output of the Pure is definitely the one to be using.

A pair of resistors to merge the output doesn't hurt, but won't be essential for a line output. The Pure's manual doesn't give a specification, but line outputs typically have a source impedance of between 100 ohms and 1k per "leg", so you will usually get away with a lead that joins them together, even it's not best-practice. For headphone outputs, mixing resistors are recommended. I usually pick resistors in the 1k to 3k3 range.

The next step would be to "buzz out" the 3.5mm to DIN lead to find out what it's actually doing. Worst-case, it might be wired across L and R, meaning the recording is the "S signal", or difference between L and R - which will be mute on a mono station, and missing bass on a stereo music programme. I know it sounds unlikely, but I have seen some really weird adaptors over the years - I remember a pack that CPC used to sell back in the '90s with some very non-standard conventions included that were best thrown away (but it was very cheap, and about half of the adaptors were very useful, so it was still good vfm - just full of traps for the unwary!)

Just a thought: if you have a set of PC speakers handy, that's a quick and easy way of checking the quality of the line output

Mark
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Old 23rd Mar 2021, 10:11 am   #20
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Default Re: Recording from DAB

Sorry to be a boring old s*d but the Stella ST454 thread on this site says that it is equivalent to the Philips EL3541, also detailed on this site.

There are 2 versions of this machine, and we are told the one in question uses DIN sockets. The only manual I can find is for the EL3549. It also has 3 DIN inputs as follows:

A 3 pin Mic, 3 pin Diode and last a 5 pin record player (phono). The manual says that should you wish to record from a radio the user should use the 3 pin diode socket.

The reason for this is as follows:

Mic Input IK for ImV sensitivity
Diode In 20K for 3mV sensitivity
Phono In 500K for 150mV sensitivity

So, I think the problem is using the 5 pin phono input. A look see at the schematic confirms that the recording level control is after the initial audio pre amps.

Turning the volume control on the radio right down when using the 5 pin DIN might help but the 3 pin DIN input, me thinks, is the one to use.

Chris
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