Tape Deck Speed

[HarvestmanMan]

Mod Note: I split this conversation from from the tape deck thread.

Too many...

Nakamichi CR-1A: Cost me $5.00. Needs a new reel motor and probably a new pinch roller. Not currently used.
Nakamichi RX-202: Cost me $15.00. Nothing wrong with it (at the moment). My main deck.
Sony TC-KE500S: Cost me $5.00. Nothing wrong with it. My auxiliary deck.
JVC KD-D50: Cost me $15.00. Records too fast, and may have a channel out. Do a Google image search for "jvc kd-d50", and my deck is the first picture there. Not currently used.
Yamaha KX-500U: Cost me $3.00. Needs a new pinch roller so it stops eating tapes. Not currently used.

As for R2R, my only deck is a lowly Akai 1730-SS. It's set up in my bedroom, and actually belongs to me dad.

 

[speakerman1]

There is a program that you can set your speed with. It has a tone generator. On your good deck record a 3000 hz tape one channel.

 

[HarvestmanMan]

There is a program that you can set your speed with. It has a tone generator. On your good deck record a 3000 hz tape one channel.

Oddly, the playback speed appears to be fine, but the recording I made a while ago was too fast. Do the recording and playback mechanisms use separate belts?

 

[Skywavebe]

In all the decks I have seen over the years no one has made a deck that uses different tape mechanism for playback and record functions. They all come from the same transport. If the speed is different in record than in play there are two possible reasons for it. One is in record mode the deck uses more power to power the Bias oscillator and thus if the supply in your deck is on the edge then it could push it over the edge and voltage might drop. The other possibility is that the motor is worn out and it is experiencing an irregular speed so that it looks like the speed in record is different than Playback but it is just the motor that can no longer keep good speed. The motor brushes wear down and the commutator gets dirty and there is where the motor changes speeds and becomes defective.
I have been replacing DC capstan motors in decks with a motor I have found that is mostly compatible with decks in general. This is the EG5302D-2B motor. Once mounted and calibrated, this motor should last a good amount of time from now but like I tell people with tape decks and disappearing parts- it does not hurt to have more than one an hand ready to install.

 

[laatsch55]

Sam!!! Glad to see ya Lad!

 

[Skywavebe]

Hi Lee,
I check in once in a while as I do on other sites. People need help all the time with their equipment but don't always find the right place to ask about it so I am on about 5 or 6 sites. I am quickly moving away from a lad.

 

[Web Police]

Oddly, the playback speed appears to be fine, but the recording I made a while ago was too fast. Do the recording and playback mechanisms use separate belts?

The other possibility is that tape was recorded on a different deck? Usually if you record a tape on a particular deck and play it back on the same deck you will not notice the speed is off unless something malfunctioned on the deck between the recording and playback. If you have a pre-recorded tape then try playing that back on the deck in question and note if the playback is too fast or too slow. The thing to note is that if you have a good ear sometimes the pre-recorded tapes speed might be slightly off too.

 

[HarvestmanMan]

What I did was take two new blank tapes, record the same thing on each of them (from a vinyl source) using a Sony reference deck, and then tested the two decks to compare how they sounded upon playback.

The JVC seemed to shift the pitch up a bit, whereas the Sony sounded fine in terms of speed.

 

[Web Police]

If you recorded both tapes on the Sony deck and they both tapes play too fast on the JVC deck, then either the Sony deck's speed is too slow or the JVC deck's speed is too fast. Or possibly a combination of both.

What you need is a reference tape that was recorded on a deck with known correct speed. Maybe try out a pre-recorded tape on both decks and see if one sounds fast or if one sounds slow. The speed reference tape will have a frequency tone that you can measure with a scope so you can adjust the speed precisely.

That is about as much as I can tell you. Maybe Skywavebe can elaborate some as he works with tape decks every day.

 

[HarvestmanMan]

I've compared tapes recorded on the Sony to the original source, and there is no change in speed.

 

[Web Police]

How did you compare them? If either deck is slow or fast you wont know by recording a tape and playing it back on the same deck. Each deck uses the same tranport and motors for record and playback. So for imnstance if the Sont deck is running slow it will run slow in the record mode and slow in the playback mode, so a tape recorded at less then 1 7/8 ips will sound fine when played back on the deck it was recorded on. If you put that tape in a properly speed calibrated deck it will play too fast.

You have to either have a tape that you know was recorded at the proper speed and play it in both decks to dteremine if one is too fast or one is too slow or they are both off speed wise. Most of the time the differences are too subtle for the ear to pickup on. If you have a cd and a pre-recorded tape of the same song, you can play them at the same time to determine if thedeck i8s slow or fast to some degree.

 

[HarvestmanMan]

How did you compare them?

I've recorded tapes on the Sony from, for example, Winamp. I've then listened to it in playback and determined that it is exactly the same speed as the source.

 

[speakerman1]

It will be because you are playing it back on the same deck.

 

[Web Police]

I've recorded tapes on the Sony from, for example, Winamp. I've then listened to it in playback and determined that it is exactly the same speed as the source.

As Larry said and I have been saying, a given tape deck will record and play at the same speed so if the deck is running too fast or two slow you will never notice. Some reel to reel decks with record at multiple speeds, but if you play back the tape at eh same speed you recorded it of course it will sound fine. The only time you will notice speed issues if present is when you record a tape on one deck and then play it back on another.


You need a speed calibration tape to accurately set the speed on your deck.

 

[speakerman1]

Go to Daqarta. It has a tone generator and you read the hz tapes when you plug your deck in and set the speed. You can make a 3000 hz tape if you have a known good deck. If not you will have to borrow or buy.

 

[jaetee]

I recently dialed-in the play speed and azimuth on a Nakamichi LX-3.... but I did it ghetto-style. I'm sure this will make some of the more technically adept shudder with disapproval, but I will share my method anyway.

First I went to another internet forum to find out exactly where the adjustment for motor speed is on my LX-3. Turns out it's a tiny hole in the back of the capstan motor.

Since I don't have any elaborate diagnostic gear or a tone-generator, I put on a Queen song that I
have on vinyl and on a pre-recorded tape. I quartz locked the speed on the turntable and played the record on the main system. Then I plugged headphones into the tape deck and started the tape right when the record hits the beginning of the song. Tape was way slower, so I adjusted the tape motor to faster speed until every beat in the headphones was right on top of the beats on the main system. I could tell I had it nailed (or was at least very, very close) when I started to hear natural flanger effect between the headphones and the monitor speakers as I moved my head closer and further away from the main speakers. It's a very noticeable, cool swishing type effect which I seem to recall Steve Miller used in a lot of his songs, as do many electronica DJs nowadays.

The whole process was not very scientific and took about six passes of "You're my Best Friend" until I was satisfied I had the speed acceptably close (note I did not use the word "perfect"). I am a club DJ, so I'm very trained and comfortable at matching beats. It might take you a few more times.

Comparing the dynamics of the vinyl to the tape during my speed adjustments, it was pretty obvious that azimuth was well out of line. Alot was being missed by the tape and it sounded quite lifeless...

So, next I took off the cassette door and adjusted azimuth until the Queen tape literally "came to life," so to speak. Using a screwdriver, I gently turned the azimuth adjustment back and forth until the treble was at it's most vibrant and the stereo separation was at its best. It's actually pretty obvious when you get "close." Then I put in a higher quality tape that was recorded by my Nak RX-505 (which had been dialed in professionally not too long ago) and tweaked it just a very tiny bit more until I got that tape to sound as good as it could. Then I was done.

I did not mess with the head height adjustment at all, and don't feel like it needed it.

That was several days ago now, and after sampling how the LX-3 played many more tapes since then, and how well the LX-3 records (and how those tapes sound on my RX-505 and RX-202) I am extremely happy with the results.

 

[Web Police]

I recently dialed-in the play speed and azimuth on a Nakamichi LX-3.... but I did it ghetto-style. I'm sure this will make some of the more technically adept shudder with disapproval, but I will share my method anyway.

First I went to another internet forum to find out exactly where the adjustment for motor speed is on my LX-3. Turns out it's a tiny hole in the back of the capstan motor.

Since I don't have any elaborate diagnostic gear or a tone-generator, I put on a Queen song that I
have on vinyl and on a pre-recorded tape. I quartz locked the speed on the turntable and played the record on the main system. Then I plugged headphones into the tape deck and started the tape right when the record hits the beginning of the song. Tape was way slower, so I adjusted the tape motor to faster speed until every beat in the headphones was right on top of the beats on the main system. I could tell I had it nailed (or was at least very, very close) when I started to hear natural flanger effect between the headphones and the monitor speakers as I moved my head closer and further away from the main speakers. It's a very noticeable, cool swishing type effect which I seem to recall Steve Miller used in a lot of his songs, as do many electronica DJs nowadays.

The whole process was not very scientific and took about six passes of "You're my Best Friend" until I was satisfied I had the speed acceptably close (note I did not use the word "perfect"). I am a club DJ, so I'm very trained and comfortable at matching beats. It might take you a few more times.

Comparing the dynamics of the vinyl to the tape during my speed adjustments, it was pretty obvious that azimuth was well out of line. Alot was being missed by the tape and it sounded quite lifeless...

So, next I took off the cassette door and adjusted azimuth until the Queen tape literally "came to life," so to speak. Using a screwdriver, I gently turned the azimuth adjustment back and forth until the treble was at it's most vibrant and the stereo separation was at its best. It's actually pretty obvious when you get "close." Then I put in a higher quality tape that was recorded by my Nak RX-505 (which had been dialed in professionally not too long ago) and tweaked it just a very tiny bit more until I got that tape to sound as good as it could. Then I was done.

I did not mess with the head height adjustment at all, and don't feel like it needed it.

That was several days ago now, and after sampling how the LX-3 played many more tapes since then, and how well the LX-3 records (and how those tapes sound on my RX-505 and RX-202) I am extremely happy with the results.

I have adjusted the speed on decks using a similar method, but I just timed the cd and then played the tape and adjusted the deck so that the tape played for the same amount of time the disc did.

 

[HarvestmanMan]

I listened to a tape made on the JVC on a completely separate deck, a Nak RX-202. The pitch was actually spot-on. As far as I know, the Nak's speed is spot-on, as tapes recorded on that deck sound fine on other decks.

Can't find the test tape I made with the Sony, but I've played back other tapes from that deck on the Nak, and they sound fine as well.

I guess I was just hearing things after all.

 

[VintageShadow]

I guess I was just hearing things after all.

Maybe some different equalisation when playing can give the impression of a slightly wrong speed, this happened to me and when checking the deck with test tape everything went fine, so who knows?

 

[ke4mcl]

what happens when you play a pre-recorded tape on the problem deck? is play speed ok?

if speed is ok on a pre-recorded tape, make a recording on the problem deck and play it back on your known good deck. what happens then? if the speed is off on that tape i would be looking at the power supply like sam said. recording puts more load on the power supply than playing back. if your suspect deck's power supply is failing. it may have enough oomph to play fine but when you hit record, the extra load puts it over the edge.

might want to take a look inside at the filter caps in the power supply. any bulging or leakage? if you have a voltmeter and enough confidence, measure voltage on the filter caps during playback and then again while deck is recording. tell us what you get.