Teac 40-4/DX4

[calco]

Hello Everyone- I have a Teac 40-4 with the DX 4 unit. I want to add a mixer for earphones and mic. I have all of the patch cords and main cable hooked up, where does the mixer go in the hookup wiring? Stupid question but I do not have any info on the DX-4 for hookup and my 40-4 manual does not have any info either on hookup for a external mixer. I appreciate the help in advance.

 

[sweetbeats]

You connect the mixer as you normally would to the 40-4 inputs and outputs without the DX-4. The control cable from the DX-4 to the 40-4 not only carries audio signals to/from th DX-4, but control signals as well to control the encode/decode state of the DX-4. Does that help at all?

 

[calco]

Hi Sweetbeats-I am using #1 and #3 on the mixer of the DX-4 for in/out. I have nothing on the #2 and #4 of the mixer at this time.Do all of the patch cords stay in place. Where will I connect the cords going to the outboard mixer?

 

[sweetbeats]

Mixer of the DX-4? I'm not sure I understand. I think maybe we need a picture of the connections on the back of your 40-4/DX-4.

What mixer are you using?

 

[murugan19]

Mixer of the DX-4? I'm not sure I understand. I think maybe we need a picture of the connections on the back of your 40-4/DX-4.

What mixer are you using?

Hi sweetbeats,
I also have a Teac Tascam 40-4 with the dbx module (DX-4) - see attached.
I also have the Teac Tascam Series 3 mixer - see attached.
Unfortunately, I received everything (and the RCA patch cables) but I have the same dilemma as calco in connecting everything.
I have attached the pictures of the connectors as you requested in your post so I hope you may be able to figure this out.
Unfortunately, even though this is an excellent deck (and mixer) there are no manuals available. Even HFE (of which I am not a menber) only has the 40-4 Owner's manual WITHOUT the DX-4. I did manage to find a manual (internet search) but the relevant page is scrambled and only one part of the DX-4 interconnection is explained (see attached).
I understand that this is an old thread but am hoping that you (or someone else) can come up with the interconnection (40-4 to DX-4 to M3 mixer) - or the 40-4 to the DX-4 which would be a start. Unfortunately, the 40-4 does not have a headphone output so I cannot play it as you are well aware. I could connect it to an external amp (pre-in) but again my quandry of how the 40-4 and the DX-4 comes into play.
Keeping my fingers crossed,
Sincerely,
John Graham.

PS: I took a look at your youtube channel and the nearest I came to my mixer is the Tascam Series 5B you have. My M3 is similar except it is a 8x4 channel mixer and does not have the Echo & Cue section. Also do not have the SOLO in the ASSIGN section. Other differences can be found in the photo I attached. But like you, I'm impressed with Teac construction and quality.

 

[sweetbeats]

The interconnections between the DX-4 and the tape machine as well as with the mixing console are labeled on the back of the DX-4…don’t get distracted by the “ENCODE”/“DECODE” labeling. Notice there is a RECORDER section…the top row of jacks, right? And they are in IN/OUT pairs by channel right? They’re numbered 1~4. The “IN” jacks on the DX-4 connect to the output jacks of the tape machine and the “OUT” jacks connect to the input jacks. Simply line up and connect the track 1 output of the tape machine to the RECORDER IN jack for channel 1 one on the DX-4, track 1 input to the RECORDER OUT jack for channel 1 on the DX-4, repeat for track 2/channel 2 and so on.

As far as connecting the MIXER section jacks, the bottom row of jacks on the DX-4, to the mixing console, there are different ways you can do that, and it really depends on your setup. But if it was me and I had a Model 3, I’d connect the LINE OUT 1~4 jacks of the Model 3 to the MIXER IN jacks 1~4 on the DX-4, and the MIXER OUT 1~4 jacks of the DX-4 to the LINE IN jacks 5-8 on the Model 3.

I *highly* encourage you to study the Model 3 manual. There are many examples in there with diagrammatic drawings of connections and associated explanations, along with, of course, instructional guidance on the features and controls of the console. You really owe it to yourself to read the manual with the console in front of you, educate yourself, and then come here after making that effort to ask questions to refine your understanding. This is not meant to come across as critical or a “dig”, but it can take someone here just as much time to explain basics to somebody as it takes for you to make some quality time and study, and in the end if you invest that time you’ll have volumes more knowledge to build on compared to what you’ll gain from somebody on the internet in that amount of time, and have taxed the time of others far less. My goal is for you to increase in knowledge and have freedom in that to more fully enjoy and use your equipment. Knowledge is power.

Do let me know if you need clarification regarding my suggestions for interconnections above.

 

[murugan19]

The interconnections between the DX-4 and the tape machine as well as with the mixing console are labeled on the back of the DX-4…don’t get distracted by the “ENCODE”/“DECODE” labeling. Notice there is a RECORDER section…the top row of jacks, right? And they are in IN/OUT pairs by channel right? They’re numbered 1~4. The “IN” jacks on the DX-4 connect to the output jacks of the tape machine and the “OUT” jacks connect to the input jacks. Simply line up and connect the track 1 output of the tape machine to the RECORDER IN jack for channel 1 one on the DX-4, track 1 input to the RECORDER OUT jack for channel 1 on the DX-4, repeat for track 2/channel 2 and so on.

As far as connecting the MIXER section jacks, the bottom row of jacks on the DX-4, to the mixing console, there are different ways you can do that, and it really depends on your setup. But if it was me and I had a Model 3, I’d connect the LINE OUT 1~4 jacks of the Model 3 to the MIXER IN jacks 1~4 on the DX-4, and the MIXER OUT 1~4 jacks of the DX-4 to the LINE IN jacks 5-8 on the Model 3.

I *highly* encourage you to study the Model 3 manual. There are many examples in there with diagrammatic drawings of connections and associated explanations, along with, of course, instructional guidance on the features and controls of the console. You really owe it to yourself to read the manual with the console in front of you, educate yourself, and then come here after making that effort to ask questions to refine your understanding. This is not meant to come across as critical or a “dig”, but it can take someone here just as much time to explain basics to somebody as it takes for you to make some quality time and study, and in the end if you invest that time you’ll have volumes more knowledge to build on compared to what you’ll gain from somebody on the internet in that amount of time, and have taxed the time of others far less. My goal is for you to increase in knowledge and have freedom in that to more fully enjoy and use your equipment. Knowledge is power.

Do let me know if you need clarification regarding my suggestions for interconnections above.

Hi sweetbeats,
Thank you very much for the excellent and prompt reply to my requst for help in interconnects between the Teac404-DX-4-M3.
Part 1: SUCCESS!!!!!
I connected the 404 and the DX-4 module by your instructions - they are clear and I had no problems following them.
(I had also spent my time over the weekend trying to find any information and found a 404 Owner's Reference Manual from manualslib. Although pg23 (see attached) is a little garbled, it has the same instructions as yours so that was reassuring that I was on the right track)
Playback off the bat on the 404 (by observing the VU meters on a 4 track tape) was great! This is true for both 7 1/2 and 15 ips and small (7") and large (10.5") reels.

Onto testing Record Mode: See TEAC 40-4 Owners Manual-pg 24.pdf, TEAC 40-4 Service Manual-pg15-RECORD-RECORDING MODES.pdf, TEAC 40-4 Service Manual-pg33-CONTROL OF DX-4 FROM 40-4.pdf - attached

Part 2:
Unfortunately, I couldn't get any VU meter signal indication on Record. I was depending on that since there is no Headphone output on the 404.
I have attached some photographs on the various scenarios that I used for trying to get some VU meter signal indication:
The interconnection for the 404-DX4-M3 was by your instructions in Part 1 above - But I couldn't get any VU meter signal indication on Record mode (despite various scenarios for Output Select (Norm/Input/Monitor) and Function Select (1/2/3/4).
So I disconnected the M3 from the 404 (by disconnecting the patch cables from the DX-4 Mixer section to the M3) to keep things simple and make trouble shooting easier.
Tried a signal to the RCA inputs on the DX-4 Mixer Inputs (on the DX-4 module - the Encode Out and Decode In were still connected to the 404 Input-Output section - but no VU meter indication on Record Mode (tried various scenarios on 404 Output Select and Function Select -see photos attached).
The DX-4 and the 404 are working in unison (DX-4 IN switch engaged) - example, when I go to Record mode on the 404, the DX-4 module automatically switches to Encode mode.
The DX-4 automatically switches to Decode Mode (DX-4 IN switch engaged) when I disengage Record, No Function Select and Output Select to Norm. Also, when I depress each Bypass button on the DX-4 module, each Encode & Decode LED will turn off. This is also true if I disable the DX-4 module (DX-4 Out switch).

Part 3:
To make it even simpler, I disconnected all patch cords between the 404 Input-Output section and the DX-4 Module Recorder-Mixer section.
Tried:
Direct RCA input to the 404 Input Section
Direct RCA input to the DX-4 Mixer Input section
Direct RCA input to the DX-4 Decode In for the DX-4 Recorder section.
No signal indication on the VU Meters.

Part 4:
I reconnected with the instructions from the manual that I manged to get off the internet and reconnected the 404 (Input-Output Section) with the DX-4 (Recorder-Mixer section) - see TEAC 40-4 Owners Manual-pg 23.pdf attached - but no VU Meter indication (same scenarios on Record as before).
The DX-4 and the 404 are still working in unison - example, when I go to Normal (No Record) mode on the 404, the DX-4 module automatically switches to Decode mode. DX-4 Bypass switch on each track works (no encode/decode LED light up), same with if I turn off the DX-4 module (DX-4 Out).

Part 5: Independently Testing the M3 (see Teac Tascam Model 3 Mixer Owners manual-pg10.pdf) - Fig 5 - attached
Note: I did not connect the 4 channel recorder shown but connected the M3 Line IN inputs to a signal. No Optional Monitoring, Control Room Monitors and Studio Phones connected. All other all other BUSS patch cords are connected - see photo Teac Tascam Model 3 Mixer-1_800x600.jpg attached
On the M3 (see photographs attached on what setup I'm using - for Input/ATT/EQ/ASSIGN/Pan/Level):
From the Manual, I learned that the M3 is a complicated (but very versatile mixer) - I spent the weekend reading through the M3 Owner's manual and to keep things simple I decided to test it on it's own since it has so many combinations (Assign, Aux In, cascading Busses, Submixers/pans, etc).
As I said, I disconnected the M3 from the 404 to keep it simple for testing.
I connected 4 RCA inputs to the Line In on channels 1 thru 4 and left all the other jumper patches as by the manual. I also switched the channel (1-8) inputs to Line (Mic & Phono off), no MIC Attenuation, no EQ, Assign to D (direct) and no other Assign (1-4), No Pan, Each BUSS output slider (straight Line Fader) to about mid point.
Unfortunately, I don't get any VU meter signal indication for a signal on each (1-4) Line IN.

I'm sure I'm missing something on both the 404 and the M3 and am hoping your expertise could guide me to the correct connections.
No hurry, take your time in mulling over this and whenever it is convenient - I have attached a lot of documentation.

Sincerely,
John Graham

Note: Since I can only attach 10 files - I have continued the attachments below.

 

[murugan19]

Hi sweetbeats,
Continuation of my attachments to Post above (#7)

 

[murugan19]

Hi sweetbeats,
Continuation of my attachments to Post above (#7)
Hopefully, I haven't made a mess of things and keeping my fingers crossed that you can set me on track.
Sincerely,
John Graham.
Please let me know if I missed any attachments or you need additional info.

 

[sweetbeats]

Take the DX-4 and Model 3 out of the picture. Are you able to connect a line level source to any of the 40-4 inputs directly and record signal?

 

[murugan19]

Take the DX-4 and Model 3 out of the picture. Are you able to connect a line level source to any of the 40-4 inputs directly and record signal?

Hi sweetbeats,
Thank you for the prompt reply and advice.
I had disconnected the interconnections between the 404 and DX-4 (see Part 3 of my Post #7 above). No VU meter movement on any channel (1-4) with a source fed to the Input RCA jacks on the 404.
I had also disconnected the interconnections between the DX-4 and the M3 mixer (see Part 2 & Part 4 of my Post #7 above) with no VU meter movement on any channel.

But I notice a phrase you used "line level source". This has given me an idea: Maybe I'm using too low a signal (I am using an analog audio signal generator (400 Hz/1KHz at 100 mV). I will have to check the specs on the input sections of the DX-4 and the M3 to see what the Input requirements are.
From a quick check I find that the 404 Line Input is -10 dB (0.3 V) impedance; greater than 20k ohm, unbalanced, and the Line Output is -10 dB (0.3 V) load impedance; greater than l0k ohms, unbalanced.
For the M3: Line input - 1) Line impedance: Greater than 20K ohms; 2) Nominal input level: - 10dB (0.3V); 3) Minimum input level: - 16dB; 4) Maximum input level: +24 dB

I think I am using too low an input level - I will check tonight and report back tomorrow.
I also need to check the circuit diagrams and parts list to see if too low a level of an input will not allow the first transistor forward bias.

Sincerely,
John Graham

 

[RRuskin]

Output source should probably be on "input."

 

[murugan19]

Output source should probably be on "input."

Hi Rick,
Thank you for the advice but I don't know what you mean by "Output source" and ""input"". Would appreciate it if you could clarify please.
Sincerely,
John Graham.

 

[murugan19]

Take the DX-4 and Model 3 out of the picture. Are you able to connect a line level source to any of the 40-4 inputs directly and record signal?

I think I am using too low an input level - I will check tonight and report back tomorrow.

Hi sweetbeats,
Thank you for your patience.
I decided to go back to the manuals (both the Owner's and Service Manuals for the 404 and the M3).
This gave me an idea: Maybe I'm using too low a signal (I am using an analog audio signal generator (400 Hz/1KHz at 100 mV). So I rechecked the specs and the schematics on the input sections of the DX-4 and the M3 to see what the Input requirements are.
I find that the 404 Line Input is -10 dB (0.3 V) impedance greater than 20k ohm, unbalanced; and the Line Output is -10 dB (0.3 V) load impedance greater than l0k ohms, unbalanced.
For the M3: Line input - 1) Line impedance: Greater than 20K ohms; 2) Nominal input level: - 10dB (0.3V); 3) Minimum input level: - 16dB; 4) Maximum input level: +24 dB
Buss input, sub-mix buss input - 1) Input impedance Greater than 10K ohms; 2) Nominal level - 2dB (0.78V)
Monitor input - 1) Input impedance Greater than 10K ohms; 2) Nominal level - 2dB (0.78V)

Again from the manuals:
Value of "dB" in the Data refers to 0 dB= 1V, except where specified. If a Test Set or AC voltmeter calibrated to 0 dB = 0.775V is to be used, appropriate
compensation should be made.
For example, -10 dB (0.3V) is applied to the Line in jacks, the AC voltmeter which is connected at the line output jacks reads - 7.8 dB (0.3V) instead of -10 dB (0.3V).
I also checked the circuit diagrams (and corresponding parts lists) and saw that a too low a level of an input will not allow the first transistor forward bias.

Conclusion: I am using too low an input level <-16dB !!!!

I have been used to -10dBV (.316V), and +4dBu (1.228V) for calibrations. Audio meters don't specifically make known the units of reference (dBu, dBV or dBFS level of the signal), so I take 0dB as the standard operating level of the system regardless of dBVu or dBu). dBVU always tells me how much below or above the standard operating level of the system the signal is.

I also have prerecorded Quadraphonic and Stereo tapes, so since I had VU meters on the 404 showing at least -3dB on a tape I was using (origin unknown), I threaded the Quad and Stereo tapes and measured the outputs - they varied between 0.4V and .7V (Peak V - Peak Hold, dbx unit off)
Once I realized my mistake, I started by using a 0.316V signal and voila, the VU meters on the 404 (Input from Mixer 1-4 on the DX-4) and the M3 (Line Input on Line Inputs 1-4) registered approx -12dB. Increased the signal to 0.712V and SUCCESS!!
Both the M3 and the 404 VU meters register -3dB.

Next, I will start with music (pre-outs from either my Denon amps or my OPPOs) as Line Inputs to the M3 and Line Outs from the M3 to the 404 DX-4 Inputs and record while I try various scenarios on the M3 EQ/Pan and ASSIGN. I will leave the ASSIGN on Channels 1-4 as 1/2/3/4 respectively (Channel 1 ASSIGN 1; and so on), but vary the ASSIGN on Channels 5-8. Will report back.
I am tempted to use the amps as my music source as they have both Pre-In and Pre-outs - this way I can monitor the recording on the 404 (Function Select will be 1/2/3/4) on my speakers (rather than my headphones on the M3) by switching the 404 Input Select to Input or Monitor.

Thank you for your help - it is greatly appreciated.
Sincerely,
John Graham.

 

[RRuskin]

Hi Rick,
Thank you for the advice but I don't know what you mean by "Output source" and ""input"". Would appreciate it if you could clarify please.
Sincerely,
John Graham.

Hi Rick,
Thank you for the advice but I don't know what you mean by "Output source" and ""input"". Would appreciate it if you could clarify please.
Sincerely,
John Graham.

1s place all function switches in “record.”
Then engage the switch that actually says “input.”
Then apply your signal.
Chances are you will need the input level on the 40-4to be set @ 7 or 8 to match “0" coming from your Model 3.

 

[murugan19]

Take the DX-4 and Model 3 out of the picture. Are you able to connect a line level source to any of the 40-4 inputs directly and record signal?

I think I am using too low an input level - I will check tonight and report back tomorrow.

s place all function switches in “record.”
Then engage the switch that actually says “input.”
Then apply your signal.
Chances are you will need the input level on the 40-4to be set @ 7 or 8 to match “0" coming from your Model 3.

Hi sweetbeats and Rick,
Since I realized that I was using too low of a signal level and finally got the M3 to work with a higher signal level, I tried recording.
I had success mixing and recording (and monitoring the recording (Input Select - Input (Source) only)) by using the Pre-ourts from my OPPO BDP83 (5.1 -FL/FR/RL/RR/C/SW) on the OPPO and Channels 1-6 (same order) on the M3. Used the ASSIGN on Ch5 to route the Center to 1 & 2 and CH6 ASSIGN 1, 2, 3, 4 to route the Sub Woofer to all 4 channels. M3 Ch 1 thru 4 ASSIGN was 1 (Ch 1), 2 (Ch 2), 3 (Ch 3), 4 (Ch 4).

PROBLEM: I found that if I plugged in my HDMI to monitor my OPPO (OSD), I would get a hum from the M3 - all channels (1-8)! Strange (regardless of any channel Line Input or combination of). I ran a grounding wire from the M3 to my Power Conditioner and then to the OPPO but the hum continued. I did that since the M3 has a 2 core power cord (unlike the 404 which has the standard 3 core (Hot/Neutral/Ground) power cord. Also checked the OPPO (both) Setup (Audio Settings) - they are the same as LPCM out (96kHz) (Tried RAW out too). No change on the hum.
So I disconnected my HDMI cable (I have a brief video on that).

Would appreciate your thoughts on the hum (it wasn't feedback but a definite low frequency hum).

My Toshiba TV has 3 HDMI ports - the hum was present regardless of the HDMI port being used or using different HDMI cables or using a different source (an OPPO UDP203).

I was using the OPPOs as source as it was easier than having to pull out any of my Denon amps that I use for my analog music since they have Pre-In and Pre-out jacks (AVR987/AVR4308CI/AVR2307CI), routing the OPPO to the Denon via HDMI, re-connecing amp Pre-Out to the M3 Line In and the 404 Mixer Out to the Pre-In on the amplifier.

Disconnected the HDMI on the OPPO, played various 5.1 music and I had QUAD recorded to my tape!
Switched out the OPPO BDP83 to the OPPO UDP203 and hooked all 7.1 (FR/FL/RR/RL/SR/SL/C/SW) channels to the M3 (1-8).
Since the 404 is a 4 channel R2R, I had to use some judicious ASSIGN on the SR/SL and while doing that I also enabled EQ 3K 4dB Boost) and Panned them since I had to redirect them to FR/FL/RR/RL. I tried enabling 200 Hz on the EQ for the SW but the bass became too heavy.

I will try with one of the Denon amps: Oppo to Denon via HDMI, Denon Pre-out to M3 (Ch 1-8), M3 Line out to 404 Mixer Inputs (1-4), 404 Mixer Out (1-4) to Denon Pre-in (one advantage of this would be that I can monitor on my speakers rather than my headphones (plugged into the M3 (rear 1W jack) and monitor the recording by both Input (source) and Monitor (tape) by the 404 Input Select. OPPO OSD will be by Denon Monitor (HDMI) to the Toshiba (Input HDMI)
Will let you know if the hum is the same, greater or disappears.

This is the first time this (hum) has happened - I used the same setup (OPPO to my Akai GX635D and Dokorder 8140) with no hum. Both the decks have 2 core power cords (which I want to change to the better (and safer) 3 core, polarized plug power cord). I have changed my Advent 100As, and Teac AN-180 Dolby Noise Reuction units to 3 core power cords (I had to drill out the holes for the larger diameter power cord and retaining strain relief). I cannot change my Sony He-2 Head De-Magnetizer (casing too small). My Lafayette Tape eraser was easy since it had a large diameter cord (it draws 9A).

The movie with the hum is too large to upload here so the link is: 06-Hum on M3 when HDMI plugged into any source ()

Sincerely,
John Graham.