Akai GX365D Bias Adjustment 

I did not hear much explanation of what the adjustment was. Just setting the asmuth on the record head. From the organised noise {music} he plays , I could not tell if the tape speed was right.

Most Akai was good but they did have a few dogs.

@@12voltvids what do you mean?

Hey there is an idea.

@@camurgo I bought one when they first came out and it has been rock solid other than the elastomeric strips and batteries

Those adjustments shouldn't need to be changed after they've been setup correctly. The only reason to adjust them is if you change an important part in the recording circuitry or if they go "bad" (dust getting stuck in there is an issue, and I've had one go bad because another part went "wonky" and sent a high DC current through it). After they've been set it's a good idea to put some sort of tamper proof glue on the control to prevent vibrations from changing them.

Aging part syndrome , the pot has become intermittent through age . The playback record head has probably lost some tape contact over the years too . You should not need to reset these controls unless a serious issue has developed , but this equipment is after all as old as the hills and it doesn't stay in spec. for ever because parts do deteriorate.

1. Speed calibration. 2. Playback head azimuth (first corse & then fine adjustment). 3. Input (playback) level. 4. VU meter calibration. 5. Before tape frequency response. 6. Thread calibration tape & adjust to recorded reference levels . 7. Check frequency levels from calibration tape. 8. Remove & store calibration tape. 9. Thread blank tape that you'll bias the deck to. 10. Adjust bias trap on deck. 11. Record head azimuth (first corse & then fine adjustment). 12. BIAS ADJUSTMENT HERE. 13. Recording level adjustment. 14: Recording eq adjustment. 15. Frequency response check. 16. GET DRINK OF CHOICE AND ENJOY YOUR RECORDINGS! 👊🏾👊🏾😄

All my tapes are as old as the hills. I have a box full of that Ampex tape I used. All brand new sealed oxide tape.

@@12voltvids I guess you still get tapes to transfer. My mom had a few when she taught choir some were from CBC and some from the community channel. All different track formats.

@@markanderson350 I do get tapes to transfer to digital. Mostly video tapes, but I had a client a few months ago, a singer that recorded several pieces of music in a studio in Montreal (it was french vocals) recorded on DAT. She wanted the music on CD and the studio she did the recording at had long dumped their dat equipment, so I got the call to transfer some DAT master tapes. I get cassette tapes, and micro cassette tapes of family talking letters, along with reel to reel. I had a reel to reel tape recorded by a navy serviceman during WW2 on the ship that he sent home. His daughter found these tapes and brought them to me. She teared up hearing her fathers voice in this talking letter that was sent to her mother from his warship in the pacific. She had never heard this tape, so had a bunch of copies made on CD to give to all her brothers and sisters. I get lots of stuff like that, and old home movie films that people find .

@@12voltvids That is really good because you need to maintain all this old equipment to play this material. Plus often, the speed is out or head alignment and so on. You may have an old machine you store for years to do this and when you fire it up, it no longer works. Old reel to reel was often in half track mono and it may not play properly. Later I heard of wire recordings. Try to play that stuff, good luck. Yes someone has to do this and no matter what, the technology can be outdated. Who knows what lays ahead 50 years from now in archiving and recording.

The opposite. You want to change the bias to match the tape.

Yes you are correct. Got to stick to that formulation the deck was adjusted for.

No it was my tape and it is just standard bias Ampex tape

I am guilty of leaving mine turned on until the auto power shuts it off.

Yes

Probably not. If you're bias is incorrect it will generally affect the frequency response the bias is a little low you tend to have higher frequencies recorded if the bias is a little bit too much then the high-end rolls off

@@12voltvids I've been experimenting with the recorder these last few hours, there is only distortion when the needles are right on top, but I think it's normal, I recorded a Shamrock brand tape and the sound seemed a little muffled, but then I used an old Scotch and it sounds much better, this recorder 30 years later continues to work as if time does not pass by, thank you very much for the answer sir, good luck for the channel and best regards from Portugal.

They really don't last that much longer. I was given this pack of batteries about 5 years ago. Just using them up.

The capacity differences are negligible. I always use economy alkaline batteries, because the big brand names are stupidly expensive, especially the 9V ones. And I experienced Energizer and Duracell batteries leaking well within the 'best before' period (without draining them!), but I never ever had this with any budget batteries I use (I used to use Tronic from Lidl, or Excell from a nearby Chinese store - not absolute rubbish, noname Chinese stuff). Oh, and of course, for high consumption devices, I use NiMH - Tronic brand of course, it costs the same as a non-rechargeable Duracell or Energizer, and very reliable. Even for my multimeter, since there're low self-discharge types available, from the same Tronic brand, for the price of a primary Duracell. And I had one served me for 5 years!

@@mrnmrn1 I have had really good results with some sunbeam NIMH cells I picked up at Dollarama. Use them in an old calculator with a nice VFD for the readout.

@@12voltvids You said your Fluke is quite power hungry. Then why don't you use NiMH it it as well? I like this little Fluke, but I'm not quite impressed with its screws. Self-tappers to a battery compartment?! With about 100 hours battery lifetime? A lot of the $20 multimeters have threaded brass inserts in the plastic for the screws of the battery compartment. This Fluke costs many times $20, and they saved that $1 (maybe just $0.5) per unit for the metal inserts. Bad boys.

@@mrnmrn1 NIMH are lower voltage, and they slowly self discharge. A new 9volt battery every year isn't too bad.

I bought this one used at a hamfest about 25 years ago for 12.00

@@12voltvids what a great deal on that meter ,I think next month ,I probaly try for that fluk 101,it kind of like yours ,it auto ranging ,yours is better but I am on a fix income .unless I find a fluk fairy or a goid deal .thanks

The various test points are outlined in the manual. For azimuth it us just the line out. For record bias it is the trimmer for the bias oscillator but every one is different so a manual is a must to do it right.

@@12voltvids Thank you.

I believe at 3 3/4 the frequency response is only to 10khz and it starts rolling off well below it. Mine also sounds like an radio at 3 3/4 ips. Some decks used cross field heads which improved the sound at slower speeds. Frequency response is a function of the head gap. This is why most VCRs were 4 head. A pair of sp and a pair of EP heads. To optimize picture quality at both speeds. A head gap optimized for 3 3/4 would fall short at 7 1/2

Thanks a lot for the answer mr. 12volts!! I forgot to mention that my 4000d is the infamous GX. I got some higher VU measures with basf tapes than sony ones in recent test i got some tdk but no Scotch tapes which are the reference for rec calibratrion. In fact the xfield heads are much better for slow speeds. Is there a chance for better results if i change the transitors or others components?

@@andre_deboer Unfortunately the frequency response is governed by the gap in the heads. Narrow gap heads work better in high frequencies at slower tape speeds but also don't have the signal to noise ratio that wider Gap heads allow. So the manufacturer has to decide what is more important better signal to noise ratio at higher tape speeds or better frequency response and lower signal to noise ratio at all tape speeds most companies chose the faster tape speed and better quality. The crossfield decks did something different they had a second head that was on the back side of the tape that assisted in driving the high frequencies are driving the lower frequency cuz it was deeper into the tape and letting the higher frequencies ride on the edge of the tape and they work really good but not many decks use them.

@@12voltvids thanks again. Its my second reel to reel recorder. I guess ill have to get a better rtr in some future time. Tks for the hints. Your Knowledge is very impressive. Im big fan of your work

When you calibrate the rec trimpots in which position you leave the front panel rec potenciometers? And after scotch tape, which i dont have do you know another brand like tdk or Sony for me to use on my calibration

That was what the service manual said to use. I downloaded the manual from hifi engine

12voltvids Thank You!

Years ago a friend stuck a live phone cord in his mouth to "strip the wires" as he was trying to make a cable so he could plug it into his tape recorded to record direct from the phone line. Little did he know that the phone line has 52 volts on it. He literally pissed himself and so did the rest of us, but it was from laughter.

@@12voltvids lmao, over here in the uk the phone line voltage sits around 12volts dc dut when it rings it goes up to 70v. I often use to connect a small radio up to the phone line for power but you only get a few hundred mA. Back in the day. in the bell switching selectors day

@@chilledoutpaul 12v? That sounds pretty low. You must be a long way from the switching office. I work for the phone co. Battery voltage here is 48v. 24x 2 volt cells in series. They sit on a float charge so around 52.5 leaves the office DC. The ring generator sticks about 130 AC on top of the DC voltage to make the phone ring. That wakes you up if you are handing bare wires in a pole top terminal when someone rings up the line you are working on.

@@12voltvids 😆 ha ha i can imagine. talking about 48v that's what our traffic light system works on over here. and our underground (metro system) traction voltage is 630volts. anyway you may have the higher telephone voltage but we have the higher single phase to ground (mains voltage) 240v lol. Dave happy 4th of july. Paul 😉

@@chilledoutpaul Our traffic lights operate on standard 120v. Our subway and elevated train runs 600v DC as to the trolley busses. Here 120v phase to ground and 240 phase to phase. That's what I charge my 2 electric cars with 240 volts. Our big appliances run 240. Small stuff 120v a little safer than 240 at the plug. In 3 phase power here the voltage 208 phase to phase but ilon single phase service 240. I believe the railway signals use 30v dc. Was reading that somewhere when I was reading up on what the light signals mean.

It's a pass fail test.

@@12voltvids ;) {:>}

Hi biased

@@12voltvids Ha!

@@infinitecanadian Unless using Ferichrome tape, then it is "the Lo - High"

@@12voltvids Lol.