Akai Deck - Head Replacement

[reubensm]

Received a PM from forum member sarith, not allowed by the portal to reply to his PM, hence posting his question on the forum:

Hello friend, I have a doubt. I have this old Akai double deck. I would like to change the playback and record heads. I have alps glass metal, super metal, sendust and few other type of heads. Which would be good for rec/pb head and pb only head? Thank you

As far as Akai decks are concerned, the model number is key. If the model number has the alphabets "GX" in it, this would mean that the deck has a glass head. Kindly note that the impedence of the head is very important. If you have the old head with you, you can use a multimeter to measure the impedance and then replace it with a head of similar impedance. A glass head can be replaced with any other type, if the size and impedance matches. Glass heads however are a class apart.

In my opinion, sendust heads are also very good (use one in my NAK) but critics have their own opinions about them (at times, not very favourable)

 

[sarith]

Received a PM from forum member sarith, not allowed by the portal to reply to his PM, hence posting his question on the forum:



As far as Akai decks are concerned, the model number is key. If the model number has the alphabets "GX" in it, this would mean that the deck has a glass head. Kindly note that the impedence of the head is very important. If you have the old head with you, you can use a multimeter to measure the impedance and then replace it with a head of similar impedance. A glass head can be replaced with any other type, if the size and impedance matches. Glass heads however are a class apart.

In my opinion, sendust heads are also very good (use one in my NAK) but critics have their own opinions about them (at times, not very favourable)

Thank you sir, for the reply and suggestions. I will do as you instructed. I have a normal digital multimeter with which I think I can test the impedance of the heads. Model no: is AKAI HXM30W, so no glass head it seems . I don't know if it's my profile settings that made it not possible for you to reply to my message. I will check that too. Thank you, again!

 

[reubensm]

Thank you sir, for the reply and suggestions. I will do as you instructed. I have a normal digital multimeter with which I think I can test the impedance of the heads. Model no: is AKAI HXM30W, so no glass head it seems . I don't know if it's my profile settings that made it not possible for you to reply to my message. I will check that too. Thank you, again!

While measuring the impedence of the existing head, disconnect it from the circuit and do so. If you have the deck's original spec sheet, you are likely to find some info regarding this. From my experience, just like with phono cartridges, different heads have different sound signatures, so if you don't use the exact replacement, the sound signature of your deck may change.

On another note, since you are talking about a double cassette deck, the head on the playback head on the playback deck is likely to be the same as on the record/playback deck. Similarly if you make a replacement, its better to replace the heads on both the playback deck and the record/playback deck with the same type/brand of replacement head to maintain continuity in sound signature.

Please ensure that your heads are calibrated properly after replacement. An easy way to get close to the previous head azimuth setting is to play back a tape recorded on the deck with the old head (and factory calibration) and calibrate your new replacement heads accordingly (assuming that the tape has a good pressure pad )

 

[sarith]

While measuring the impedence of the existing head, disconnect it from the circuit and do so. If you have the deck's original spec sheet, you are likely to find some info regarding this. From my experience, just like with phono cartridges, different heads have different sound signatures, so if you don't use the exact replacement, the sound signature of your deck may change.

On another note, since you are talking about a double cassette deck, the head on the playback head on the playback deck is likely to be the same as on the record/playback deck. Similarly if you make a replacement, its better to replace the heads on both the playback deck and the record/playback deck with the same type/brand of replacement head to maintain continuity in sound signature.

Please ensure that your heads are calibrated properly after replacement. An easy way to get close to the previous head azimuth setting is to play back a tape recorded on the deck with the old head (and factory calibration) and calibrate your new replacement heads accordingly (assuming that the tape has a good pressure pad )

Hello again sir , I checked the head model details of my Akai and both heads look exactly the same though they have different model/serial numbers. I have few identical pair of heads like the JVC (Japan), SS (sendust), MX metal (Japan), JLE, MS (Philips). So I will do a Impedance check and choose one. I had a thought about using each head on another playback only cassette deck (Aiwa) and see how each one sounds. I have managed to find and buy few unused Sony, TDK and Maxell blank cassettes.

Also I am thinking of swapping the presets in the circuit board with some old Philips pot controls (unused). I guess it's better to use lin pots than log. There are around 12 presets for bias, playback, record, pre-amp, motor speed (high speed dub) and dub pre. I don't have to make any custom hole in the cabinet as there is this square socket for connecting the rest of the system (tuner, amp, TT) which is of no use for me. I changed the pinch roller wheels and all the belts.

One guy has an unused Pioneer dual well deck CTW-503 R. But the fact that it has logic/automatic tape mechanism is kind of a turn off for me (Hard to repair and small heads). But it seems there are good reviews about the sound quality of Pioneer decks. Also Marantz, Onkyo (AC-110V fixed), dual well automatic decks and Sharp dual well normal deck are available too.

I checked my profile settings and private messaging was set to friends and moderators. I think I have rectified that problem correctly

 

[reubensm]

Also I am thinking of swapping the presets in the circuit board with some old Philips pot controls (unused). I guess it's better to use lin pots than log.

A linear preset has a resistive element of constant cross-section, resulting in the resistance between the wiper and one end terminal being proportional to the distance between them. However a log preset has a resistive element that either tapers physically from one end to the other, or is made from a material whose resistivity varies from one end to the other. This results in a device where output voltage is a logarithmic (or inverse logarithmic depending on type) function of the mechanical angle of the pot.

Most (cheaper) "log" pots are actually not logarithmic, but use two regions of different, but constant, resistivity to approximate a logarithmic law. A log pot can also be simulated with a linear pot and an external resistor. True log pots are significantly more expensive.

(above with reference to wikipedia)

Circuits as a whole or certain sections of circuits may be designed specifically to accomodate log or lin presets or pots. This would usually be specified in the service manual. Ideally it is not a good idea to go in for carpet replacements. It is better to go with the technical reccomendations for the circuit as per its designers. However on another note, there is no harm in trying. At times, the non-conventional tweeks produce amazing results (atleast to the human ear).

 

[sarith]

It is better to go with the technical reccomendations for the circuit as per its designers. However on another note, there is no harm in trying. At times, the non-conventional tweeks produce amazing results (atleast to the human ear).

That's what makes me want to do the tweaking . Even after reading the difference about both log and lin presets/pots, I am confused on whether to use log or lin pots. Well I think I have to play around with both log and lin pots to know which suits better

 

[sarith]

Kindly note that the impedence of the head is very important. If you have the old head with you, you can use a multimeter to measure the impedance and then replace it with a head of similar impedance.
In my opinion, sendust heads are also very good (use one in my NAK) but critics have their own opinions about them (at times, not very favourable)

Hello sir , I have checked the impedance of both Akai heads and the Pb head is around 300 ohms and the Rec/Pb is around 210 ohms. Sendust almost touches 300 ohm mark and one of the glass metal head touches 214 ohms. Also checked a Pioneer CTW-404R dual deck which has good Pb but not so pleasant rec capability. It was 'made in Malaysia' model. I guess not all pioneer decks are good.
Your suggestions were really helpful, Thank you.

 

[Sandesh]

Sarith can I buy a sendust head from you? Please do let me know. Thanks!

 

[reubensm]

Hello sir , I have checked the impedance of both Akai heads and the Pb head is around 300 ohms and the Rec/Pb is around 210 ohms. Sendust almost touches 300 ohm mark and one of the glass metal head touches 214 ohms. Also checked a Pioneer CTW-404R dual deck which has good Pb but not so pleasant rec capability. It was 'made in Malaysia' model. I guess not all pioneer decks are good.
Your suggestions were really helpful, Thank you.

By the time cassette deck manufacturers started putting out double cassette decks, the quality had dropped tremendously. The good old single decks are much better performers.

 

[sarith]

Sarith can I buy a sendust head from you? Please do let me know. Thanks!

Sure. I think I have 3 or more spare sendust with me. I guess I will upload the image of the heads I have just for reference. For the sake of curiosity, may I know on what deck will you wish to use the Sendest? Is it just for playback or recording too?

 

[sarith]

By the time cassette deck manufacturers started putting out double cassette decks, the quality had dropped tremendously. The good old single decks are much better performers.

Hopefully one day I will have my hands on such a deck (still holding due respect to my Akai). I forgot to mention the model no: of my Akai. It's HXM-30W

 

[Sandesh]

Hi Sarith, plan to use the head on my Nakamichi CR2. Reubensm would reccomend that? Im a complete newbie to this. Reubensm would be also grateful if you can suggest a repair person in Bangalore or close by to get my Nakamichi spindle problem fixed. I'm really frustrated that that player just played for one day and conked out!

 

[reubensm]

Hi Sandesh, not familiar with repair options in Bangalore. With regard to your NAK CR2, here is the list of original NAK heads for all NAK Models. If the Sendust head available with sarith is a NAK original, its serial number should feature here:

Nakamichi Heads:

BA04927 Head Assembly (TD-1200)
CA08311 GA01294 RP-9E Record/Playback head (480Z)
CA08137 P-8L Playback Head Ass'y (482Z)
CA08300 R-8L Record Head Ass'y (482Z)
CA08524 GA02216 R3LH - Record head, replaces GA02034 (BX-300)
CA08525 GA02085 P-8LH Std Trans Playback Head (RX-505)
CA08659 R-3L - Record head, 3.5 micron gap Crystalloy (BX-300, CR-5, CR-7)
CA08658 P2H-L, P-2H3L Playback head, 0.8 micron gap Crystalloy (BX-300, CR-5, CR-7)
CA08757 P5D Playback head (TD-300)
0G01365 E-2D (RX-202)
0G01371 RP-2G (RX-202)
GA00101 P53 playback head w/mount
GA00102 R-52 Record head w/mount
GA01050 R-8L Record head see GA02084 (481, 582, 582Z, 681ZX, 682ZX, LX-5, RX-505, ZX-7, ZX-9)
GA02007 R-52 Record head
GA02012 R/P-53 Record/Plaback head
GA02013 P-53 Playback head
GA02014 E-54 Erase head
GA02017 E-8L Erase head See GA02103 (480Z, 481, 482Z, 582, 582Z)
GA02034 P-8L Playback head See GA020?5 (I think it is GA02085) (481, 582, 582Z, 681ZX, 682ZX, LX-5, RX-505, ZX-7, ZX-9)
GA02039 See GA02012
GA02040 R/P Head-BL
GA02083 E-8LH - Erase head (680ZX, 681ZX, 1000ZXL, 1000ZXL Limited)
GA02084 R-8LH Record head See GA0221? (680ZX)
GA02085 P-8LH Playback head 680ZX
GA02101 See GA02132 (Playback head for 1000ZXL)
GA02102 See GA02133 (Record head for 1000ZXL)
GA02103 EOK Erase head (682ZX, LX-5, ZX-7, ZX-9)
GA02132 P-8LZ - Playback head (1000ZXL Limited)
GA02133 R-8LZ - Record head (1000ZXL Limited)
GA02162 PA-1L - 0.6 micro gap Crystalloy Playback head 4-track/2-channel-stereo (Dragon and maybe the TD-1200 also)
GA02201 E-4F Erase head (BX-300, CR-5, CR-7)
GA02203 P2C-3L Playback head Laminated-Crystalloy core, 0.8 micro gap(TD-400 TD-500 TD-700)
GA02217 R-3LZ Record Head for GA02133
E-2D - Erase head (BX-100, BX-125, RX-202)
E-8L - Erase head (ZX-7, 680ZX)
P-8L - Playback head, 0.6 micron gap width, Crystalloy core (ZX-7, 482Z, 1000ZXL, 700ZXL, ZX-9, LX-5, RX-505)
P-8LH - Playback head, 0.6 micron gap width, Crystalloy core (RX-505)
P-9F - Playback head, 0.6 micron gap width, Crystalloy core (670ZX, 680ZX)
PA-1L - Playback head, 0.6 micron gap width, Crystalloy core, 4-track, 2-channel stereo, split gap - 1 channel in each direction (Dragon & TD-1200 all versions)
R-8L - Record head, 3.5 micron gap width, Crystalloy core (ZX-7, 482Z, 680ZX, 1000ZXL, 700ZXL, Dragon., ZX-9, LX-5, RX-505)
R-3L - Record head, 3.5 micron gap width, Crystalloy core (BX-300, CR-5, CR-7)
RP-2D - 1.2 micron gap, Record/Playback head (BX-100 BX-125, RX-202)
RP-2G - Record/Playback head (RX-202)
P2C-5D - Hard-Permalloy core, 1.2 micro gap (TD-300)
The 1000 used a 0.7micron playback head and a 5micron record head. I don't know which P/N.

Also if would be useful to do an impedence match before changing the head if proceeding with an alternate option for replacement (and not the listed one).

On another note, suggest you have a read through the following page for a better understanding on magenetic tape heads:

JRF Magnetic Sciences: Tape Heads-An Introduction

Some NAK trivia, do you know where NAKs were actually manufactured? Here is some light on that front:

Where are various Naks made (from the website listed below):

From some of the replies to my query about Nak decks manufactured in countries other than Japan, I suspect that the lower grade decks were slowly phased into subcontracted manufacturing during the 1980s. By the 1990s, most Nak decks were manufactured in other Pacific Rim nations. In some cases, quality issues became an issue as subcontracting increased. Appears that the BX, CR series decks were done mostly in Taiwan, possible South Korea, and the late 1980s mobile components were done predominantly in Hong Kong. Here's a start to short list what my speculative chronology is for Nakamichi cassette deck manufacturing locations from the 1970s thru 1990s.....

Nak Tri-Tracer series - Japan
Nak ZX/ZXE/ZXL series - Japan
Nak LX series - Japan???
Nak Dragon - Japan (& later Taiwan???)
Nak CR1 thru 4 - Japan & Tawain
Nak CR5 & 7 - Japan???
Nak RX202/303/505 - Japan
Nak DR-1 - Japan
Nak DR 2/3 - Malaysia & Taiwan (S.Korea?)
Nak Cassette Deck 1/1.5/2 - Japan and maybe Taiwan & S. Korea
Nak DR 8 & 10 - Japan and maybe Malaysia too
Mobile Nak TD 500/700/1000 - Japan
Mobile Nak RD 460 & TD 560 - Hong Kong
Mobile Nak Amps - Japan & Hong Kong
Mobile Nak Speakers - Japan & Hong Kong

A one-stop shop for info on NAKs where I sourced all the info on this post, from (scroll down): Scott's Nakamichi FAQ Page

Note on Sendust heads at this site:

The only deficiencies of the Sendust heads is bass rolloff at 25-30Hz, rather than 12-15Hz, and mildly depressed HF PB response(not so much on the 480/LX-3/RX-303), which is EQ'd on the record amp side in the BX & later 2-heads. The single capstan 2-head decks are less prone to lose HF with wear due to not having the pressure pad lifter, so the tape is forced into the wavy wear areas. I certainly agree that head wear is last place to look for HF loss, but in this 482 case, it seems fairly definite.

 

[reubensm]

If your NAK CR2's belt has gone bust, replacements can be easily found on eBAY, like this one:

Nakamichi Oco 80034 Belt Kit BX150 BX 2 Mr 2 CR 1 CR 2 Ships in 24 Hrs | eBay

The investement is just about 1000 bucks (INR) and about 2 hours on Saturday afternoon

 

[sarith]

Also if would be useful to do an impedence match before changing the head if proceeding with an alternate option for replacement (and not the listed one).

Your post is very informative sir. Sandesh, the head I have is not NAK model. I was also thinking of asking you the impedance of your NAK head. I will pm you a detailed pic (the reading side) of heads I have with impedance details

 

[Sandesh]

If your NAK CR2's belt has gone bust, replacements can be easily found on eBAY, like this one:

Nakamichi Oco 80034 Belt Kit BX150 BX 2 Mr 2 CR 1 CR 2 Ships in 24 Hrs | eBay

The investement is just about 1000 bucks (INR) and about 2 hours on Saturday afternoon

The guy who I showed it to says there's something wrong with the powering of the transport...Nothing is wrong with the belt.

 

[Sandesh]

Reubensm is there anyother place where I can get the deck repaired outside Bangalore (with in the south) without losing the original parts of the Nak deck and without losing a lot of money?

 

[reubensm]

Reubensm is there anyother place where I can get the deck repaired outside Bangalore (with in the south) without losing the original parts of the Nak deck and without losing a lot of money?

Not to sure as I've never engaged anyone for such repairs. If you don't find anyone and if my brother and I can find some time, we can help out and do a professional job. Our next project is a vintage Garrard RC210 changer restoration which we plan to start next week. We are expecting some key parts and a replacement tone arm to arrive with a friend, from the UK

 

[reubensm]

As requested by Sarith, attempted to close this thread, but could'nt find the close option. thanks.