Monday, August 1, 2016

DIY Quad PRE/POWER DIN-RCA interface

While awaiting parts for the Proac clone to arrive, I finally had the need to make the following for myself (after making a few for clients).

It's a simple interface converter to enable old Quad models to be connected to other equipment. Pin-outs are at http://myoldvintagehifi.blogspot.sg/2012/02/bi-amping-quad-303.html

Plastic case from EBay
4-pin DIN for Quad pre/power amp connectivity to RCA
RCA from Ebay
Decided to try using a solid copper core for transporting the LHS and RHS signals, as the previous units were completed using normal cables. Earth connectivity remain unchanged.
Solid core copper cable used for connectivity
Been using it everyday for the past week ... so far, so good 

Saturday, July 2, 2016

DIY - PROAC 2.5 clone (Part-1)

I decided to initiate a DIY clone of the infamous PROAC 2.5 as have given up trying to purchase one in the used market after searching for years. A hifi dealer I frequently dealt with, informed he has never came across one for sale yet.

Searching the internet for information, the most promising clone seem to be the one at http://www.justblair.co.uk/blog/137-diy-proac-response-25.html as there were positive feedback from previous owners of the actual unit who long for another chance of ownership, and, made the clone using the information from the link as reference.

From past experience, my main hurdle was the enclosure. I am not capable nor have the equipment/facilities necessary to fabricate them. Fabricating them locally would cost "an arm and a leg".

My previous EBay contact (REF: DIY LS 3/5A) quoted an expensive cost for the cabinets only (with S&P)!!!

Fortunately during my exploration of the Chinese version of EBay, I stumble across a vendor who fabricates speaker enclosures. Hence I provided the above link for reference and the vendor says NO PROBLEMO. Total cost would be much lower. Naturally I placed the order and now praying for the best ...

In the meantime, I am going thru the parts list and buying most of the necessary parts from the Chinese EBay site. After all why pay a 3rd party who would purchase from China and resell to you for a profit, right?

We have to face the facts, most items are nowadays manufactured in China - there is really no choice.

I will only be buying the capacitors and actual drivers from non-China sources.

Hope to update next month, once I receive the items.


Monday, June 6, 2016

DIY - Experimental Open Baffle speakers (Part3)

Apologies as I have been busy with my (discounted) shopping spree on China's version  of eBay ... kept feeling I had not done something recently!!! Finally remembered what it was...

After much searching, found what seem to be the proper replacement for the original crossover board on the Pioneer S-D77 (now DIY Open Baffle) speakers - see pix(s) below.

Original crossover from the Pioneer S-D77
Replacement crossover from China

The replacement was a ready made 2nd order 3-way crossover with 2dB boost on the HF.

How does it sound vs the original crossover?

Initially the PRC crossover sounded as if it someone had place a thick floor mat over it - even with the 2dB boost! After a couple of days, it began to remove the "thick floor mat" - details was then neither here or there, but reproduction was beginning to open-up. After a few more days, it sounded close to the original crossover. About a week later, bass details started leaping out.

A few of my visitors were pleasently surprise by the quality of audio reproduction from the DIY Open Baffle, when driven by my Audiolab 8000A.

Hmmm ... how much did I pay for my pair of production speakers from the shops??? Bloody hxxx ...

Sunday, May 1, 2016

Internet streaming using PC via USB DAC

Finally had the time to hooking up my DIY TDA1541 DAC to the PC via USB to the hifi set.

The PC is an older laptop which I have since redeployed for live streaming for songs (Spotify, etc) and sports event(s), etc. Since the USB DAC was Plug&Play compatible, setup was a breeze after making sure all the necessary cables are in-place, and, flicking the toggle switch on the back of the DAC chassis.

Initial setup for testing

As  this is the 1st time using the DAC components, initial reproduction was a tad bassy when compared to the output from my Sony ES tuner, for the same FM station. Otherwise the details were all present. Will update once it has been run-in.
The DIY USB DAC with TDA1541
Connections on the rear

Friday, April 1, 2016

Philips CD-880

The Philips CD-880 was my 1st proper CD player. I actually had my heart set on the Philips CD-650 but was informed it was no longer in production, and, the CD-880 was it's successor when I had save enough to buy one in 1989. Paid $1250 for the CD-880.


Philips CD-880 pix from the net

Don't think I need to go over the specifications etc for the unit as it is quite a well known unit and there are many sources of such information on the net. 

What I will do is provide information regarding what's not well known about the CD-880. I owned one for 13 years before deciding to sell it.

The unit was mainly plastic and thus quite light. If memory serves, was about 6kg. The laser does not read from the old blue dye CD-R which were available at the time.  The tray mechanism was not as solid as the Sony ES series but did an adequately job; had a built-in adapter for the smaller single version of CD.

The remote was well design and pleasant to use.

Variable output from the CD-880 had too much HF for my taste. At that time, I tested the results by connecting the CD-880 directly to a Carver power amp with a pair of Celestion SL-6s. Fixed output was much better but still a little lean on the bass. Extremely fluid and rich mids thanks to the TDA1541A.

Another plus was the shock absorption capability of the attached feet to the base of the unit - the CD-880 would play non-disruptively unless you gave it a hard knock squarely on it's chassis!

Personally I think the display presentation of the CD-880 was the best of the lot ... looks cool, even after more than two decades!!!

Do I have any regrets selling my CD-880? No, as I still prefer the sonic signature of it's predecessor.

Tuesday, March 1, 2016

DIY - Experimental Open Baffle speakers (Part 2)

(continuation from Part 1)

After some plastic surgery, the ugly duckling was transformed to the below. Woofers were salvaged from the original Pioneer S-D77. Replacement midrange are AIWA and tweeters Celestion.

The resultant open baffle
Initial layout after hooking up the misc components

Frontal view
How does it sound?

In short - blew my socks off (... can't find them)!!! I NEVER expected such promising results. The resultant open baffle (aka OB) sounds extremely open and natural. Using the setup in the living room, I could hear additional details from my favourite CD(s) I never realised were in the recordings ... till now! Even so, bass reproduction seem to change drastically between CD(s) which could be due to the resulting impedence or matching of the make to do components. Nevertheless this seem to be the common sore point for the many OB(s) on the net.

Was originally planning to dispose of these cabinets after some mucking around ... I now intend to order some decent components for further exploration. Much followup would be necessary before I can finalise the replacement crossover for the OB ... guess will require a Part-3 for the OB in the near future.

In the meantime, I started performing "trial and error" tests using the many components in my collection. Changing the DAC in the above setup produces large differences in the quality of reproduction.

Monday, February 1, 2016

DIY - Experimental Open Baffle speakers (Part 1)

Since I now have a crippled pair of Pioneer S-D77 speakers at my disposal, I went thru my inventory of spare drivers to determine if any could be attached to the cabinets to get them going again.

Unfortunately none of the available drivers could not be mounted onto the cabinets as per original as the baffle cutouts were (again) just too small.

As the cabinets were glued together (no screws), it is very troublesome to attempt fitting the available parts from internally. Fitting them externally onto the cabinets would create a Frankenstein ... the boss will not approve!

I was considering salvaging the usable parts before disposing of the cabinets. It was then the idea hit me - why not convert them into an experimental Open Baffle speaker?? Always wondered how a pair of open baffle speakers would sound in my living room after hearing a pair of Gradient Helsinki at a local AV show couple years ago. LOVELY ... until they told me how much a pair costs!!!

Anyway... back to reality.

Planned steps of action are:-

1. Investigate available DIY open baffle (OB) designs on the net
    - Most the OB implementations on the net seem to be ground up implementations eg from scratch
    - These implementations have several common characteristics
      - baffle to house the drivers
      - some with, others without a base for bracing the baffle
      - wide unrestricted rear to maximise sound dispersion
      - OB kits seem to cost an arm and leg, even before shipping
      - minimal information on the crossovers deployed on most projects
        - need to test before we will know if a different crossover will be required for an OB?

2. Draw the desired outlines onto the existing cabinets
    - Since I have a jigsaw and sander handy, decided on a simple straight line cut-out of cabinets
    - Will retain only the baffle and the speaker connectors on the base

Cutting outlines for the cabinets on masking tape. LHS cabinet shows the rear, RHS cabinet shows the side
3. Remove all drivers and misc components from the internals. Ensure the misc cabling out of harm's way when jigsaw bites

Stock crossover on cabinet before the jigsaw bites
4. Jigsaw away the undesired portions of the cabinets*
    - Extract the stock crossover afterwards since originally fastened to the side of the cabinet
      - Tried unsuccessfully to remove the crossover before jigsawing
        - The enclosed cabinet makes for difficult DIY-ing

5. Sand away any sharp edges after the jigsaw is done*

*For those not living in Singapore, I need to explain the reason for delaying the metamorphosis. As I am one of the many Joe's residing in a government flat (just about 90% of the population), I can only create the mess in the external areas (with the all the accompanying din) during limited hours of the day and must cleanup afterwards. Would be an effort to do so after jigsawing and sanding the cabinets. Since the authorities do perform a wash-up of these external areas on a certain day of month, I should take advantage of this scheduled activity! Heh heh heh ....


6. Install the available pairs of tweeter and midrange units (same Ohms) onto the inside of the baffle
7. Reuse the original woofers
8. Reconnect all components to the correct wiring and polarity to the original crossover
9. Test the resultant OB


Friday, January 1, 2016

DIY - possible simple solution to deteriorating sound from a Quad 33 channel

Over the years I discovered it is necessary to clean the copper contacts on the add-on boards on some vintage hifi components every so often. This is especially true for my Quad 33 since I am now residing in the tropics. The Leaks seem to be trouble free at the moment ... touch wood

Some of the symptoms I have experience are the following, and, these occurred even after I use contact cleaner on the potentiometers and push-buttons:-

- one channel cutout and remain silent after some initial low level crackling upon powerup
- crackling sound on one channel which seem to get louder and occur more often as time goes by
- volume on one channel which seem to get lower and lower over time

One option is to use contact cleaners. Spray some onto a cotton-type cloth of sorts and use it to rub against the contacts. Unfortunately I find the results does not last long. You would need to repeat the procedure about every 3-4weeks due to the effects of the hot and humid climate.

After some experimentation I now use a different procedure. A good quality pencil eraser is recommended. Give these copper contacts a good rubbing with the eraser. I normally hold the board in one hand and ensure only the contact end of the board are say 1cm are inside the edge of a table. Then use the other hand to deploy the eraser. This will ensure minimising the possibility of damaging the board, Once completed, please ensure no eraser leftovers are on the contacts before reinsertion into the unit,

My Quad 33 boards seem to require such maintenance every  few months. One of my clients with a Quad 33 has the same issue and was quite surprise by the effectiveness of such a simple solution.

So save yourself a costly trip to the shop by giving the above a go before that.

Tuesday, December 1, 2015

Pioneer S-D77

A friend asked for assistance with his Pioneer speakers, which seem "unwell".

When the pair of speakers arrived at my door step, they look "tired" as the cabinets were in average condition (6.5-7 out of 10). Initial inspection indicated the tweeters on both speakers have been damaged with one woofer look worn. Both mid-range drivers look to be in reasonable condition. Specification on the cabinets are 180W 6Ohms and are not bi-wireable. My guess is each cabinet weight about 12kg.
Frontal view

View from the rear with bass port "covered"

Once hookup, it was immediately evident both of the tweeters were not operational. When checking the drivers individually, I discovered one of the mid-range was not operational as well. Even so, the presentation was decent, actually quite pleasing to the ear. The stock crossover is simplistic with a single inductor with two bipolar capacitors and a single semi-conductor current breaker - no resistors.

Hence the 1st option was to replace the damaged drivers. Unfortunately we then discovered the original replacement units are quite pricey (in USD), especially after shipping from overseas.

Second option was to source for 3rd party alternatives. This was when we realised the baffle cutouts were unique, customised for original parts only. As my friend and I do not have a portable router, it was not worth purchasing one for a "1-off" task, in addition to the 3rd party alternatives.

Thus my friend decided to dispose of the speakers. It was mine to recycle. Now what should I do with this pair of crippled speakers? Or rather what can I do to it???

Sunday, November 1, 2015

DIY - ferrite isolator on tuner antenna cable

In the recent weeks, I would hear some unnatural clicking sounds from the tuner in the hall every so often. 

Initially though the tuner require maintenance. Thus I connected that tuner to my 2nd set for verification - no such issue?

Hence the issue was specific to my main setup. I have been adding more electrical components to that locality. Guess some of the newer components were not as well constructed with less than proper shielding.

Solution? 

Most cost effective solution I could think of was to use some spare ferrite isolator (plastic assembly with two pieces of ferrite core) from my "junk box". 

1st attempt using a single ferrite core produce good results with much reduce clicking. Since I had a few, added another for better effect. That seems to have done the job - see pix below.


Was getting carried away and started putting the ferrite isolators on the TV antenna cables as well. Adding the 1st was effective as it did clear up the pix somewhat. Adding the 2nd was disasterous as the TV pictures were pretty blurry!!! Hence removed the 2nd ferrite core from the the TV antenna cabling.

Oh well ... you won't know till you try it

Thursday, October 1, 2015

Technics RS-M45

The RS-M45 was the 1st cassette deck I own. Bought it as part of the "808-series" of slim profile components from Technics with IR remote capability, in 1980.

Do not have the actual pix as the RS-M45 was sold many years ago - hence will refer to one from the internet. I actually kept the RS-M45 for another decade after selling off the "808-series" components before letting it go. Should have kept it... (***regrets***)

Technics RS-M45 from TheHifiEngine database
Specs are available at http://www.hifiengine.com/manual_library/technics/rs-m45.shtml

In those days, Technics was one of the more affordable brands which produce decent turntables and cassette decks (Nakamichi cassette decks were "King of the Hill" then).

The RS-M45 shared the many of the important core electronics with other high-end Technics units of its time eg RS-M02/65/85, except it does not have all the "bells and whistles" available on the front panel. Nevertheless it was a great cassette deck for the price eg "best bang for the buck" back then.

One GREAT feature was the electronics ability to compensate for dropouts. When I play certain cassette on other cassette players, you would hear the dropouts eg sudden loss of volume on certain positions of a song. These dropouts can be rather annoying ... especially when listening to one of your favourite tracks. On the RS-M45, it would proceed as if nothing was wrong!

Tuesday, September 1, 2015

DIY Better indoor FM antenna

I encountered FM reception issues when setting up my 2nd set comprising of the Quad FM3/33/303 in the spare room.

The  setup in the main hall had access to the radio antenna for the building. However there was no such access point in the spare room.

I initially experimented using a bare wire antenna (pix below). 
Bare wire antenna and the removed SMA connector from the other antenna experiment

While the Quad FM3 could receive stereo broadcast, the signal strength would waver eg LHS and RHS indicators would dim and brighten every so often. You would hear distortion(s) every now and then.

Checking the shops in the neighbourhood reveal the available indoor antennas were either too cumbersome, expensive or look like something from Dr.Frankenstein's basement!!

Hence I then search thru my recyclable items (aka junk pile) and came across a WIFI antenna scavenged from a dead router eg 2.4Ghz 54Mbps. As the WIFI antenna required a SMA connector, I had to procure a suitable mounting interface online (see pix below) as the local DIY or electronic part stores does not carry such a component(???).
SMA base with 3m cable and SMA connector

WIFI antenna and the SMA base with cable
WIFI antenna mounted onto the SMA base

Once the SMA base arrived, I cut off the SMA connector at the end of the cable (Ref: 1st pix) and strip the coax cable to enable connectivity to the olden-type TV antenna connector (see below).

Old TV-type connector with the stripped cable from the SMA base
Old TV type antenna connector inserted into Quad FM3

Connecting the above setup to the FM3 produce a solid unwavering signal. The STEREO, LHS and RHS signal indicators on the FM3 now remain lit brightly all the time!

Solid tuning lights and Stereo indicators on the FM3 after using the WIFI antenna
Location of the SMA base with WIFI antenna respective to the FM3

Saturday, August 1, 2015

Appropriate speaker cables for my DIY LS 3/5A with DIY AB1

Not sure if anyone else has similar experience with their LS 3/5A with AB1.

The combination was pleasing to the ears and even a musician friend was complementary of the presentation. However I felt the presentation could be further improved, especially if the HF was to be as fluid as that of horn or horn-loaded-tweeter.

Tried using the original QED and vintage Canare cabling but to no avail. Hence I search the market for used Van Der Hul MCD-352, as I had previously heard it on a friends' Celestion SL6 driven by a Plinius set. After some time, I did manage to acquire the VDH and it did provide improvements.Unfortunately the improvements were not to my expectations.

I then installed my original QED Silver Anniversary (not the XT) for comparison, since both are silver-type speaker cables. 

Viola!!! Everything fell into place when driven by one of my Quad FM3-33-303 sets. Yes, should have trial the QED Silver Anniversary 1st before searching for the VDH.

Another case of the solution being closer to home than one might think!



Wednesday, July 1, 2015

Sansui AU-20000

Sold my mint condition Sansui AU-20000 a number of years ago and did not have any photo's of it.

For those not familiar with the unit, please refer to http://www.classicaudio.com/value/san/AU20K.html for pictures.

From memory the unit weight about 22kg and was pretty retro looking with a lighted VU meter for both channels. Unfortunately you can not disable the lights, only the metering. Hence the VU lights can be quite distracting, especially in the night.

The AU-20000 was the top-of-line of the Professional Series, with had all the bells and whistles you can think off eg swap L-R channels. Operation was pretty straight forward but I prefer the ease of enabling the tuner from the AU-9900.

The buyer said it sounds like his newish MacIntosh. He was surprised the components were atleast 30years old! Inform him it would sound much better once he got it service and recapped. 

Why did I decide to sell this mint condition top-line unit, you ask?

The AU-20000 has an extremely fluid HF. Bass was acceptable but neither authoritative nor flabby, Would certain be improved after servicing. The AU-20000 was extremely gruntly as well - much much gruntier than I would ever require from it. However I did not find the AU-20000 reproduction to be as natural sounding as the AU-9900A. 

About a year after I sold my AU-20000, I met another seller (of his AU-20000) with similar feedback. Even so, the unit was sold within a day of posting.


FYI The following archive has details pictures of a AU-20000 restoration

Monday, June 1, 2015

Test - Streaming audio via Apple Airport Express

Was intrigue by such facilities when I visited the local AV show last year.

The vendors at the AV show were using a streaming service to demonstrate their wares - amplifiers and speakers. They would ask the listeners for preferences and initiate the demonstrations via a mini IPad.

Researching the above I decided to give streaming a go using an older model Apple Airport Express as we have an IPad in the house. This is because the small-sized 802.11n Airport Express are now reasonably priced. 

There are many free (but degraded) streaming service available. I settled on Spotify as my kids were already using it.

The following items will be required to make it work:-
- An Apple product (Android app to access Airport Express is not free)
- An Apple Airport Express (or alternative)
- Audio cable with 3.5mm mini-jack with L/R RCA outputs. or. optical cable with mini TOS to TOS connectors
- USB cable for printer connectivity (optional) to enable wireless printing
- Ethernet cable to enable the Airport Express to function as wireless router, bridge or repeater (optional)
- Register to choice of online streaming service or use playlist on your Apple device

Physical connectivity is straight forward. Connectivity setup requires a bit more work. Please refer to manual or online tutorials for the connectivity setup.


Once setup, I can control the volume and songs to be played from the iPad. There was a 1-2second delay between issuing the command on the iPad and hearing the results from the amplifier.

Quality from the free streaming service was reasonable with some adverts in-between material every once in a while. We did experience buffering time-outs when the iPad was not accessing the wifi via AC-protocol. My wifi setup comprise of a ASUS RT-AC56S connected to a Huawei fibre modem (with fibre cable into the apt).

Overall the free streaming service was a good and convenient way to hear new material before committing to buy the CD ... Yes I still prefer the quality from CD after testing MP3 at high bitrates (320 and above) against the original CD.

Friday, May 1, 2015

Sony CDP-X7ESD with Marantz CDA-94 DAC

Was clearing the storeroom and came across the old battleship ... the X7ESD weight more than most of my integrated amps!!!

X7ESD as transport with CDA-94 as DAC
Since the CDA-94 was already on the hifi rack, took the opportunity to pair the X7ESD with the CDA-94 (previously with the CD650).

The X7ESD has been in-storage for atleast 3years. Even so, using it upon power-up was like it never left the hifi rack. Everything just works as expected. The CDP output volume was stronger than that of the CD650 and CDA-94. Reproduction from a familar CD thru the CDP was of very good quality, thought the HF was a little brighter than it should be. Switching to the DAC output, everything fell into place though the output volume was lower. In fact I was surprise to hear delicate items reproduced with natural clarity as well as bass which has not been evident before this occassion!!!

So much for the theory of a transport conveying 1's and 0's only, therefore the 1's and 0's are the same from any player!

In summary, the X7ESD pairs extremely well with CDA-94, as if they were made for each other.

The X7ESD, CDA94, G90X and ST333ESXII form a group in my collection of higher end vintage gear, with wooden panels on the sides.

Wednesday, April 1, 2015

Sansui AU-555

Sold my prestine condition AU-555 quite a number of years ago ... still wondering if I should have let it go (with original manuals), or, keep after recapping it.

I know I have some pix of the unit but can't seem to locate them ... when you require them! Hence will use the following links to pictures on the internet 1st and update the blog once I do find them.

From Audio-Database

From Amp8

From memory the unit has a very nice tube-like presentation and weight more than it look. Output was pretty much balanced with a tad more HF than bass, I normally set the bass to +2 and rarely use the LOUDNESS switch. Nice bonus is the separate bass and treble controls for each channel. However there is no tone control bypass.

Main weakness was the lack of additional inputs, plastic flip switches which are hard to replace, speaker terminals using a actual screw which made changing speaker cables an exercise in-itself, and, no speaker protection during power-on/off. 

Otherwise operating the unit was quite a pleasant experience as the dials had a nice feel to them.

Normally had the volume to just before 9 o'clock before it was at a nice easy listening volume via the Meridian A500 or the Celestion SL6s.


Sunday, March 1, 2015

TDA1541-based CD player vs TDA1541-based DAC

Finally had the opportunity to setup these two vintage units as a pair - the Philips CD-650 as transport and the Marantz CDA-94 (reviewed by DutchAudioClassics) as DAC.

Philips CD-650 as transport and Marantz CDA-94 as DAC

The Philips CD650 has been recapped (some new caps with different values) according to suggestions@DIYAUDIO (no other modifications).

The Marantz CDA-94 has been recapped using better quality components only - original values are used.

The Philips CD-650 and Marantz CDA-94 are connected via (vintage) Monster Cable Interlink-400 to the Sansui AU-G90X. Digital content from the CD650 is delivered to the CDA-94 via a Klotz OT206 digital coax cable.

How do they compare?

Initially no difference upon usage straight from of storage.

After a week or so of continuous usage, the differences became more apparent. Even so, the differences would only be noticable once you turn up the volume past 8 o'clock on the Sansui.

The CDA-94 is as per the review on DutchAudioClassics - in short delivers to high expectations!

The CD-650 seem possess a slightly larger HF headroom and just a tad more aggressive in it's presentation. Reproduction from both are realistic and 1st rate!

I find myself preferring one to the other, depending on the music genre. Even so, both are very competent implementation(s) of the TDA1541 DAC.

Sunday, February 1, 2015

DIY - DIN input cable for older Quad(s)

Apparently these components are getting quite nowadays. Even the cabler(s) I frequently use are no longer interested to restock the 4-pin and 5-pin DIN (half moon or 180-degree) connectors once their stock run out. They inform there is not much interest in such items nowadays. 

Since I was in the Sim Lim area, decided to check out electronic part stores for the availability of the 4-pin and 5-pin DIN connectors (required by the Quads), as well as the availability of the female RCA connectors. As per informed by the cablers I frequent, these items are becoming rarer nowadays. Most shops do not stock them any longer. If you do locate stock, these tend to be the lower quality components eg discovered the DIN connectors with black plastic covers tend to disintegrate  after some time. Hence I try to avoid these when possible.

Here's an example of the required cabling - my older cable.

Thursday, January 1, 2015

DIY - Replacing broken glass (glue-on) on vintage tuner

Finally had time to replace the broken glass on the Sansui TU-9900.

Will not be using the other Sansui TU-9900 face plate (sent by the seller) as I maybe relocating to another part of the world in the near future. Hence I bought a Perspex replacement from eBay for the job and save the real glass replacement for another day - the original glass parts are rare ... very very rare!

Removing the face plate was straight forward.

1. Power off the unit and disconnect the power plug from the AC socket.
2. Remove the dial(s) from the face plate. Torx screw drivers required. The volume dial uses a smaller screw.
3. Push all the buttons on the left side of the face plate in and gently pull out the power on/off switch.
4. Remove the cover (8 screws;4 on the sides and 4 on the rear) to access the two screws inside, holding the face plate up 
5. Remove the two screws on the bottom of the unit holding the face plate to the chassis
6. Gently nudge the face plate away from the chassis
7. Put the face plate onto a soft surface eg towel, newspaper, with the face facing down
8. Use a bottle of electronic contact cleaner spray - similar to the one I am used. Do use the long nozzle provided
9. Spray onto the edges of the glass in very amounts eg just enough for it to get under the area of the glass. This is done to ease removal of the glass which has been secured to the face plate with double-sided adhesive 
10. Leave for a minute or so and then use a pair of pliers to assist with removal of the broken glass - it should just came off with a gentle tug - mine below
Glass after removal from the face plate
11. After ensuring all the glass fragments has been removed, I then use my fingers to remove the old double-sided adhesive from the face plate
With the removed original double-sided adhesive
12. Then use tissue or cloth to clean up the remaining fluid and let it dry.
13. About 5-10minutes later, I took the perspex replacement to position it into the face plate - DO NOT REMOVE ANY OF THE ADHESIVE sides yet.
14. Ensure the grooved edges of the perspex is facing into the face plate in the correct position before removing the adhesive protectors around the edges and pressing the perspex onto the face plate eg verify the 2-holes on the perspex are in the correct position
15. Once completed remove the rest of the coverings on the perspex and reassemble the face plate onto chassis eg reverse order of the dis-assembly
16. I now have the below

After perspex replacement
Looks great ... again!!!


Monday, December 1, 2014

DIY - Increasing number of inputs on vintage sets

I like using my vintage Quad 33-303 combo but was often frustrated by the need to disconnect-reconnect different sources due to the limited number of inputs on the 33 aka TAPE, DISC1 and DISC2.

Checking the internet, the total cost for proper input expansion boxes would be quite prohibitive since I would require a few such units for my numerous vintage sets.

I have a similar issue with speaker selector boxes .. for another post in the near future.

Then I came across the AV selector below and thought, why not try it?

Top view
View of the output RCA(s) to the amp, pre or processor
View of the possible input RCA(s)

Operation is simplicity itself. Connect the LEFT&RIGHT RCA(s) on the OUTPUT to your PRE or Integrated AMP. Then connect the desired Inputs to INPUT1/2/3 and use the selector accordingly.

An example is the below when deployed on my Quad 33-303 set.


Connecting various inputs to the Quad 33
Noise? Crossover "leakage"? Loud crackle when using the selector?

Been using it for a few weeks now and no sign of any undesirable issues or sounds yet ... you would not even suspect the AV selector was in-place unless you peered at the back of the set!

Saturday, November 1, 2014

Revisiting the Marantz PM-45

Recently stumbled upon the service manual for the unit. Hence time for a revisit.

In the past I had recapped the unit by only swapping the capacitors with better quality equivalents spares (I had on hand) on the main amplifier board.

After reviewing the schematics, it was quite apparent the key area for improvement was the amplifier board - rest of the circuitry adhered to the K.I.S.S philosophy.

The following pix is for the amplifier section of the Marantz PM-45 from the previous post.

Amplifier section from previous post
There were differences in the amplifier section vs the schematics for my unit??? Maybe late production changes?

Top view after 2nd recap
Close-up of the recap area

Important signal path changes
In the last pix above, the red and yellow outlines indicate changes which are necessary for converting the PM45 into quite a decent unit!!

The yellow outlined items are the new changes introduced after the previous post. The yellow box on the RHS shows that the previous EPCOS replaced with WIMA equivalents. Previously the EPCOS replaced the original green poly(s). These poly caps were not present in the schematics of the service manual.

The yellow box on the LHS required better quality 10uF 50V EC - used Panasonic FC.

The red outlined items on the LHS originally had 470uF 6.3V but were 220uF 6.3V in the service manual. Cause for the extra warm sound. Hence I replaced them so with United Chemicon 220uF 6.3V.

The red outlined items on the RHS were as per previous post (Nichicon 100uF 16V). I added 153J poly bypass to them, to permit HF to pass thru.

The results were startling with the above changes.

Note: Other EC caps on the amplifier board need not be audiophile caps - any decent quality EC will do as they are not in the signal path.

Wednesday, October 1, 2014

DIY TDA1541A DAC with USB interface (***Update#3***)

Bought the following DIY TDA1541A DAC for a test drive as always been curious of the reproduction quality from such products.


DIY chasis with everything inside
Size comparison against a CD 
Rear view
Initial impressions of the purchase? 

The unit was sent via a double-box cocoon. Superb built quality with a solid feel.
Layout within chasis

Works fine once the necessary connectors were in-place. Source was the el-cheapo Samsung DVD ($39.90 from a local supermarket chain) via SP/DIF. Initially connected to my Accuphase and later to the Audiolab 8000A to see if there were any difference in the quality of reproduction with different amps in play (no difference). Meridian A500 speakers were deployed. 

Close-up of the stars

The DIY runs a little warm as the chasis is an enclosed box. Only the red LED is in-used eg indicate power availability, although another two LED(s) were available on the faceplate. Looking about the motherboard, many Chinese brand EC(s) were deployed. Very few EC(s) were ELNA Stargate and Panasonic FC.

Initial impressions from the DAC (straight out of box) reproduction was an off-pitch with a bias towards the HF. After a couple of days, the DAC began to sound right. A week later, I can't help but to BE IMPRESSED!!! 

Reproduction was good enough to give my Marantz CDA94 a run for the $$$. Of course the CDA94 wins  hands down since it has dedicated power supplies, dedicated clocking board, etc. But for the total cost ... you can't help but to be most impressed by the reproduction capability of the DIY! 


1JAN2015

Finally managed to obtained the Philips version of the opamp(s) to replace the TI 5534.

WHAT A DIFFERENCE!!! Vocals are now beautifully reproduced with realistic depth and detail!! 



8MAR2015

I added a Wima 0.022uF bypass to each of the output capacitors which are located just before the output RCA jacks. 

This was done to lift the super thin veil from the DIY TDA1541 reproduction. The effect of the bypass can be heard after about 30min of usage, resulting in a bigger HF headroom.  

Next change would be to replace the Chinese made caps with my preferred ...


27Mar2015

Finally replaced the Chinese made 2x330uF 16V at the output stage and the 10uF 50V from the input with Panasonic FC equivalents. Must say the Panasonic FC replacement(s) made quite an impression as the Chinese made caps tend to be produce flabby bass.
Chinese-made caps replaced
Philips BC 0.027uF bypass on the Panasonic FC 330uF 25V output caps
Panasonic FC caps added to the final output stage (next to RCA)

I used long leads on the bypass(s) as the board is mounted on shorter screws towards the back where the RCA(s) are. Otherwise would not be able to place the board onto the chassis.