Sunday, December 1, 2019

Obsession with Digital-to-Analogue (DAC) converters?

A friend recently asked why do I prefer using DAC(s), to using a dedicated player as I seem to have gained a few el-cheapo DVD players as transport? My friend still uses a vintage Marantz CD-72.

The summarised the PRO and CON(s) after a long discussion are:-


PRO
- Using a DAC, your favourite sonic signature will be preserved

- Not necessary to use a expensive and/or hard to repair player to act as transport

- Unlikely to break down often as a DAC does not have many physical moving parts

- Can replace the transport with a decent DVD player that's pretty affordable nowadays since DVD players are no longer the flagship players

- Can be part of a AV setup as long as your Audio-Video equipment has a SPF/DIF output eg android box, streamer etc

- Much improved audio presentation as a DAC hifi component has been optimised for the sole purpose of production of audio only eg best example is the Marantz CD-94 being enhanced with CDA-94



CON
- When your favourite CD/DVD/transport dies, the cost for repair and/or replacement will be expensive

-  May not be able to rescue the player due to way most companies operate today eg stock min parts

-  Need to evaluate many players before you can find a satisfactory audio quality compromise (if not repairable)


I look at it is a way to "future proofing" my setup and preserving the preferred audio signature.

Tuesday, October 1, 2019

Another low cost DIY tube buffer kit (***Update***)

Bought a different version of the low cost DIY tube buffer kit to try.

The new toy uses two  Chinese 6J3 tubes, with option of US made 5654W(s). My initial purchase was with the default Chinese made 6J3.

The main PRO for this 2nd DIY set is more space around the capacitors in the audio critical path eg the yellow poly(s), permitting a much larger variety of potential substitution choices.

Initial kit purchased

Similar layout to the previous kit but with more space for swapping the critical capacitors

Uses non-mainstream EC capacitors on the PCB

The default 6J3 purchased with the kit

Assembled kit in-action 

This new kit has the same power requirements and input-output layout(s). However, the output volume for the new kit is much lower than the previous. The potentiometer output is even at low volumes and cames with a volume knob which also functions as a power-on/off switch. To enable more space on roughly the same footprint, the new kit uses SMD resistors which were pre-soldered onto the PCB.

How does it sound?

Best way to describe is as if someone enabled a "tonal normaliser" on the output😬.

When I contacted the seller, they assured using the US made 5654W would make a "night & day" difference. Many online reviews does mention the US made 5654W(s) are worth the upgrade. Thus I placed an order for a pair since these did not cost an arm or leg!

Will update next month once I received the 5654W(s) and give them a spin.


1Nov2019

6J3 (LHS) vs 5654W (RHS)

Been using the buffer kit with the newly installed 5654W(s) for past few days and can confirm they do produce a remarkable improvement over the 6J3(s). Received the 5654W(s) quite a bit later than usual and suspect that is due to the decrease in the number of shipments from PRC with the on-going trade-war between the two big economies. 

Thus did not have the opportunity to run-in the 5654W(s) properly before this update. At the moment I can safely say that the "tonal normalisation" has been removed. The DIY kit is beginning to sound like a proper tube component.

Will allow the 5654W(s) to settle in before deciding if to start substituting the capacitors in the critical path.

Sunday, September 1, 2019

Low cost DIY tube pre-amp / buffer kit

While trawling the PRC eBay, I came across a low cost DIY tube pre-amp kit which was advertised as a possible tube buffer as well. Definitely easier and cheaper than try to procure a X10-D from the used market, as those goes quite quickly once listed.

The completed DIY unit mounted using magnetic feets on top of a cheap DVD player

Received the DIY kit with all parts as per advertised which does not include the 12VAC 0.8-1A power adapter, potentiometer knob, mounting feet nor the plastic casing.

The good news is the PCB is well adorned with marking of component position and values. And the potentiometer has a built-in ON/OFF switch.

Bad news is the PCB is extremely compact, with most of the critical components located very close to the others. Would help if you used a soldering iron with a fine or small tip.

Close-up of the DIY kit; 2 of the audio path critcal capacitor on top with the other 2 on the bottom side of the PCB (not visible)

One minor minus point is that the potentiometer does not came with a knob and volume at the lowest setting was not balanced. Hence once switch on, you need to turn the volume up slowly until you could hear a balance volume on both LHS & RHS speakers.

Another minor minus point is that there were no labelling for the INPUT and OUTPUT terminals on the PCB or the optional casing. It's only stated on the instruction sheet (provided in Chinese), with schematic of the PCB. The design uses the X10-D methodology for doubling the input voltage but implemented for a lower cost 7-pin valve instead.

The major minus point is the location and available space for the 4 critical capacitors on the audio path - 2 for input and 2 for output. Due to the severe space restrictions, your choice of capacitors are severely limited by physical size, lead length and available values (if you wish to keep everything on the PCB). In addition, the compact PCB makes swapping capacitors a "pain in the neck".

How does the default kit sound when used as a tube buffer?

Reproduction is surprisingly clear with good details BUT with a heavy HF bias. The default Chinese 6J1 provided seem to be adequate for the moment.

Am still performing substitutions and listening to the new components (once they have settled) on the audio critical paths. Once done, will then decide if the supplied Chinese 6J1 x 2 should be swap out.

Post to be updated at a later date.

Thursday, August 1, 2019

DIY - possible simple solution for deteriorating sound from the channel of a Leak integrated amp

Recently I had an inclination to go listen to my Leak Stereo 30Plus setup in the spare room.

When I switch the unit on, the LHS works fine. The RHS channel let out a few muffled grumbling sounds before turning silent. Repeating the procedure produced the same results. I then tried various settings on the balance control as well as turning the volume up and down. There were extremely low squeaks from the RHS output.

Thus I suspect the issue was similar to that of my Quad 33 (post in the past) - due to oxidation of the contact points on one of the boards of the Leak. The internal setup of the integrated Leaks (Stereo series and Delta series) are all similar.


Please power off the unit and disconnect the power before proceeding any further.

General layout of the integrated Leak amplifiers, with the L&R boards on the LHS of the unit


Since my unit had issues with only the RHS channel, I concentrated on the two boards with "R" on the top of the grey plastic bar. To access the boards, you need to gently lift the plastic bar (which is held down by a gentle spring).

I pulled only the "R" boards from the motherboard and sprayed a little contact cleaner into the board cradle of the motherboard. Then returned the boards to their cradle and return the grey plastic strip onto it's grooves - the way I found them.

Left the unit alone for about 30min or so before restoring all the connections ... all's well again!😄

So before you head out to visit the repair shop for a similar issue, give the above a go 1st.😉

Monday, July 1, 2019

Revisiting Marantz CDA-94 - Transformer failed (again)

A couple of months ago, I was enjoying the pleasant results from the CDA-94 when the front display suddenly went dark and there was no longer any music from the hifi set.

I powered off the unit, disconnected the power line (VERY IMPORTANT) and checked the unit's main fuse with a multimeter eg F001 - it was fine. Was puzzled. Hence I reconnected everything and tried to use the DAC again. Still "dead in the water", I repeated the previous check and discovered F001 blew this time. F001 is supposed to be 250V 200mA but had been previously replaced with a 250V 500mA since the 200mA fuses are pretty hard to came by (where I am).

Next I proceeded to check all the fuses on the various PCB(s) with the multimeter; all the existing fuses were fine. Hence suspect a shorted transformer, most probably L001 again since it had been replaced long ago and another visitor on my previous post informing of the same issue. Since I had some spare 500mA fuses handy, I could replace F001 but this time, remove the power to L001 before performing the power-on test. Bingo! The unit could be power-up without L001.

First a recap. When L001 was replaced years ago I did not have access to the Marantz CDA-94 service manual (courtesy of HiFiEngine) and thus did not know how to proceed as there was no information on L001 as there were no markings on the bloody thing!! A retired repair techie from DIYAUDIO advised to use a lower spec transformer instead. Hence I purchased a 12V 133mA toroid with dual secondary(s) from Element14. In those days there were not many choices and you had to pay thru your nose for the part (since they charged for courier delivery if you did not meet the minimum purchase sum). Since the replacement transformer had dual secondary(s), the kind DIYAUDIO techie provided guidance on how to connect the new dual secondary transformer (the original transformer had 3-cables, the replacement came with 4-cables). I have since learnt that the replacement transformer with dual secondary(s) was connected using the center tap technique

Fast forward to the present - was checking the internet for replacement recently ... boy has times changed! You would be overwhelmed by the available choices and surprised by how much prices has lowered!!!

Previously would have loved to install a Talema 7XXXX-series replacement but the cost was prohibitive then since the local agent had minimum purchase requirement(s) etc etc while eBay shipping from overseas was quite expensive. Nowadays it's possible to procure the OEM equivalent for a pretty decent price. 

While trawling the net for information, came across a translated site informing all the transformers used in the CDA-94 were with 1A output. 

Hence settled on the 15W version with 15Vx2 secondary(s) and 500mA output per secondary and the matching mounting PCB - see pix(s) below and additional information on the respective caption(s).

L001 replaced with the blue OEM transformer

Replacement transformer on mounting PCB attached to chassis bracket using plastic screw with additional washer between PCB and the chassis mounting bracket

Close-up of the replacement transformer and cabling

"Center tap" technique hookup at terminator end; fuses after the termination point upgraded from 500mA to 750mA

Please note the cabling used for the replacement transformer were salvaged from it's dead Noratel predecessor.

The CDA-94 back in business again ... now considering procurement of  some heatsinks for the opamps, TDA1541A and the SAA7220 chips.

Saturday, June 1, 2019

Add-on heatsinks for Audiolab 8000A

I usually rotate the amp in-use (in the hall) every once in a while. Currently it's the last series of UK made Audiolab 8000A with 'F' in the serial number.

The external casing of the 8000A was running quite warm in the local tropical weather. Hence I search for suitably large piece of heatsink to assist with heat dissipation - inspired by the design of the casing on my long ago Musical Fidelity X1A.

After checking a number of websites, I had to give up my initial idea of acquiring a single largish  heatsink. Discovered that could became a rather costly exercise, with possibly pricey postage too!

About a week later, I came across a PRC website which had some attractive looking heatsinks on offer but these were smaller than what I had in-mind. Then the idea hit me - I could arrange several of these smaller heatsink(s) in such a manner that they could assist with heat dissipation from the critical areas of the 8000A, as if a single large piece of heatsink was deployed.

Each heatsink is anodized aluminium and measuring 150mm x 70mm x 11mm. Used 6 of these heatsinks and arranged them (as per pix) with a spacing of 1-3mm between them. As most of the heat on the external casing were from the LHS of the 8000A, I arranged the heatsinks on the LHS closer to it's neighbour vs those on the RHS.


8000A with several add-on heatsinks

Aesthetically pleasing too, no complaints from the boss ... yet😁

Wednesday, May 1, 2019

Minor maintenance of a Quad 33 (on behalf)

Was assisting a friends' friend with minor maintenance on his Quad 33.

Sounds ok initially after power-up but takes about 25-35min before sounding right.

Hence only replaced the two main EC on the PSU and a few of the older poly(s) on the DISC board (see pix below). Used an older generation of poly(s) for the DISC board, to maintain the sonic charm as much as possible.

Sound surprising decent with clearity once more.

They don't make them like they used to these days - not put together with "love and tender loving care" these days, just mass production for the sake of profits.

Initial testing after minor maintainence
New EC caps on the PSU
"Newer" poly(s) on the DISC board

Friday, March 1, 2019

Alternate Radio via Internet (***Update***)

After my previous FM reception issues in January 2019 were (more or less) resolved, I experimented with alternative access to radio eg internet radio via various readily available smart devices which can be connected to the hifi set.


Please note a reliable and fast internet connection will be required for uninterrupted streaming (as per my previous post for an minimalist audio streaming box). 


It was then I realised I could use an Android box to access Internet Radio via app(s) as my unit has both USB & TOS-link for digital audio output, to a DAC. The Android box is able to access AC WIFI as well, hence no need for a ethernet cable.

For testing purposes, I installed a internet radio app at random from Google Play and used a USB cable between the android box to my DIY DAC. I then selected a NZ radio station. Sounds as good as a local FM station with just a tad more bass. Once steaming has been initiated, you can power off the TV as it is no longer required.

Due to the promising results, I will need to invest in a new TOS cable with smaller connectors as my current cable could not fit into the densely populated rear of the small android box eg have a large-ish HDMI connector next to the TOS  socket. Using a TOS link should result in better quality audio reproduction from the DAC.

Will update once I received the TOS cable from overseas (local prices are quite ridiculous).




Android box and DIY DAC used

Rear view of the android box and DIY DAC

Internet radio app menu screen on TV

Radio station accessed by internet via android box


Update 1Apr2019


Received the el-cheapo TOSLINK purchased via the internet and works fine. It was necessary to use a TOSLINK connector with smaller dimension(s) as the rear of the Android box is pretty cramped.

Used as link between the DAC and Android TV box. Audio quality is good using the el-cheapo TOSLINK but is limited to stereo only as the DAC is for tradition stereo reproduction only.

New el-cheapo TOSLINK between the large HDMI connector and the blue USB-2 cable

Normal TOSLINK connector on LHS and the el-cheapo TOSLINK connector on the RHS



Friday, February 1, 2019

Alternate analogue FM reception for the living room (***Update#2***)




First a background of the change in the existing setup.

In Singapore, most of the population (>90%) live in a Housing Development Board (HDB) flat aka government flat. Traditionally there would be standard antenna access points for FM and TV in every unit which are clearly marked in the living room. These antenna access point were supposed to be connected to the antenna at the top of every HDB building.

Traditional FM & TV antenna connector in HDB flats

On the Sunday morning of 6Jan2019, all I was able to hear was static from the FM radio via the access point marked FM in the living room.

When I contacted the authorities the next working day, I was informed the reported service disruption in my apartment was due to the withdrawal of all cable services by the telco Starhub. Only catch was I did not subscribing to any services from Starhub at the present time.

Hence when I visited several electronics DIY shops in the Sim Lim Tower and Sim Lim Square area, the shops informed many experience the same issue as myself. Thus indoor FM antennas and boosters😵 were flying off the shelves!

Prices were better online and I ordered a set. While awaiting the delivery, I had to use a DIY FM antenna - basically just hookup a 3m cable to the antenna socket of my Kenwood KT-5020. It's doing a decent job for the station I wanted to listen to but did not fare well for distant stations.

The order is scheduled to be delivered tonight. Will update once I have time to setup the item(s). For non-Asian visitors, this is a very busy period in the Far East as it's Chinese New Year week eg our version of Christmas😄!

Apologies for the delay for this month's post😞


Update (11Feb2019)

I purchased the following package online which includes a signal amplifier and a "multi-purpose antenna" (according to the seller's website). The booster is rated 20dB.

Signal amplifier and "multi-purpose" antenna purchased online

Assembly of the components is "easy as 1--2-3" and all that was required was a USB charger.

Unfortunately the new components did not deliver a complete solution. Signal strength on the tuner is full but no stereo light on the tuner.

Hence I bought the indoor antenna originally recommended by a number of stores, the Daiyo EU-1703.


EU 1703 Digital Indoor Slim Passive Antenna FM + DVBT 2

I then proceeded to test various combinations to determine which would provide the best reception - DIY antenna (with/out signal booster), digital antenna  (with/out signal booster), and Daiyo antenna  (with/out signal booster).

Best combination seem to be pairing the signal booster with the Daiyo antenna. Not the perfect solution as was able to receive most of the available stations with high signal strength, and,  about 90%+ in stereo.

Luckily my favourite stations were not among the low number of casualties😀


Update#2 (23Mar2019)


This diagram explains why I can no longer use the traditional designated FM and TV ports in my apartment. Starhub was using them (aka SCV port in the pix) as their "new transfer facility". Don't the residents get any say about this?




Tuesday, January 1, 2019

JVC XL-MV33 (Part-2)



Continuation from JVC XL-MV33


My skeptical friend finally decided to get his toes wet with minor recapping on the MV33 to improve reproduction.

Upon reviewing the PCB with the output RCA connectors ... I found some typical Japanese poly capacitors encase in a yellow plastic casing. These type of poly capacitors were common in Japanese brand products from the 1980-1990's (see my past article on them) and are most likely the culprits of the audio reproduction barrier - not all need to be swap out unless they are in the audio pathways.

Original output PCB

Part of output schematic for MV33 audio reproduction

The MV33 schematic from HifiEngine confirms only the ELNA EC (47uF 50V) and the yellow encased poly (1500pF) are on the audio pathway between the JRC OPAMP and the RCA outputs. The 220pF capacitors on the schematics were not present on the PCB - replaced by resistors.

As my skeptical friend was unconvinced of how much improvement can be obtained, I proposed initially changing only the two poly capacitors on the audio pathway (1500pF) - should be quite a revelation for him. Used a pair of BC (aka Philips) 1500pF poly for the swap-out. 

ELNA EC and the Japanese poly swapped out

For the first 30mins after the swap, voices were high pitched with the rest of the material sounding a little off-pitch. Thereafter the reproduction was much improved with the HF(s) sounding more natural and precise.

Even so, the overall presentation seem incomplete ... as if there was still some fog in the area. Next the ELNA EC(s) were replaced with audiophile grade Nichicon MUSE and a bypass ... the presentation improved quite a lot - reproduction was now much cleaner and begin to sound more like a decent CD player.

PCB after capacitor swap-outs

As my friend was not adventurous, we did not proceed any further. He wanted to enjoy the new improvements for the time being.

Saturday, December 1, 2018

Alternative universal RC

I had recently bought a Xiaomi Redmi Note 5 smartphone.

One unexpected bonus for this average smartphone was it's RC app. The RC app can most useful and handy eg if you had misplaced the original remote (or when someone else monopolised it)!

We used it last month to initiate the testing of the LG-V522P. 


RC app main screen on smartphone

Initial screen to add a new device
Mi App generic screen for the LG-V522P

It's most unlikely you would lose your smartphone as most owners would have it handy. And it's locatible via the various "find my phone" facilities eg ring as loud as possible facility!

Thus this sort of smartphone is a keeper once retired from it's primary duties - it's your "new" universal RC!!

Thursday, November 1, 2018

Another budget CD source - LG DV522P

I was introduced to this budget CD source, the LG DV-522P (with co-axial digital output) by a neighbour. He wanted to determine the quality of audio output from it.

The LG DV-522P is a budget DVD player with literally no visible display, only a red LED once power-up. There is provision for a USB source. The unit is RC capable but he had misplaced the RC. Hence we used my "newish" universal remote instead (works like a charm - topic for another post).

No display with only LED to indicate piower-on

Only basic RCA outputs on rear

As my neighbour does not own a DAC, we decided to test the unit via the analogue L-R outputs hooked up to my budget valve EL-34 integrated amplifier (... budget src to budget amp, fair right?) which was paired to the DIY LS 3/5A and matching subwoofer.

I must say I was quite impressed with the results. The presentation was respectable for the price range😮😲!  Who would have thought such a budget combination could deliver any impressive result.

Would have loved to have more listening time with this little mighty mouse...



Monday, October 1, 2018

Technics RS-M02

The RS-M02 was the top end cassette deck for the Technics Concise series (small-size or micro components).



Pix from VintageTechnics

Apologies for the pix from the internet as it's kind'of small and can be difficult to locate in the storeroom (aka the blackhole!!). Will update with pix of the internals once I came across the little critter.

Don't be fooled into thinking the RS-M02 is a lightweight due to it's smaller dimensions. It's a solid performer weighing 5.5kg!

Think of the RS-M02 as a miniaturized RS-M65 without the fine bias and headphone output volume controls but was upgraded for Metal Oxide tapes. Hence the RS-M02 has all the performance of a high-end Technics cassette deck, for the Concise Series.

Saturday, September 1, 2018

Celestion SL-6s


In the late 1980's I literally fell "head-over-heels" for the Celestion SL-6 after listening to a pair at my friend's place in NZ.

By the time I scaped enough to buy a pair with a proper amplifier for them, the SL-6 was no longer available and had been replaced by the SL-6s. Hence I bought a pair of SL-6s instead, with the metal sand filled stands from the local NZ agent via the home based hifi dealer at the shore (aka North Shore to Aucklanders).

I still own that pair of SL-6s but have not used them since about 2006. Hence I enclosed pixs from the net till I have the urge to drag them out for a spin.


Pix of the SL6s from the internet

As there are so many articles and reviews on the SL6s, there is no need to repeat the obvious. I will just add on item(s) I discovered along the years of ownership.

I always admired the beautiful wooden finish as the bark rings would flow seamlessly from one panel to another, on each of the speakers. Many a visitors who's seen the pair always pester for a sale (told them if you want them, compensate me for my loss as I never put them up for sale)... still have them, these are REAL KEEPERS!

From memory the SL6s require plenty of grunt to be be driven properly, rather than Watts. Once so, they are real pleasers. The bass deficiency can be addressed using a active sub (suitable for hifi not HT). If I remember correctly, the active sub need to be set to somewhere in the region of 125-150Hz  with volume just about 1-o'clock - TBC once I dig out the sub as well!!!

For instance, I was using the SL6s with a Sansui AU-555 before putting them into storage. Watts was not so much the issue as grunt. The AU-555 is rated as 20W per channel with only a Damping Factor of 12. Many advise using an amp of atleast 50-60W for the task. Yet, the Sansui AU-555 could drive the SL6s beautifully to decent volumes with the volume knob at 10 o'clock and/or above. No issues doing so for atleast 8hrs a day on the weekends.

Another surprise was when I swap out the SL6s (86dB) with the Meridian A500 (89dB) - the output volume remained roughly the same.

Hands getting itchy now since this bring backs bloody fond memories of my years spend with the SL6s ...

Wednesday, August 1, 2018

Carver C-2 pre with M-200t power amp

While in NZ, I finally settle on the combination of a Carver C-2 pre-amp partnered with a Carver M-200t power amplifier. Could only afford this budget combination then which was able to drive the Celestion SL6s decently.

Both the pre and power amplifier had an external pewter finish on the front plate which was pleasant "eye candy".

The C-2 pre-amp performance was about average, not the best at what it does but the sonic results were acceptable. The four square ON-OFF toggle switches provided quite a flimsy feel. Usually left the C-2 in tonal bypass mode as I did not like the sonic signature from them.

I think the M-200t power amplifier was the better half of the combination with enough grunt to drive the Celestion SL6s decently. When place into mono-block mode, the M-200t truly sounds amazing! My major complaint were the el-cheapo clip-in speaker cable connectors. They could have used slightly better speaker connectors. Sigh ... could not afford 2 of these power amplifiers at the time ....

I enclosed the following pix(s) from Googling the internet as I did not have any pix(s) of my units,

Pix on internet via Googling - front

Pix on internet via Googling - rear of the units

Sold the combination Carver pre and power amplifier in the Wellington area before heading off overseas to take up a  MNC job offer in late 2000. Not much of a choice then as the NZ job market was not great at the time ...

Sunday, July 1, 2018

McLaren 602 pre and 702 power amplifier

Continuation from McLaren A150B


While at that hifi dealers home on the North Shore* (basically the district across the bridge, on other side of Auckland CBD), he had a set of McLaren 602 pre and 702 stereo amplifier hook up in his living room.

*As the locals say ... North Shore - where the real people live


I REALLY LOVE THE REPRODUCTION from this combination! It sound just right - natural with all the details, just like "being there"!! Alas ... it cost as much as my used Honda Accord hatchback ... sob sob

As far as I could determine, these units were sold in the UK and Australia outside of NZ. It was  reviewed on AudioEnz


Friday, June 1, 2018

Onix RA-65

I visited The Cathay (in Singapore) not long after it was newly opened at the end of Orchard Road. There used to be a largish CD shop (think it was a HMV) on the ground floor.

Believe they used to have some sort of arrangement with one of the HIFI resellers, as they were different speakers and amplifier (deployed near the shop) entrance every so often.

Just so happen I was shopping for a floorstander at the time - hence paid a bit more detail to any decently priced hardware on demo. I visited the shop on a few different occasion(s) to listen to the various hardware in-use. During this period they demo a Nait-5 and a Onix A-65 driving a pair of Magnaplanar 1.5 (or 1.6?) over several weeks.

From ONIX website


When I re-visited the shop a few months later, the Nait-5 was no longer in the shop. Hence I was curious and asked regarding it. The shop assistant informed the Nait-5 threw in the towel and they used the Onix instead.

I was not looking for a amplifier then but was suitably impressed by the RA-65, enough to want to became a new owner!

Here cames the bad news ... was informed that Onix model was no longer available and that it belong to the shop, not the HIFI dealer. This seem to happen a lot to me ...

For the curious, I have never owned a Magnaplanar ... yet

Tuesday, May 1, 2018

Another budget EL34 integrated

Could not resist buying the following budget integrated EL34 SET amp from China - 8W per channel, about 7.4kg and with a toggle input selector!

Front view
Rear view

Internals of the amp

This amp took a while longer to be run-in before sounding right. Since I no longer have access to the other unit for comparison, believe this white unit require the volume knob to be turn to about 11-o'clock before the volume was equal to about 10-o'clock on the previous black unit. It is grunty enough to drive my DIY LS 3/5A with AB1 without issues.

Will update again once I have more listening opportunities with my new toy ...

Sunday, April 1, 2018

Revisit - DIY TDA1541A DAC with USB interface

After a couple of years, the unit began to sound more and more bass-ier?

Discovered the PRC made TEAPO capacitors had an oily film on them eg the 5 greenish capacitors on left side of unit close to the OPAMP(s). Sure enough, there were many feedback on the internet about these leaky PRC capacitors.

Topview of DAC internals with only final stage output caps replaced

The bad rep TEAPO PRC capacitors used for OPAMP power supply
TEAPO 220uF 35V replaced by United Chemicon 470uF 35V capacitor

Decided to take the opportunity to replace the Panasonic FC on the final outout stage with ELNA STARGAT(s) (with HF bypass) since I had to do some soldering.

Resultant internals after TEAPO replacement and final stage capacitor swap out with ELNA STARGATES

How does the result sound?

SUPERB is the word I would use.

In a A-B comparison against my upgraded CD650, they were very close, nearly  INDISTINGUISHABLE!!!

Thursday, March 1, 2018

McLaren A150B (not Tag-McLaren)

Many would not have heard of the McLaren brand of amplifiers from NZ. I certainly didn't till I was looking to setup a proper hifi set of my own when living in Auckland, New Zealand in the late 1980(s).

Please do not confuse the NZ McLaren brand of amplifiers with the Tag-McLaren series which was basically Audiolab UK with better quality components and finishing.

The 1st McLaren I encountered was the A150 (70W per channel) integrated amplifier at a electronics shop then located near the bottom of Parnell Rise (around 1990). Was not too impressed by it's abilities.

The 2nd McLaren model I came across was the A150B (hifi dealer's home on the North Shore) and it's reproduction was much improved but had a upper HF cutoff. The reproduction was quite decent for a 75W integrated amp driving the Celestion SL6s properly.

For my then available budget, it was a definate shortlister along with the Onix OA20.

Pix of McLaren A150B from AudioNZ