A.C Magnum IA-125 (***Updated#2***)

This is the newest edition to my collection - so new I had not even had a chance to power it up yet!

Front

Top view

Back

Internal

An acquintaince informed these units are quite collectable nowadays and had regretted selling his unit many years ago.

There seems to be little information on the net on the IA-125. Basic information is about 40W RMS per channel, 10kg and was made to sound like a valve amplifier.

Update - 6Feb2012

Did not connect the unit to my speakers as had some doubt on the direction to turn the volume knob. Removing the top cover requires a hex key of sorts for 7 screws - I made do with a medium Torx screw driver.

Testing the volume pot connectors with a multi-meter reveals volume is zero when the dot on the knob points noon. Increase volume by turning clockwise.

Powering up the unit after connecting the CD player and speakers - you get the normal THUD, typical of Brit amps without any speaker protection - as per other famous Brits e.g Naim NAIT, early Exposure(s),  etc.

This little amp has SPADES of drive and sounds great right after power-up!!! The IA-125 rewards when partner with high quality components. Reproduction is detailed, with clearity and the infamous British warmed. 

Am still marvel-ing at how musical the unit can be!!!

Sansui AU-G90X

Front, angled view

The AU-G90X amplifier is an old favourite. The matching tuner is the TU-D99X. The G90X is a X-Balanced integrated amplifier. Other X-Balanced units I have are the B-2101 and B-2102.

Sounds as good as ever, even after about 2 years in storage. Previously I had great difficulty convincing myself to put the unit back into storage. Took several months before I got around to it!

Bottom view, in storage box

Top

I had recapped the unit a few years ago as it took more than an hour before sounding right. When examined, all the EC(s) in the PSU board showed leaks. Other EC(s) in the pre and power amplifier section showed signs of usage over many years. Panasonic ECA/FC/FM, Rubycon, Vishay BC, OSCON, silver mica(s) and Wima(s) were used during the recapping. No replacement was performed on the tone control board, since these were hardly utilised.

The original plastic foam used for cushioning the buttons were so old they disintegrate upon touch! Hence I replaced them with similar sized equivalents. The resultant produces a nice cushioned feeling when depressing the buttons.

Top view, without cover

Close-up of power amp section

Close-up of  phono section, after internal separator removed

Apologies as I forgot to take a pix of the rear in my haste to get the beastie operational.

The current pix(s) does not show the pre-amp board as these are only visible once the face plate has been removed. The PSU board can be seen from the top but is mostly obscured by the mounting before the faceplate.

Will update the missing portions another day.

Found the following while searching the internet for reviews on the "not so common" G90X.

A Swedish Magazine begun 1983 to use "Anagraph" for displaying an amps behavior. When they 1986 checked AU-G11X and AU-G90X the comment was that (Translation) they never before got an anagraph so perfect as they got with AU-G90X. The only hint can be seen at 50kHz and 100W but this hint is the smallest we have seen. Output power at clipping is stated to be 150W at 8 ohms but we measured 170W across whole frequency range

Anagraph for the AU-G90X

Uploaded the following brochure of the G90X as the information is scarce on the internet.

Blaupunkt P-60

A simplistic turntable, designed with the minimalist in-mind.

Front

The P60 is a belt drive auto-return turntable with option for 33 and 45 rpm records and includes an adapter for the the older 45rpm records. Since the P60 does not have any power on-off switches, the platter rotates upon power-on. There is no strobe light. The only other button is the STOP button which will cause the arm to return to it's resting place. There original arm has anti-skid with tracking adjustment. 

Original mat

Original stylus

Even so, the P60 was sonically pleasing. Sounds superb when playing any LP in good condition. The P-60 was well designed, so much so when I drop the dust cover after starting a track, you would not heard the dread loud thud. Does no favours for any poorly maintained records though...

I was listening to an old favourite - country music from the sound track of the movie Coast to Coast, starring Robert Blake and Dyan Cannon. Could hear all the details re-produced properly with no skipping, mis-tracking or the external influences when I was jumping up and down next to it (when it was place on the floor)!!! 

Not bad for a simple but well designed turntable from the early 1980's

Without mat

Bottom view

Internal view from bottom

Meridian 602

The 602 is the dedicated CD transport from the 600 series and was part of the company's no expenses spared range of hifi components from the mid-80's. The 602 was design to use the Philips CDM-4/PRO lens.

The 600 series were constructed using anodised aluminum to ensure durability with minimum maintainence requirements. One unique characteristics of the 600 series was the deployment of twin blocks to separate power supply from control electronics, to minimise disruptions from power sources.

The 602 can be partner-ed with components from the 200's series and can be place into standby or operation mode remotely. Normally I would use the Philips Pronto programmable remote to control the 602 as it is less cumbersome than the original Meridian 209 (pix from internet as need to locate it in the store room; feels like a brick and eats 9V battery's for breakfast!!!).

The DAC which partners the 602 is the Meridian 606 which I had to perform maintained earlier on.

Stand-by mode

Rear

Tray extended

Play mode

The 602 can be partner with other DAC(s) for good results. In fact, I only discovered how good the 602 was when I partner-ed it with the Audiolab 8000DAC vs the Audiolab 8000CDM. After the shoot-out, I proceed with substituitions on the Audiolab 8000CDM.

Late model Quad 303 (3rd unit)

I managed to purchase a Quad 303 with a IEC power socket and the large capacitors facing upwards. Such units were produced between 1980-1985.

Front

So far, have not tested the usability of the unit as I need to take out the Quad 33 to partner it. It does power up and the heatsink does warm up after left power for a few minutes.

Thus I decided to open up the unit to view it's state.

Before clean-up

After cleanup

Before cleanup the layer of dust was about 2-3mm with a few feathers in the unit??? Had to remove the heatsinks to vacuum the boards. Rest of the unit was dusty enough.

Capacitor tops after vacuuming

When tested, the unit works fine without issues.

MicroMega DUO.BS

The MicroMega DUO.BS is a bit stream DAC in a compact package, with high-quality components all round.

It is dimensionally similar to my Mission DAC5 which uses the high-end Philips TDA1547 DAC. The DUO has an additional TOSLINK for input when compared to the DAC5. Both DAC(s) have a power-on switch with stand-by mode and a Phase-invert facility.

Front

Back

 The DUO.BS has better isolation of the transformer than the Mission DAC5 and uses available space to the maximum with 2 PCB(s) separated by a metal plate at the critical junctures.

Top from angle

Bottom from angle

Side view

How does the DUO.BS sound? When I did a A-B comparison between my X-10D and the DUO.BS - found them to surprising close in sonic quality (after warm-up with Phase Invert enabled). The DUO.BS is pleasure to listen to, after warm-up since I do not normally leave the unit on stand-by for extended periods when not in-use. You would not believe it is a bit-stream unit when listening to it!

Onix OA-20/2

Heard my 1st Onix amp in 1988, a OA-20. Should have bought it then...

Front

Slant view

More than 20 years later, chance upon a OA-20/2 in good working condition - not making the same mistake twice!

The Onix deserve it's well earn reputation of a great performing unit with grunt- an excellent example of British audio quality. Although rated at a lowly 30W RMS and weight a mere 4kg, it is no push over. The unit was hardly warm after running for a few hours with the volume at 7 o'clock. This was more than enough to drive my honeycombs to a decent volume in a room 30ftx20ft.

After warm-up, the Onix was revealing. The mid and HF was fluid when playing a CD of well recorded piano pieces. Bass could be better but acceptable, may consider a recap later on (since it has been over 20 years).

Top

Back

Component view from back

Little wonder these units are seldom available in the resale market. And are quickly snapped up when they became available!

Update - 30Jul2011

Finally decided to perform maintenance on the electrolytic capacitors in the power amplifier section, as the reproduction seem a little muddle on critical passages.

Upon closer inspection, notice the unit had been repaired before and a unknown brand of EC, "Sun" was used in the power rectifier section as well as one side of the power amplifier. Replaced the 100uf 10V with Panasonic FC and the original 4.7uf 50V with Panasonic ECA of equal values in the power amp section. Left the Sun EC in the power rectifier section as that should be adequate for the task. Using better quality EC and substituiting the pairs of EC in the power amp section provided the desired results. Source is the Sony CDP-333ESA which is now connected directly to the Onix without the tube buffer. The Onix is now driving my Mission 753 Freedom's via 1.5m of the original QED Silver Anniversary (with enough silver to cover most of the cable diameter).

Original amp section

Capacitors replaced from power amp section

Musical Fidelity X-10D

With the help of a friend, I finally managed to purchase a X10D.

Front

Rear

Since completing and tweaking the Lite LS-29 (clone of the X10), though it would be interesting to compare the stock X10D vs the tweaked LS-29 @ http://myoldvintagehifi.blogspot.com/2010/11/diy-tube-buffer.html

Stock PCB

The stock X10D uses Philips 6922 valves and produces a rich mid, nice high with a lean low after power-on. About 15-30min later, the bass becames fuller but I find the high can be just a tad brighter than an actual presentation should be. The X10D seem to have a slight roughness around the edge as well, particularly on voices. I was using a gold CD recording of a singer whom I heard during a live performance for comparison.

The LS-29 produces a more authoritative low and  "richer" high while retaining the rich mid of the X10D. The reproduction of the LS-29 was more natural.

Finally decided to recap using lessons learnt from the LS-29.

Recapped PCB

Upon power on there was a immediate bandwidth improvement, compared to the stock X10D which was more reserve in presentation. Voices were now more natural and realistic.

After a week or so, decided to change the 0.22uF Wima(s) to the older MKS-C 0.33uF in the audio section. Initially sounded overly bassey. After a couple of weeks, it's sounding very close to my Tubelog when performing A-B comparisons - with a bit more HF extension, maybe due to the use of silver mica's in th output stage.

Update - 18Aug2011
Finally swapped the Philips 6922 with the Russian 6N23P-EV. Reproduction clarity improved.

Sansui AU-217

The Sansui AU-217 is a 30W RMS per channel integrated amplifier from 1974 with a damping factor of 80. Total power consumption was 145W. Hence it packs quite a punch and was able to drive my Celestion SL6S with ease.

The stock unit sounded bass heavy with some high frequency roll-off. Details are semi 'veil-ed'. The stock AU-4400 had a more balance presentation but lack the punch of the AU-217. Personally I prefer the AU-4400 to the AU-217.

Front

Rear

The AU-217 was later recapped using silver mica's, OSCON, Panasonic FC and ECA, Wima and Rubycon. Generic EC were deployed in the non-audio sections.

Once recapped, the AU-217 can be a real shocker! Most of my visitors who heard it though it was atleast a 70-90W RMS per channel unit as it was able to make my Celestion SL6S sing with ease - packs a much bigger punch than the Arcam Alpha 8 power amp of 50W RMS per channel!

The quality of reproduction is heavily influence by the four 100uF 50V caps which are arranged in a 'L-shape' next to the large PSU caps. The other influential EC caps are the two 470uF 50V caps near the middle of the motherboard.

Please note there is a group of ceramic caps on the opposite side of the amp (away from the transformer) which influence the HF and should be replace with caution.

On my AU-217, replacing the large PSU caps resulted in extremely minor improvements.

In the past, the unit was only slightly warmish after running the unit for atleast 8-12hrs a day during the weekends.

Since you are unable to bypass the tone controls, it was necessary to replace all the non-EC capacitors there. I replaced them using Wima's of equivalent value and the effort was immediately rewarded with a fluid and transparent presentation - eventhough the tone controls were left at '0'.

Weakness includes limited connectivity to single pair of speakers,and, no speaker selector.

Otherwise quality sound at low power consumption!!!

View from rear after recapping

View from side after recapping

Poly's normally replaced

Just realised I have never included the pix of the poly's I normally replace e.g from the pre-amp sections, since they were the source of the off-tune reproductions.

"Bad"on left, acceptable on right

The ones I found to be "bad" (aka off-tune) are those on the left in the above pix e.g green and creamish poly.

The yellow poly's on the right are acceptable but I find them to be "warmish" with slight degradation to the higher frequencies. I normally re-use these as by-pass(s) with good results.

Sony CDP-333ESA

The remote capable 333ESA is a well build, 220~240V unit which weights about 12kg.

This CDP was recapped a while back after my friend puchased it on my behalf overseas. Hence apologies as I do not have the original pix of the internals.

CDP with Tubalog via TOS link

Rear

On the rear, the unit has a pair of fixed and another pair of variable outputs. Digital output is via TOS link only.

In stock form the unit portrait voices well in a warm conveying manner, unfortunately at the expense of background details. The background details were push back and well "veil-ed".

The previous owner installed a EMI filter but left it un-earth to the chasis. To rectify the issue, I placed a piece of old leather under the filter to isolate it from the chasis - see below.

Power filter with insulation

I recapped the audio section of the board only, leaving the power filter caps in-place since these seem to be in good condition and more than adequate for a CDP.

To remove the veil from the background details after initial recapping, I upsized 4x0.1uF green poly(s) in the audio path with 0.22uF Wima(s) aka the medium sized Wima's in the pix. In addition, I upsized the two capacitors in the top left (rear view) from 10uF to 22uF to "mellow-nise" the reproduction. Electrolytics were replaced using Panasonic ECA/FC, Nichicon Gold and Rubycon of the same values. Naturally the better components are placed in the audio section of the board.

Top view

View of motherboard from rear

The results?

A past visitor who was familiar with the Sony ES range of CDP(s) was pleasantly surprised at the performance and level of detail my 333ESA was delivering since he knew stock non-X7 models could not  deliver the level of detail and warmth he was hearing! He is correct as my X7ESD is superb in many pleasing ways - saving the best for a future post ...(bloody heavy too!!!)