DIY - Tube Buffer (***Updated#2***)

I finally gave up trying to get my hands on a used Musical Fidelity X-10D and bought a DIY PCB based upon the infamous unit thru a DIY outlet.

Used my spare NOS Russian 6N23P-EV(s) for this project - as per my Musical Fidelity Tubalog. Other components include the Audiophiler and Wima's (red and yellow "bars") for signal path, EPCOS for non-signal path, Nichicon MUSE (outlet recommendation), and Rubycons.

I began using a regulated "off-the-wall" PSU 12V 500mA to power the PCB. Sounded terrible with much "audio breakage". When I contacted the DIY outlet, they informed the original design was based on a unregulated PSU e.g wavely line vs bar with 3-dots above on the PSU. Sounded much better once fed the proper diet!

Started tweaking since it is now operational. Initially used Nichicon Muse 1000uF 35V capacitors (light metallic Green) as per recommended by the outlet. Later replaced these with equivalent Multi-Comp (aka United Chemicon) on my 2nd iteration as there was no audible difference via my Leak, mod DVD2900 and HoneyComb speakers when I replaced them.

2nd iteration

The highs and mid-range sounds extremely nice. Bass was better than before insertion of the PCB into the circuit but a little "muddle round the edges".

On my 3rd iteration, I replaced the 1st two filter caps with a single Rubycon. The "yellow" Wima was replaced with a larger value Silver Mica.

Wundabar!!! Everything fell into place.

3rd iteration

Another view of 3rd iteration

Forth iteration. Replaced the Rubycon 10uf with Panasonic FC 22uf, as these were on the signal path. Sounds rich and life-like thru the Luxman L410, especially the piano pieces.

Update#1

I found the following schematic from the web and updated it with the changes made. The shaded area is the section which is in the signal path. Changes are in red text. The shaded area of the schematic clearly shows the audio signal path and I personally believe money should be spent on components in the shaded area. I tried better components in the unshaded area before and there were minimal improvements except for the upgrade of the power filter caps from 1000uF to 2200uF. I used 16V instead of the original 35V as I measured the voltages at these points and were below 16V. Using 2200uF resulted in a quieter background in the output e.g when you are next to speakers and no music was playing. And I did not use the 4007 diodes as per the schematic as I had many IN4004 leftover from my Quad 33/303 upgrades.

Schematic with changes

Update#2 - 27Sep2012

Both channels died and the valves do not glow anymore.

Checking the power section of the PCB reveals the 2.2R 2W resistor to be faulty and when tested shows a value above 400ohm.

Replaced the 2.2R 2W did the job!

Bang & Olufsen BeoCenter 5000

The BeoCenter 5000 is a AM/FM/LW receiver with the BeoMaster remote.

Although conceived in 1980's, the unit remain stylish 20 years later.

Front view with FM reception

With hidden controls revealed

The unit weights a solid 10kg and has an internal fan in the amplifier section. The amplifier outputs 50W RMS per channel.

BeoMaster with hidden controls reveal

BeoMaster in action

Will not go too much into the unit as there is a dedicated B&O site online with detail information.

Am currently using the unit for FM reception as it seems most adapt for the purpose - the FM reproduction is simply superb!

Musical Fidelity A1X

Regrettably, I had sold my pristine condition British made A1X without taking pix(s) of the internals.

Luckily, these are readily available on the internet. There are many articles on the mods, tweaks and recapping for the infamous unit so I will not go into those in detail.

As per other units in collection, I had recapped the A1X and obtained much improvement. Most noticeable was the definition and strength of the bass once the 4x10,000uf caps were replaced. And I put a bypass of 0.1uf (recycled poly) on the 10,000uf caps.

What I did discover along the way was not mentioned in any blog or website. After completing the above (as far I had searched on the net), I notice the A1X performed much better but was lacking in the ability to resolve details in the background ... it was definitely there but something was holding it back.

I reviewed the schematics (which are plentiful on the net - example below) and noted C15 and C16 are on the signal path.

Since I did not have the original pix of my A1X, I will use the following from the internet to illustrate the caps I am referring to e.g caps with 22 written and indicated by the arrow pointers in red.

sample with arrowed indicators

I replaced these 22pf caps with 33pf silver mica's. When tested, it sounded like a valve unit - warm, full bodied with all the details!!!

When the buyer of my (previous) A1X first heard the unit, he literally "fell head-over-heels" over it. He had previously heard other A1 and A100 units as well as the reincarnation.What more can I say ...

Luxman L-410

The L-410 is a Class-A bias (first few watts only) integrated amp and it really runs hot. The L410 is a high-power component, and, was previously able to drive my renown power hungry Celestion SL6S with ease.

Before re-cap, you could hear same off-key note from my Emi Fujita album (as per Nait). The offending component was traced to the pair of 'white translucent' 0.047uf non-EC cap on the pre-amp board.

After re-cap using better quality components e.g Wima, OSCON, Panasonic FC, Elna Audio, EPCOS, Siemens, Rubycon, Panasonic ECA, Elna Starget, Nichicon, AVX, silver mica and, Philips BC, the L-410 became truly transparent. Pairs well with my recapped Musical Fidelity Tubalog and Marantz CDA-94.

Please be aware of the bi-polar caps in the power amp section.

I believe the L-410 is Class-A for the first 8W or so (not documented anywhere) as once the volume dial passes just over 9 o'clock you notice it run not as hot as before and the "grunti-ness" increases - in the Luxman tradition of the L-510, etc. The other 'give-away" is the use of the "shark-fin" heatsink normally found in vintage Luxman's which run hot.

The following is a pix of an original L-410 (not mine) which was located on the net.

Original pix from internet

The following is my set after almost all the electrolytic (except the pair of 15000uf) and most of the non-EC caps were replaced.

View from front after recap

The following is the top view.

From top

The following pix are close-up(s) of the various sections, after they have been recapped.

Pre-amp board

Tone control board

Power amp board

Leak Delta 30

Technics SB-X700 (aka "Honeycomb speaker")

I recently acquired a pair of SB-X700 speakers in good working condition (with original speaker stands). These are quite rare in the used market. Summary of details at http://www.vintagetechnics.info/loudspeakers.htm

With cover

Cover off

Bass reflex design. Side panels sound thin when softly tab on (except the back).

Sounds pretty analog. Bass was "flabby" and mid-range lack definition. Plenty of low frequency resonance as well due to thin side panels.

Has "potential" ...

The speaker rests on a metal plate at the top of the stand. The speaker can be easily shifted when on the stand. Hence I decided to try the following. Put a "sticky mat" and eight rubber pencil erasers on each of the stands. The speaker will be place on top of the stand with the mat and erasers. The idea is to create an "iso-layer" which would absorb vibrations from the speaker e.g idea from "earthquake proof-ing" procedures!!!

Next I obtain 2 small water bottles and fill them to just over half volume. You can see them place into the internal chamber of the speaker stand on the prior picture. These will act as "dampeners" - like sand bags inside speaker stands.

Water bottles from inside speaker stand

Once done, firing the amp up verifies the theory - bass was firmer and reproduction became more natural with clearity to match!!!

Actually sounds pretty decent... 

DIY - Kwak Clock 7 (1st attempt)

This is my 1st attempt to DIY the KC7 using mainly parts recycled from my previous DIY(s).

I have not install the KC7 as yet, since I will require one of my "non-favoured " CDP to be the test unit aka "guinea pig"!

As to date, I have only used a multi-meter to ensure connectivity of the solder parts (where possible) following the instructions for the KC7 e.g clock from CDP, test for voltage before IC and the J309 is inserted.

You can E-mail Elso for the details via DIYAUDIO.

Will update once I have the opportunity to test the KC7.

Naim Nait 1

Sansui TU-D99X

Sansui C-2102 (***Update#2***)

The The C-2102 is the matching pre-amplifier for the B-2102 power amp. I use the C-2102 as the pre-amp to provide signals to my C-2102 and C-2101 for horizontal bi-amping.

One of the unique features is of the C-2102 is the use of parametric equalisers for tone control. It is known to possess a good phono stage.

Front

Rear

I bought the C-2102, B-2102 and B-2101 from the States a few years ago before postage prices sky-rocketed!!!

Original internals

After recapping

Bottom view

Caps used include Panasonic ECA and FC, Wima, silver mica, EPCOS and OSCON.


Update - 24Mar2012

Took the C-2102 out to partner the B-2101. Was initially disappointed by it's performance - sounded reserved and the high's did not flow naturally.

Hence I replaced the OSCON with a Nichicon on the motherboard. Replaced the WIMA 0.022uF at C26 with a Russian Paper-In-Oil (PIO) 0.047uF (back to original value) as it is in a tonal ladder.

Close-up of motherboard area with changes

In addition, removed the previous bypass under the motherboard and place a Philips BC 0.026uF bypass to C26 as the highs required a slight adjustment.

The results in a word - WOW!!!

Quad 303 (2nd unit)

Found the following pix(s) of my 2nd Quad 303 which was recapped and re-biased in 2009. Though it would be interesting to post them. 

I acquired a 2nd Quad 303 to enable bi-amping using my Quad 33 and FM3.

I tested the unit after purchase and it was functional but with a slightly lower volume on the right channel.

When I open up the internals, I was shocked (!!!) and surprised it was still functional (Hint: Right channel board)

The are pix of the original unit before it was recapped. Will add pix(s) of the recapped unit once I take it out from storage.

Overview

PSU board

Right channel board with broken capacitor!!!

Left channel board

The resultant unit after recapping can be viewed at http://myoldvintagehifi.blogspot.com/2010/12/quad-303-after-recapping-2nd-unit.html

Marantz CDA-94

Another rare DAC from my collection, the well known partner for the well beloved CD-94 - the Marantz CDA-94. The DAC chip deployed is the infamous Philips TDA1541.

Front

There is much more information on the unit at http://www.thevintageknob.org/MARANTZ/CDA94/CDA94.html and http://www.marantzphilips.nl/marantz_cda94_d_a_converter/

The unit really sounded sickly when I acquired it.

Once recap with quality components though-out (Wima, OSCON, Panasonic  FC, Stargets, etc),  sounds really analog. My good friend (who bought my tuned Sansui AU-4400) heard the unit after I recapped it (in 2009) via the Naim Nait 1 though it was a tube DAC and wanted to get one for himself!!! He was extremely disappointed once he discovered the CDA-94 is extremely rare in the used market.

After recap

Main DAC board with dedicated PSU section

PSU board for all other motherboards

Audiolab 8000T

Deltec PDM1 (before PDM 1.2)

Audiolab 8000A (serial number with 'F')

The Audiolab 8000A's with the alphabet 'F' in the serial number were the last production batch before Audiolab was sold to Tag McLaren.

I was lucky enough to secure a unit from a seller who lived down the road!!!. After doing so, I sold my British made Audiolab 8000S (serial number with  'E') and 8000A (serial number with 'D').

The newer 8000A still sounded "a bit raw" and less polish than the higher end units in my collection. Hence I decided to recap the unit using better quality parts, as well as performing some minor tweaking along the way.

My unit with 'F' in s/n

Original

The following pix was taken after the work was done using OSCON, Wima, Panasonic FC and ECA, as well as silver mica's.

Before Wima's inserted into pre-amp section was substituted with silver mica's 

This is what's under the big ribbon cable - the pre-amp section.

After the four silver mica's were inserted

The left side (from front) casing of the unit runs warm as the phono section has it's own voltage regulators which uses the left side of the internal casing as heat sink. I attached two heatsinks to the side to help reduce heat levels.

Took the opportunity to capture a 30second video to show the results, using my basic digital camera. The video was captured in MOV format and has not been modified in any manner of form - direct from the digicam to the PC and uploaded to the blog. 

 

Was quite impressed by the ability of the basic digicam, although my daughter says it does not do justice to the real setup.

Philips Pronto programmable touch screen remote

This is the Pronto I use to control the various units in my collection ... most useful as I do not have to hunt high  and low for the originals when I take a unit from storage to listen. It is seen in it's cradle which functions as a charger as well.

Screen for Audiolab 8000CDM

Pronto charging in cradle

I programmed and customised the Pronto for the Philips CDP, Meridians, Denon HT units, TV, VCR, etc.

The model was reviewed at http://www.remotecentral.com/tsu3000/index.html and the Philips support website is at http://www.pronto.philips.com/

Philips CD-650 (***Update#2***)

The CD650 is probably my favourite TDA1541 chipset CDP.  I have two such units - the other unit is literally  NOS!! I sold my CD880 and kept the CD650!!!

I had to recap the unit after the image produced was leaning towards the left (from front) - common issue for old Philips-based CDP(s). I had several owned a number of other Philips based CDP's (Philips CD880, 670, 460, 640, 624, 634, 482, 931, AK601; Marantz CD52 Mk1, CD52 Mk2; Mission PCM 4000, 7000) and this always happens after 10yrs of usage. 

Only the electrolytic capacitors were swap out for better quality ones - no reclocking or opamp change necessary. The only exception were four of the Philips blue poly caps which were salvaged from my dead Mission PCM 7000, swap out for the silver coloured ones in the original from the opamp area e.g 1n and 2n4.  You can see the changed capacitors in the following pix.

                                        

SK Fong heard the unit as well when he was visiting and was quite impressed - by it's condition as well as sonic qualities after the recapping. And yes it does look like it was taken out the box and this is 1986 ...

I even demo picking up the unit and shaking it vertically as well as horizontally while a CD was being played - you would not heard any skips etc aka as if it was place on a iso-platform. That's 1980's quality for you!!! 

Someone else I know with a Marantz CD50 had to place the unit on a self-made iso-platform using springs to produce similar results.

Update#1

I realised I did not mention the following. I used a Philips BC 0.027uF (blue square poly) as bypass for each of the Nichicon Muse. This was done to permit the high frequencies thru.

28Mar2011 - Update#2

Uploaded the brochure cover for the unit as these are scare on the internet.

Audiolab 8000CDM

Here is the perfect partner for the 8000DAC, the 8000CDM (a bit dusty as just taken out from storage).

CDM and DAC playing a CD recorded with EQ

In theory the "swap-out" should not have been necessary as a transport's sole purpose in life was to read the CD best it could and provide the output in digital form e.g binary 1 and 0's. Binary "1" means high, binary "0" is low. There is not suppose to be any levels of quality in sound relating to the "1" and "0"'s. The DAC then converts the digital signal to analogue signal for us to hear.

Errr ... I found much difference after the swap out was done.

Here's the front view of the 8000CDM after some of the internals were swap out.

Top front view

Bottom view

Followed by the view from the top. Have added a heatsink to the voltage regulator transistor at the back of the unit as it ran hot - not sure why they was no heatsink on it in the 1st place.

Lastly the close-up of the signal processing area which is located behind of the CD transport mechanism. Higher quality components used are OSCON, Wima, EPCOS and silver mica's as well as Panasonic ECA and Rubycon capacitors. Reclocking should not be necessary as there are IC's for PLL in this area.

View the blog for my Audiolab 8000A at http://myoldvintagehifi.blogspot.com/2010/09/audiolab-8000a-serial-number-with-f.html to see and hear how the units perform together.