Analogic Sound

Analogic Sound

Archive for June, 2013


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June 28th, 2013 at 2:07 pm

Posted in Automotive repairs

Kenwood KD-727 r&r

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Picture 359

This turntable was born in mid 80’s. You can also see it under the name “TRIO”.
It comes from the beginning of the plastic era, the one we still live in. As you can imagine this is not a high performance turntable but is a quality product made in Japan.

It uses a MC(moving coil) cartridge but since it came without it I installed a MM(moving magnet) AKAI-PC35 cartridge wich is a good cartridge.Now the turntable can be matched with a lot of audio amplifiers as most of them have PHONO stages dedicated to MM cartridges.

The big advantages this turntable offers are:
Low maintenance(direct drive), it is not at all sensitive to transport and can handle a lot of abuse, all this comes together with a decent sound.

Defects were:
-missing cartridge, installed akai PC-33 with RS-33 stylus
-old belt for arm transport, belt was replaced.
-worn arm transport rail rubber suspension, replaced with silicon ones.
-you could hear in the speakers when listening to music(slow passages) the servo mechanism coming in from time to time, this was solved by using a siliconic grease for arm transport.

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Another picture with this turntable

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June 27th, 2013 at 7:34 pm

Posted in Kenwood KD-727r&r

Technics RS1506US r&r

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This is a nice project that somehow initiated this idea of starting ‘’ . The Technics RS1500 series is one of the latest produced by Technics back in late 70’s early 80’s.
We are talking about very high quality solid state products. What is so special about this reel2reel is the isolated loop tape path, a full direct-drive unit with very low wow&flutter.


The deck looks fantastic, sounds fantastic and is a ‘very nice to have it’ reel2reel. Every time you press play, it turns you back in time and for me it’s the best ‘time travelling’ machine.

Though these decks are famous for their high quality, they are aging like everything on earth. The deck was running but had problems with recording level, tape path adjustments, capacitor leakage and noise produced by dried out bearings.

It was in need of a complete r&r job, a very time consuming job and this is how all has been performed.

First of all , we considered purchasing a service manual wich covered all drawings of the electronic boards and adjustment procedures(mechanical and electronic).

I decided to replace all capacitors with high quality components from Panasonic.We have a supplier for high quality components.


this is how the old capacitors looked like, notice the corroded terminals due to capacitor leakage:

here is the unopened box with all new capacitors :

power supply module recapped:

more pictures with soldered components and boards:


We used the internet and forums for as much information as we could get about these Isoloops. I found something interesting about a nice upgrade on the line amp to reduce distortion and increase gain by a simple modification. I will post this here with many thanks to A.N.T. Audio from

Here comes the mechanics:

replacing capstan bearings

more bearings:

we used high quality SKF bearings designed for high speed operation.


Finally we put everything back together and with the use of service manual and our ‘old school’ minilab managed to adjust the deck properly.



The final result is a reel2reel who will last for many years from now on and it will be a delight for listener’s ears.
There is nothing more relaxing than seeing this beauty at work, you can never stop looking at it.

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June 27th, 2013 at 7:28 pm

Technics SB-7000 r&r

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These speakers are my daily listening to music device. Designed in late 70’s, this is Technics’s statement in audio world. They sound absolutely natural.
Their main feature is Linear Phase filter wich is the key for the soundstage these speakers provide.
For more information about what is all about Linear Phase you can read this:



Though they were puchased in mint condition, soon, after few days of listening, a problem appeared to me.
One of the tweeters had a problem , it didn’t sound as sharp and powerful as the other. At first i suspected the crossover but after various tests it seems the problem was in the tweeter itself . The coil partly detached from the membrane (age deffect).

The repair was performed with extreme care and now the unit sounds perfect to my ears.

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final result:

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June 27th, 2013 at 3:17 pm

Pioneer PL-L1000 r&r

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This turntable is one of the vintage beauties born back in 1979. The unit is so special mainly beacuse of its advanced tangential tracking using a linear motor. It is a unique engineering design wich improves performance and looks impressive also.

The turntable is a direct-drive. It uses a high quality Stable Hanging Rotor wich runs smooth even after 30 years of service.

The unit is extremely sensitive to transport. I saw this unit for sale “for parts” in the north of Italy at a fair price.

Here are some photos of the repairing process. This turntable sounds clear&powerful.
part 1 intervention :


At this point we performed this repair actions:
-cleaning&lubing the jog control shuttle
-cueing belt was repaced, cueing motor bracket rearranged
-cleaning, lubing and rearranging linear motor bearings, they were badly alligned mostly due to bad transport(this unit has its own transport procedure&kit when it comes from the factory)
-glue the dustcover
-fitting a new stylus

part 2 intervention:

After a few days of usage the unit showed some new defects wich were solved :

– the radiator for the motor driver had a poor thermal contact, radiator rearranged
-the speed lock/logic control components resoldered , some capacitors replaced so this solved the speed lock problem
-since I was there again, I lubed the main motor with Motip PTFE white grease, as it was bone dry.

According to service manual there is also a zero point adjustment but this turntable didn’t need that to be done.Once it is placed on level ground, works perfect.

Now it’s a fully working beauty!


Small update (april 2014)

No new problems appeared but I noticed that one of the rails for the head had a little play, a plastic bush was gone so it was replaced with a “home made” one as you can see in the picture.


I will post more pictures with the mainboard and with the main motor driver:



A lot of (inexperienced) users talk(on forums) about vinyl and it’s analogic sound, after years of discussion they realize that the wow&flutter matters a lot! that is a smart conclusion for them!

Just look at these parameters on :

Wow & Flutter : < 0,025% (WRMS) < 0,013% (WRMS, measured at FG output) ROTATIONAL Build-up time : within 90° at 33 1/3 rpm Speed deviation : < 0,002% Speed vs load : stable up to 220g drag load Speed drift : < 0,00008% per hour at 33 1/3rpm < 0,00003% per temp degree change at 33 1/3rpm. This is an impressive japanese work of art!

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June 27th, 2013 at 11:13 am