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Old 13th May 2010, 07:21 PM   #51
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Thank you for the update sakis. However I made a mistake, it was the Behringer A500 I meant. The EP500 is indeed a better quality amp and more expensive.

Interesting comments on the class-a amp. Class-ab rocks
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Old 13th May 2010, 09:09 PM   #52
amt is offline amt  United States
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Any thoughts on the class A version of the P3A, the P3B?

25W Class-A Power Amplifier


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Old 13th May 2010, 09:54 PM   #53
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The P3B is the exact same circuit as the P3A, with just a different bias and lower supply rail voltages correct? I am confused why he says that the P3A pcb cannot be used.

-David
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Old 14th May 2010, 03:42 AM   #54
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Quote:
Originally Posted by richie00boy View Post
Thank you for the update sakis. However I made a mistake, it was the Behringer A500 I meant. The EP500 is indeed a better quality amp and more expensive.

Interesting comments on the class-a amp. Class-ab rocks
you didnt make any mistake the all subject and pictures is from the A500 ....

as about commnents regarding the p3A in class i am probably the wrong person to be asked sine i know nothing about it

as told the P3a is very happy with 30-50 ma and my standard version is about 120

I will ring a bell though once more that my son's version that was created with BD829-30+2SA1302-3281 plays so good and by far better than BD139-140 while still is biased very low like 40-50 ma

kind regards sakis .....
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SERVICE ΕΝΙΣΧΥΤΩΝ ΚΑΙ ΙΑΠΩΝΙΚΩΝ ΜΗΧΑΝΗΜΑΤΩΝ ΗΧΟΥ www.eastelectronics.gr
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Old 14th May 2010, 05:15 AM   #55
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hei ...richie00boy...since you are UK located it could be a nice idea to pick up a phone and find out for us the whereabouts of AC Magnum and if possible a schematic ....just for the record

( AC Magnum is a proper name though for this machine since it could be easilly used as an AC ( airconditioner) but only for winter season )
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SERVICE ΕΝΙΣΧΥΤΩΝ ΚΑΙ ΙΑΠΩΝΙΚΩΝ ΜΗΧΑΝΗΜΑΤΩΝ ΗΧΟΥ www.eastelectronics.gr
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Old 14th May 2010, 06:06 AM   #56
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Hi Sakis,....keep up the great work. Thanks for the really interesting thread. I'm gonna stay tuned!
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Old 14th May 2010, 06:55 AM   #57
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Default servive nikko 8085

i love NIKKO products .... each and everyone of them i lay my hands on was a masterpiece on its class

here is this model 8085 ..integrated amplifier with a tuner standard repair and no upgrades for that one .... will mean total cleaning tuning and recaping

after that and especially for the specific model that seems that is made especially for germany which of cource means stupid 5pin DIN plugs everywhere and even more stupid .- speaker plugs


after the repair a wonderfull very sensitive and suprizinglly sensitive tuner come up ... before the repair aft functions and a bit of frequency roll of problems have been fixed with simply replacing the caps .... no coil or cap to be touched resulting an extremlley acurate tuner

add to this that in radioamps the tuners often do not produce decent sound but not for this one ... the tuner actually sounded wonderfull

the preamplifier section sound German ... tone control will add wonderfull sonics both for bass and treble ... bit coloury but that is ok i think for this style of amplifier loudness and phono stage is arround the same philosophy

wonderfull simple amplifire section original powerfull toshibas will guaranty more than 60 heavy real watts per chanel coming from a big trafo and big caps ...relativelly big heatsink will also ensure that amp will run cool even if pushed .... excellent dula transistor in the input and wonderful control of the idle and ofset ////


it has been fun to work with a very nice japanese amp especially made for the german ...odd combination

here is a picture

( please also keep in mind that i keep schematics for most of the equipment i repair and also have very good memory if you need just e mail me )
Attached Images
File Type: jpg nikko 8085.JPG (140.6 KB, 872 views)
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Last edited by east electronics; 14th May 2010 at 07:01 AM.
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Old 14th May 2010, 07:08 AM   #58
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a small thing

when i started the thread i had in mind to compaire everything i repair with my P3A ...i presume that it is obvious that in some cases its simply no point

kind regards sakis
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Old 24th May 2010, 06:31 PM   #59
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Default Service pioneer sx-450

HERE is a nice machine ...as simple as it can be ...low in power nice preamp small sweet amplifier ...unfortunatelly quasi ( i dont know why i state this as a minus but i do )

had the chance to listen to it before and after the thing was half dead ...over used, all capacitors inside completely dried out, sounded very mufled with a bad bandwidth and very telephone sound ...no ends at all

complete recaping tuner also ...very stable and accurate but bit hissy ... expected i think for a tuner that old and that simple

still a very sweet litle machine could be a perfect secondary system ... or if pre and main seperated the main amplifier could perform superb with a pair of sensitive speakers

selector section kinda noisy crosstalk figures are probably bad ...but with only one active source thing is quiet ok

beyond caps replaced did some litle things with the inputs since those was filetred with ceramics but also with very big values that reduced bandwidth .... reasonable for the time to protect from RF injected in but now days sources areby far better so it was good to let the amp free a bit more to enjoy some high frequencies

Costumer liked to have the speaker binding post replced ... so we did

here is some pictures
Attached Images
File Type: jpg PIONEER SX-450.JPG (88.4 KB, 817 views)
File Type: jpg SX-450 inside.JPG (173.9 KB, 809 views)
File Type: jpg SX-450 binding post.JPG (80.3 KB, 786 views)
File Type: jpg sx-450 damage report.JPG (120.4 KB, 784 views)
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Old 29th May 2010, 04:42 PM   #60
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Default Service luxman l3

poped in the shop for service and if possible som kind of upgrade ...eventhough is the first time that i open one of these i have heard before from other costumers that these are simply nice small amps like all of them of luxman at the time ( or most of them ) ( i will have to exclude all STK3082 models )

Any way from various owmers i have heard that the amp is fine but kinda of dark especially in high frequencies

belive it or not this particular ruther cheap comercial amplifier is properly builted or better say properly designed cause i think that on the way many things went wrong ...

problems located in three areas

one that capacitors electrolytics in the amplifier board are placed onatop horizontally and beyond the fluid issue that concetrates in one are and loose capacitance having caps onatop is a temperature collector ...

two
that way too many ceramics are involved in signal path and divisions of the amplifier so beyond thebtotal recaping ive done the favour to replace input with MKT filter with silver mica and miller caps here and there with styroflex caps ...

three
and worst i would say was the vbe transitors of both chanels that evnthough had the proper size soldered in the proper area to sense temperature actually was never installed in the right place ( as seen in photos ) and to my understanding that was simply an assembly error that manage to convert the white cream to almost dust from time and temeprature combination

Result that amplifier was overheating and had thermal runaway which was an issue that we fixed

Amplifier now measures and sounds by far better ...it is a quiet amplifier concidering the way and tiome it was made even though ahs seperated bass and treble controls these remain quiet accurate offset is ultra low 0.001 and with a very good adjustment and also biass was quiet high for this type of amp but after the repair was extremelly stable ...

since in the some time in the feature i will see on of these again it will be interesting to notice if they are made proprely in the VBe area and my piece had simply an assembly error

here is some pictures
Attached Images
File Type: jpg luxman l3 inside.JPG (155.7 KB, 253 views)
File Type: jpg luxman l3 left pcb.JPG (127.7 KB, 207 views)
File Type: jpg luxman l3 left vbe.JPG (109.8 KB, 204 views)
File Type: jpg luxman l3 right pcb.JPG (102.5 KB, 189 views)
File Type: jpg luxman l3 right vbe.JPG (85.6 KB, 173 views)
File Type: jpg luxman l3 tone.JPG (75.2 KB, 158 views)
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Last edited by east electronics; 29th May 2010 at 04:53 PM. Reason: got my shelf a new key board
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