Την βοήθειά σας παρακαλώ...

[Σωτήρης Τουμαζάτος]

Απάντηση: Re: Απάντηση: Την βοήθειά σας παρακαλώ...

Φτηνος λαμπατος Ενισχυτης επισης, χωρις να ειναι Κινεζικος (??) ειναι και αυτος.

http://www.palcom.de/deutsch/PRODUKTE/ta70.htm

Και επιδεχεται αρκετη αναβαθμιση.

Επιγραμματικα τι αναβαθμιση μπορει να δεχτει;

 

[Μιχαλης Σπερτος]

Re: Απάντηση: Re: Απάντηση: Την βοήθειά σας παρακαλώ...

Επιγραμματικα τι αναβαθμιση μπορει να δεχτει;

Τελειως επιγραμματικα : Τα παντα

Για αρχη αυτα απο http://www.hifi-forum.de/viewthread-111-558.html



Hello,

Here are some of the (cheap and simple) modifications I did to my Dynavox VR-70E.

My general experience has been that capacitors play a big role in the overall sound. The standard capacitors in this amp are bad sounding cheap junk. That said, all the other parts also play a big role in the soundquality

1) Remove input capacitors = first capacitor of each channel after the volume poti. Replace it with a straight wire: Improvement: big! Much deeper bass and clearer sound. These caps have no function but to filter out dc from the cd-player, but the output stage of your cd-player has output caps with the same function, so they really do nothing except mess up your music!

2) Replace coupling capacitors (0.47µF) with high quality types, best are paper-in-oil (you can find them cheap if you search a little on ebay): improvement: huge: much clearer sound, deeper and more controlled basses (even with the same value replacement). There's no real use in replacing with higher values.

3) Replace decoupling capacitors with high quality types, best are paper-in-oil

4) Replace the lousy standard Chinese EL34 with =SED= El34: biggggggg improvement: terrible floppy bass is gone, sound has much more air etcetera

5) Replace the Chinese 6f2 with other type ECF82 = 6U8A. I found the standard chinese not so bad, but a little laid-back midrange. I've tried several makes of ECF82 and EI are in my opinion the best: airy, flowing sound + you can see their construction is top quality

6) Remove the lid (Haube) that covers the transformers: this opens up the sound (the cover shields them magnetically, which has certain advantages, but also results in a more 'closed' sound)

7) Replace the standard diodes (needless to say they are junk) with (Ultra) fast soft recovery diodes. I just did this an hour ago and am surprised with the result: much more airy sound and more controlles basses, music comes more in the room instead of staying in the speakers, huge authority!!!

Future modifications:
- replacing the very very crap volumepoti with a stepped attenuator with 1% tolerance RN military spec metalfilm resistors: this should give a much better imaging (I'm really not happy at all with the imaging at the moment, no pinpoint at all!!! + much clearer sound). A good quality carbon pot like Alps is also good, but imo 20k is a difficult value to find

-replacing the cheap elkos in the power supply with paper-in-oil should also be a big step forwards

-Maybe replacing all the resistors with high quality carbon types (allen bradley). I haven't disected the standard resistors yet, but am pretty sure they are cheap metalfilm type. Expected improvement: warmer, less sharp sound

- replacing all the capacitors with better quality types

My opinion about this amp is that the most expensive parts (= power transfomer and outputtransformers) are of good quality, especially considering the ridiculous price, and I like the schematic. If you spend a little time and change the components with higher quality types (what the amp comes with is really cheap junk and this literally messes up your music) you can bring it to a MUCH higher level + it's a wonderful experience to solder, replace and then hear the improvement!!!

I'm not talking about marginal differences, each of these tweaks is clearly audible for ANYONE. Try it and thank me later!!!

Don't hesitate to ask if you have any questions or if you'ld like me to mail you a copy of the schematic.




ΚΑΙ μετ/στες Εξοδου

 

[Μιχαλης Σπερτος]

Those will keep you busy for some time ...

Τιμη στην Γερμανια 450 Ε plus shipping expenses.

 

[sbolakis]

Απάντηση: Re: Την βοήθειά σας παρακαλώ...

Η γνωμη μου ειναι αυτη 是英语High-Fidelity的缩写，直译为"高保真"，其定义是：与原来的声音高度相似的重放声音。那么什么样的音响器材的重放声音才是Hi-Fi呢？迄今为止仍难以作出确切的结论。音响界的专业人士借助于各类仪器，通过各种手段，检测出各种指标来决定器材Hi-Fi的程度，而音响发烧友则往往通过自己的耳朵去判断器材是否达到心目中的Hi-Fi。判别重放声音高保真程度的高低，不仅需要有性能优良的器材和软件，而且还要有良好的听音环境。因此，如何正确衡量音响器材的Hi-Fi程度，还存在着客观测试和主观评价的差别。

 

[sbolakis]

Απάντηση: Re: Την βοήθειά σας παρακαλώ...

προτημησε ελληνικο γιατι σε λιγα χροννια θα μας παρουν και τα σωβρακα οι κινεζοι :624: