Jump to content

jack

Returning Member
 View Profile  See their activity

  • Posts

    23

  • Joined

  • Last visited

 Content Type 

Posts posted by jack

  5. krell ksa5 klone

    in Do It Yourself

    Posted

    Thank you, this helped me a lot!

    on DIY forum, that Pars mentioned, Algar added a CRC filer:

    "Then on the supply added an input CRC filter (4R resistor and second 4700uF cap) to reduced a little the regulator input voltage from 32V to 30V, since I increased the bias current.
    That will reduces the pass regulator power dissipation.

    That also reduce the amp already low noise floor. Regulator input ripple went from 300mVac to 100mVac..."

    How was this connected? is it between the leads of the existing 4700 uF caps?

  8. krell ksa5 klone

    in Do It Yourself

    Posted

    Hi AlSp

    I built KG's device as a pre. There is not much information in this thread about how this amp. reproduces sound.
    IMHO there is no need to use a thicker layer of copper, bearing in mind that you will be using a maximum of 30 Watts.

     

    I believe we could use better capacitors and resistors.

     

    Cheers

  9. krell ksa5 klone

    in Do It Yourself

    Posted

    1 hour ago, wink said:

    Yeah, if it sounds good doesn't necessarily mean it is good......

    True! If it sounds good does not necessarily mean it will taste good ;-)
    Since good is subjective what does good mean to you in audio gear? in what area doen an opamp has to excel in order to be qualified as good?

  11. krell ksa5 klone

    in Do It Yourself

    Posted

    I am still testing. Yesterday my burson v5i s opamp arrived, they still need to run for a dozen of hours for the final test, however as of now I can tell that they bring much more improvement in my DAC (DIY based on ESS9028) than in my preamp (that is the the KSA5).
    The idea of "upgrading" the opamps in the KSA5 came after i received counterfeit OP27 from ebay: the sound was terrible with lots of noise. Once i replaced them with Analog Devices original OP27G from Mouser, the KSA5 started to sound great, and then with BurrBrown's OPA445 even better IMHO, as i find it sounding natural.

    I also think about replacing my nichcons KA with KG, not sure what it will change, or if it will change anything though.

    Building, replacing, testing is an activity i really enjoy, that relaxes me a lot after a hard day at work. I should have chosen electronics instead of economics for my studies ;-) my lack of knowledge is a serious limiter for me, but you gentlemen and a great support and help. thank you!

  12. krell ksa5 klone

    in Do It Yourself

    Posted

    Pars. PSU is running @ 23.2 V DC. Transformer is 27.5 V AC.

    I no not mean opamps in the PSU. as i already know that they either work or or not work. I think you told me that previously ;-) so i changed the op27 to the cheaper op07 and the psu seems fine.

    I have heard Operational amplifier have their own sound charecteristics or signature, therefore looking if changing OPAMPS in the amplifier will "improve" or change anything. I have testes the op27 and OPA 445 i find the forst one less precise with to much lows.

  19. krell ksa5 klone

    in Do It Yourself

    Posted

    http://www.antekinc.com/as-0528-50va-28v-transformer/ Earlier in the thread (had you read it) KG said you need ~35V raw dc, so 27 * 1.414 will get you ~38V minus the diode drops for the rectifier(s). I haven't looked at the schematic, but assume a bridge, so -1.4V, so you are at about 32.6V raw DC. Might work. 27-28V transformer will get you closer. 28V Antek above would put you at (28 * 1.414) - 1.4 = 38.2V. It appears some have built this with a 25V transformer.

     

    Thank you for explaining. I have read this thread several times, nevertheless it happens to me to ask silly questions as I know less than a little about electronics ;-)

    Am I correct ?The best would be to have a transformer maid with a voltage between 27 and 28 V so that DC right after the rectifier (bridge) is 35 V. I think this can be done since my toroids are custom made.

    I have also read in this thread that some pushed PSU voltage higher and changed opamps. Could someone tell me if this is worth it? What are the benefits? I can still return my ops. So why not benefit from a good advise.

     

     

    Sent from my iPad using Tapatalk

     

  21. krell ksa5 klone

    in Do It Yourself

    Posted

    On 3/2/2017 at 5:24 PM, Pars said:

    Linear Systems makes one now. Trendsetter has them, and they also have the LSK389.


    Sent from my iPhone using Tapatalk

    Trendsetter want to charge me like hell for shipping. Found some on ebay. hope they are not fake ;-)

    I am looking for a transformer, I read in this forum, that 2x27V 50VA should be used. my question is 27 V with or without load.

    Is my understanding correct that the board will draw less than 400mA (0.4 A x 21 V= 8.4 VA)so should not make a difference for a 50VA transformer?

  23. krell ksa5 klone

    in Do It Yourself

    Posted

    Hello 

    First of all i would like to thank the authors for the awesome work done, to bring those devices available to us. I am starting my trip with building the ksa5 and using it as a line pre-amplifier. do you think this is a good idea or it is first of all a Headphone aplifier, and there are better solutions for the price when it comes to pre-amp.

×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.

  I accept