Class D Audio

Assolutamente d'accordo con Roby, le potenzialita' di questo ampli vanno verificate con ben altri diffusori, anche se e' gia divertente far suonare gli skythe cosi bene e cosi forte. Forse mi faccio impressionare, ma sentire l'aletta cosi calda in classe d fa' una certa impressione. Sara' suggestione, ma un aiuto mi tranquillizerebbe, sopratutto nel lungo termine.
Per i costi, nel mio caso, acquisto tramite sito con paypal, totale prezzo del kit con spedizione, 184€ a cui aggiungere 29€ di dogana e dazi. L'ampli che ho preso e' quello da 250W su 4ohm, 125 su 8ohm e 500W in mono.
Consiglio vivamente il loro alimentatore, con un trasformatore pesantissimo e ben fatto, gelido anche dopo un'ora di volume elevato, splendido.

Wushuliu ha scritto:[quote = "roby2k"] You know the output impedance of your pre valve?


For madqwerty
With 50k I think there is indeed a problem of impedance.
No buzz, semlpicemente adjust the volume almost all the last quarter with consequent difficulty in regulating the right level of listening. Moreover and most importantly, I had the sensation of a sound a bit compressed, especially when I went to lower the volume, I can not describe, but with the 10k you just feel more enjoyment, a airy sound already with low volumes. That's probably the exact term and airiness. [/ Quote]

Roby, I think you are correct about the amp needing low input impedance. I just received this tube buffer Indeed today.

http://cgi.ebay.com/Indeed-Valve-Buffer-Pre-Amplifier-6N3-5670-2C51-6CC42_W0QQitemZ290363747981QQcmdZViewItemQQptZVintage_Electronics_R2?hash=item439b072e8d

It has high input impedance and very low output impedance. My setup is now WDTV -> SR4002 pre-outs -> Tube Buffer -> Class D Amp

I have only listened to it for an hour. The Good Side: Improved separation and imaging, more like the Sure amp. Soundstage is even wider (!). Improved clarity (? Not sure yet). Bad side: Not as 'smooth', high end a little sharp. But I have read that tubes need several days to break in, so I will wait before making a final judgment. I do think that the overall performance of the amp is improved (of course the amp sounds amazing on its own).


w
 : afro:

Do you have news?

Cristi vende un ampli basato sullo stesso chip IRS2092 IC:

http://connexelectronic.com/product_info.php/products_id/103?osCsid=asal6g59kjb3ukhk5s2ehrdkr4

Cmq gli alimentatori di Cristi dovrebbero andare bene perchè sono entrambi duali da quanto ho capito hanno sia la V+ che V-. Ma forse non convengono visto i prezzi di questi kit su ebay

R!ck ha scritto:Cristi vende un ampli basato sullo stesso chip IRS2092 IC:

http://connexelectronic.com/product_info.php/products_id/103?osCsid=asal6g59kjb3ukhk5s2ehrdkr4

Cmq gli alimentatori di Cristi dovrebbero andare bene perchè sono entrambi duali da quanto ho capito hanno sia la V+ che V-. Ma forse non convengono visto i prezzi di questi kit su ebay

che non è altro che l'evaluation board della international rectifier senza alcuna modifica.
Gli switching di cristi credo che andrebbero proprio bene con i classdaudio.
Quello che bisogna capire è qual'è migliore: la tradizionale o la switching?

Questo Roberto è per te!

Hi R!ck,

Although I do recommend a preamp for the best performance, you can also use a potentiometer. I think a 5K pot will give good results.

Please let me know if I can be more help.

Thanks,
Tom

Do you have news? [/ Quote]

I've been doing a lot of modifications and listening to the Buffer Indeed. Replacing the power supply capacitors and input / output capacitors.

Changing the capacitors gives interesting results. I do not know if it is due to the buffer design, the transparency of the classd, or both, but using different capacitors creates a very, very big difference in sound. I replaced the original FK 1800uf Panasonic caps with 1000uf Elna Silmic II and replaced 2 more caps w / Elnas. Result was a very warm, very analog sound. Smooth midrange. The high frequency were definitely damped. Strong bass. Soundstage was not as wide as before. Not as dynamic. I did not have the patience to wait the recommended 100 hours for burn-in, the sound was too extreme so I pulled those out and replaced all caps w / Panasonic FM. Result was the extreme OTHER: Really clear, crisp, less bass, very transparent, but harsh high end. Again, I did not have the patience to wait too long so I mixed them up. All FM, except the large-cap Which are Elna. This creates a nice balance. this time I will wait the 100 hours.

Does it improve the Class D sound? Some ways yes, some ways, no. The improved imaging and separation are definitely no matter what combination, everything else is just Flavoring to your own taste.

I also built one of these kits: http://diyaudioprojects.com/Tubes/6418-Tube-Preamp-Headphone-Kit/

And it does a surprisingly good job. Really made an impression w / the OPA2134 opamp. Only problem is mine has a constant low level hiss. Other builders do not have this problem, so I am trying to fix it. Definitely worth trying out. Aside from the hiss I liked it better than the Indeed.

Bottom line is the Class D does respond very well to a pre of some kind. I have ordered a B1 Buffer PCB, so that's next (and will probably be what I use, as it should be FAR better than the other two).

[img] [url = https://servimg.com/view/14601531/9] [img] https://i.servimg.com/u/f90/14/60/15/31 / buffer18.jpg [/ img] [/ url] [/ img]


: Afro:

R!ck ha scritto:Questo Roberto è per te!

Hi R!ck,

Although I do recommend a preamp for the best performance, you can also use a potentiometer. I think a 5K pot will give good results.

Please let me know if I can be more help.

Thanks,
Tom

5K..........................che non è facile trovare.
Comunque era la risposta che mi aspettavo.
Grazie.

Wushuliu ha scritto:Do you have news? [/ Quote]

I've been doing a lot of modifications and listening to the Buffer Indeed. Replacing the power supply capacitors and input / output capacitors.

Changing the capacitors gives interesting results. I do not know if it is due to the buffer design, the transparency of the classd, or both, but using different capacitors creates a very, very big difference in sound. I replaced the original FK 1800uf Panasonic caps with 1000uf Elna Silmic II and replaced 2 more caps w / Elnas. Result was a very warm, very analog sound. Smooth midrange. The high frequency were definitely damped. Strong bass. Soundstage was not as wide as before. Not as dynamic. I did not have the patience to wait the recommended 100 hours for burn-in, the sound was too extreme so I pulled those out and replaced all caps w / Panasonic FM. Result was the extreme OTHER: Really clear, crisp, less bass, very transparent, but harsh high end. Again, I did not have the patience to wait too long so I mixed them up. All FM, except the large-cap Which are Elna. This creates a nice balance. this time I will wait the 100 hours.

Does it improve the Class D sound? Some ways yes, some ways, no. The improved imaging and separation are definitely no matter what combination, everything else is just Flavoring to your own taste.

I also built one of these kits: http://diyaudioprojects.com/Tubes/6418-Tube-Preamp-Headphone-Kit/

And it does a surprisingly good job. Really made an impression w / the OPA2134 opamp. Only problem is mine has a constant low level hiss. Other builders do not have this problem, so I am trying to fix it. Definitely worth trying out. Aside from the hiss I liked it better than the Indeed.

Bottom line is the Class D does respond very well to a pre of some kind. I have ordered a B1 Buffer PCB, so that's next (and will probably be what I use, as it should be FAR better than the other two).

[img] [url = https://servimg.com/view/14601531/9] [img] https://i.servimg.com/u/f90/14/60/15/31 / buffer18.jpg [/ img] [/ url] [/ img]


: Afro:

Thank you very much for your experience.
Now I'm using only a 10K alps pot with very good result.
Next step is a 5K pot and B1 buffer, one for time, but i don't know when.

Roberto.

Roberto, did you tried a new fuse yet?

One last recommendation for this amp: I highly, highly, highly recommend replacing the 2 .47 uf .1 uf Epcos and output filter caps (the big blue caps). I have replaced mine with the well-regarded Dayton film / foil bypass caps. Cost: $ 5. I no longer need the buffer. All the issues with this amp that I believed needed to be corrected by the buffer or preamp are now gone.

http://www.parts-express.com/pe/pshowdetl.cfm?PartNumber=027-458

It makes sense as the Epcos are basic low-cost caps. I used them to replace the cheap polyester caps in the buffer. I would have used better but there was no room on the buffer PCB. They are okay, but nothing special.

Obviously an amp like this needs better than these caps for the output filter (as anyone who built tripaths w / input and output filter caps caps knows).

The amp now sounds outstanding. Near-perfect in my setup. It is a difference that would be audible to anyone. It is totally transparent and very, very clean.

Make sure to use a good iron, the PCB is thick so take your time.

I can not recommend this enough. Any decent cap will be better than the Epcos, so you can spend as much or little as you want.

I think this is it for me as far as this amp is concerned. I do not think it can sound any better (well. ..): mmm:

(sigh, I've given up on getting any links or smilies or bold fonts to work. This is the only forum I have this issue)

Very interesting...I getting more and more interested. I would be interesting to compare it against a ta3020 or Hypex since it costs about an half!

Mi piacerebbe proprio saper come va questo ampli raffrontato ad un ta3020 non mi sembra così inferiore leggendo i ds...e costa praticamente la metà.

R!ck ha scritto:Very interesting...I getting more and more interested. I would be interesting to compare it against a ta3020 or Hypex since it costs about an half!

Mi piacerebbe proprio saper come va questo ampli raffrontato ad un ta3020 non mi sembra così inferiore leggendo i ds...e costa praticamente la metà.

Be, io sto aspettando la fiera dell'elettronica qui a Genova per prendergli un case adeguato a questo ampli, ma se nel frattempo qualche possessore del 3020 volesse ascoltarlo sarei disposto a mandarlo per una prova.

Chissa se al "dottore" interessa ...Sarebbe il più competente visto che ha anche gli ucd!
Dal basso della mia inesperienza rimane il più economico ed il più semplice da realizzare oltre ad essere il più completo dal momento che le protezioni contro la continua sono on board!

Wushuliu ha scritto:Roberto, did you tried a new fuse yet?

Not yet.
I'm waiting for a new fuse holder than I will buy a good fuse.

Wushuliu ha scritto:One last recommendation for this amp: I highly, highly, highly recommend replacing the 2 .47 uf .1 uf Epcos and output filter caps (the big blue caps). I have replaced mine with the well-regarded Dayton film / foil bypass caps. Cost: $ 5. I no longer need the buffer. All the issues with this amp that I believed needed to be corrected by the buffer or preamp are now gone.

http://www.parts-express.com/pe/pshowdetl.cfm?PartNumber=027-458

It makes sense as the Epcos are basic low-cost caps. I used them to replace the cheap polyester caps in the buffer. I would have used better but there was no room on the buffer PCB. They are okay, but nothing special.

Obviously an amp like this needs better than these caps for the output filter (as anyone who built tripaths w / input and output filter caps caps knows).

The amp now sounds outstanding. Near-perfect in my setup. It is a difference that would be audible to anyone. It is totally transparent and very, very clean.

Make sure to use a good iron, the PCB is thick so take your time.

I can not recommend this enough. Any decent cap will be better than the Epcos, so you can spend as much or little as you want.

I think this is it for me as far as this amp is concerned. I do not think it can sound any better (well. ..): mmm:

(sigh, I've given up on getting any links or smilies or bold fonts to work. This is the only forum I have this issue)

Thanks very much.
Can you post some images please?

Ciao, schede e super alimentatore arrivati!!!

Prime immagini dell'alimentatore

https://2img.net/r/ihimizer/img705/4215/alimentatore2.jpg
https://2img.net/r/ihimizer/img13/4131/alimentatore3.jpg


A presto.

Rob

Robfug ha scritto:Ciao, schede e super alimentatore arrivati!!!

Prime immagini dell'alimentatore

https://2img.net/r/ihimizer/img705/4215/alimentatore2.jpg
https://2img.net/r/ihimizer/img13/4131/alimentatore3.jpg


A presto.

Rob

Ciao ma questo quale è ....... quello da 250 w su 4 ohm?
Il trasformatore ci va in un case da 8 cm?

Luciano.

pentrio ha scritto:

Robfug ha scritto:Ciao, schede e super alimentatore arrivati!!!

Prime immagini dell'alimentatore

https://2img.net/r/ihimizer/img705/4215/alimentatore2.jpg
https://2img.net/r/ihimizer/img13/4131/alimentatore3.jpg


A presto.

Rob

Ciao ma questo quale è ....... quello da 250 w su 4 ohm?
Il trasformatore ci va in un case da 8 cm?

Luciano.

Credo che l'omonimo Roberto abbia preso due schede da 250watt su 4ohm con un ali da 400VA per poi configurarle a ponte in modo da ottenere 500 watt per canale su 8 ohm un mostro di potenza.
Mi sbaglio?

A proposito......

Roberto ti ricordi che ci siamo scritti già in passato? E' un piacere ritrovarti su questo forum, benvenuto.

[quote = "roby2k"]
Thanks very much.
Can you post some images please? [/ Quote]

Here are some pics. At the last minute I decided to change the caps for some Dayton Foil Vitamin Q Oil Paper-Caps I had lying around, and then switched the RCA interconnects w / some silver wire from Partsconnexion. The 5th and 6th pics were before I changed the caps. Sounds fantastic! I am definitely done now. Promise! P

https://i.servimg.com/u/f10/14/60/15/31/img_1810.jpg
https://i.servimg.com/u/f10/14/60/15/31/img_1811.jpg
https://i.servimg.com/u/f10/14/60/15/31/img_1812.jpg
https://i.servimg.com/u/f10/14/60/15/31/img_1814.jpg
https://i.servimg.com/u/f10/14/60/15/31/img_1815.jpg

Ciao Roby, certo che mi ricordo! Si, le schede che ho preso sono quelle da 250 su 4 ohm e le lascierò così senza ponticellarle mantenendo la biamplificazione verticale passiva alle mie SP38...dovrebbe venir fuori qualcosa di interessante considerando che raddoppio la potenza...

Si, il trasformatore, non con poche difficoltà, si riesce a mettere in un case 23X28X8
Presto posterò anche i "finalini", poi vi farò sapere le impressioni di ascolto.

Le tue impressioni di ascolto sul clone 2.5? Anche io, a casa dei miei ho lo pseudo clone delle 2.5 fatto con lo scan D2905 e mi sà che qualche provetta la farò anche con quelle.

Ciao a tutti.

Rob

Robfug ha scritto:Ciao Roby, certo che mi ricordo! Si, le schede che ho preso sono quelle da 250 su 4 ohm e le lascierò così senza ponticellarle mantenendo la biamplificazione verticale passiva alle mie SP38...dovrebbe venir fuori qualcosa di interessante considerando che raddoppio la potenza...

Si, il trasformatore, non con poche difficoltà, si riesce a mettere in un case 23X28X8
Presto posterò anche i "finalini", poi vi farò sapere le impressioni di ascolto.

Le tue impressioni di ascolto sul clone 2.5? Anche io, a casa dei miei ho lo pseudo clone delle 2.5 fatto con lo scan D2905 e mi sà che qualche provetta la farò anche con quelle.

Ciao a tutti.

Rob

Per biamplificazione verticale passiva intendi un ampli per diffusore ?
Io mi trovo benissimo con le mie clone. Sicuramente il resto dell'impianto fa la sua parte e devo dire che ne sono molto molto soddisfatto.
Però ho tanta voglia di provare queste schede a ponte, ma ne ho una sola.
Come ho già scritto altre volte, ritengo giustificata la biamplificazione con crossover sul segnale, quindi attiva.
A maggior ragione, nel tuo caso, configurerei le schede a ponte. Se ne hai voglia, fai delle prove e vedi la configurazione che più ti aggrata.

Buon divertimento.

Certo la soluzione biamplificazione attiva è un altro mondo, comunque troppi parametri variabili in gioco per me. In questa configurazione, biamplificazione verticale passiva penso sia meglio lasciare la versione stereo su 4 ohm a parità di alimentazione, ma mi posso sbagliare!! ....

Farovvi sapere...

Wushuliu ha scritto:[quote = "roby2k"]
Thanks very much.
Can you post some images please? [/ Quote]

Here are some pics. At the last minute I decided to change the caps for some Dayton Foil Vitamin Q Oil Paper-Caps I had lying around, and then switched the RCA interconnects w / some silver wire from Partsconnexion. The 5th and 6th pics were before I changed the caps. Sounds fantastic! I am definitely done now. Promise! P

https://i.servimg.com/u/f10/14/60/15/31/img_1810.jpg
https://i.servimg.com/u/f10/14/60/15/31/img_1811.jpg
https://i.servimg.com/u/f10/14/60/15/31/img_1812.jpg
https://i.servimg.com/u/f10/14/60/15/31/img_1814.jpg
https://i.servimg.com/u/f10/14/60/15/31/img_1815.jpg

Many thanks,
So you replaced 4 caps in total?
Do you not replaced the 4 cylinder big blue cap near inductor also?

Robfug ha scritto:Certo la soluzione biamplificazione attiva è un altro mondo, comunque troppi parametri variabili in gioco per me. In questa configurazione, biamplificazione verticale passiva penso sia meglio lasciare la versione stereo su 4 ohm a parità di alimentazione, ma mi posso sbagliare!! ....

Farovvi sapere...

Bene,
Mi raccomando, almeno una trentina di ore di rodaggio. All'inizio suonerà con alti un pò arretrati, ma col tempo miglioreranno e non di poco.

[quote = "roby2k"] [quote = "Wushuliu"] [quote = "roby2k"]
Thanks very much.
Can you post some images please? [/ Quote]

Here are some pics. At the last minute I decided to change the caps for some Dayton Foil Vitamin Q Oil Paper-Caps I had lying around, and then switched the RCA interconnects w / some silver wire from Partsconnexion. The 5th and 6th pics were before I changed the caps. Sounds fantastic! I am definitely done now. Promise! P

https://i.servimg.com/u/f10/14/60/15/31/img_1810.jpg
https://i.servimg.com/u/f10/14/60/15/31/img_1811.jpg
https://i.servimg.com/u/f10/14/60/15/31/img_1812.jpg
https://i.servimg.com/u/f10/14/60/15/31/img_1814.jpg
https://i.servimg.com/u/f10/14/60/15/31/img_1815.jpg [/ quote]

Many thanks,
So you replaced 4 caps in total?
Do you not replaced the 4 cylinder big blue cap near inductor also? [/ Quote]

Yes, I replaced 4 caps. The .47 ufs are too large to put on top so as you could see I had to solder them
on the bottom of the PCB.

I considered replacing the large electrolytic caps but it turns out they have very good specifications. Very low impedance. Just as good as Panasonic FC (the Panasonic FM and Elna are not available in high voltage), so I left them alone ...