Topic: SAKURA AV-200T Tube Amp

[JojoD818]

in case 1, buffer has unity gain, well, almost, gain is provided by the SS output stage..
in case 2, tube input stage provides voltage gain, the SS output stage only provides current, voltage gain is unity, or one.....

exactly...

BTT: I hope to get the chance to listen (with my gears) a previously modified av200 tonight... sana matuloy. 

[JojoD818]

btw, Tony, can you see any trimpots on the amp board? my eyes can be playing tricks on me again... 



i've always wondered how the amp section was biased... the size of the heatsink tells a lot but I still want to "touch" one and see for myself...

[iiinas]

in case 1, buffer has unity gain, well, almost, gain is provided by the SS output stage..
in case 2, tube input stage provides voltage gain, the SS output stage only provides current, voltage gain is unity, or one.....

in theory, which is a better design concept in which better sq can be achieved? case 1 or case 2? 

[macdon]

exactly...

BTT: I hope to get the chance to listen (with my gears) a previously modified av200 tonight... sana matuloy. 

I would eagerly await your feedback el presidente 

[JojoD818]

in theory, which is a better design concept in which better sq can be achieved? case 1 or case 2? 

In a perfect world, both should be the same. Both will present a very high source impedance, however, tube sound tends to sound more prominent when they "amplify" the signal as such in the 2nd case.

There are many applications for buffers, take the tube hybrid gainclone (JLTi) of Joe Rasmussen for example, the tube buffer is there not because of it's looks or just to have a tube in there. The tube buffer is used to isolate the input of the gainclone from the varying resistance that is being presented by the volume control.

In essence, the gainclone will change it's high frequency response dependent on the position of the volume control which in fact acts as a low pass filter (together with the gainclone's input capacitance). Adding a buffer in front of the amp isolates the volume control from the gainclone and the tube buffer presents a constant impedance to the amp, independent of the volume control's position.

I would eagerly await your feedback el presidente 

Sana nga matuloy Brader...

[kenchix1]

Yes pareho lang, ganyan ang ginawa sa av200 with the exception na tube rectified yun input buffer.

When you say tube buffer input and ss output it means that the "amplification" is still done by the ss output stage and the tube buffer only has a gain of 1 (kaya nga po buffer). That is how this av200 is Sir.

On the other hand, it is also possible for a hybrid amp (tube input/ss output) to have the "amplification" done by the tube section (gainstage na ito, hindi na tube buffer ang tawag), it is then followed by a "power follower" (often times referred to as a current amplifier) that has a gain of 1 which drives the speaker.

To recap, there are 2 ways to make a hybrid.
1. Tube buffer input -> SS amp output stage
2. Tube gainstage input -> SS power follower

I hope this clears things for you Sir.

Cheers



Edit:
There's a 3rd way pa pala, you can use high current voltage regulators and use them as power followers too to drive speakers, the gain is still dictated by the tubes in such a case.

Thanks sir, that I understand.

[reynold]

I have another questions for the Masters...

i read somewhere (posted by sir Tony) that the small tubes of this amp can be replaced by 12AT7 tubes and sir JojoD agree..., so tube rolling is possible and safe for this amp, right? may ibang tubes pa ba na pwede? And for those big tubes naman, pwede rin ba tube rolling dun and what is the safest tubes na pwede dun na available sa market today at madaling hanapin?

just curious

[iiinas]

In a perfect world, both should be the same. Both will present a very high source impedance, however, tube sound tends to sound more prominent when they "amplify" the signal as such in the 2nd case.

There are many applications for buffers, take the tube hybrid gainclone (JLTi) of Joe Rasmussen for example, the tube buffer is there not because of it's looks or just to have a tube in there. The tube buffer is used to isolate the input of the gainclone from the varying resistance that is being presented by the volume control.

In essence, the gainclone will change it's high frequency response dependent on the position of the volume control which in fact acts as a low pass filter (together with the gainclone's input capacitance). Adding a buffer in front of the amp isolates the volume control from the gainclone and the tube buffer presents a constant impedance to the amp, independent of the volume control's position.


Sana nga matuloy Brader...

depends on the implementation....and your tastes....

if you are more into tubes, you may find case 2 to be better....else you may find case 1 better...

thanks sa mga sagot! well, i find my jdlabs tube hybrid's sq very pleasing. neutral sound, which is how i like it. so i guess i like case 2.  

but if the sakua/sakura is case 1, i hope i will be able to listen to one in a foreseeable future. its really a great piece of equipment at its price. the beauty of it is price for admission into tube sound need not be expensive anymore.  

[JojoD818]

I have another questions for the Masters...

i read somewhere (posted by sir Tony) that the small tubes of this amp can be replaced by 12AT7 tubes and sir JojoD agree..., so tube rolling is possible and safe for this amp, right? may ibang tubes pa ba na pwede? And for those big tubes naman, pwede rin ba tube rolling dun and what is the safest tubes na pwede dun na available sa market today at madaling hanapin?

just curious

I believe that the 12AT7 "replacement" was used in a different context. Iirc, we were talking of possible modifications (not upgrades) that requires re-wiring. (Disclaimer) I personally don't suggest such a replacement until I can confirm what tube pinout was used in the av200.

Tube rolling is possible for all types of tube equipment naman sir, but we only have to be sure which type is it so we can make further suggestions.

[JojoD818]

i do not see any....

just as I thought. I wish it still is a class ab with a fixed bias nga lang.

[reynold]

I believe that the 12AT7 "replacement" was used in a different context. Iirc, we were talking of possible modifications (not upgrades) that requires re-wiring. (Disclaimer) I personally don't suggest such a replacement until I can confirm what tube pinout was used in the av200.

Oh i see, so it's for upgrades pala. Thanks Sir Jojo, i'll be waiting for your feedbacks kapag napag-aralan mo na ang AV200

Tube rolling is possible for all types of tube equipment naman sir, but we only have to be sure which type is it so we can make further suggestions.

E bakit kasi tinanong ko pa 'to, ang lakas naman ng pakiramdam ko na ganito ang kasagutan sa tanong ko, hehehe for the sake of other members na lang siguro kaya ko naitanong

Maraming salamat Sir JojoD

[JojoD818]

E bakit kasi tinanong ko pa 'to, ang lakas naman ng pakiramdam ko na ganito ang kasagutan sa tanong ko, hehehe for the sake of other members na lang siguro kaya ko naitanong

Maraming salamat Sir JojoD

Sabi ng titser ko noon bata pa ako... "Kapag hindi ninyo naintindihan, huwag mahiya na itaas ang kamay..."

 

[reynold]

Sabi ng titser ko noon bata pa ako... "Kapag hindi ninyo naintindihan, huwag mahiya na itaas ang kamay..."

 

Korek, i agree

[JojoD818]

Sa wakas nakahiram din ako nito...



Build quality looks good for it's price... unfortunately I cannot open this for it's not mine and I need to send it back asap. 

Btw, it says 5Z4P on the 2 rectifier tubes, no id on the peanut bulbs though. 

[macdon]

Sa wakas nakahiram din ako nito...



Build quality looks good for it's price... unfortunately I cannot open this for it's not mine and I need to send it back asap. 

Btw, it says 5Z4P on the 2 rectifier tubes, no id on the peanut bulbs though. 

Sound impressions perhaps? 

[iiinas]

Sound impressions perhaps? 

+1 

[qguy]

At mag paalam na "Mam may I go out ?"

Sabi ng titser ko noon bata pa ako... "Kapag hindi ninyo naintindihan, huwag mahiya na itaas ang kamay..."

 

[markcrenz]

this amp has fet differential/current mirror input stage, tube VAS stage in differential mode, this in turn buffered by a pnp transistor in a commen emitter type stage finally driving the mosfet output stage...melting pot of all active devices....

in theory, you can also have a fourth type, that is both tube and ss stages have voltage gains....

nosebleed!!! overheat utak ko...

[oweidah]

oayan may nagbenta na > http://www.pinoydvd.com/index.php?topic=105066.0

[gutierrez]

  bili bili na

[markcrenz]

... unfortunately I cannot open this for it's not mine and I need to send it back asap. 

sayang. ano kaya IC o transistors ng amp nito?

[reynold]

we'll find out in 2 weeks time...promise.....i'll be looking into viability of tweaking also...

eto ang hinihintay ko

[JojoD818]

Sound impressions perhaps? 

+1 

In the short amount of time I had with it I find the music too compressed (or tends to compress) for my taste. It's like when I turn the volume up, only the mids increases magnitude, the lows and highs gets left behind, the result was Beyonce sounds like she has a cold while singing and sometimes tends to be too sibilant. It's hard to describe really, but again, with such a short amount of time, I was like in a rush.

The good news is that I will have another shot at it next week, this time with a lot longer foreplay and more intimate relationship - I was promised to get to see it naked. 

[JojoD818]

i forgot to mention the Luxman LV-103/105 series....they use the 6CG7 tubes as VAS stage, they were raved at afaik, getting good reviews....

this amp has fet differential/current mirror input stage, tube VAS stage in differential mode, this in turn buffered by a pnp transistor in a commen emitter type stage finally driving the mosfet output stage...melting pot of all active devices....

in theory, you can also have a fourth type, that is both tube and ss stages have voltage gains....

Iirc, it was Prof Leach who always talk about operating the VAS stage in Class A - and what better active device to do this than a vacuum tube... the hotter, the better. 

[macdon]

I got to visit anthony late last night & went home with a borrowed "modified" Sakura to evaluate. For evaluation purposes, I used my Rotel flagship RCD-1072 with Xindak suspension ball shackles, bi-wire speaker cables and the proac clone 2.5 with Scanspeak drivers.





I really wanted to hear an un-modified Sakura to compare with a modified version but unfortunately Anthony only had modified ones.

To begin with, do take this all with a grain of salt as I was skeptical myself in using a floorstander speaker with having a low 86db sensitivity rating. The amp did fill my living room with adequate music at a comfortable level & it has an impact to a degree but most times it was brite with no depth or weight.
There was no 'midrange lush' that is common with tube gears which actually made me think that i was just using a solid state amp.

However, even at a modified price of 6.5k - its hard to beat and to anyone looking for their first (SS or Tube) amp should atleast audition this amp. Just remember to pair it with higher sensitivity speakers of 89db and up.

[dencio105]

Any update on this sir?:

In the short amount of time I had with it I find the music too compressed (or tends to compress) for my taste. It's like when I turn the volume up, only the mids increases magnitude, the lows and highs gets left behind, the result was Beyonce sounds like she has a cold while singing and sometimes tends to be too sibilant. It's hard to describe really, but again, with such a short amount of time, I was like in a rush.

The good news is that I will have another shot at it next week, this time with a lot longer foreplay and more intimate relationship - I was promised to get to see it naked. 

[docsialu]

any new feedbacks regarding this amp?

[JojoD818]

Any update on this sir?:

Unfortunately, no new update sir. Hindi kami natuloy nun ka-date ko due to time constraints.

I hope TonyT has some news...

[reynold]

paging Sir Tony.....

[dana]

yup, got mine just now......Jems had it listed for 3850, but when i asked seller Alma, she told me i can have it for 3500, so without further ado, i got one....expect my review in a day or two....

initial impression....mas pogi sa personal yung amp....

welcome back Sir TonyT...aside from your isound mpressions, if you feel like it, baka pede nyo po kuhanan ng kahit konting basic measurements including freq. response para sa mga curious...

thanks