Kondo Ongaku Rectifier Tube

[Uwiik]

Not sure where to post this question but the tube only sub is pretty quiet so I post this here.

My Kondo Ongaku is the newer model where it comes stock with GZ34 rectifier tubes unlike the Ongaku from Kondo San era where it came stock with GZ37. I already have what is considered the top cream for GZ34 which is Mullard on mine but I found a matched quad NOS Mullard GZ37. Just wondering if anybody know for sure if it’s OK to roll GZ34 to GZ37 recti on the newer Kondo Ongaku, I would love to hear how Ongaku sound as intended by the late Kondo San himself with GZ37, not GZ34.

Thanks

 

[Uwiik]

Nobody?

Kondo didn’t reply my email….. hmmm spending in excess of 100K on their products and they didn’t bother to answer me… made me think twice about the brand and here I am contemplating to risk a world war with my wife to order Kagura… maybe not……but I like the sound from Japanese audio… damn!!!

I don’t understand the Japanese, they know how to make great and the best bulletproof products but they really are the worst in communication and business agility. I deal with customers worldwide and all my 3 Japanese clients just doesn’t grow at all, like literally 0 growth of business and I have been dealing with them since 2007-2011-2015 and still until today always have hard time communicating ANYTHING, most if not all communications are one way, they all just order the same cheap and common stuff all the time with zero change, heck even my Pakistani customer’s business grew more than the Japanese. Maybe Pakistan should start making high end audio, perhaps they will be better than the Japanese!!!

OK I am ranting here but I don’t think I am expecting unrealistic expectations, I just want my questions to be answered after spending 100k plus on their damn amplifiers.

 

[Uwiik]

I tried to call them, no answer, then I sent them a not so nice (very not nice actually LOL) follow up email and I got answer in literally 5 minutes!!!! Funny enough the answer from them got my nasty message deleted…LOL!! Showing me that they actually read their email all the time but just didn’t bother to answer. Damn!!

Anyway, for future reference to anyone needing this information, the answer is NO, GZ37 is NOT compatible with newer Ongaku. See screenshot below.

 

[Uwiik]

I asked further about this



and this is the answer



I began to doubt his answer, perhaps it’s just formality standard template answer without any real knowledge behind it? We all know the old OG Ongaku came with GZ37 tubes which later changed to GZ34, so the answer above is false.

@gian60 @howiebrou any help or experience here?

 

[howiebrou]

I asked further about this

View attachment 85159

and this is the answer

View attachment 85160

I began to doubt his answer, perhaps it’s just formality standard template answer without any real knowledge behind it? We all know the old OG Ongaku came with GZ37 tubes which later changed to GZ34, so the answer above is false.

@gian60 @howiebrou any help or experience here?

I know Charles. He is not in Japan, he is here in Hong Kong. Send me a PM and I will give you a hand.

 

[Zeotrope]

Nobody?

Kondo didn’t reply my email….. hmmm spending in excess of 100K on their products and they didn’t bother to answer me… made me think twice about the brand and here I am contemplating to risk a world war with my wife to order Kagura… maybe not……but I like the sound from Japanese audio… damn!!!

I don’t understand the Japanese, they know how to make great and the best bulletproof products but they really are the worst in communication and business agility. I deal with customers worldwide and all my 3 Japanese clients just doesn’t grow at all, like literally 0 growth of business and I have been dealing with them since 2007-2011-2015 and still until today always have hard time communicating ANYTHING, most if not all communications are one way, they all just order the same cheap and common stuff all the time with zero change, heck even my Pakistani customer’s business grew more than the Japanese. Maybe Pakistan should start making high end audio, perhaps they will be better than the Japanese!!!

OK I am ranting here but I don’t think I am expecting unrealistic expectations, I just want my questions to be answered after spending 100k plus on their damn amplifiers.

I hear you. I also have a complete Kondo system. They have replied to me in the past, but you need to communicate through your dealer. Kondo is a small company. They rely on their dealers to communicate with clients.

 

[Guscom]

Hi,
I posted same question in another Kondo Ongaku thread. I wrote to Charles of AN Japan some time ago asking if I can use cv378 (gz37) rectifier on my old Ongaku instead the gz34, he answered quickly and kindly (as usually, I have to add):
“
Dear Sir,

Thanks for your email !
All Ongaku come with GZ34 as rectifier tubes. GZ37 is NOT compatible with GZ34 in the Ongaku design.
So please don't use GZ37 as it will overload the power transformer.

BR
Charles
Audio Note
“

 

[Guscom]

But I think that some audiophiles used to change their rectifier to gz37 (or cv378 or cossor u52) instead gz34, I read this on a particular thread about Ongaku on the forum review33. I know that the Kondo manufacturing standard are very very high (and the price too) and usually their devices are built like a tank, specially the older one, and the very heavy power transformer is so oversized that (imho) it can withstand current deliveries higher than the standard one. But this is obviously at the owner's own risk because the factory explicitly states that the use of other valves instead of the gz34 can damage the power transformer.

 

[mtemur]

gz37 is not equivalent to gz34. since both having indirectly heated cathode, both have cleaner sound and I wouldn’t bother using gz37. the problem using other than equivalent rectifiers is getting a slightly shifted frequency response besides electrical issues. at least that’s what I observe when I use gz37 and other rectifiers in a tube amplifier. the overall tone of the amp shifts a little bit up or down depending on the rectifier type. as a result I found it’s best to stick original or equivalent rectifier IMHO.

 

[tedwoods]

The original Ongaku (Audio Note Japan) used four 5Y3 rectifier tubes. Their European pin equivalent is the U50, but a GZ30 can also be used.
Certain users have since tried either 5V4/GZ32's or 5AR4/GZ34 tubes, which are both higher voltage rectifiers and although not the original design tubes, can still be used with relative safety.
Only the original Audio Note Japan Neiro and Kegon used 5U4 rectifiers (one and two respectively), which can be substituted with U52 or GZ37 tubes.

 

[Guscom]

As I reported some posts ago, Kondo factory answered that all Ongaku come regularly with the GZ34 tube rectifiers. I know that over the years three series of Ongaku have been produced (mainly), the first had the inputs on the front and was smaller than the others, the second had the inputs on the side and dimensions equal to the current series and had the red “Ongaku” label on the front, and the last, which is the current one, is the KSL version with similar dimensions. I don’t know what rectifiers It used on the first series but I know that the 2nd used to have gz34 as stock rectifiers but someone changed with Gz37 (cv378) and someone used to have the cv378 “big bottle” (similar to cossor u52). Maybe some others forum’s members can tell us more and give us some additional infos. I know gian60 has a lot of Ongaku experience and has some friends who also own the first Ongaku series and the next series. About the Neiro (ANJ) I owned 3 different devices, one of 1994 and others two from 1997 (if I remember good). All used 5U4G as rectifiers. I don’t know about old Kegon.

 

[tedwoods]

Yes, I must clarify that I am referring to the earliest version of the Ongaku (with exposed pre-amp tubes in the front and elevated rectifier chassis on the back). The schematic for the second version does show 4x5AR4 rectifiers. I also used to own the Neiro...