Topic: Official Cayin Thread

[JojoD818]

tonyt, one other thing.  What do you suppose that choke is doing in the center of the amp?  What purpose could it server?  My friend says that it was actually bypassed in my amp.  We were guessing that it was a choke filter, but that doesn't make sense with a SS power supply, does it?  or does it have some other function?

is the choke disconnected/not wired?

that does not concern me much, if it is connected after the bridge it can help a bit too...

i am sure the chinese designers are playing to the market, buyers, many of whome knows next to nothing about tube circuits, and distributors that likewise does not bother to know on a technical level about the products they sell.... :'( well couldn't blame them though.....

i am sure the decision to use the rectifier tube was the "myth" about tube rectifiers as better sounding than ss rects... they are just playing up to it....

fortunately, tube circuits are very easy to decipher, a look under the hood is all it takes to reveal its inner secrets....

tube amps are about output transformers....get it right and you have a winner of an amp....

it is not the tubes per se, but what you do with them......

I can't agree more, the OPTs really plays center stage in tube amps. I'm sure the official statement from Cayin should be here soon, festivities in China are soon coming to a close I guess.

[qguy]

Most reviewers concentrate on the sound and those specs that are easily seen, ie number / type of tubes, watts etc..its very rare that a reviewer would really look under the hood and inspect each connection. Bottom line is, if the sound is good, the review is good. undoubtedly the sound is excellent by my standards.. SS or tube rectified it does not bother me at all.

Hi guys,

  These amps have been reviewed around the world, and no one has noticed this yet.  What does that tell us about the quality or the reviews?

[qguy]

Interesting what Cayin engineers would say about this issue

Although I am pretty sure there is an actual use of the tube, as it would be unforgivable to just put a tube in there for show in your top of the line product for an integrated amp.  If it was a design flaw,  plugging the whole seems to be an easy task as there is a separate cover plate that can be replaced rather than changing the entire chassis. As a manufacturer, it would have been easy / cheaper (I am assuming) to install a name plate on the center of the amp rather than installing a 5ar4 tube + sockets.

Do you still get that power on delay w/o the 5ar4 ?

[ATJr.]

Found operating points for 6550 class A1 push-pull, values are for 2 tubes:

DC Plate Voltage ..................395
DC Screen Voltage .................395
Cathode-Bias Resistor..............200 Ohms
Peak AF grid to grid voltage.......70
Zero Signal Plate Current..........170mA
Max signal Plate Current...........174mA
Zero singalDC Screen Current.......12.5mA
Max Signal DC SCreen Current.......23mA
Effective Load Resistance, Ra-a....5600ohms
Total Harmonic Distortion..........1.5 Percent
Maximum-Signal Power Output........34Watts


Looking at this data, it is possible to get 30watt ouput as claimed ........

notice that for one channel, current drain is 170mA, a single 5AR4 can handle this in mono, but two channels from the same tube is asking too much....this will explain why the solid sate rectifiers ended up there.....

still it is also possible that the tube is not there for "Showmanship" alone, it could also be that the tube was used to supply the drivers and preamp sections, in that role the tube will last the lifetime of the amp.

if anybody can email me the schematics, we can defenitely find out for sure.

[Adam Warlock]

I am sorry we cannot do it given that these are patented by Cayin - although we are more than happy to show them to you without releasing any copies.

This thread is very busy in the past days, Thanks to ptubeh for raising the query. I also extend my sincerest gratitude to Sir/s TonyT, JojoD, Qquy and to the guys who shared their insights. More patience please, Cayin is still on holiday but we will post their reply once we have them.

Sir Tony, sorry we can't email you the schematics but if you have free time we will gladly show it to you over a cup of coffee or tea    Maybe we can sched, so Jojo and qquy can dropby too   

Again, many thanks guys....

Cheers

[ptubeh]

You guys sure seem like good fellows.  To bad I don't live in the Phillipines.  I would love to join you.

Tony, remember that gguy found that his amp works without the rectifier tube plugged in.  So I don't see how the rectifier tube could be used for the preamp tubes.  Doesn't that make sense?

[ATJr.]

no it doesn't. ....guess those china boys got their hands on the cookie jar....time to give them a slap on the hand for being naughty.....

[ATJr.]

Sir Tony, sorry we can't email you the schematics but if you have free time we will gladly show it to you over a cup of coffee or tea    Maybe we can sched, so Jojo and qquy can dropby too   

i would love to, except that i am in Russia at the moment, though my IP adress points to Ireland cause i do happen to be working for an Irish company....but thanks anyway....

[ATJr.]

Hi ptubeh,

 I would like to ask you about the output traffo since it has caught my attention when you said the you decided to take frequency response readings even before you listened to it, and that you found it to be "from 10 hz to 60khz", now that is a mighty good reading to me, specially the 10hz part....

now i would like to know at what power level did you take those measurements? did you take it at an ouput level of 1watt? 10 watt or 30 watts?...

can you ask your friend for me?

[qguy]

Not me that was 4krow..

Tony, remember that gguy found that his amp works without the rectifier tube plugged in.  So I don't see how the rectifier tube could be used for the preamp tubes.  Doesn't that make sense?

[4krow]

  Actually guys, I didn't take any readings of the output of my amp. All I was doing was repairing a defective power connection. And my amp is the 55watt output model. I did, however, take out the rectifier tube, and then turn the amp on. It seemed to be fine, but I did not raise the volume very much, since I really didn't need any new suprises. So now, we must wait for the reply of Cayin to explain themselves. In the meantime, I'm wondering if a 5UAG rectifier tube is able to be substituted for the 5AR4. Anyone who may have info., I would appreciate it.....Greg

[qguy]

Do you still get that power on delay w/o the 5ar4 ?

  Actually guys, I didn't take any readings of the output of my amp. All I was doing was repairing a defective power connection. And my amp is the 55watt output model. I did, however, take out the rectifier tube, and then turn the amp on. It seemed to be fine, but I did not raise the volume very much, since I really didn't need any new suprises. So now, we must wait for the reply of Cayin to explain themselves. In the meantime, I'm wondering if a 5UAG rectifier tube is able to be substituted for the 5AR4. Anyone who may have info., I would appreciate it.....Greg

[AudioAmplified]

Sirs,  WOW... busy thread.

Hopefully Cayin can reply by next week as work will resume from their "chinese" new year break. Patience my friends. Also... requesting a little respect for us too hehehe   Calling us (well i cant speak for other countries) distributors who doesn't know a thing about what we sell is a little harsh or personal dont you think.  All we want is to wait for Cayin to make the official reply and it happens to be chinese new year break hence the delay.

While waiting for Cayin's reply, we would also like to clarify that it is the country distributors who are responsible for their marketing as Cayin does not actively publish their products.

It is just disheartening to read some of the posts that makes us look like the alabang boys.

Peace

[ATJr.]

It is just disheartening to read some of the posts that makes us look like the alabang boys.

sorry if seemed to be in your face, i apologize.....

however, there is no need to feel that way, after all you did not do the design an manufacture, you merely distributed their products, and from what i heard, those cayins really sounded great.....i don't think anyone can blame you for that.....

as with all things coming from China, there will always be quality issues...

even Japan, Korea, and Taiwan once upon a time went thru that process....

it is feedback from consumers that will make them do better...so let us take this as an opportunity rather than a negative thing.....

[ATJr.]

  Actually guys, I didn't take any readings of the output of my amp. All I was doing was repairing a defective power connection. And my amp is the 55watt output model. I did, however, take out the rectifier tube, and then turn the amp on. It seemed to be fine, but I did not raise the volume very much, since I really didn't need any new suprises. So now, we must wait for the reply of Cayin to explain themselves. In the meantime, I'm wondering if a 5UAG rectifier tube is able to be substituted for the 5AR4. Anyone who may have info., I would appreciate it.....Greg

AFAIK, a 5U4 has higher drop than the 5AR4....besides your amps seems fine without those tubes, why bother?

[4krow]

gguy,   Yes, there is the delayed turn on witout the rectifier tube.

TonyT, Maybe shallow of me to admit, but the 5U4G(or whatever that number was) looks cooler than 5AR4. Might as well go for sexy if there is nothing else to benefit.  hehheheheh, Greg

[ptubeh]

Hi ptubeh,

 I would like to ask you about the output traffo since it has caught my attention when you said the you decided to take frequency response readings even before you listened to it, and that you found it to be "from 10 hz to 60khz", now that is a mighty good reading to me, specially the 10hz part....

now i would like to know at what power level did you take those measurements? did you take it at an ouput level of 1watt? 10 watt or 30 watts?...

can you ask your friend for me?

Hi Mr TonyT,

I will ask him the details.  We have been trying to get him an account here, but the new account dialog has been blocked the last couple of day.  If he can't get an account soon, I will ask him to write something up and I will post it for him.

[ptubeh]

sorry if seemed to be in your face, i apologize.....

however, there is no need to feel that way, after all you did not do the design an manufacture, you merely distributed their products, and from what i heard, those cayins really sounded great.....i don't think anyone can blame you for that.....

as with all things coming from China, there will always be quality issues...

even Japan, Korea, and Taiwan once upon a time went thru that process....

it is feedback from consumers that will make them do better...so let us take this as an opportunity rather than a negative thing.....

Mr TonyT,

I love this post of yours.  I feel exactly the same way.  I do not blame the distributors at all.  It is not their job to dissect a circuit.  And I am raising this issue for exactly the reason that you alluded too, that is, the only way to get these kind of thing fixed is to for consumers to raise the issue.  I am not saying that Cayin doesn't make good products, but I am suggesting that they be more straightforward in delivering what it appears that they promise.

[Adam Warlock]

Guys,
Below is a reply (copy/paste) from Cayin, its their 1st day of work coming from a holiday. Please bear with us. Well keep you updated

 

Cheers


Forum Statement: Cayin a70T
Wednesday, February 11, 2009 10:39 AM
From:
<[email protected]>
View contact details
To:
"Noel Deslate" <[email protected]>
Dear Noel,

Thanks for your mail and kind help on the issue of products improvement.

I have already looked through the email you have sent to me and got the general idea. Later I will translate together with Emma for our technician Chen so that we can have a clear discussion accordingly. Any progress or news about this we will let you know.

Thanks and best regards!

Yours,
jhn

[ptubeh]

Hi Adam W.

Thanks for the followup.  I am really interested to hear the response.  My friend, who is an excellent tech, re-biased my amp for Class A1 operations and set up the hybrid bridge rectifier.  I finally am home and have a chance to listen.  It is excellent, set up in this way.   I am using Electro Harmonix KT88's,  RCA 12bx7's  in place of the 12ax7 tubes and some Sylvania gold pin primo 12au7a 's.  This setup is wonderful to listen to.  So the amp is inherently very good.  I just want to know what the original bias setting were supposed to be, because mine were way off.  Further, why do they advertise it as A2 when it is clearly an A1 circuit?  And for a bonus, what is the explanation of the 5AR4?  I have heard from an amp designer that even though it technically does nothing, that it improves the sound in some "magical" way.  Hard to believe, I know... But maybe the Cayin engineers are magical thinkers.

Also, for you triode bigots, my friend changed the triode mode to pentode so that we could a/b pentode/ultralinear with the push of a button.  I am thinking that pentode may be even better than ultralinear.  Yes, I know that is not a very popular opinion... 

With the original bias settings, triode mode was a non-starter.  I guess we ought to check out triode mode with the new bias settings just to see if the the biasing was messing up triode mode.  But I am betting that pentode may be the winner as far as my tastes are concerned.  Call me a Luddite if you wish...

[qguy]

Hi

Does this mean you still have the SS diode and 5ar4 working on the amp ?, I was under the impression that you would be eventually doing away with the 5ar4 and SS diodes and wire it up using a beefier tube recifier (GZ37 was it ?)

Try the NEW SENSOR Tungsol 6550, I find it a lot smoother than the EH KT88.

Hi Adam W.

  My friend, who is an excellent tech, re-biased my amp for Class A1 operations and set up the hybrid bridge rectifier. 

[ATJr.]

I am not saying that Cayin doesn't make good products, but I am suggesting that they be more straightforward in delivering what it appears that they promise.

when Bob Caver submitted his cube amp for review, it turned out that his amp delivered something like 199watts, now the reviewer was willing to take this as "no big deal" but Bob said no, and off he went back to his lab...

then, a year later, after tweaking and resubmitting the same amp for review...the amp turned up a bit more than the 200watts claimed...

the lesson here is that, claims should always be on the dot, and verifiable....there is nothing wrong if the amp claimed to deliver 35watts can in fact deliver more than 35watts.....but it is always wrong to claim 35watts on an amp that can only do 34watts...

[ptubeh]

Hi

Does this mean you still have the SS diode and 5ar4 working on the amp ?, I was under the impression that you would be eventually doing away with the 5ar4 and SS diodes and wire it up using a beefier tube recifier (GZ37 was it ?)

Try the NEW SENSOR Tungsol 6550, I find it a lot smoother than the EH KT88.

Hey gguy,

Great suggenstion re. Tung Sol 6550.  I had a little too much Sri Lanka Lion Stout last night.  So it took the edge off of the EH tubes.  I had been using the Tung Sol 6550s and I am back to them, minus the stout.   They are really nice.

We wired up the rectifier to be half solid state and half tube.  I had used the GZ37 and today tried a Sovtek 5AR4.  It started arching within  20 seconds of turning the amp on.  So appparently the 700uf capacitors are a bit much for the 5AR4 - which further indicates that the power supply would have to be completely re-designed if a tube rectifier were to be used.  No way can the 5AR4 actually keep up with changing the caps.  The GZ37 is beefier and will probably work for a while.  I put a NOS Sylvania 5V3 in which is beefier still.  But the power supply is marginal in this configuration.  So we will return it to its original SS rectification. 

Also, with the Class A1 bias at 25W output, the power transformers get quite hot after about 5 hours of continuous use.  So I really want to know how this amp was supposed to be biased.  We are beginning to suspect that it was biased quite low so that the power transformers would not heat up so much.

Finally, minus the Sri Lanka Lion stout, I decided that ultralinear sounds better in my system.  You get a little more fullness and detail in pentode mode, but in my system it comes with a small price.  The sound is more etched.  I like the more mellifluous ultralinear sound, I think.  Your mileage may vary...

[ptubeh]

when Bob Caver submitted his cube amp for review, it turned out that his amp delivered something like 199watts, now the reviewer was willing to take this as "no big deal" but Bob said no, and off he went back to his lab...

then, a year later, after tweaking and resubmitting the same amp for review...the amp turned up a bit more than the 200watts claimed...

the lesson here is that, claims should always be on the dot, and verifiable....there is nothing wrong if the amp claimed to deliver 35watts can in fact deliver more than 35watts.....but it is always wrong to claim 35watts on an amp that can only do 34watts...

Hey TonyT,

We can't seem to get more than 25W out of this in ultralinear mode with Class A1 bias.  I don't know how Cayin came up with their specs.  They claim it is a Class A2 circuit, which my friend say it is absolutely not.  The only way to get more power would be AB1, but the manual says "30W Class A2".  Hard to figure out what is going on here.

I am afraid the days of Bob Carver have faded in to the past...

[AudioAmplified]

Finally a constructive reply from Cayin.

From: John <[email protected]>
Subject: Forum Statement: Cayin a70T
To: "[email protected]" <[email protected]>
Date: Thursday, February 12, 2009, 4:41 PM

Dear Noel,

Thanks for your reply.

I have finished translating the following email for our technician Chen. Please
look at the following comments from him:

1. Under the brand name of Cayin A-70T do have two kinds of products, however
we have not changed the model name. One kind is Class A2 while another kind is
Class AB1 with 55W+55W power output. Originally Class A2 kind of products are designed for the China
 mainland market which is only sold in China. Class AB1 products are for overseas market.

2. As for what the guy has described in the following comment we have used
sevral diodes under the 5AR4 tube socket for rectification. It is because the
current of 5AR4 is not enough to supply the four pieces of KT88. So we have take
the method of hybrid rectification in order to have a strong enough current
which can have a positive effect on the sound. We do have another kind od
proudcts which uses 5AR4 tube and diodes to configurate a Tube and solid-state
hybrid bridge rectigying circuit just as SC-6LS preamplifier.

3.As for the question why there was massive (5% - 10%) crossover distortion at
10W output, if the circuit is all right and nobody has changed something. It
should be the problems of tubes which are not matched or misfunctioned. It can
be solved by tube replacement.

Thanks and best
 regards!

Yours,
john

Our comments:

1) Sir Ptubeh - Since you got your unit used from the US it is hard for us to determine which version you have.  There might be a possibility you got a "grey market" unit from China which is class AB1 or there could be a mix-up with the US distributor... many reasons could occur here but definitely yours is most likely class AB1 and there is an AB1 version and an A2 version.  pm me your serial number and we can help you check.  Or you may contact www.cayinusa.com (the US distributor) so that he can help you with your unit. I really really hope your unit did not come from HK grey market traders who refurbishes the units and re-box them selling as new units.

2) The 5AR4 is a hybrid rectifier.  We also at fist thought that it is pure tube rectified but upon opening it; its not.  However, there is a sonic and wattage difference if you take out the 5AR4 which we have concluded in blind tests with random customers.  Cayin never mentioned that the A70T is tube rectified in their site or manual.  The only person who mentioned that it is tube rectified is a reviewed from enjoythemusic. 

3) As for the distortion... hard to say since your unit is used.  Again cayinusa.com can better help you with this.

Finally, sir patubeh - would it be ok to kindly pm us your technical questions and we can help you liaison with Cayin to get answers rather than posting them here since your version might be different from what we are selling (we sell German export version at 230V 60Hz) and could confused our less technical customers.

[AudioAmplified]

sir patubeh.  I pm'ed you some technical answers

[ptubeh]

Thanks for the response.  I don't buy the explanation of the 5ar4, although I know others who have said that this configuration makes as sonic difference.  But it is not really hybrid.  We implemented a true hybrid arrangement and the 5AR4 does not seem to be able to handle it.  The original design all but bypasses the 5AR4 which is why the amp works without the tube.  Anyway, we could argue this and come to no conclusion.  So I will use PM and send you the serial number.

And I want to say that I really appreciate and respect you for having followed through on this issue.

Best regards... and look for my PM

[AudioAmplified]

Thanks for the response.  I don't buy the explanation of the 5ar4, although I know others who have said that this configuration makes as sonic difference.  But it is not really hybrid.  We implemented a true hybrid arrangement and the 5AR4 does not seem to be able to handle it.  The original design all but bypasses the 5AR4 which is why the amp works without the tube.  Anyway, we could argue this and come to no conclusion.  So I will use PM and send you the serial number.

And I want to say that I really appreciate and respect you for having followed through on this issue.

Best regards... and look for my PM

Thanks sir.  We were really sincere when we said that we will get Cayin's response to this issue and were not just trying to avoid the topic.  No one is perfect and the only way to learn and improve is to take on concerns constructively. 

As for the 5AR4 - yes Cayin did say that its not enough, thus the need for the diodes.  Schematics and what the best design is a never ending question... near the realm of whats better ss or tube.  Sonically, there is a difference when you take out the 5AR4 from our blind tests.  So let us all enjoy the music and let our ears decide

pm us anytime you have questions and we will try to get answers for you since kababayan ka.  You may also email cayinusa.com

[ATJr.]

The 5AR4 is a hybrid rectifier.

i think you mean the 5AR4 and the ss rects is a "hybrid rectifier" yes?

2. As for what the guy has described in the following comment we have used
sevral diodes under the 5AR4 tube socket for rectification. It is because the
current of 5AR4 is not enough to supply the four pieces of KT88. So we have take
the method of hybrid rectification in order to have a strong enough current
which can have a positive effect on the sound. We do have another kind od
proudcts which uses 5AR4 tube and diodes to configurate a Tube and solid-state
hybrid bridge rectigying circuit just as SC-6LS preamplifier.

good enough reason to use ss rectifiers.....

[AudioAmplified]

Yes sir Tony.  Sorry was typing quickly and did not proof read.  My bad.

In any case... back to regular programming  

We will be launching our new Audio Amplified website.  Hence our old site will be down for a few days.  Our web designer is currently conducting the final proof reading to ensure that there are no mis-information or typos. We also have a few new products to share in our new website.

Thanks...