[Stevesebastianb]

Hi, I am seriously thinking about buying this amp., has anyone had any experience with this amp that they would like to share? The specs: -

Integrated Tube Amplifier with Headphone Jack

Cyber-30 is a single-ended class A integrated amplifier. It uses no global feedback. The 12AX7/ECC83 is a dual triode, which acts as input and drive tube. The 2A3 is self biased . AC voltage applied to the input goes first to the front panel volume control and then to the 12AX7/ECC83. The 12AX7/ECC83 provides voltage gain and drives the 2A3 output tube. The 2A3 is transformer-coupled to the load.


SPECIFICATION:

Output impedance for speaker : 16 W , 8 W
Output impedance for headphone : 10 W - 600 W
Output power : 3.5 W x 2 RMS 1kHz
Frequency response : 10Hz - 36kHz - 3dB (1W)
Harmonic distortion : <1% (1W, 1KHz)
S/N ratio : 90dB
Input sensitivity : 600mV
Input connector : 1 set (RCA)
Power consumption : 86W
Vacuum tubes : 2A3 x 2, 12AX7/ECC83 x 1
Dimension : 320 (L) x 260 (W) x 150(H) mm

 

[moonboy403]

I had the Cyber 10. It's not bad but not very good considering its price tag. There was hissing issue with low impedance cans.

 

[Stevesebastianb]

I will be listening to the Cyber 30 today, also wondering how they would sound with a pair of Sophia Electric Globe 2A3 Mesh Plates /ceramic base?

 

[moonboy403]

How much does the Cyber 30 cost?

 

[Stevesebastianb]

Approx. US$850.00

 

[gundam91]

Haven't visited these forums for a long time. My headphone rigs are just collecting dust in the study room these days. This amp was my first experience with 2A3 tube. It takes some getting used to as it sounds very different than any other tubes. Some people likes the sound, some don't. I've used some NOS RCA as well as Sovtek tubes on mine. The only complain I have is that mine has a constant hum noise that you can hear during quiet passages. You can biased the tubes to minimize the noise, but I was unable to completely silence it. I've not been able to verify whether any other owners is experiencing the same issue. Other than that, it is a pretty good amp. I wanted to hook it up to some very efficient speakers to see how it performs as a speaker amp.

 

[Bostonears]

I've got one of these amps. The headphone output is driven off the same circuitry as the speaker outputs, except for a couple of impedance matching resistors.

I'm using mine with 2A3C tubes (from China) that are ridiculously good for the price. The 12AX7/EC83 tube probably has more effect on the sound than the 2A3 tubes, though. Fortunately, the 12AX7 is a cheap tube, so you can easily tube roll to experiment with the sound.

Overall, the amp sounds marvelous, and if you've never experienced the midrange magic of 2A3 tubes, it can be a revelation, particularly with reproduction of the human voice. The sound is almost holographic.

However:

1) If you plan to use it with speakers, they had better be high sensitivity to get any oomph out of this little amp.

2) If you plan to use it with low impedance headphones, e.g. Grado or Denon, you will have very little usable working range on the volume control. By the 9 o'clock position, they may be louder than you're likely to want to listen.

3) With low impedance headphones, I do get slight audible hum. It's not noticeable with high impedance phones.

 

[basb]

I also have the cyber 30 and agree with Bostonears: best to use high sensitivity speakers. I use fostex full-range speakers and senn HD600 headphones and love the sound.

However, I do have a question to other cyber 30 owners:
The speakers and headphones are connected simultaneously to the amplifier, when I switch to 'headphones', there is still sound coming through the speakers!
This is annoying because the main purpose of the headphones is to use them so I don't bother others

. Is it just my unit or is this normal?

This also made me wonder: the speakers and headphones are both connected to the same transformers right? The manual said it is necessary to always have something connected when the amp is turned on. As I understand, SET amplifiers must be connected when turned on because otherwise it'll burn the transformer. Is it safe to use only the headphones, with no speakers connected? Probably is, I've used it with just the headphones, but would like to make sure.

Anyway, I love the amplifier. I paid E450 a few years ago and think it's great value for money, it's very well build and sounds great.

 

[gundam91]

Correct. I am only using it with headphones. No problem at all. I think the "leakage" issue you noticed has something to do with the design. Maybe cheap switch?

I tried biasing them, but I still hear hum with my headphone during quiet passages or when no music is playing. And I am using the Senn HD600/HD650...

 

[Bostonears]

Quote:

Originally Posted by basb /img/forum/go_quote.gif However, I do have a question to other cyber 30 owners: The speakers and headphones are connected simultaneously to the amplifier, when I switch to 'headphones', there is still sound coming through the speakers! This is annoying because the main purpose of the headphones is to use them so I don't bother others . Is it just my unit or is this normal?

On my unit, there are separate speaker outputs for 8 ohm and 16 ohm speakers. The headphone jack and front panel switch are in the 16 ohm output circuit. So if speakers are connected to the 16 ohm taps, when you the move the front panel switch to the "headphone" position, speaker output will stop. If speakers are connected to the 8 ohm taps, the front panel switch has no impact on speaker output.

Quote:

Originally Posted by basb /img/forum/go_quote.gif This also made me wonder: the speakers and headphones are both connected to the same transformers right? The manual said it is necessary to always have something connected when the amp is turned on. As I understand, SET amplifiers must be connected when turned on because otherwise it'll burn the transformer. Is it safe to use only the headphones, with no speakers connected? Probably is, I've used it with just the headphones, but would like to make sure.

As long as either headphones or speakers are always connected, there shouldn't be a problem. If you only have headphones connected and no speakers, you must always leave the front panel switch on the "headphone" position. If you switch it to the "normal" position, as would be used for speakers, neither headphones nor speakers will be connected, and the transformer will be at risk. Also, in a configuration with no speakers, never unplug the headphones while the amp is turned on.

 

[Bostonears]

Quote:

Originally Posted by gundam91 /img/forum/go_quote.gif I tried biasing them, but I still hear hum with my headphone during quiet passages or when no music is playing. And I am using the Senn HD600/HD650...

If you are handy with DIY electronics (and know what you're doing so you don't kill yourself around high voltage components), see this post from Audio Asylum, in which a poster named Wise Lee describes how the Cyber-30 has multiple groundings, possibly creating an internal ground loop in the amp. Depending on the source of your hum, the modification described in that post MAY reduce background noise in the headphone output.

Similarly, in this post, Wise Lee notes that you can also electrically isolate the headphone jack from the chassis, to eliminate another possible source of noise.

 

[basb]

Thanks for the replies. I checked information on my fostex speakers (fe167e), nominal impedance is 8 ohms but impedance ranges from 16-8 ohms throughout the frequency range so that won't be a problem I guess. Will try the 16 ohm taps.

Just like gundam91 I also hear slight hum during quiet passages when using the headphones, I remember someone saying it's because ac voltage is applied to the heater, making some hum inherent to the construction. Anyway, I don't know much about tube construction and while I understand how to carry out the modifications as described in bostonears' links, I don't feel comfortable working with potential deadly voltages

Stevesebastianb: did you end up buying it?

 

[Stevesebastianb]

Hi everyone, have not been on for quite a while. Caught up in new job and other hobbies. Yes I did end up buying the amp and confirm that observations are correct, there is slight hum on very quiet passages but I have found experimenting that this is also affected dependant on the type of tubes used. RCA's Cunningham which I have now seem to increase the hum but appear to have the best overall sound signature. The hum is something I can live with as it is very very low. Using different impedance headphones also affects this result.

I am actually very pleased with the end result and purchase although I must say that the sound signature is not for evryone's taste.

The most sonically pleasing amp that I have found so far is the Hlly MK-III 3 "Super Tube" Headphone Amplifier which uses the "Super Tube" Sovtek 6H30 PI x 2.

 

[Stevesebastianb]

Just to update everyone intersted in 2A3 tubes, I just purchased a pair of Chinese tubes (matched pair) known as Guiguang 2A3C after listening to them. I do not normally recommend Chinese tubes since they do not impress me sonically but with these tubes I was most impressed. They are miles ahead of any Shuguang tubes and better in some respects to some NOS western tubes. Whats's more they do not cost you a fortune.

Nice subtle details stand out well and overall balance is very good, very good value for money.

 

[gundam91]

How much are they selling these tubes in Hong Kong? I just did a quick search, and it is only available in the U.S. through eBay from a seller in Hong Kong, but he wants US$200 for a pair shipped!