Advise on Consonance Cyber 20 suitable tubes.

I have the cyber 20b, which is the same amp with no separate power supply. By all indications, it sounds the same as the 20. I also have RS2i cans. I initially used the Ei EL 84's, (yugoslavia), but have found the genalex gold lions to offer a more balanced presentation, smoothing out the upper register and tightening up the bass.

I also have the cyber 20b. I'm using a Raytheon 5814 which I recommend highly. A nice, laid back, lush yet detailed sound. I have also used RCA cleartops 12au7, these are cheap and widely available. But these have a more pronounced high end and are very forward. Still quite musical though.

I was using the stock russian el84 tubes, but now I've got a hold of NOS RCA blackplate EL84s. Very nice. 3-D soundstage and a slightly laid back sound combined with deep black background and nice detail.

Thanks for the tube tips... I'm about to get my 20b upgraded to remove mains hum and maybe some of the other internal organs... ?

Best

James

Hello... not yet actioned. :-(

I will report back as soon as there is a result. Current preferred headphone partner srh940 doesn't hum too loudly with it... This is totally mt go to amp at the moment. It is so strange. After 4 years of being a bit 'meh', suddenly, it has produced magic with dt250 and srh940. Could be my ears of course!!!

Best

James

I wouldn't necessarily agree that the Cyber 20 is not ideally suited to low-impedance cans. This is certainly true of OTL tube designs, but as a high-ish current transformer-coupled design able to put out about 1W into 32 Ohms, it should be no problem. In fact, many owners use it to drive Grados!

Having said that, using a tube amp to drive orthos is a bit of a challenge. The Cyber 20 can drive the HE-500s, but will run a mile at the sight of HE-6s! It is imperative that the impedance matching switch on the front panel (the Cyber 20 has one, I don't know abut the Cyber20b as I am not familiar with this version) is set to "low". On the "high" setting, all of the life is sucked out of the music, and the amp appears to be fighting a losing battle. I presume this switch toggles between two sets of transformer taps (correct me if I'm wrong).

Regarding the specific combination with the HE-500s, both soundstage and linearity are massively improved over the HD600s (oh, and the hum is now barely audible). Both the HF grain and the bass "bloat" of the Sennheisers are gone. However, transients appear slightly soft, and there is a reduced sense of treble extension. Both of these aspects have improved with burn-in, however, and I am hoping that this trend will continue. Additionally, I am using some quite warm-sounding output tubes (1967 Russian Philips EL84s). I am hoping that the switch to Psvanes (which are reputed to sound faily transparent and fast, and are good value here in China) will improve matters further. At the moment, the HE-500s only have about 40 hours on them!

Finally - the velours pads sound MUCH better than the pleathers. With the original pads, the sound was shut-in and "plummy".

The new tubes should arrive by the WE.

Very interesting comments - thank you! You have me lusting after the HE500... again 

I believe the 'b' has the same broad specification except the external/power supply and wholly metal finish. There may be other component variations...

Your comments about high vs. low are interesting. I tend to go with the setting that 'sounds best' on a particular track but I think I might be being a bit of a philistine here   e.g. both the Shure 940 and Grado RS-1 have more 'body' on the high setting despite lower impedance transducers. This may well be at the expense of accuracy. Low has less hum... as you indicated!!

I'm still frustrated generally with RS-1 and K701. The RS-1 sounded amazing with a friend's Cyber 30 but have never sounded that good with any amp I've owned. The Cyber 20 is probably no worse than the GS Solo Ultra Linear and has a better soundstage for RS-1.

I will get around to addressing the mains hum issue (I don't want to be parted from it). For ref. this is the suggested approach I got from my dealer. I checked the frequency of the hum and it is definitely 50hz UK mains....

There are a few possible sources for mains hum to break through, it could be insufficient smoothing of the HT supply, insufficient smoothing (or even AC) on the heater supply or a lack of adequate screening between the power stages and the audio stage (either due to location of transformers or wiring screens etc). The first two are relatively easy to sort out as long as we have sufficient space inside - it’s been a while since I’ve looked inside one but I think we should be ok without having to build a separate power supply box.

 

If the transformers a mutually coupling (too close together) then that’s probably when we would have to consider a separate power supply box, but there may be another less intrusive solution (a small increase in feedback, although this will reduce gain a little too). Two boxes can cause other problems as we end up with multiple earth points (causing more hum) and a difficulty of getting the high voltage supply between boxes completely safely – neither is insurmountable but I’d always try to work on the one box solution if at all possible.

Best

James

Get the Psvanes! I'll repeat that, in case I didn't make myself clear. GET THE PSVANES!!!!

All of the issues I had with the lack of "snap" and "bite" have been addressed- if anything, the sound is now on the bright and fast side. That Mullard CV4003 is definitely staying in there!

The tube is very different from the Russian Philips EL84. Not just in the way it sounds, but also in its construction. It is quite a bit smaller, has a "halo" getter and a very different internal structure. To be honest, it doesn't look much like an EL84 at all - but it sounds amazing. BTW - it also gets very hot!

Finally, I don't miss my old Stax Lambda any more. 

Given the low sensitivity of the HE-500s, hum continues to be virtually inaudible.

To be honest, Opera should fit the Psvanes as stock. This alone would justify a price increase...... I think a Psvane driver tube could be a bit much though, if the sound signature is the same.

The Russian EL84s (I have 4 matched ones) are going in my old Leak Stereo 20 when we get back to Europe....