Tube substitues for the GK-1

T-Bone · « **Reply #20 on:** 16 Jan 2004, 02:45 pm »

Andy I listen to just about anything short of classical. Haven't made it there yet.

But I'm certain at some point I will. Some of these new R&R bands are pretty cool. The old blues men would have to be my favorite for right now. I started out with R&R in the late 60's and kind of went back the other way into jazz and now blues for about the last four or five years. But the Headbanger part of me still reappears on occasion. There is still something special about feeling a driving bass line literally pound you in the chest...

Ginger I appreciated reading your evaluation between the ECC88 and ECC189. When I (Hugh

) was sorting out an assembly mistake on my TLP I noticed slightly different voltages at R4 A/A' and R4 B/B' when the 6ES8 was inserted. I would assume the 6ES8's electrical characteristics had something to do with this. I don't honestly know but either way it will be interesting to hear the differences between the two tubes.

Thanks,
Brad Kizer

DSK · « **Reply #21 on:** 18 Jan 2004, 06:10 am »

Hi,
About a year ago I did some testing with various tubes in my GK-1. I had the original 6ES8's, Sovtek Reflector 6922's, Philips JAN 6922's, Sovtek 6H23's, and Siemens gold pin 7308's.

From memory, the JAN 6922's were more detailed, dynamic and quieter than the 6ES8's, with greater bass impact.

Relative to the JAN's the 6H23's were even quieter, more coherent and balanced. They were more organic with better inner detail and nuance. Overall the presentation was more relaxed, effortless and controlled.

Then I installed the Siemens gold pins .........HOLY $%^&! This was like a component upgrade. The walls of my listening room suddenly vanished and I was in a large concert hall, with more natural soundstaging than I had ever heard. The staging was much wider and a little deeper, with much better imaging and separation, yet better coherence. Front to back layering was definitely improved. Rather than listening to a good system and speakers, I was now listening to a live performance. The presentation had so much greater ease and effortlessness, with no loss of dynamics and not a trace of hardness. The music was simply more real, natural, pure, engaging, organic, emotional. I have not removed these tubes since. I hope they don't go kaput as they are becoming increasingly hard to find and very expensive.

To put things into some perspective (and remembering that this is all very subjective), I would rate the tubes out of 10 as follows in the GK-1 ...
National 6ES8 = 6
Philips 6922 JAN = 7
Sovtek 6H23 = 7.5
Siemens 7308 = 9

As always YMMV.
Cheers,
Darren.

Larry · « **Reply #22 on:** 18 Jan 2004, 06:42 am »

Quote from: DSK

To put things into some perspective (and remembering that this is all very subjective), I would rate the tubes out of 10 as follows in the GK-1 ...
National 6ES8 = 6
Philips 6922 JAN = 7
Sovtek 6H23 = 7.5
Siemens 7308 = 9

Sometime back, I tried Philips 6922 JAN with comparison to National 6ES8 and agree with your comments on these two. I left the Philips 6922 JAN in my GK-1 permanently afterwards.

I am interested in the Siemens 7308. Can you share with us how much it costs and where we can get it?

DSK · « **Reply #23 on:** 18 Jan 2004, 08:14 am »

Hi Larry,
I installed the pair of Siemens almost a year ago and had them sitting in a drawer for a couple of years prior to that. They were initially bought to try in a BAT VK-30 pre-amp (6 tubes) but I couldn't get any more and ended up using 6 of the Sovtek 6H23's in the BAT. In A/B testing, Hugh's GK-1 smoked the BAT (which I still have in a cupboard somewhere) so I bought a GK-1 and later did some mods such as the tube rolling and replacing the cermet pot with a modded TKD resistive attenuator (as used in the CTC BlowTorch pre-amp) etc.

I bought bought the Siemens (and 6H23's) from Kevin Deal at Upscale Audio, before he introduced his Cookie Jar restrictions (only those who have purchased components from him can now buy the rarer tubes from him). From memory, they were US$60 each but I have heard they are way more than this now, if you can even get them.

Since then, a friend in the audio industry stumbled across a pair of the Siemens in the back of some guy's cupboard (the last pair) in Australia and got them cheap. He agreed that they were the best he had tried in the GK-1 (he had also tried Philips, Telefunkens, Rockets, Mullards) with the Mullards E188CC's being his second choice.

Cheers,
Darren.

Jens · « **Reply #24 on:** 18 Jan 2004, 10:40 am »

Larry, Darren,

Very interesting experiments you've been doing.

A future GK-1R owner (I'm waiting for Customs to release my kit

), I'm listening very closely to your comments.

Tube rolling is extremely easy and very similar to swapping opamps, as I've doing with my current preamp with success.

Anyone who can come up with a source for those Siemens goodies?

Also, since I know Hugh has done a lot of experimenting with the tubes as well - how about about a comment, Hugh?

Cheers,

AKSA · « **Reply #25 on:** 18 Jan 2004, 02:40 pm »

Sure Jens!

Tube rolling is very much personal taste. A definitive answer is sadly just not possible.

I know others who have replaced their 6ES8 with a 6922 and thought it a backward step. Same for quality 6DJ8s. On balance not everyone agrees, and some quite definitely disagree. It's difficult to be categorical here, and so I'll demur by simply saying the 6ES8 is the designed tube, but such is the versatility other frame grid tubes can be swapped in to taste, and this is VERY personal. Some like extreme detail and accuracy, in which case a nice 6922 is de rigeur, others like warmth and emotional engagement, in which the 6ES8 is appropriate, and others like the extreme accuracy with a hint of tube lushness with the 7308.

For those who are really curious, I really do recommend swapping in different tubes. Remember, the GK-1 is an analog signal processor, not a rigid amplification system, and people's tastes are legion....

Cheers,

Hugh

Jens · « **Reply #26 on:** 18 Jan 2004, 06:36 pm »

He, he, Hugh!

I thought you might answer something like that

Good comment - though - because this is a very personal matter.

I do think the Siemens goodies sound very interesting and might try them at some point.

Anyone know a source for the Siemens gold pin 7308s?

Cheers,

Larry · « **Reply #27 on:** 19 Jan 2004, 03:49 am »

Hi, Jens and Darren,

As Darren said, the Siemens 7308 is very rare and expensive. I found only one link http://www.tubeworld.com/7308.html selling for US$350/pair. I am not sure if this one is the same as Darren has. According to the webpage, even Siemens 7308 varies a lot through years.

The price is beyond what I am willing to pay for two tubes at this stage. If Jens likes to try, they have 4 pairs on their list.

I might try Mullards E188CC, if it costs less. (I have not found a source yet.) Or maybe one day I go and listen to Darren's if I got a chance to Melbournce.

DSK · « **Reply #28 on:** 19 Jan 2004, 04:37 am »

You'd be most welcome Larry.

A while back I had a pair of Amperex 7308's, also a highly acclaimed tube, but they were in my AH! Tjoeb CD player that my father now has. Although they were a slight improvement over the Philips JAN 6922's in the AH! Tjoeb, they were not as much of an improvement as I had expected from all of the Amperex 7308 worshippers. It would be interesting to hear them in the GK-1, but the chance of borrowing them from the ol' man are slim

Larry · « **Reply #29 on:** 19 Jan 2004, 11:30 am »

Hi, Darren,

I will let you know if I got the chance. But at the moment, I have no plan to travel to Melbournce yet. Cheers.

Jens · « **Reply #30 on:** 20 Jan 2004, 11:05 am »

At the price mentioned by Larry, I will definitely not be trying the Siemens 7308 anytime soon.

Very good postings on tube rolling and experiences. Looking forward to trying some of the tubes - when I get the GK-1R built, that is!

Just received the kit, but it will take me a while to build it - I have to work hard to afford this kind of luxury!

Cheers,