Conrad Johnson GAT ...

Marcus

Member Sponsor
Oct 5, 2012
229
11
18
#61
Hi Marcus, I have not used EAT tubes...but think very highly of the EAT tube dampers which I use on my NOS Amperex US PQ White labels in my CJ GAT. They work exceedingly well. If you use the EAT tubes, please post!
I use original tubes in my GAT. Tried ART tubes too, but they were too noisy. I've heard that EAT tubes are "the way to go" with the GAT so I wondered if someone here has some experience with these tubes. They're very expensive though - 99 EUR fot Selected type and 145 EUR for Diamond...

As far as Cool Dampers are concerned, I used them in my CT5 but in the GAT they are no longer necessary. Original rubber rings work just fine.
 
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Marcus

Member Sponsor
Oct 5, 2012
229
11
18
#62
I had the Finite Elemente (an older version) and the Silent Runnng Audio Craz racks side-by-side. There was no comparison. The SRA was cleaner, less muddy, more transparent and better frequency extension.
If you can, try the current version of the Master Reference or better still Master Reference Heavy Duty rack (with 5-point Cerapuck support), both of course with the Resonator Technology...
 

LL21

Well-Known Member
Dec 26, 2010
10,729
49
48
#63
I use original tubes in my GAT. Tried ART tubes too, but they were too noisy. I've heard that EAT tubes are "the way to go" with the GAT so I wondered if someone here has some experience with these tubes. They're very expensive though - 99 EUR fot Selected type and 145 EUR for Diamond...

As far as Cool Dampers are concerned, I used them in my CT5 but in the GAT they are no longer necessary. Original rubber rings work just fine.
Funny...now that you mention it, i have heard that exact comment before as well. I may give that a shot...let me know if you do. Meanwhile, i prefered the EAT tube dampers over the red rings which i have put away.
 

Marcus

Member Sponsor
Oct 5, 2012
229
11
18
#64
Hi Marcus, I have not used EAT tubes...but think very highly of the EAT tube dampers which I use on my NOS Amperex US PQ White labels in my CJ GAT. They work exceedingly well. If you use the EAT tubes, please post!
I got a matched pair of JJ 6922 from Brent a month ago and put them into my GAT. I was NOT impressed. Yes, this tube is VERY quiet, detailed, airy and bright, but also thin and bass lacks weight and energy. I put back the original Electro-Harmonix and it sounded more robust in the low end, instruments got back their bodies and more balanced presentation was restored. So, JJ not good for CJ...

I'm waiting for NOS US Amperex PQ White label and EAT tubes and will compare...:)
 

MylesBAstor

Member Sponsor & WBF Founding Member
Apr 20, 2010
11,221
1
36
#65
I got a matched pair of JJ 6922 from Brent a month ago and put them into my GAT. I was NOT impressed. Yes, this tube is VERY quiet, detailed, airy and bright, but also thin and bass lacks weight and energy. I put back the original Electro-Harmonix and it sounded more robust in the low end, instruments got back their bodies and more balanced presentation was restored. So, JJ not good for CJ...

I'm waiting for NOS US Amperex PQ White label and EAT tubes and will compare...:)
You've described the JJ to a tee!
 

LL21

Well-Known Member
Dec 26, 2010
10,729
49
48
#66
I had the Finite Elemente (an older version) and the Silent Runnng Audio Craz racks side-by-side. There was no comparison. The SRA was cleaner, less muddy, more transparent and better frequency extension.
If you can, try the current version of the Master Reference or better still Master Reference Heavy Duty rack (with 5-point Cerapuck support), both of course with the Resonator Technology...
I have put my GAT in an 'isolation sandwich...Under: HRS Nimbus Couplers + HRS M3 Isolation shelf; On Top: 2 HRS Long, Double-Thick Dampers, 1 Artesania Damper (and 2 Finite Elemente Resonators...which I don't think work that much).
 

LL21

Well-Known Member
Dec 26, 2010
10,729
49
48
#67
I got a matched pair of JJ 6922 from Brent a month ago and put them into my GAT. I was NOT impressed. Yes, this tube is VERY quiet, detailed, airy and bright, but also thin and bass lacks weight and energy. I put back the original Electro-Harmonix and it sounded more robust in the low end, instruments got back their bodies and more balanced presentation was restored. So, JJ not good for CJ...

I'm waiting for NOS US Amperex PQ White label and EAT tubes and will compare...:)
Thanks for that...good to know. I like the US Amperex PQ White label a lot...my favourite except that mine are a bit noisier than my Mullards...which come very close in quality once I use the EAT Tube dampers.
 
May 30, 2010
14,651
264
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Portugal
#68
Anyone has experience with Philips/ECG JAN 6922 NOS tubes in cj equipment? As far as I know they are used in Metronome top DACs.
 

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LL21

Well-Known Member
Dec 26, 2010
10,729
49
48
#69
Sorry...had experience with Jan in Zanden only...generally, an extremely musical, lyrical, lithe tube...perhaps not the most 'power' but very good. But super microphonic. Use an EAT tube damper with them if you can. Otherwise, on CJ GAT, I like Mullard CV2493s best so far. Myles likes Teles...and I am tempted to try them myself.
 

XV-1

Well-Known Member
May 24, 2010
1,647
55
48
Sydney
#70
What a difference new tubes make. After 4 years 2 months of owning the amazing Telefunken E88CC 6922's I decided it was time to buy some replacements. Upscale audio has gone from being $129 per tube to now $395 per tube!!

thanks to Lloyd, he had 2 very lightly used Tele's for a lot less as he now has GAT2.

WOW - the new tubes are faster, have deeper bass, better detail and treble extension is better. very happy. don't need to think about GAT2 for a while now :p

amazing how tubes work and work and the sonics sort of get worse but you don't really realise as the GAT was still sounding good. I have estimated I have done at least 16,000 hours on the first set of tele's.

cheers
 

uber2

New Member
Nov 4, 2016
5
0
1
Sweden
#71
Im contemplating a Gat, but am worried for the highish gain. My speakers have 107db sensitivity.
Anyone know if it’s adjustable - Perhaps as factory modification?
 
Mar 28, 2012
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#72
Im contemplating a Gat, but am worried for the highish gain. My speakers have 107db sensitivity.
Anyone know if it’s adjustable - Perhaps as factory modification?
The gain issue has come up several times before on various fora, and IIRC, it's easy to deal with, I believe without a mod of the GAT per se.. A resistor or the like is inserted aft of the output from the preamp. If no one answers here, check some of the other CJ owners fora. The answer is out there somewhere, and it's not a big deal. I believe another factor is the input sensitivity of the power amp, but I'm not totally sure about how that works. Sorry I can't provide more detai;, but I think others will chime in.

The GAT is marvelous. Cheers!
 
May 30, 2010
14,651
264
83
Portugal
#73
I have answered this question before - the GAT has fixed gain, it can't be changed without affecting sound quality. However the relevant parameter is signal to noise-ratio at 1V output that is 100dB - exceptional for a tube preamplfier.

Considering the very high speaker sensitivity the critical detail is amplifier gain - I would not use an high gain amplifier with a tube preamplifier. If we still want to match them the solution is using an audio transformer with a ratio of 4 to 1 - we get a 12dB improvement in signal to noise ratio. I have used Lundhal and Jensen transformers for this purpose, as well as the excellent but expensive Flex Connect https://smcaudio.com/products/flex-connect/
 

LL21

Well-Known Member
Dec 26, 2010
10,729
49
48
#74
Hi Micro. Interesting...what do you think of the CJ GAT 2 (25db gain) with the Gryphon Mephisto which is 31db gain? The Wilsons are 95db as you already know. It works fine in the system and dead silent providing tubes are quiet...even ear practically touching the tweeter. I imagine not as much volume control as some might prefer/be used to...but overall, works (for me)

That said, would be interested to know what the specs above say in regards to what i am experiencing (volume/gain-wise). Thanks!
 
#75
Most of the conversation here seems to be about tubes for the original GAT.

As a UK owner of a GAT Series 2 preamp, mine came supplied with Philips PCC88/7DJ8 tubes, whereas the original GAT used 6922's.

I have owned my GAT2 since 2016 and it has had one change of tubes so far. These were replaced soon after purchase by the UK importer/distributor, due to noise and the replacement Philips PCC88's came from CJ.

I have since purchased spare pairs of Philips PCC88's and Telefunken PCC88's from another internet source and these have been kept in a drawer until such time as it became necessary to replace the pair in the GAT2.

Recently, I have become aware of noise, in the form of louder than usual tube rush and what I would describe as "fluttering" from the left channel, so rather than remove and clean, I decided to try a fresh pair, but this time, the Telefunken PCC88's.

Initial impressions are of a much quieter set of tubes with a more solid sound, especially in the bass.

Further listening will dictate whether they possess the other attributes which make the GAT2 such a musical and transparent preamp.
 

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