QUAD II - Tube swapping

Inversed picture of KT66


Out of curiosity, after I'd finish the modification on the QUAD 22 pre amplifier I started swapping tubes around. The sound and difference in musicality, brands and makes, for every tube used in the QUAD 22/II was suprisingly significant. This along with the fact that original NOS tubes are VERY rare these days - and even if you find them, they will usually cost a fortune.  For those of us that do not have the original valves (or like to stash them for later) the big question is: what new valve do I best put in my QUADs?

As everyting in Hi-Fi audio, there is no 'best' option and a lot comes down to personal taste. But how do you know if the valves you are looking at in shops, are your taste soundwise? I have asked this question myself a few times and because there are little reports from other users about all tubes, it is rather difficult to make the right choice at once.

Used for the test are KT66's from Saratov white label, Valve Art and the new reissued Genalex Gold Lion.



Beeing able to compare all three brands activly for about two weeks, it gave me enough time to judge them and form an opinion about there musical - aswell as build quality.

To get a more nutral test result, I asked my brother to come over and listen. He did for almost a whole day and wrote his opinion down for me to use and match with my own. As my brother is a musician himself and likes good HiFi - owning QUAD ESL's for over 30 years, I consider his opinion very valuable. And he has not much experience with tube amplifiers on ESL's which is even better for a clear judgment.

Onto listning! Starting of with the Gold Lion just to get used to the setup and room. Joel Grare was first, pushing the QUADs to the limits with his percussion and bells. Followed by Terry Callier and Jimpster to get not overly acousical. After Jimpsters digital music we gone on to vinyl with Tom Waits Heartattack And Vine. And some mp3's which we skipped the rest of the day.



Valve Art The Valve Art's are very pleasant. The first difference you'll notice is there open top end, uncovering musical details more - like taps on tombs and symbals, bells etc. The very low end is still there - like the giant tomb on Joel Grare's tracks.

There is a downside of all this however. Terry Callier's voice for example seemed shrinked and flat with the Valve Art's. And so was the guitar and drums on Heartattack And Vine. The background cafe on Tom Waits's - In Shades, seemed very close.

Build quality is not impressive. They are gassy, have blue glow and leave black marks on the glass after some time. The glass is shaped like the original GEC but thin and I have one which is put aslope on it's feet. They stay relative cool which is nice.

Overall tags: very good definition and sweet top end, sometimes too bright - thin in the top end, little body - Somewhat narrow.

Retail price is about €80,--

Hight resolution photos: #1 #2



Saratov As I understand, the Saratov's are same build as Groove Tubes KT66 HP which are no longer available. But the Saratov's are. This tube sounds much closer to the Genalex, we started with. The 'body' is back - Strong mids, good base. A very nutral tube for all music we played.

Build quality seems good overall. Thick glass and straight but there are some differences in details. The desighn is very close to the original GEC.

Overall tags: very equal soundstage all over the audio range, good mid range, sometimes a bit boomy but softer low end, smooth top end, powefull.


Retail price is about €95,--

Hight resolution photos: #1 #2



Genalex The Gold Lion made a very strong impression to us. Most acoustical music recordings sound very real, round and yet detailed. It gives the instruments and voices the body they have when you hear them live. Guitars sound like my own guitar and voices sound like real voices - If you know what I mean. Not too bright but real with body.

Build quality seems excelent. All four look equal in detail - are straight and have thick glass. Apart from the three getters they look quite similar to the Saratov. They get relative hot and are slightly bigger then the others.

Overall tags: very equal soundstage all over the audio range, strong mid range, good low end, somewhat softer top end, yet very defined, very powerfull - instruments sound more live, like on stage.

Retail price is about €130,--

Hight resolution photos: #1 #2 #3




It is surprising to hear so much difference in various tubes. I noted this before when swapping ECC83's in the QUAD 22 preamp. Most difference between the KT66's we used lies between the Russian and Chinese tubes. The Valve Art's were quite attractive at first but the longer we listened to the Saratov's the more we started to like those.

Personally I like the new Genelex KT66 re-issue the most. They have a slight more body then the Saratov, making them sound a bit more 'live'. The Valve Art's are last on my list although I enjoyed them for many hours. Second are the Saratov's, more powerful and better mid range. First choice are the Genalex - they throw in just that little bit extra.

My brother liked the clearance of the Valve Art's a lot at first. Mentioning missing crystalline with the Saratov and Genalex but concluded, after listening longer, that the last two were more neutral and sounded very 'real'.  He suggested to stick with the Genalex for now although liking the Saratov more - maybe...



Equipment used for testing

Amplifier QUAD 22 (modified) - tubes: ECC83 Telefunken <> smoothplates, EF86 Mullard SHORT (screen type) mesh yellow print.
QUAD II (refurbished) - tubes: EF86 RTC (Holland made (Philips Heerlen)) SHORT (screen type) mesh, GZ32 Philips (Holland made at Heerlen).
Source Rotel RCD-970BX Thorens TD-125 mkII, standard tone arm, Denon DL-160 cartridge.
Speakers QUAD ESL 63.


Music used for testing

CD's Joel Grare - Paris . Istanbul . Changhai - tracks 10,11,12. (edit: Alpha decided to take down their website while changing it... see www.alpha-prod.com)
Terry Callier - Timepeace - track 2 (Lazarus Man).
Jimpster - Messages from the Hub - track 3 (Messages from the Hub).
Vinyl Tom Waits - Heartattack And Vine - tracks 1, 2 (2 in particular)



PS. I switched back to the 34/909 combination for now, since the summer is coming and the 22/II heat up my room too much. The 909 throws in a lot power though which is fun but I'll go back to the tubes as soon as the weather let me!