[Dimu]

 
Comparing GEC KT66 to GEC TT21 sound is similar, and similar deficiencies observed on the same recordings where TT21 did not sound good. I think the issue is that I am hearing the difference between 12AU7 and E80CC much more than the difference between RCA black plates, TT21 and KT66. Tried  three types of 12AU7- Brimars, Amperex-made Electronics for Medicine and Telefunkens. There are differences, but nothing like E80CC.
 
Which means combining TT21, KT88 or KT66 with E80CC would be really awesome. It appears that this amp's power transformer is its biggest limitation... So for now E80CC and RCA black plates are back in the amp.

 

[Dimu]

It appears that this amp's power transformer is its biggest limitation...

 
I have ordered a custom R-core transformer with 50% higher current capacity on the 6V secondary. This should give me ability to run tubes like TT21 and drive them to full potential with preamp tubes like E80CC. This transformer will have bigger core and I will likely need to drill the bottom to move output transformers so that space opens up for this bigger power transformer. If timing works out I will swap out both power and output transformers at the same time, but that depends on when Lundahl are approved and available.

 

[Dimu]

 
More adapters arrived. Tried USSR 6H8C and Raytheon VT-231 manufactured for US Army/US Navy after Germany's surrender but prior to Japan's surrender. Both sound very good, definitely better than any 12AU7 I tried, but I still like E80CC the most. Those 6H8C are by far the best value though- in terms of the sound you get per dollar spent on tubes.

 

[aedaza]

Hi to all,
Just wantes to comment on my experience with some preamp tubes on this amp

New production Tung Sol 6189: nice tube. It is a good all over the spectrum kind of tube, with great detail, but some what lacks a bit of bottom.

Sylvania 5814A 3mica gray plates: really nice and some of the most detailed highs. I should spend some more time with this one, but it is a nice balanced tube, but lacks a bit of omph on the low end.

Raytheon 3 mica black plates: this one is ok, but kind of a disapointment. You know, 3 mica and black plate? Expected a mid range with more meat, but it is a tube with nice highs but somewhat shy mids and lows.

Rca 5963 blackplates: this one is a good suprice. It is energetic, great bass and mids. It lacks a bit of detail on the high end, but it could be a good complement to a system lacking a bit on the low deparment. It is a cheap tube, so worth the try!

Rca cleartops 12au7a: love this one. It resolves the spectrum so nice. It has a very nice and open and high end and good botomless lows. It can be a bit bright sometimea, but this tube deserves some respect!

Cbs 5814a blackplates: my favorites... a midrange lifelike, lows that you can feel in the stomach and very nice highs.

I have been wanting to try the e80cc but dont know how the amp will handle them. Currently running some new prod goldlion kt88s. Nice too.

 

[Dimu]

  I'd also recommend trying out a nice pair of 807s, with adapters if you want a different flavor as well.

 
Waiting for Cossor 807 round plates to arrive, as well as adapters for them. This is about the only tube other than 6L6GC that I can run with E80CC with the stock power transformer. EL12 spez might fit into the transformer power budget as well, but reliability of that calculation depends on the accuracy of rectifier efficiency estimate.
 
 

 

[Dimu]

I have been wanting to try the e80cc but dont know how the amp will handle them. Currently running some new prod goldlion kt88s. Nice too.

 
Of all the tubes I tried (and I tried a lot of different tubes, all of them NOS, some of them costing north of $250 per pair) E80CC is the best driver for this amp that I found. Better than 6SN7, better than 12BH7, and definitely better than anything with small plates (i.e. ECC82, 12AU7, CV4003, etc). Notice, however, that you can't just plug them in- you've got to upgrade the rectifier first. This will allow you to run 12BH7, 6SN7, E80CC, as long as you use 6L6GC power tubes. You can't mix those large plate driver tubes with power tubes like EL34, KT66 or KT88 as it will overload the power transformer. Upgrading rectifier is cheap and simple, upgrading power transformer not so much.
 
Regarding new production Russian tubes- I can't comment specifically as I would not buy any of those. I'll take any tube made in US or UK over anything made in Russia, new or old. The best factory in USSR was located in Moscow, and it is closed now. The second best was in Leningrad (you might know it as "winged C")- closed as well. So anything new you are buying is not even top quality by USSR/Russian standards. And those standards were never comparable to GEC or RCA or GE or many other quality US and Western European manufacturers.

 

[Dimu]

  I'd also recommend trying out a nice pair of 807s, with adapters if you want a different flavor as well. 

 
Just tried Cossor 807s. These might be my favorite 0.9A tubes! I think RCA black plates are going to get some rest while I am going to enjoy richer bass of Cossors. Thanks for the suggestion!
 
P.S. these are not $50/pair tubes but still very good value for money compared to some more popular tubes like KT88 or KT66 or even RCA black plate.
 
 

 

[Dimu]

Comparing many good tubes is hard work
Today's challenge is Telefunkens made in Berlin. These bias very differently based on my tester's results but still the amp eats them up and produces beautiful sound!
 

 

[Effusion]

Dimu,
 
Glad you're liking the 807s!  Those Cossors look really nice; they're the ones with the ceramic bases, correct?  I haven't had the pleasure of trying them yet.  I really like my smoked glasses, probably the best, then followed by a few military productions, including Sylvania, Westinghouse, and CBS, then the European variants, which some tie with the military US ones, then probably last the abundant standard RCAs, GEs, etc.  To me they are sort of between a KT88, a KT66, 6550, and even a bit of the 6L6GCs.  Nice full sound with plenty of weight.  I've seen the Cossors go for quite a bit, but the other brands are as cheap as NOS power tubes for the Elekit really get; I paid $25 or less for most pairs, however you have to factor in the adapters.
 
Thanks for posting all your experiences with rolling the Elekit!  Very interesting and really amazing how many different types you've been able to use; crazy how versatile this amplifier truly is!  I'm going to have to try out a few in the near future, especially the 6SN7s, as I've always really enjoyed that type.
 
If you ever get the time, it would be really cool if you were to ever put together a matrix of sort for all the different non-standard types you've successfully tried in the Elekit, plus some general info on what is required to run them.  I think it could really help out both current owners who are looking for different options and/or different flavors as well as those on the fence about going with an Elekit.
 
Keep the impressions/findings coming! 

 
aedaza,
 
Welcome to the club!  Thanks for sharing your impressions of some of the various tubes you've tried thus far.  I don't have much experience with the new production, but I agree about the CBS 5814a, they are one of my favs!  If you really like the CBS, I'd recommend trying a pair of Westinghouse 5814a's as well.  To me they are a bit sweeter than the CBS, being both more delicate and airier, with a bit better soundstage.  The CBS have more weight/punch though.  Let us know how things progress!
 
JK,
 
I finally got around to trying out the Amperex 7316's and I've got to completely agree with you, they are amazing!  Very nice all around and probably my top pick as far as the balance between musicality and resolution/accuracy.  Whereas my 7730's are a bit too clinical at times and with certain power tubes, the 7316's bring the almost same benefits as they have, but with a more natural fluidity and balance.  Thanks for the suggestion!
 
As a side note...
 
I just had my unit upgraded with AMRG Carbon resistors and also replaced my 4 Amtrans AMCO film coupling caps with Mundorf EVO Supreme Silver/Gold ones.  I've got to say that this made a very noticeable difference, even prior to proper burn-in, and has improved everything from the detail to the soundstage/imaging.  It also sounds more natural now as well.  I highly recommend trying them if you are interested in upgrading; the Mundorf's aren't cheap, but worth it when you consider all the money one can spill out on tubes, etc.  If you're interested in these upgrades when ordering a unit, Victor offers them as part of his Supreme Upgrade.  Very nice indeed.

 

[Dimu]

  I just had my unit upgraded with AMRG Carbon resistors and also replaced my 4 Amtrans AMCO film coupling caps with Mundorf EVO Supreme Silver/Gold ones.  I've got to say that this made a very noticeable difference, even prior to proper burn-in, and has improved everything from the detail to the soundstage/imaging.  It also sounds more natural now as well.  I highly recommend trying them if you are interested in upgrading; the Mundorf's aren't cheap, but worth it when you consider all the money one can spill out on tubes, etc.  If you're interested in these upgrades when ordering a unit, Victor offers them as part of his Supreme Upgrade.  Very nice indeed.

 
I had Mundorfs from the very beginning, in fact I used Mundorfs even for C19/C20 which was not easy to pull off due to limited space. My preamp also has Mundorfs that Victor offers. The amp has AMRG in all positions that Victor had them available for, the rest are AMRS. The preamp has four naked Vishays, bunch of AMRG, three native resistors and the balance are AMRS. The only way to improve on that is to use Vishays but that would double the price of the whole unit.
 
I also used TDK pots in both the amp and preamp- Victor has those too. It fits into the amp as is, and for preamp I had to cut out the board as it is bigger than the stock Alps pot.
 
I upgraded bypass capacitors to even higher ESR than what is offered in the DX kit, and I upgraded most of the other capacitors with high temperature automotive models.
 
Basically most of the parts from my kit have never been soldered as I did extensive upgrades upfront.
 
Another upgrade was using leaded silver solder from WBT. The amp worked from the first attempt and has been perfect ever since.

 

[Dimu]

  Dimu,
 
Glad you're liking the 807s!  Those Cossors look really nice; they're the ones with the ceramic bases, correct?  I haven't had the pleasure of trying them yet.  I really like my smoked glasses, probably the best, then followed by a few military productions, including Sylvania, Westinghouse, and CBS, then the European variants, which some tie with the military US ones, then probably last the abundant standard RCAs, GEs, etc.  To me they are sort of between a KT88, a KT66, 6550, and even a bit of the 6L6GCs.  Nice full sound with plenty of weight.  I've seen the Cossors go for quite a bit, but the other brands are as cheap as NOS power tubes for the Elekit really get; I paid $25 or less for most pairs, however you have to factor in the adapters.
 
Thanks for posting all your experiences with rolling the Elekit!  Very interesting and really amazing how many different types you've been able to use; crazy how versatile this amplifier truly is!  I'm going to have to try out a few in the near future, especially the 6SN7s, as I've always really enjoyed that type.
 
If you ever get the time, it would be really cool if you were to ever put together a matrix of sort for all the different non-standard types you've successfully tried in the Elekit, plus some general info on what is required to run them.  I think it could really help out both current owners who are looking for different options and/or different flavors as well as those on the fence about going with an Elekit.
 
Keep the impressions/findings coming! 

 
I think I am close to the end of trying different tubes- not much left to try really. The one I still want to try are GEC ATS25 with round plates- those are similar to my Cossors 807. GECs come with ceramic bases, Cossors that I have are not ceramic- you can see the brown bases on the picture I posted earlier. The ones I still did not try were Tungsol 6550 (have not found NIB pair yet) and because of the high price I chickened out on experimenting with WE 350B due to their screen grid voltage specs. I suspect that 350B would actually be ok because it is rated as "design center values", but Elekit would not agree with this opinion despite repeated queries so I gave up on that.
 
Regarding summary on what I tried and what I would recommend:
1. make sure to triple current rating of the D7 rectifier. I would not run the amp without this upgrade as it would leave the amp limited to 12AU7 (and other related variants) for the driver tubes and even the best 12AU7s that I tried appeared to noticeably limit performance relative to tubes with bigger plates (and bigger plates require bigger cathodes which in turn require bigger heaters which results in more load on the rectifier and the power transformer).
 
2. with this upgrade in place I prefer E80CC for driver tubes with other notable options being 12BH7 and 6SN7. I use Phillips E80CC made at their Harleen plant (these can be recognized by having a delta code etched on the glass) and I tried Brimar 12BH7. There are many 6SN7 choices to try but the best (like Soviet METZ version or TungSol round plate version) are close to impossible to find in good shape. Since use of these tubes limits available heater current from the power transformer for heating output tubes you can use 6L6GC and 807 tubes with these drivers. For 6L6GC I liked RCA black plates the most, and round plate Cossor 807s were very good too (this is what is in my amp now but those tubes are difficult to find in NIB condition). GE or Sylvania 6L6GC are good budget options here and are easy to find. Another interesting option is GE

7581A.​

 
3. The next level is upgrading the power transformer. This is a challenge and I have not done mine yet (even though I have the transformer with 50% more heater capacity waiting to be installed). This will allow to run tubes like:
- GEC KT66- these tubes are awesome and are still possible to find unused.
- GEC KT88/TT21. I did not find any NIB KT88 but I did manage to source TT21 which are at least as good if not better.
- 6550- I tried Sylvania and GE versions, TungSol is supposed to be even better but it is as difficult to find as GEC KT88 these days.
- EL34- Mullards made in England are considered best and those with lower XF codes cost more. RFT from East Germany are a cheaper option (these are branded as Siemens and many other brands).
- EL12 spez- these are very cool tubes made by Telefunken in Berlin. There are other versions but I have only tried genuine Telefunkens.
 
Of these tubes my favorites are KT66, TT21 and El12 spez, however I have not been able to listen to those long term due to transformer limitations so I am not sure which of these three I like best.
 
Of the tubes that I mentioned the following require adapters (easily available on eBay):
- 6SN7
- TT21
- el12 spez
- 807/ATS25
 
What I would not recommend:
 
- I would not recommend running any of the tubes from the list under #3 above without power transformer upgrade because E80CC with good 6L6GC or 807 will produce more consistently enjoyable results than any output tube driven by any 12AU7.
- I would not recommend buying any new production tubes- there are too many good NOS choices to enjoy while they are still available
- I would not recommend buying used tubes not only because you don't know how much quality life is left in the tube but also because as cathode wears it produces a smaller electron cloud which gives the tube less of a buffer when it starts clipping. This means that new tubes will produce more pleasant clipping than old tubes (talking about used vs unused here, not about new manufacture vs NOS).
- I would not recommend using anything that is underrated on either anode/plate volgate or second grid voltage. For example Soviet 6P3S and 6P3S-E are dirt cheap and have interesting sound, but I don't know how long they will last in this amp. 6P3S is rated to just 1000 hours and abusing it will likely result in quick deterioration.
- I would not recommend trying to put bigger plate tubes into TU-8500 preamp- those should be either 12AU7 or 12AT7. I am currently running 12AT7 Mullards in there.
 
Finally, I started listening in ultralinear mode and then I switched to triode mode, and I think I noticed some difference. However now I am planning to switch back to ultralinear next time I open the amp to give it more power which will reduce clipping.
 
Overall this amp is amazing and is greatly recommended for both the fun of putting it together (especially if you start upgrading components) and for the continued enjoyment of the awesome sound that comes out of it.

 

[Effusion]

Thanks for all the info!  It really helps make sense of everything you've tried and what you had to do, and still do, in order to make it all happen.
 
Wow, nice job on the upgrades!  I bet your unit sounds so much better than a stock one that you'd have trouble telling that they are the same amp without seeing them.  I may look into upgrading the pot at some point and it's nice to know that the TDK fits perfectly, while the Blue Alps mhamel I believe installed needed a little tweaking.
 
I see what you mean about the Cossors, I guess I figured them to be ceramic sense the ATS25's are and the only pictures I've seen, they had white bases as well.  Very cool that yours have brown instead of white, I had not seen that before.  I have several ATS25's, one pair is even hand-painted and no other stamping since it is so old!  They are very good and their plate structure looks quite different to a normal 807.  I tried a very nice pair of NOS Mullard QV05-25, but these do not work with the amp as is and they blew my FET, so I do not recommend them unless you think you can tweak the amp to handle them.  Other than that, I have all 3 versions (different getters) of the newer militarized 807s, the 5933, and they are pretty good.  I've always felt that they were a bit more solid-state sounding than the general 807s and lack some of the tubey sound in general, maybe even a bit clinical in comparison, but they are worth a shot, if at least to see how they respond in your system.
 
I do have a pair of Tung-sol 6550's and they do sound very nice.  I also have a pair of RCA's and GE's, both the coke bottle and the ones that look like larger 6L6GCs.  To me, the GE 6550s that look like larger 6L6GC's, with green lettering I believe, sound the best, then probably the Tung-sol and RCA's.  The GE coke bottle ones were my least favorite.  I also have not tried an original Genalex KT88, as they are impossible to find and if you do, they are way too expensive.  I have other KT88's though (Penta Labs, Mcintosh, etc.) and to me the 6550 shares many characteristics with it; they both have great speed and slam.  However, I think I generally prefer the more musical and open sound of the KT66, with my smoked glass GEC pair being my current fav.
 
As far as EL34's, I've found some to be very nice, while others have fallen a bit flat.  I believe others have had better results with EL34's in UL mode rather than Triode.  Some of my favorites have been the Mullards, Siemens, Telefunkens, and Tesla's (both yellow label and "blue" glass).  One that really surprised me and is also one of my favs is the RCA Japan later production, which I got for cheap!  I have also tried the RFT's as well as the Winged "C" and they are both nice as well, giving some of the best soundstage, as also with the Tesla's.  Many of my pairs have had issues with the pins not being properly tapered off, so I use socket adapters for them as to not damage/ware the amp's sockets when I roll.  In general though, some of the other power types give me more impact and weight in the low end as well as speed/attack than the EL34's due in general, so I only really use them for when I'm listening to something that I want to have a more delicate/intimate feel to, such as classical music.
 
I'll let you know if I have any questions before I try some 6SN7s, etc.  It may be a while though, as I only really have singles that I've used with other amps and would need to get pairs.  I've tried a ton of 6SN7s in the past and it is a very fun tube!  In my opinion the Tung-sol Round Plates weren't worth all the hype, as others gave me more of what I was looking for and at cheaper prices.  Same thing went for the "Bad Boys" as well as the RCA smoked glasses; both fell a little flat in my system compared to others.  I tend to prefer anything militarized, especially the brown bases and also "T" plates with square or "D" bottom getters, such as early Tung-sol and CBS.  The Brazilian aluminum RCA's also really kick the sound out as far as soundstage goes, the Brimars are quite good in the highs, the black glass National Unions have a ton of bass slam and extension, and my RCA smoked glass military brown base gives great sound from head to toe, if not for them being pretty rare.
 
As far as 12au7s, I agree and tend to prefer the variants a bit more than the standards.  My favorite currently are Amperex 7316s, 5814a (both CBS and Westinghouse a bit more than the RCA's, etc.), my gold pin 7730's, CV4003's, Brimar 13D5's, and Tesla ECC802S.  I also tend to like most of the European types, except for a few Russian, ECC82's generally more than the standard 12au7s.
 
It all just really shows how crazy tube rolling can get, especially with this amplifier!  With so many options you have to be careful not to drive yourself nuts!  I'm just glad others have also had such great experiences with this amplifier and its versatility.  For me, it is the amplifier I will hold onto for the rest of its days, enjoying every ounce of musical bliss it extends my way.  It also all reassures me that my review and constant recommendation of this amplifier is not only true to my own experiences, but to others as well.
 
Happy listening and keep letting us all know where the journey is taking you!
 

 

 

[Sonic Defender]

Questions for those who have had some time with this unit. If I wanted to order a new one made for me, but didn't have a great deal of extra money beyond the basic stock configuration, what would you recommend as the most affordable, impactful upgrade I could ask of victor. I'm lucky to live moderately close to the distributor so no import fees anyway. I am looking at adding a tube amp to my collection, but frankly I won't get much into tube rolling as it is just a hyper complex area and I don't want to go down that rabbit hole. So I don't need the best tube amp and I was actually considering the Ember when this caught my attention. Any thoughts/comments? Thanks.

 

[JK-47]

Sorry to say, but you should probably stay away from tubes... Or go with GE 5814A input tubes @$20 a pair, and GE 6L6GC power tubes @$60 a pair, or play it safe and get modern tubes and know your amp will never live up to it's full potential. It's the truth...

 

[vkung]

I recommend to pick option #1 upgarde parts (upgrade the signal path to AMRS carbon resistor). If you have a  bigger budget later, you can replace the Amtrans AMCO to Mundorf EVO Supreme Silver gold.  and the driver tube (12AU7).