Suggestions for tube rolling Croft integrated anyone?

[Stowa]

Hi All,
New member from New York.
I just acquired a Croft integrated and I'm pairing it with the Harbeth P3XD's
in a desktop setting.
I set up this rig about a month ago,everything is new including the Mark Grant VD speaker cables,
HDX1 interconnects and a Topping E30 Dac.
I run Spotify and Itunes for casual sessions and listen critically with
my AR TT and Sumikko MMT arm w/ Hana EH cart.
I'm not in a big rush to swap out tubes because I want to
really get accustomed to the sonic signature of the gear BUT
I do get that itch to try my stash of tubes,especially on the phono stage.
I have a matched pair of Raytheon 5751's/12ax7's of Genalex Gold Lions/Mullard CV4004's/IEC 1960's Mullards.
and
my single tubes include a JAN 1963 12ax7/GE 1980 12ax7/Re-Issue Mullard 12ax7/Tung-Sol 12ax7 as well as a single Mullard CV4004
& a Fisher West German 12ax7

I've read that the tube configuration looking straight down on the Croft from left to right is
tubes #1&#2 are the phono and #3 is the pre amp.
The system sounds very good, revealing of upstream sources but with a tiny bit of harshness that
I'd like to see if I can soften.
I have a wide variety of music and I have to say the Harbeth's can carry it to my satisfaction.
So what would be the protocol to start the process?
Pre-amp tube first and then wait a bit or start first rolling the phono stage only?
Any suggestions deeply appreciated.
p.s.
I have contacted Glenn about a month ago but he hasn't responded so I don't
want to pester him.
Thanks!

[worrasf]

Welcome to the world of Croft. Wise choice - see my post from yesterday on Glenn's superb customer service.

Like many others who I'm sure will comment I have spent literally years swapping tubes in my many and various Croft preamps and power amps. I have a large box full of NOS and new tubes from dozens of makers. If you have the merest trace of OCD stop now before you go mad. LoL [emoji1787]

Seriously though the single thing I have learned is that as with all things HiFi in the end it all comes down to personal taste - the sound that best floats your boat which like as not will not be the same as mine or many others.

After spending a lot of money on NOS Tesla's, Mullard's, RCA's, Mazda's TFK's Westinghouse, Sylvania, Brimar Philips etc etc but you get the picture all with varying appeals and dislikes I have come back around to sticking with (almost) what Glenn uses. In my 25RSLS line stage I use 3 (mine is modded to include an output buffer for a headphone amp) Tesla gold pin 12BH7a's and 2 Tesla gold pin ecc83s's in the power stage. I use a Tesla gold pin ecc99 in the power amps. This combo gives me a clear, neutral dynamic presentation that I like - others may not.
Glenn will not comment on tubes I can tell you from many conversations he struggles to find consistent quiet non microphonic NOS tubes so sticks to the Tesla's.
Others will I'm sure give you other equally valid opinions and suggestions.

I presume your amp has the red print Tesla's Glenn usually uses? If it's only a tiny bit of harshness you want to change then try the gold pin versions for little money. Swapping to any NOS will like as not produce a bigger change.

Hope you have fun and enjoy the adventure.
Don't say you haven't been warned LoL [emoji28]

Steve

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[Firebottle]

Good post Steve :thumbsup:

[worrasf]

Good post Steve :thumbsup:

Thanks Alan

[Stowa]

Hi Steve,
Thanks for the detailed response.
One very important consideration I left out was that I use the Croft for
work.
I'm a film /video editor and the unit is on at least 12 hours a day 7 days a week.
I mentioned this to Glenn and my AD and they said no problem.
I've found that the amp runs mildly warm,plus it's near a window
with just enough clearance to not be harmfully vulnerable to the weather while at the same time
get a mild breeze indirectly.
So I'm thinking JJ's Gold pin per your suggestion,Gold Lions or I've just read about the Long Grid JJ's
sold on Tube Depot...you have any experience with these tubes?
Thanks

[worrasf]

Another reason to use new production valves IMO. The preamps do run a bit warm with all those valves but as long as you leave plenty of space above the top case it won't be an issue.
No direct experience of the ones you mention. I have tried the expensive new production TJ full music and Psvanes but was underwhelmed.

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[Floyddroid]

Hi Steve,
Thanks for the detailed response.
One very important consideration I left out was that I use the Croft for
work.
I'm a film /video editor and the unit is on at least 12 hours a day 7 days a week.
I mentioned this to Glenn and my AD and they said no problem.
I've found that the amp runs mildly warm,plus it's near a window
with just enough clearance to not be harmfully vulnerable to the weather while at the same time
get a mild breeze indirectly.
So I'm thinking JJ's Gold pin per your suggestion,Gold Lions or I've just read about the Long Grid JJ's
sold on Tube Depot...you have any experience with these tubes?
Thanks

If you are wanting to stay clear of harshness stay clear of the Gold Lion's

[Stowa]

Hmmm,that hasn't been my experience in various phono stages or preamps,but
everyone's taste and ears are different.
Anyway, what advice as to the procedure of rolling..
Pre-amp valve first then wait a bit to analyse.
or
roll phono valves only first?

Thanks

[worrasf]

Personally, I'd start with the phono stage valves

[Stowa]

Thanks

[Lawrence001]

I beg to differ but if you're not gelling with the valves in there, you risk still not enjoying the sound when you upgrade the phono stage valves as the line stage valve may still have the same issue.

If it were me I'd spend some time listening to the digital side and if you hear the edge that bothers you then sort that first.

Once it's gone from the line stage then do some listening to the TT. If the edge has gone, job done. If it's still there then you can start rolling the phono stage valves too.

If the edge is not there with the digital side in the first place, then move straight onto rolling the phono stage.

If you sort the phono stage out first you risk overcompensating for the harshness of the line valve, and if you then have to change that to get the digital side sorted then you risk having to make further changes to the phono stage to compensate.

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[Stowa]

I just rolled the Genalex Gold Lions into the phono stage of my Croft Integrated and
it was a really bigger than expected improvement.
The JJ's while very detailed and transparent were to my ears too much of
a good thing.
The Lions smooth out the glassy bite that the JJ's can exhibit and make the overall presentation
more airy with added weight and without losing the detail.
Since I run the Croft 12 hrs/7 days a week a new production tube is
more practical and I'll have to save my stash of NOS tubes when I reconfigure the system down the road.
I'm also thinking of adding a third Lion in the line stage and or trying Psvane.

[Stowa]

I beg to differ but if you're not gelling with the valves in there, you risk still not enjoying the sound when you upgrade the phono stage valves as the line stage valve may still have the same issue.

If it were me I'd spend some time listening to the digital side and if you hear the edge that bothers you then sort that first.

Once it's gone from the line stage then do some listening to the TT. If the edge has gone, job done. If it's still there then you can start rolling the phono stage valves too.

If the edge is not there with the digital side in the first place, then move straight onto rolling the phono stage.

If you sort the phono stage out first you risk overcompensating for the harshness of the line valve, and if you then have to change that to get the digital side sorted then you risk having to make further changes to the phono stage to compensate.

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I just saw your post...thanks for the advice.
I might revert back to the JJ's and go line stage first.
Thanks again.

[Stowa]

I went back to the JJ's in the phono stage
and welcome the added detail that the Gold Lions were masking a bit.
To be continued...

[Lawrence001]

I went back to the JJ's in the phono stage
and welcome the added detail that the Gold Lions were masking a bit.
To be continued...If they are all ECC83s then you can now try a Gold Lion in the line stage.

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[Marco]

Hi Joe,

Welcome to AoS!:)

Apologies if I've missed it, but which tubes are you using now (your full current line up), particularly in the phono stage, if it's vinyl you're playing most often, and also what would you hope to gain, in terms of improving on the sound you currently have?

For me, if you can find good quality and reliable NOS varieties (and I've rarely struggled to do so with my amps) then, sonically, they'll knock ANY modern production tubes into a cocked hat! Quite simply, there is no real comparison.

My favourite NOS 12AX7 types are Mullard M8137s, genuine original Teslas (from Czechoslovakia, not JJ), Amperex 'Bugle Boys' (beware though as there are many fakes) and La Radiotechnique/FRT/Dario Miniwatts, shown here: https://tubedatabase.co/tubes/dario-miniwatt-by-r-t-la-radiotechnique-ecc83-12ax7-mc2

Those are super-rare, but if you can find some, trust me they'll blow your mind!:eyebrows:

IME, the key to finding the best sounding NOS tubes is always to go for the oldest vintage varieties, so for example with ECC83/12AX7s, you want late 1950s/early 60s, as that was their 'golden era', when they were constructed with the very best materials, and the main reason why modern production tubes can't compare, simply because they're grossly inferior in that respect [and now only made in China and Russia].

Furthermore, go for military spec varieties, which would've originally been used in professional applications. These are generally more robustly constructed, less microphonic, are of more consistent quality, and so liable to last considerably longer than standard types - and MOST importantly of all, when buying NOS valves from any seller, only do so if they show proper test measurements!

It's the ONLY way of having a reasonable guarantee that you'll be getting something decent, and when looking at the measurements always try and buy closely matched pairs (even better fully balanced), as that will make a BIG difference in terms of how they sound, and also how long they're liable to last.

Anyway, hope that helps:cool:

Marco.

[Marco]

As an aside, this is a great place to buy NOS tubes: http://www.nostubestore.com/

Top-notch stock, mostly military spec, and great customer service!:cool:

Marco.