Croft Series 7 monos

[Jimbo]

Is anyone using the Croft Series 7 mono blocks and are they worth upgrading to from the Stereo series 7 amp or are they only useful in certain applications?

[Wakefield Turntables]

I await this thread with baited breath as I'd like a set!

[awkwardbydesign]

Wrong thread?

[The Black Adder]

Is anyone using the Croft Series 7 mono blocks and are they worth upgrading to from the Stereo series 7 amp or are they only useful in certain applications?

They are useful in all applications.. The Croft mono's will fry your noodle compared to the straight 7.

[Wakefield Turntables]

Why?

[awkwardbydesign]

Why?
Did you mean me? If so, then this- "Turntables and all analogue SOURCE equipment and ancillaries."
I'm not bothered, but it might fly better in the appropriate sub-forum.
If not me, then as you were!

[Jimbo]

Hey Joe, Did you have the 7 Mono,s or 7R Mono's?

I don't really need more power but i am thinking of upgrading my Series 7 and was wondering if I would get a more significant improvement in SQ using mono 7's rather than a stereo 7R?

[The Black Adder]

Why?

Below...


Hey Joe, Did you have the 7 Mono,s or 7R Mono's?

I don't really need more power but i am thinking of upgrading my Series 7 and was wondering if I would get a more significant improvement in SQ using mono 7's rather than a stereo 7R?

Not had them but I've heard the 7R mono's.

I've had the 7R stereo amp and that was superb!!! The mono's bring better defined bass, better seperation etc. I really liked them but in the end I missed the sound of BIG output valves so I went with those.

But don't get me wrong, the mono's do have a big sound and plenty of welly but big output valves (when done properly) gives me that little bit more punch. The 7 version of the mono's will still bring better separation and improved SQ I should imagine and everything else but the 'R' version gives the sound a much more refined and controlled signature IMO. - I'm sure others have their experiences in what comes with the R badge but that's what I felt.

I think it's a good move to get your current amp upgraded (with it's extra half) to the mono's - See what you think, then if you decide to go for the R then get those upgraded later. :)

Can you get to hear some?

[Jimbo]

Below...



Not had them but I've heard the 7R mono's.

I've had the 7R stereo amp and that was superb!!! The mono's bring better defined bass, better seperation etc. I really liked them but in the end I missed the sound of BIG output valves so I went with those.

But don't get me wrong, the mono's do have a big sound and plenty of welly but big output valves (when done properly) gives me that little bit more punch. The 7 version of the mono's will still bring better separation and improved SQ I should imagine and everything else but the 'R' version gives the sound a much more refined and controlled signature IMO. - I'm sure others have their experiences in what comes with the R badge but that's what I felt.

I think it's a good move to get your current amp upgraded (with it's extra half) to the mono's - See what you think, then if you decide to go for the R then get those upgraded later. :)

Can you get to hear some?

Tricky getting to hear some Joe as i think Glenn makes most to order and don,t think there are that many out there. Need to try with my system aswell.:scratch:
I am with you regarding big valves, they do sound a bit more effortless and open. Pity Glenn does not build his all valve OTL amps anymore they were very good indeed in that respect.12723

[The Black Adder]

That's true, James.

But Glenn will service and update the OTL's accordingly - Might be worth having a look around. :)

[Wakefield Turntables]

Joe answered my question. Thanks mate.

[awkwardbydesign]

:doh::lol:

[Jimbo]

I await this thread with baited breath as I'd like a set!

Hi Rexton,

Are you still deciding wether to plunge into the Croft pool or are you undecided what Croft combination to buy?

[Wakefield Turntables]

I'm already in the croft pool mate I own the micro basic preamp. Im still pondering trialling the top end two box pre-amp, the escapes me :doh: A friendly AOS member has offered a trial of his. What makes you ask?

[Jimbo]

I'm already in the croft pool mate I own the micro basic preamp. Im still pondering trialling the top end two box pre-amp, the escapes me :doh: A friendly AOS member has offered a trial of his. What makes you ask?

I saw a post a few weeks back you mentioned trying a Croft pre and was just interested to find out if you had gone any further with Croft stuff. :)

[Wakefield Turntables]

Well if the the micro basic is anything to go by then I should presume the top end stuff should be bloody fantastic :eek:

[Jimbo]

The Micro 25R is fabulous, not really sure need to go any further with the pre. I have been told that changing some of the resistors to non inductive types almost brings this up to the RS level.

However I think I could do better than the standard Series 7 power amp but not sure what would best way to go, hence my question about mono blocks. I have efficient speakers so power is not an issue but control and SQ might be bettered with mono's?:scratch:

[Jimbo]

Back in June 2014 I put this post up as I wanted to know if I should move from a Series 7 Croft to the monoblock Series7 power amplifiers. Not that many people have heard the Series7 monoblocks so I was always keen to scratch this itch and try for myself.

Rewind 15 years or so and I remember sitting in a house in Bridgnorth listening to the then purveyor of Croft gear demonstrate to me the Croft Cypher OTL monoblocks with a vinyl front end and a pair of SP2 Spendor speakers. I was astounded at the sound I heard so much that it remains embedded in my memory as a benchmark all these years later. For Croftophiles who have not heard of the Cypher these were a rare pair of monoblocks using the 6As7G valve rated at 7W output that I think retailed at about £4,000. Not many people heard those either!

Anyway back to the present and having the urge to try some current Croft mono blocks I decided to investigate purchasing a pair. It then struck me that I would have to sell my Stereo Series 7 and buy a pair of 7 monos or have mine converted. However I then enquired about using my Stereo 7 with another Stereo 7 as
Monoblocks not in a bridged form but just using a single input channel on each and corresponding speaker output. This would utilise a dedicated PSU and transformer from each amp in a similar way to a monoblocks 7. Enquiries were made and the big thumbs up was given with a suggestion that using 2 x Series 7 Stereo amps would give very good results indeed!

So I purchased another Stereo Croft series 7 power amp and hooked this up to with my other Croft series 7 and Croft 25R+ Preamp. After a suitable power cable was found I ran it in for a day and then spent last weekend listening.

So how did it sound? Well I am not sure if anyone else has done this so it may well be a first but by the end of the weekend I found it difficult to stop putting vinyl on up until midnight last night. Rarely do i put something in my system that makes me want to play my entire record collection but this combination did!

I will try and convey the improvement this combination made to my system compared to a single power amp. The entire exercise was also witnessed by my 'golden ears' partner Helen who has a much more down to earth approach than myself to Hifi but by the end it even captivated her so much she didn't want to stop listening.

I spoke to a friend this morning and gave an example of the experience when you used to go to the cinema and you watched the ads and then the screen curtains would open wider and the full sound system kicked in and you went to the main event. The soundstage is not particularly deeper but certainly wider and fuller. Information that was just perceptible at the extremes in each speaker was now much more vivid and pronounced. Stereo effects were now precise and obvious where as with the single amp they were a bit hazy. But the biggest differences were the vocals and scale and timbre of instruments. The two amp configuration simply expanded what was there in the recording sometimes to an awesome degree.

Vocals seemed compressed before but now had a depth and fullness to them that was fabulous and were portrayed in a holophonic and very transparent soundstage. Instruments, especially stringed instruments had a bite and timbre that plumbed a few octaves lower. Take a steel stringed guitar (Ry Cooder) or electric harp (Andreas Vollenvieder) and the harmonic bloom and dynamic abilities were now astounding. The power and dynamics simply opened up as if they had been held back before. My single Stereo 7 sounded as if it hardened up when very dynamic stuff was played but the monoblocks were effortless and totally unconstrained. One other observation was the smoothness and lack of grain or distortion to everything. I wasn't aware of it before but switching to the monoblocks it became apparent there was something less refined with the single Croft 7.

The way in which I had connected the two Series 7 amps meant I was still only getting 45w per channel so there was no extra power but the complete separation of the signal going in and separate transformer and power supply allowed the amps to deliver each channel with so much more dynamic clout. Honestly some of the stuff I listened to and knew really well was at another level altogether, almost like another recording!

Having dual volume controls on the Croft pre also meant any imbalance between the two amps could easily be dealt with, not that there was much at all. I now get totally why Glenn likes separate volume controls and why in the past mono configurations of his amps was always the preferred route. It brings about a profound improvement over a stereo amp set up that has to be heard to be believed.

After two massive listening sessions of about 15 hours I decided in order to check and validate what I had heard I would directly A-B the single Stereo Amp against the mono configuration. I picked three tracks from different but excellently recorded albums and played them first on my single stereo Croft 7 then on the monoblocks.

The difference was stunning and absolute, there was no way back. The sound and aural presentation of the Croft monoblocks was so addictive and wonderful there was no way I could go back to a single stereo power amp.

All my music has now taken on another lease of life and I only wish I had gone down this route earlier!:)

[Firebottle]

Just what I found when I scratched the itch to make monoblocks :yay:

It is definitely the reduction of inter-modulating distortion from one channel to the other, something you think beforehand that surely can't be much of a problem.
Now you know that removing this low level 'hash' just reveals what is there to really get the passion and enjoyment flowing :D

Excellent result.

[Jimbo]

Just what I found when I scratched the itch to make monoblocks :yay:

It is definitely the reduction of inter-modulating distortion from one channel to the other, something you think beforehand that surely can't be much of a problem.
Now you know that removing this low level 'hash' just reveals what is there to really get the passion and enjoyment flowing :D

Excellent result.

Probably even more so with an OTL design.:)

[struth]

Good to hear your super mega happy :)

[Jimbo]

Good to hear your super mega happy :)

Cheers Grant. Spent quite a few years putting my system together and this was always in the plan but as it all costs so much money it had to be one of the last pieces of the jigsaw. :)

[brian2957]

Having heard your excellent system recently James , I must admit that this result was a tad unexpected . Your system was sounding so good and so perfectly balanced in your room when I heard it that I must say I thought it would be difficult to improve on it . You took a chance by buying the second power amp and it has paid off so well done . It's just a shame that I'm not nearer and could pop round for an hour or two to have a listen .
For those who haven't heard James system , it was one of the most nicely balanced and beguiling systems I have ever heard . This new setup must sound very very good indeed :D

[Jimbo]

Thanks for your kind comments regarding my system Brian. I am extremely sensitive to changing components or equipment in my system as it shows up straight away, hence I have kept it very simple but carefully set up and tweaked for a long period. I only change or add major bits rarely and they have to earn their place by enhancing what I have in a positive way. I am not looking for different but an obvious improvement which is a difficult balance to achieve.

Using two Croft amps simple gave me more of everything I have in a better way. Rarely nowadays does the hair stand up on the back of my arms when I listen to something new but it did at the weekend. That beguiling aspect of the system was even more liquid and transparent but still kept all the detail and visceral impact when needed. As Alan mentioned earlier you don't know what hash or distortions is there in your system until you remove it!

The Croft mono configuration is certainly another step towards audio nirvana for me. Addictive, compelling and beguiling with a live realism that even astonished me, especially on vocals and cleanly recorded instruments.

You can judge it for yourself again hopefully one day Brian.:)

[Haselsh1]

My plan for last year was to buy a pair of Croft Series Seven monoblocks but in the end I spent a good deal more on a Prima Luna power amp as I wanted to go the whole valve route. I also bought a Prima Luna phono preamp as well. My only problem with the power amp is that it weighs 30kg and is a bugger if it needs moving. Other than that, I think I made the correct choice. Of course I'll never truly know though.

[eksiil]

I'm streaming Tidal Hifi via a Raspberry Pi3 + PiDac+ into a pair of Croft 7R monos and don't know whether to laugh or cry. straight into the monos, well recorded sound is almost *too* vibrant, alive & present. routed via the Croft MegaMicro II preamp, the slam subsides, but voices especially take on a very sumptuous, spatial quality. for the first time I think I know what "euphony" means in this context. maybe there are two different nirvanas.

[Ali Tait]

So the preamp is not transparent then?

[eksiil]

So the preamp is not transparent then?

no. the voices sound "more real" with the preamp, according to a just-departed guest who played his own songs.

[Jimbo]

Could I ask Ahto how you position your monoblocks, do you stack or separate them. Also do you plug them into separate wall sockets?

A picture of your system would be great if you would be kind enough to put one up?

[eksiil]

Could I ask Ahto how you position your monoblocks, do you stack or separate them. Also do you plug them into separate wall sockets?

A picture of your system would be great if you would be kind enough to put one up?

pleasure, though the picture isn't the best. I have them side by side in a thick DIY rack made out of slabs of wood (I find it significantly improves the sound of valve gear especially). I've also placed little cutouts from a sheet of sound isolation material under the monos' individual feet.

https://www.dropbox.com/s/g66wq87ccdvrb01/WP_20170208_16_25_28_Pro.jpg?dl=0

[Jimbo]

pleasure, though the picture isn't the best. I have them side by side in a thick DIY rack made out of slabs of wood (I find it significantly improves the sound of valve gear especially). I've also placed little cutouts from a sheet of sound isolation material under the monos' individual feet.

https://www.dropbox.com/s/g66wq87ccdvrb01/WP_20170208_16_25_28_Pro.jpg?dl=0

I like the organic approach! I was thinking best to keep the amps separated. Thanks Ahto

[Frazeur1]

That is excellent news, James! I was thinking similar thoughts awhile back when another Series 7 amp came up for sale. I almost bought it, but funds were a bit tight at the time. This might be tucked away for future use though!

I also have found benefits with this type of mono bloc in my Naim setup by using two Nap-100 stereo amps this way. I have been doing that with them for a couple years now, and while power ratings are the same, there is a noticeable increase in clarity and drive, an ease to the music(yes, even with Naim amps!) that has made it worthwhile. I have obviously been laughed at several times on a couple of other forums for even suggesting such a thing, yet the same folks will blather on about how wiring transformed their entire system. Go figure.

Anyway, good for you! I may follow you at some point with my Crofts!

[Jimbo]

That is excellent news, James! I was thinking similar thoughts awhile back when another Series 7 amp came up for sale. I almost bought it, but funds were a bit tight at the time. This might be tucked away for future use though!

I also have found benefits with this type of mono bloc in my Naim setup by using two Nap-100 stereo amps this way. I have been doing that with them for a couple years now, and while power ratings are the same, there is a noticeable increase in clarity and drive, an ease to the music(yes, even with Naim amps!) that has made it worthwhile. I have obviously been laughed at several times on a couple of other forums for even suggesting such a thing, yet the same folks will blather on about how wiring transformed their entire system. Go figure.

Anyway, good for you! I may follow you at some point with my Crofts!

I didn't need any more power in my system but as you found the drive and dynamics are better. I also found they improved vocals and I lost some hash or low level distortion resulting in an overall smoother, refined sound. I believe this was as a result of reduced crosstalk.

Two Croft 7 power amps are also a cheaper way of upgrading to monoblocks and if you don't like them you have a spare Stereo amp which can easily be sold on. I am just installing done more electric sockets now as I need more which should also benefit the mono amps.

[Frazeur1]

James, another benefit-or potential one going this route too, could be the possibility of biamping with a pair of the stereo series 7's. Not every speaker if capable may benefit from this, but certainly an option. This has stuck in my mind as a potential for me later on, have been giving thought to moving up to a pair of Larsen 6 which do have the capability of being biamped. Just another thing to try down the road if I go that route. Of course this is another are that gets talked down often, but I do feel as if there can be benefits to be had potentially.

At any rate, enjoy your amps and system, and most importantly, the music!

[Jimbo]

James, another benefit-or potential one going this route too, could be the possibility of biamping with a pair of the stereo series 7's. Not every speaker if capable may benefit from this, but certainly an option. This has stuck in my mind as a potential for me later on, have been giving thought to moving up to a pair of Larsen 6 which do have the capability of being biamped. Just another thing to try down the road if I go that route. Of course this is another are that gets talked down often, but I do feel as if there can be benefits to be had potentially.

At any rate, enjoy your amps and system, and most importantly, the music!

Glenn Croft himself mentioned using the Stereo 7's for biamping so definitely worth investigating in future. He also mentioned a couple of ways of using two Croft 7's as monoblocks.

"You can also use a jumper lead to put the input into both channels and use one channel for the bass and one for the top end if your speakers are bi-ampable. Or you can use a jumper cable to put the input into both channels and link the two positive output together with a short piece of wire - this will combine both channels together to give a bit more power and a lower output impedance."

[Frazeur1]

Interesting, especially that last bit on linking the two positive outputs giving a bit more power and lowered out put impedance. Sounds almost scary...

Usually I am in the camp of buying a better 2-channel amp initially, than doing with lesser and biamping later, but sometimes through good deals or having something laying around that works, you find some improvements that maybe might not have been in the mind originally. I may have to keep my eyes on a good buy for another Series 7, they crop up here every now and then. Worth a punt I think!

[Jimbo]

Listening again last night Tim and there is definitely greater clarity. I have heard some detail back in the mix on some recordings I was not aware of before.
Soundstage is also bigger and greater depth back and front. Another aspect that has become increasingly noticeable is the transparency in the system, certainly up a notch.

The improvements are subtle, not massive. From what I have heard I would say if I had listened blind it was if my preamp had been upgraded. The improvements bought by the mono power amps are unexpected and not what I presumed.

[brian2957]

Sounds like a nice upgrade to an already excellent system James . It will be interesting to see what your planned upgrades to the mains will bring .

[Frazeur1]

Very good James, I would say I had similar results too with my Naims. Subtle yes, but very well worthwhile in the long term listening. I look forward to how things go longer term for you here.

I am curious about your preamp, did you buy your Croft 25R+ right off, or did you upgrade a 25 in steps? I have been tempted to try the 25R, but not sure totally what it would bring to my situation, as I do not utilize the phono stage at the moment, just one input for my source. While I have no doubts it is certainly great, it is more of a matter of utilizing its capability versus the outlay money-wise. Bang for buck? I am totally pleased with the standard 25, no gripes at all, and really, I find it really good. Unfortunately there are no dealers in which I could listen to this, so kind of stuck.

The second Series 7 definitely interests me though, and I may just give this a go in the next couple of months when I have some spare funds(hopefully). Keep us posted!

[Jimbo]

Very good James, I would say I had similar results too with my Naims. Subtle yes, but very well worthwhile in the long term listening. I look forward to how things go longer term for you here.

I am curious about your preamp, did you buy your Croft 25R+ right off, or did you upgrade a 25 in steps? I have been tempted to try the 25R, but not sure totally what it would bring to my situation, as I do not utilize the phono stage at the moment, just one input for my source. While I have no doubts it is certainly great, it is more of a matter of utilizing its capability versus the outlay money-wise. Bang for buck? I am totally pleased with the standard 25, no gripes at all, and really, I find it really good. Unfortunately there are no dealers in which I could listen to this, so kind of stuck.

The second Series 7 definitely interests me though, and I may just give this a go in the next couple of months when I have some spare funds(hopefully). Keep us posted!

The Croft 25R was purchased as a standard product. I then had the line stage changed to the RS linestage which has a 12BH7a valve instead of ECC83 and uses non inductive resistors. I then changed all the valves in the phono stage and regulation stage to NOS Tesla E83CC and the linestage valve to a NOS RCA valve. The improvement over a standard Croft 25 is significant.

If you want to upgrade yours Tim to this level maybe contact Glenn Croft himself and he will do the work for you directly.

[Firebottle]

The improvements bought by the mono power amps are unexpected and not what I presumed.

I think it is interesting that you have said 'unexpected', when with hindsight it is understandable where the benefits come from.
I had an open mind when scratching the itch to try monoblocks and was very pleasantly aware of the improvement in transparency when they were plumbed into the system.

Another incremental improvement on the law of diminishing returns, yeah :yay:

[Jimbo]

I think it is interesting that you have said 'unexpected', when with hindsight it is understandable where the benefits come from.
I had an open mind when scratching the itch to try monoblocks and was very pleasantly aware of the improvement in transparency when they were plumbed into the system.

Another incremental improvement on the law of diminishing returns, yeah :yay:

Absolutely agree Alan, it is the law of diminishing returns and you could surmise an expensive route to go for a small gain. But can you then live without those gains?

I have found every small step i have taken has taken my system to a completely different level compared to where it was when I first lashed the items together. Interestingly I could actually reverse the process and listen to my system in its original form but I don't think it would be half as involving or enjoyable.

[Frazeur1]

James, I have given thought to having mine upgraded, the only real negative is that I am on the other side of the big pond, so would have to ship them over to Glenn. Not that I wouldn't do it, it certainly has crossed my mind.

Alan, I think with most things in our hifi world, it is always good to have as much of an open mind to things as possible(note to self here). I know when I tried my little Naim amps and took a pair of them and used them like a mono's, I was aware of the "potential" sonic benefits, as I have witnessed this before, but wasn't too sure it would necessarily be transferred to something I could really hear as an improvement and not just different in this instance, and with this gear. Fortunately as you said, definite improvement in transparency.

Always nice to hear when others too have similar experiences! Especially when they are good ones!

[Jimbo]

James, I have given thought to having mine upgraded, the only real negative is that I am on the other side of the big pond, so would have to ship them over to Glenn. Not that I wouldn't do it, it certainly has crossed my mind.

Alan, I think with most things in our hifi world, it is always good to have as much of an open mind to things as possible(note to self here). I know when I tried my little Naim amps and took a pair of them and used them like a mono's, I was aware of the "potential" sonic benefits, as I have witnessed this before, but wasn't too sure it would necessarily be transferred to something I could really hear as an improvement and not just different in this instance, and with this gear. Fortunately as you said, definite improvement in transparency.

Always nice to hear when others too have similar experiences! Especially when they are good ones!

Yes that is a small issue and could be bit costly in shipping terms. Maybe the other option would be to sell your 25 and buy a 25R? Nice to hear folks on the other side of the pond have discovered Croft and really appreciate you input Tim. I think Stereophile magazine did a review of the Croft Integrated a few years back and were quite taken with it. They should go back and review Glenn's separate pre and power amplifiers. I think they would be suitable impressed.

[Frazeur1]

Yes, it was nice to get some US press on the Crofts at the time. It would be nice to see more coverage/reviews on the separates too. The Stereophile review did create a little bit of a stir over here, but like many things in audiophile land, I think it was seen as another "flavor of the month" which is what tends to happen often, and real merit gets tossed aside. Plus too many of the folks that take measurements as the utmost end all, be all, dismissed the little integrated due to the results of JA's measurements-not something I want to bang on about here, as it has been covered before. Me, I don't listen to measurements, I listen to the music, and this is where the Crofts do shine. Screw measurements to some degree. Art and Stephen were happy too with the music it made.

Probably you are correct that selling my Micro 25 and just buying an "R" version would come in cheaper, possibly. I may talk to my distributor over here if it comes down to looking more seriously at the "R", maybe they will have a better solution perhaps.

I do think that there are those that really appreciate what the Crofts do, and do like the understated "spartan" look of them as well. Count me as one of them. While I do tend to every now and then switch things up between my Naims and Crofts, I have to say that the Croft overall just sounds right. Good stuff for sure!

[hifi_dave]

Despite the reviewers raving over the sound of the Croft Integrated, the magazine published measurements which were described to me as "political". Certainly hasn't affected sales one jot.

[Frazeur1]

Dave, you would know more about those measurements and the reasons than I ever would, and probably most of the readers too. I probably shouldn't have said anything about it anyway, as it really means nothing to me either. I tend to think of most US audio types that read Stereophile may be a bit more finicky. Then again, maybe not. It seems to me that so many over here base their buying decisions on reviews/flavor of the month gear instead of using their own ears. While I like to read reviews of various kit on occasion, it tends to have little influence on me.

Hard to say what affect it had-if any-on US sales. I think again, the Croft gear would be dismissed by many here on looks and the dual pots alone, although I readily admit, I have no numbers to base my comment on. If so though, it would be a shame, as the Croft gear punches well above its weight and cost for the most part. I personally hope Glenn can continue to make his wonderful little gems for a long time, and I am happy that I purchased a couple of them!

[Firebottle]

.... as it really means nothing

Sorry to paraphrase your post to such a degree but the test results obtained were flawed because the conditions of test did not take into account the impedance miss match presented to the line output.
This output is different to the main output as it is not buffered, the same as probably most line/tape outputs in other pre amplifiers.

If the loading had been at high impedance then no degradation of performance would nave been found.

:)

[Arkless Electronics]

I would expect amplifiers of this type to measure awful in exactly the way Stereophile reported.

While I'm at it, and as I explained at some length a few weeks ago, there is little or no advantage to monoblocks. Whilst they will often sound better it is nothing to do with them being monoblocks and everything to do with all the resources normally spent on a stereo amp being put towards just one channel...

[Frazeur1]

Jez, but in this case, the money was already spent as a stereo amp to begin with-and comparing sound of stereo vs mono, one is only utilizing a single channel of two stereo amps, same guts, no added electronics in this case. Otherwise yes, I get what you are saying.