Monoblock upgrade?

Discussion in 'Hi-Fi Stereo Systems & Separates' started by Lusankya, Aug 27, 2018.

Tags:
  1. Lusankya

    Lusankya
    Well-known Member

    Joined:
    Aug 26, 2015
    Messages:
    1,248
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    116
    Location:
    Lusankya
    Ratings:
    +1,222
    I currently have a Bryston 4bst running Kef Reference 4.2s and am very happy with it.

    The preamp is an old Audiolab 8000c which is reasonable but will be upgraded when I stop spending all my money on scuba diving kit. I tend to run my system slightly bass heavy, it is just how I like it. I listen to a wide verity of genres depending, time and mood etc.

    I know the big Kefs are power hungary and have read on here several times on people using Bryston 7bst monoblocks and even 4 of them bi wired. So the question will I see a difference switching to a pair of monos vs the 4bst?
     
  2. Electro58

    Electro58
    Active Member

    Joined:
    Sep 22, 2011
    Messages:
    680
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    31
    Location:
    South Ockendon
    Ratings:
    +85
    The 4b is a very good power amp that deserves a much better pre amp than that rather poor ( imo ) Audiolab.
    Change the preamp first before even thinking about upgrading the power amp, it is really letting your system down.
    It would also be wise to buy a balanced preamp such as one of the Bryston models and connect using balanced XLR cables to get the best results.
    You might find that the 4B is all you need if used with a comparable quality preamp unless of course you are playing music in an extremely large room .:)
     
  3. Lusankya

    Lusankya
    Well-known Member

    Joined:
    Aug 26, 2015
    Messages:
    1,248
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    116
    Location:
    Lusankya
    Ratings:
    +1,222
    Don't get me wrong I will definitely be changing the preamp first. Just thinking about the monoblocks really and if they would make that much of a difference with what ever preamp.

    Not sure on what preamp yet. I am put off the Brystons because they require the huge power supply as well, which simply will not fit in my setup. I'll start a thread about preamps at some point but am always after suggestions if you have any.
     
  4. Deleted member 781788

    Deleted member 781788
    Guest

    Products Owned:
    0
    Products Wanted:
    0
    Ratings:
    +0
    God help your neighbours, if you intend on changing a 250W poweramp to something bigger AND you like it Bass Heavy!!
    God help you if they own a gun!
     
  5. BlueWizard

    BlueWizard
    Distinguished Member

    Joined:
    Jun 19, 2007
    Messages:
    22,626
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    166
    Ratings:
    +4,309
    From what I was able to gather, your Amp is 250w/ch to 8 ohms and the speakers are rated at 92db Sensitivity. That means you can hit 92db with 1 watt of power, and that in turn means you can hit 101db with only 8w of power.

    That is ...assuming... these are your speakers -

    KEF Reference Series Model Four loudspeaker

    The speaker is however, rated at 4 ohms. So, in that sense it does require some power, or more accurately some current capability. From the review I read, the amp is capable of 350w/ch to 4 ohms, and have Eight 4,700µF capacitors on the output of each channel of the Power Supply (37,600 µF Total/ch).

    https://www.stereophile.com/content/bryston-4b-power-amplifier-more-lg

    The only thing you might gain in Mono-Block are individual Power Supplies which could potentially have a greater overall Current capability than a single transformer driving two stereo channels.

    To know whether that would be a real advantage, we would have to know how loud you play your music. If you are playing at rattle the window ear-splitting levels, perhaps more power or more power supply is an advantage, but short of that, I'm not sure there is an advantage.

    Though not directly familiar with the AudioLab Pre-Amp, I'm sure it is fine, but not in the same class of equipment as the Bryston.

    The Bryston amp back in the late-90's was about US$2500, which is about $3760 in today's money.

    I believe the Speakers were in about the $5500/pr to $6500/pr range depending on finish. These are mid-90's speakers, so best guess in today's money, about $9860/pr.

    So, you have to decide where your priorities and your wallet are.

    As always, though you have pretty impressive speakers, a speaker upgrade always makes the biggest difference. But it would take some pretty substantial speakers to exceed what you have.

    The current Kef Reference 3, which are pretty close to your existing speakers would cost about £7500/pr and the Kef Reference 5 would cost about £10,500/pr -

    REFERENCE 3 Floorstanding Speaker

    KEF REFERENCE 3 Speakers

    REFERENCE 5 Floorstanding Speaker

    KEF REFERENCE 5 Speakers

    Both new Kef Reference are rated at 8 ohms, though they do drop as low as 3.2 ohms, but likely only at one or two very narrow frequencies.

    But ...that said... likely the first step is the Pre-Amp, though which pre-amp upgrade I'm not sure.

    Then ...again... it gets down to room size, personal preferences, and how fat your wallet is.

    There is a slight advantage to Mono-Blocks, I'm just not sure it is enough to justify the cost. Though not knowing the cost of potential Mono-Blocks, I can't speculate on the right course of action.

    Are there specific Mono-Blocks that you have in mind, what brand and model are they, and how much do they cost?

    The Brystonn 7B-ST mono-blocks are also from the Mid-90's, were you planning to by used? Or were you searching for a new equivalent?

    Bryston 7B NRB-THX, ST, & SST monoblock power amplifier 7B-ST October 1996

    These were about $4700 in the mid-90's which would be about $7720 in today's money.

    The current Bryston Line up, in the SST² models, only seems to come in a 3 channel and 5 channel version. Unless I'm missing it, I don't see Byston Mono-Block Power Amps, with the exception of some 1,000w models.

    I think it gets down to expectations and budget. How much of an upgrade to you expect to get, and are Mono-Blocks the best place to put your money? I think only you can answer that.

    Steve/bluewizard
     
  6. Lusankya

    Lusankya
    Well-known Member

    Joined:
    Aug 26, 2015
    Messages:
    1,248
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    116
    Location:
    Lusankya
    Ratings:
    +1,222
    Thanks for the extensive reply. Mine are actually the 4.2s from cira 2000/01.

    I was indeed thinking of the 7bsts same.era as.my 4bst. They usually go for around 2400 fpr the pair.

    I do listen to my music loud. Volume is not an issue with neighbours.

    I won't be upgrading the speakers anytime soon. I am very happy with them and when I do it will be something in the next level from the References. Although they look gorgeous I am not a fan of the small driver sizes in the newer stuff. Not after having 10" bass drivers.

    Like I said a preamp would definitely come first. Probably something similar era at about 1500 second hand. I have too many other interests to buy this stuff new. Just interested if the mono blocks would make that much difference.




    .
     
  7. Mark.Yudkin

    Mark.Yudkin
    Well-known Member

    Joined:
    Sep 19, 2007
    Messages:
    10,068
    Products Owned:
    0
    Products Wanted:
    1
    Trophy Points:
    136
    Location:
    Zurich, CH
    Ratings:
    +1,551
    Your power amp is quite powerful enough to drive your speakers to levels that will cause the neighbours to call the police and hate your guts (especially with the bass turned up). Using even more power will likely just blow the speakers, which may even be considered a service to the neighbours. :)

    In any case, the power amp is the "last" place you need to look if you have an audio quality issue.
     
  8. Lusankya

    Lusankya
    Well-known Member

    Joined:
    Aug 26, 2015
    Messages:
    1,248
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    116
    Location:
    Lusankya
    Ratings:
    +1,222
    I don't have a problem with sound quality issues and my neighbours are of no concern.

    I know people have run these kefs with more powerful mono blocks I was just musing would it make much of difference.

    I like my bass slightly more in your face. My friends prefer it more neutral. I don't have it turned all the way up and boomy. It is probably up and 10-15%
     
  9. Electro58

    Electro58
    Active Member

    Joined:
    Sep 22, 2011
    Messages:
    680
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    31
    Location:
    South Ockendon
    Ratings:
    +85
    I think upgrading to more powerful monoblocks will make minimal difference or improvement to your system especially as your speakers are so efficient .
    A new preamp on the other hand will make a significant difference / improvement to the sound and one of the Bryston models second hand would be ideal, everything should improve including the bass quality.
    Some people prefer to use a good quality valve preamp with Bryston power amps so this is also another option .
     
    • Thanks Thanks x 1
    • Agree Agree x 1
    • List
  10. Deleted member 781788

    Deleted member 781788
    Guest

    Products Owned:
    0
    Products Wanted:
    0
    Ratings:
    +0
    Tell me what's the point of having a 4 litre V6 engine, if you keep to 30 mile/h on your way to the supermarket?
    Now imagine if you need to upgrade it to 6 Litre v8!
     
  11. Lusankya

    Lusankya
    Well-known Member

    Joined:
    Aug 26, 2015
    Messages:
    1,248
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    116
    Location:
    Lusankya
    Ratings:
    +1,222
    Cheers. That is all I was wondering. Whethet it would be a minimal difference or major. I'll start looking into preamps soon.

    I like to buy one componant at a time so it is like having a new stereo whne it gets up graded.

    That analogy would work if I did that. I am fortunate that I can run my system at any volume I like when ever I like and do so regularly.
     
  12. Legzr1

    Legzr1
    Active Member

    Joined:
    Oct 26, 2003
    Messages:
    1,002
    Products Owned:
    2
    Products Wanted:
    0
    Trophy Points:
    63
    Ratings:
    +181
    Great speakers, great amp, average pre and decent source but you haven’t mentioned what you’d like to improve - you seem quite happy with your current system so which part of it do you find lacking?

    I’m a bit of a bass-head (at times) but not the droning, one-note variety common to badly sited speakers or poorly set up subs - tight, defined and impactful is where it’s at for me.

    I’ve owned the 3.2 and then the 4.2 for years - that Bryson is, in all honesty, all the poweramp you’ll ever need. I powered my Kefs with amps from MF (similar rated output to your Bryson with even more ability into low impedance - the Kefs are nominally rated at 4ohms but drop lower especially at the lower end of the frequency range), Krell and finally an EAD monster of an amp. They all handled the Kefs with ease but the key to that wonderful bass was a clean source and a preamp of equal quality.

    I ended up with a Krell KRC-3 into the EAD (50Kg lump of steel, half a million uF of capacitance (!!) and 8 channels at 300w/8 ohms using a transformer the size and weight of a reasonable AV receiver). Absolute overkill that worked really well with a previous MF preamp but the addition of the Krell gave me that hard-to-find impact and texture down at the bottom end.

    Preamps really do matter.
    Question yourself about what you’re looking for and hoping to improve and then try a quality preamp before going down the rabbit hole of more power or stereo-vs-mono-blocks.

    Personally, I’d go preamp, buy wisely so you can move it on if it doesn’t suit and if you really need to spend more money look at a quality, well integrated sub-woofer.

    I’ve moved on from the Krell, EAD and Kef system now using (which may seem ironic after my words above...) Nord monoblocks powering big B&Ws using the digital pre in my streamer/renderer.
    I have reasons for this and it takes nothing away from my earlier comments - top class pre and well designed power amp feeding your Kefs is all you’ll need.

    I still have my Krell KRC and EAD monster sitting idle (probably buckled the floor where they’ve sat for ages!) because I like the idea of being able to swap back whenever I fancy - once they go I know I’ll regret it.

    tl;dr - get a good pre then add a decent sub if bass still isn’t quite what you’re after.
     
  13. Lusankya

    Lusankya
    Well-known Member

    Joined:
    Aug 26, 2015
    Messages:
    1,248
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    116
    Location:
    Lusankya
    Ratings:
    +1,222
    Thanks for reply.

    Although I am happy with my system I have always known that the preamp was the weakest link and have always intended to upgrade and do that first.

    On my previous speakers I had a Audiolab 8000a and tested the speakers with several different amps my uncle had, Leak Stereo 70, Arcam a85 and a Naim Xs

    The leak and Naim in particular sounded like they had more attack and punch than the Audiolab. I only went with the Audiolab preamp because it was available at the time and I knew it to be a reasonable stop gap.

    I have had this setup for a while now so feel ready to change the preamp and see what else the system can deliver. It has always got better so looking forward to it.
     

Share This Page

Loading...