Pre-Owned Icon Audio MB845 Mono Block Valve Power Amplifier (Pair)
You can earn loyalty points on every order you place on this website. If you select to create an account at checkout, your loyalty points will be saved and you can use these to discount future orders online.
Each product page shows you how many loyalty points you can earn when you order that item. Essentially, for each £1 you spend, you earn 1 loyalty point and for every 1 point earned, 1p will be added to your loyalty point balance (this is the same as some of the UK's biggest loyalty point cards). So for example, if you spend £500, you'll earn 500 loyalty points which can be used to discount a future order by £5.00.
Only 1 in stock
Features
| Manufacturer | Misc Clearance |
|---|---|
| Warranty The length of time your product is protected by warranty | None |
Description
These amplifiers are low feedback valve amplifiers that are different in the way they delivers power. Distortion rises progressively and overload occurs gradually with a smooth rounding of the wavetops. Using a 1% distortion limit the big MB845 delivers 85 Watts, or 90 Watts with a 3% limit using the conventional 1kHz test. However, the transformers, which are large but not huge, moved into unhappiness at around 65 Watts from a 40Hz bass tone and managed around 70 Watts maximum (3% thd), so this is the true power output as far as bass heavy Rock is concerned. This result applies to both 8 Ohm and 4 Ohm taps I should add.
At a few Watts the MB845 produced around 0.2% distortion, mainly innocuous second harmonic at frequency extremes of 40Hz and 10kHz, this figure sinking to 0.05% at 1kHz, usefully below Harold Leak’s 0.1% limit! What really matters is what is going on across the frequency band below 10V output (25 Watts into a 4 Ohm loudspeaker) and here the MB845 was producing just a little low order distortion, as our distortion analysis shows, so distortion is not a problem.
Sensitivity was high at 440mV for full output, meaning it will work with many phono stages without an intervening preamp, including Icon Audio’s which have a volume control fitted expressly for this purpose. Noise was low at -102dB and hum virtually negligible at 0.3mV, making the MB845 unusually quiet - useful when sensitive loudspeakers are used.
Frequency response rolls off gently above 15kHz, the -1dB point, measuring -1.5dB at 20kHz. Whilst this is large when compared to conventional solid-state and valve designs which are mostly flat to 20kHz nowadays, it is more than countered by the intrinsic rising response of most modern loudspeakers that are commonly +2dB up at 20kHz. The MB845
will sound just detectably less bright in comparison to other amplifiers all the same.
The Icon Audio MB845 is typical of a well engineered large, low feedback valve amplifier, possessing a stable distortion pattern dominated by innocuous sounding second harmonic at normal listening levels. It should sound smooth, easy on the ear and powerful.