Bryston BP-25 Preamp, 10B-Sub Electronic Crossover, and 3B-ST Amplifier - Measurements and Review

[welwynnick]

The amp maintains good performance across frequency, here is the left channel at a few frequencies:
View attachment 469122

It's great to see some Bryston measurements, but the THD vs Power vs Freq surprised me - high frequencies were all lower than low frequencies.
Distortion usually increases at high frequencies, even with Bryston.
What measurement bandwidth did you use?

 

[MAB]

It's great to see some Bryston measurements, but the THD vs Power vs Freq surprised me - high frequencies were all lower than low frequencies.
Distortion usually increases at high frequencies, even with Bryston.
What measurement bandwidth did you use?

I used 60 kHz for that measurement.

 

[aschen]

I had a b100 integrated for a few decades and a 4B3 for maybe 5.

I hate audiophile BS less than some of y'all but more than most. Bryston hardware to me justifies its high asking price. Its built really well in the engineering sense like a nice industrial instrument. You can just tell everything fits right, operates correctly, and was made with care. I feel like a lot of high end gear uses a 2" thick face plate to hide flakey firmware and jankey layouts.

As an added bonus the company is ran by really cool people and they are serious about supporting their products.

 

[DSJR]

I take a good performance from Bryston power amps totally for granted, but my experiences with the BP25P were less stellar - and it isn't the fault of the preamp at all. I've seen other tests of the '25 to be equally excellent, but a niggle is that I wonder if the larger multi-output supply in the replacement BP26 (at nigh-on double the price I remember) might have been 'better?'

Subjective sighted comments below, so be warned

Turned on from cold (we turn everything off when not in use), I found the BP25 on all inputs and RCA as well as balanced outs, to 'sound' a bit 'cold' and 'stark.' The other choice was a Meridian 502 which 'did' atmosphere and reverb better (don't look away just yet please). I only had short two hour maximum listening sessions and thought that was that UNTIL, one night I turned off the power amp and left the preamp powered overnight. The following day, the sound was excellent, sweet, 'musical' and just as I wanted. This was repeated a few times in the ten years I owned it, so I don't think it was my ears or brain playing tricks (turned on cold first thing in the morning it reverted back). When I sold it, I briefed the new owner, who left it powered 24/7.

 

[KEFCarver]

I have a 2B-LP as well, but one channel has some hum. I contacted the US repair rep, and he kind of talked me out of having it repaired, claiming it was probably 'normal', and was not interested in arguing with him about it. I'll be very curious to see your measurements.
I haven't decided to resell it as is, or have one more go at the repair guy (they are modules, so not hard to ship.)
The 3B and 2B make a nice pair in the rack, though and would make a nice set of amps for a two way system.

I had four 2B-LP's (now only 1), and recapped all four of them, which was really a waste of time and money, and did not improve the performance (I measured the before and after cap replacement on at least one using a QA analyzer). I measured all of the caps with a Sencore LC53 which can apply 50vdc across them and they tested fine, as did the ESR using another tester. There can be other causes of hum that creep in- someone brought over a Classe' amp last week for a hum and it tested fine and when we hooked it up to speakers and shorted the amp's input it was perfectly quiet... I have been impressed with Bryston as far as their support when I had some questions about what the bias and dc offsets should be for the 2BLP.

 

[prerich]

Can't go wrong with Bryston! Their amps were in the running for powering my rig, but they were beaten out by McIntosh. Not that McIntosh performed better (couldn't tell the difference), McIntosh won the beauty contest. However for power on demand, rugged build quality, and proven years of reliability - Bryston hits every metric.

 

[MAB]

I take a good performance from Bryston power amps totally for granted, but my experiences with the BP25P were less stellar - and it isn't the fault of the preamp at all. I've seen other tests of the '25 to be equally excellent, but a niggle is that I wonder if the larger multi-output supply in the replacement BP26 (at nigh-on double the price I remember) might have been 'better?'

Subjective sighted comments below, so be warned

Turned on from cold (we turn everything off when not in use), I found the BP25 on all inputs and RCA as well as balanced outs, to 'sound' a bit 'cold' and 'stark.' The other choice was a Meridian 502 which 'did' atmosphere and reverb better (don't look away just yet please). I only had short two hour maximum listening sessions and thought that was that UNTIL, one night I turned off the power amp and left the preamp powered overnight. The following day, the sound was excellent, sweet, 'musical' and just as I wanted. This was repeated a few times in the ten years I owned it, so I don't think it was my ears or brain playing tricks (turned on cold first thing in the morning it reverted back). When I sold it, I briefed the new owner, who left it powered 24/7.

View attachment 469793

I've never noticed that on any of the Bryston preamps I have had, or any we had in the store when I sold them. I doubt the power supply is under-spec'ed (the preamp delivers 30V into 600 Ohms with no rise in distortion), I also doubt that the external box can be considered small (it's larger than a typical preamp power supply), and I doubt even more that a power supply into a small external box can manifest as you suggest (classic audiophile warm-up myth, it's a thing you know). It seems like a problem unique to your gear or experience. All of this causing the new owner to keep it on 24/7 seems like an odd solution to a potential problem on a piece of gear made by a company that does free repairs unconditionally. Maybe I just don't have good hearing, or am incredibly uncritical listener.

 

[DSJR]

I've never noticed that on any of the Bryston preamps I have had, or any we had in the store when I sold them. I doubt the power supply is under-spec'ed (the preamp delivers 30V into 600 Ohms with no rise in distortion), I also doubt that the external box can be considered small (it's larger than a typical preamp power supply), and I doubt even more that a power supply into a small external box can manifest as you suggest (classic audiophile warm-up myth, it's a thing you know). It seems like a problem unique to your gear or experience. All of this causing the new owner to keep it on 24/7 seems like an odd solution to a potential problem on a piece of gear made by a company that does free repairs unconditionally. Maybe I just don't have good hearing, or am incredibly uncritical listener.

This happened to me so often and consistently, I took it for granted, the Meridian I mentioned (and my subsequent vintage preamps) sounding 'perfect' from switch-on. I know, I shouldn't have mentioned it here... Had I been single, I'd have left the blessed thing on 24/7 and not given it a moment's thought, but herself and our cruel electricity prices dictate otherwise. I certainly don't bother about such things now... I turn the stuff on, use them as much as time allows and then switch off after. Back then, the subjectivist part of me was far more up-front I have to say...

I was also intrigued by the BP26 having more 'supplies' to each stage of the circuit (I can't remember how they were configured). Maybe this was marketing to justify the massive price hike in a not tech-savvy audiophile market?

Thanks for this review. Good to know their gear holds up well even out of warranty

 

[pma]

Here are the results of measurements of a stack of classic Bryston gear from the mid-1990s. A BP-25 preamp, 10B-Sub electronic crossover, and a 3BST power amplifier.

Great job, @MAB ! Thank you!

Should be promoted at the main review page.

 

[pma]

It's great to see some Bryston measurements, but the THD vs Power vs Freq surprised me - high frequencies were all lower than low frequencies.
Distortion usually increases at high frequencies, even with Bryston.
What measurement bandwidth did you use?

Not necessarily. The 20Hz plot is a bit polluted with mains residuals and finite PSRR.

 

[MAB]

This happened to me so often and consistently, I took it for granted, the Meridian I mentioned (and my subsequent vintage preamps) sounding 'perfect' from switch-on. I know, I shouldn't have mentioned it here... Had I been single, I'd have left the blessed thing on 24/7 and not given it a moment's thought, but herself and our cruel electricity prices dictate otherwise. I certainly don't bother about such things now... I turn the stuff on, use them as much as time allows and then switch off after. Back then, the subjectivist part of me was far more up-front I have to say...

I was also intrigued by the BP26 having more 'supplies' to each stage of the circuit (I can't remember how they were configured). Maybe this was marketing to justify the massive price hike in a not tech-savvy audiophile market?

Thanks for this review. Good to know their gear holds up well even out of warranty

The subjectivist soul inside of all of us causes lots of performative things to occur. In reality, I have no way of understanding your experience with this issue, if I had the unit in hand I could.

I got hooked on Bryston after seeing so many of our customers struggle with inconsistent behavior, odd incompatibilities, and dramatic lack of reliability. It took me several decades to finally confirm the gear was as good as I thought it was.

 

[sceptical1]

Can you show us the thd residual of the quant asylum. Your low frequency measurements are too high.

Also, the input divider should be used for unbalanced, too. The preamp should clip at 14V not 8V.

 

[MAB]

Can you show us the thd residual of the quant asylum. Your low frequency measurements are too high.
The input divider should be used for unbalanced, too. The preamp should clip at 14V not 8V.

Sorry, not following. Please be specific. Too high in what? These are all balanced measurements. 18dB Full Scale clips at 18dB, the analyzer even adds it's own distortion before that so some caution is needed.

Also, the preamp clips at 30V, not at 8V or at 14V. The analyzer clips at ~8V if on the 18dB FS setting (for example). Your language is too vague and it seems you are mixing things up.

 

[sceptical1]

The input to the quant is still being overdriven from the unbalanced output of the preamp not just balanced.

Can we see the loopback measurements for the analyser, 20-20khz?

 

[Jarrett]

There are many reviewed here. I just got my mom a WiiM amp with PEQ, it is great. I used the room correction to help her out in her apartment, she seems happy. I like the sound. I have PuriFi and Hypex, they are both great too but overkill for many, likely including myself. I did get them because the are used in a high efficiency system where the noise is audible. but barely to be honest. Otherwise the 3BST, assuming yours is performing like mine, is going to be so awesome that even a more awesome amp isn't going to make one iota of difference in the sound.

Mine do not, unless I hook them up to a really high efficiency speaker like a compression driver on a lens. Even then, I have to get my ear very close.

Are you sure it's the amp? Or is it something the amp is amplifying that the amp is hooked up to? Most likely, usually free to fix, is a ground loop.
If it is the amp, Bryston can likely fix it.

If I had a Bryston amp and didn't need another amp, I would buy a new pair of speakers.
Amps that are working properly just don't have any sound.

Yeah, cause I put my ear to it to locate it. I guess on the 4 ohm load it's working at 100W now according to the manual. Not quite going to call it a problem as it's too low to hear in most normal situations. I have a shielded power cord on the way too, not that it will fix it (better not let the forum hear this )

 

[BlackTalon]

The amp in my main system is a 4B. I bought it used in the mid-1990s. I had to send it to Bryson for repairs 7-8 years ago; it was out of warranty by 3 or so years at the time. The cause was damage from multiple electrical outages during a home reno project, where the 'temporary kitchen' was set up in the den on the circuit with the stereo. Typical 15 amp circuit (USA). My wife and MIL had a fondness for running an electric tea kettle and microwave at the same time, repeatedly popping the circuit breaker. I wasn't home most times when it happened, and I did not know about the issue. It wound up damaging both the Bryston and an Audible Illusions preamp.

I sent the amp to Bryston for repairs, and they upgrades it to 4BSST specs except for one or two small items that were not possible. Communication was great, the repair work cost was reasonable, etc., and the amp has been 100% fine ever since (and it moved to where it should have been -- the family room).

Despite how good it is, I will likely sell it and the current preamp once I can get a Buckeye integrated amp. Why? Because it will simplify the system for other users, and I'll bank a couple thousand $.

 

[phoenixdogfan]

Excellent, excellent stuff. I remember the first time I heard Rogers LS 3/5a's they were powered by a Bryston 3B (not the ST edition). That was in 1977! Bryston is the all time greatest Hi Fi brand in Canadian history.

 

[MAB]

The input to the quant is still being overdriven from the unbalanced output of the preamp not just balanced.

Can we see the loopback measurements for the analyser, 20-20khz?

Seems you aren't understanding what I measured. Or you are being too brief for me to understand. You didn't answer my earlier questions either, which might have helped me to see which part of the test you are not understanding, and what aspect or measurement seems "too-high" to you. Please be specific, put just a bit of effort here. Thanks.

I'll do in internal loopback test later. It will look just like any of the internal loopback tests of the QA403.

 

[Angsty]

I was a country distributor for Bryston in the mid to late 90's. I have personally owned a 4BST Pro and a BP25. As the distributor I was contacted by an elderly gent who owned an early 2B (not heat sinks mounted on the front) who wanted a new front plate. His was chipped and scratched. Cosmetic only. I didn't have a price but the customer didn't mind paying. My next shipment arrived with said new front plate. The invoice from Bryston didn't include a cost on the item. I (yes) faxed them that they haven't charged me. They answered "no charge". My customer was ecstatic. Only had two warranty claims, one was beer split into the unit, the other was where the owner dropped the amp.
The only complaint I got was from an existing user of 3B/4B to power his rental live rig wanting captive speaker output connectors as the binding posts wore out?
Also if a channel had failed (usually short circuit outputs), I could repair locally as the main circuit board had edge connectors to feed the heat sinked power transistor side panels. Easy to replace, only screw driver needed for same day service. I sent the dud panels back to Bryston which they replaced free of charge.

I, too, have received outstanding service from Bryston. I have had 5 units serviced with them with minor age related issues with switches and ground points.

 

[Cbdb2]

I blew up one channel of a Bryston 4B using it in a crazy way. They promptly sent us a replacement card no questions asked and it took a screwdriver and 5 minutes to replace. When a piece of gear has a 25 year warranty you know its built tough and built to fix easily.