[K.H.]

Does this riaa has any built in sub-filter?

[James Tanner]

Does this riaa has any built in sub-filter?

Hi KH

It is an option when ordering.

james

[Elizabeth]

Curious. Is this filter defeatable? or just added in?
And no one told me anything about such a device when i ordered mine.
I do not need it, but still, if i did, it would be good to be told about it by the dealer.
And i am still comfused how the MC can have three levels of gain?
I can see the MM has a jumper for the two levels.. but where is the MC adjustment?

[James Tanner]

Curious. Is this filter defeatable? or just added in?
And no one told me anything about such a device when i ordered mine.
I do not need it, but still, if i did, it would be good to be told about it by the dealer.
And i am still comfused how the MC can have three levels of gain?
I can see the MM has a jumper for the two levels.. but where is the MC adjustment?

Hi Elizabeth

We just add some caps that roll off at 6dB at about 15Hz if the customer wants - can not remember the last time we did one though.

The MM has two settings 34 or 40dB using a jumper and the MC has 2 settings of 16 or 22dB but they are soldered in during production due to the very low level signals and contact resistance at those low levels.

james

[Fullvolume]

I am confused about the gain settings also.

In the HomeTheaterHiFi review they state:

There is a toggle to select whether you are using an MM or MC cartridge. Gain is set internally by moving some jumper connectors. The available gain for MM cartridges is 35 dB or 41 dB, and for MC cartridges, 51.5 dB, 57.5 dB, or 63.5 dB. The gain setting is determined by the output of your cartridge.

http://www.hometheaterhifi.com/phono-stages/1083-bryston-bp15-phono-preamplifier.html?showall=1

[James Tanner]

I am confused about the gain settings also.

In the HomeTheaterHiFi review they state:

There is a toggle to select whether you are using an MM or MC cartridge. Gain is set internally by moving some jumper connectors. The available gain for MM cartridges is 35 dB or 41 dB, and for MC cartridges, 51.5 dB, 57.5 dB, or 63.5 dB. The gain setting is determined by the output of your cartridge.

http://www.hometheaterhifi.com/phono-stages/1083-bryston-bp15-phono-preamplifier.html?showall=1

Yes you can adjust the gain using the 2 settings in MM and the 2 settings in MC for 4 possible gain settings. The MM is user adjustable the MC is not. The gain in the MM section and the MC section add up for overall gain.

MC gain setting is determined by the source impedance of the cartridged used. From 5 ohms to 40 ohms the 22dB setting is used and from 40-150 ohms we use the 16dB setting.  A jumper is available for the user to increase or decrease the overall gain by 6dB on MM section only.

james

[K.H.]

Hi Elizabeth

We just add some caps that roll off at 6dB at about 15Hz if the customer wants - can not remember the last time we did one though.

james

With the common bassreflex speakers of today I find it strange that so few customers ask for this option. Do you think this sub-filter will degrade the sound in any way?

[James Tanner]

With the common bassreflex speakers of today I find it strange that so few customers ask for this option. Do you think this sub-filter will degrade the sound in any way?

I think depending on where the filter comes in it may affect the very low frequency response of the Phono system. If your arm and cartridge are set up properly it usually is not an issue.

james

[Elizabeth]

Sorry I am just dumb as a stump. So, the 1.5 will by itself, automatically (if i read it right) adjust it's own MC gain if it sees 5 ohms to 40 ohms it will be set at 22dB gain , and if i change carts, and then have one on it of 40 to 150 ohms it WILL automatically give a gain of 16dB.
Is this just a reality of the design? so it (appears to) slide/s down as the impedence is higher? and no magical stuff in there, just common (HAH!)  knowledge of electronic circuits?
OR, does it have some sensor that changes something inside?
Confused..
PS added: I  have never had the need of a subfilter in any system i have owned.

[James Tanner]

Sorry I am just dumb as a stump. So, the 1.5 will by itself, automatically (if i read it right) adjust it's own MC gain if it sees 5 ohms to 40 ohms it will be set at 22dB gain , and if i change carts, and then have one on it of 40 to 150 ohms it WILL automatically give a gain of 16dB.
Is this just a reality of the design? so it (appears to) slide/s down as the impedence is higher? and no magical stuff in there, just common (HAH!)  knowledge of electronic circuits?
OR, does it have some sensor that changes something inside?
Confused..
PS added: I  have never had the need of a subfilter in any system i have owned.

Hi Elizabeth,

NO it is not automatic - we wire the MC stage depending on the order.

The majority of the MC cartridges out there are lower impedances so the 22dB of gain is the standard setting.  Some cartridges like say the Denon 103D have higher imedances and that requires the 16dB setting.  Remember these settings do not affect the frerquency response of the cartridge just the noise floor.

james

[Elizabeth]

OK. I remember when i bought two BP1.5 last Spring.
The first one I asked nothing about it. and the dealer added nothing. Then i ordered a second one. and wanted the MC to be set for 100ohms. no comment from dealer, just it was ordered. So i get the second one and it is serial number immediately after the first one. The second one sounded better. i tried every sort of swapping etc. Finally I asked to return the first one with a $500 restocking fee because i would never be happy with one 'lesser' than the other.
(I offered the restock because i had in in my possession for over two months)

 Now during the wondering what the H'.. I asked can the first one be changed to be like the second one at 100 ohms? and the dealer said they told him they do nothing to them.
So clearly my dealer has not got a clue about the different gains in the MC .And whomever he is in contact with from Bryston is not communicating anything to him.
The only other odd thing was the first one had the 'squared off' corners, and the second one had the radiused corners.
I never really felt happy that the dealer did not know anything about this stuff, and it was not made clear to him by Bryston.. And that it all got buried in 'who knows what? nobody!
So now i have one, not two Bp1.5 and use a Audio Research Sp-15 for just it's tube phono stage as a second phono stage.
 I have to say my Bryston Dealer is a good guy though.

[vegasdave]

I think depending on where the filter comes in it may affect the very low frequency response of the Phono system. If your arm and cartridge are set up properly it usually is not an issue.

james

Also, with the high damping factor of Bryston amps, that helps too. True?

[K.H.]

Also, with the high damping factor of Bryston amps, that helps too. True?

Without the sub-filter; do I have to turn down the volume when cleaning the stylus?

[vegasdave]

Without the sub-filter; do I have to turn down the volume when cleaning the stylus?

I personally turn the volume all the way down to 0. Cleaning a stylus with the volume up can ruin your speakers.

[K.H.]

I personally turn the volume all the way down to 0. Cleaning a stylus with the volume up can ruin your speakers.

No problem with my Trichord Delphini MkII NCPSU, with built in sub-filter, but I have seen basswoofers move a lot without. That said, I never clean the stylus with volume at high setting. 

[Elizabeth]

NO! I never turn down the volume because i WANT to hear the sound as I cannot see the tiny stub of stylus on my Dynavector 17D3 and find it only by the sound.
The oddest sound is using the  Denon ultrasonic cleaner (out of production, rare) with the volume up.
As for the Benz glider, with it's stylus sticking a 'foot' out, I want to know exactly how much pressure I am exerting, and again, that is by sound.

[95Dyna]

The only gain setting of the five possible you can't achieve as the unit is setup from the factory is the 51.5 db.  That would require a jumper change on the stepup transformer from the factory set 22.5 to 16.5 db which you would then combine with the 35 db. MM setting.  The 57.5 db setting can be achieved by setting the MM stage to 35 db combined with the factory 22.5 db step up factory setting.  The 63.5 db is reached by setting MM to 41 db.  That being said, I too am stumped looking at the diagram in the manual as to how you would change the stepup tranformer from 22.5 to 16.5.

[vegasdave]

Right, it depends on your cartridge. If your cantilever is very thin and delicate, having the volume up a bit might not be a bad idea.

[James Tanner]

The only gain setting of the five possible you can't achieve as the unit is setup from the factory is the 51.5 db.  That would require a jumper change on the stepup transformer from the factory set 22.5 to 16.5 db which you would then combine with the 35 db. MM setting.  The 57.5 db setting can be achieved by setting the MM stage to 35 db combined with the factory 22.5 db step up factory setting.  The 63.5 db is reached by setting MM to 41 db.  That being said, I too am stumped looking at the diagram in the manual as to how you would change the stepup tranformer from 22.5 to 16.5.

Hi 95Dyna,

The MC has small solder points on the circuit board in order to attached the small wires from the step-up transformer.  The way the wires are configured will determine the gain setting. The voltages at this level are extremely low and a direct connection is much better for performance than a jumper.

james

[cheviot100]

I'm digressing a bit but I seem to recall James saying that the mm/mc phono stage in a BP26 is the same as a BP1.5. That being the case, is there similar internal adjustability with a BP26 for gain etc. as with the stand alone phono stage?
 
Furthermore, I hava a somewhat rare and oddball Rega Apheta cartridge on my P9 - are the factory settings for the Bryston phono stage appropriate? I'm having trouble deciphering this stuff: http://www.rega.co.uk/downloads/Apheta%20Manual.pdf and http://www.rega.co.uk/downloads/Ios%20manual%20.pdf  and reconciling it with the BP1.5/BP26mm/mc manuals.
In short, are the Bryston factory settings such as they are on my BP26 mm/mc fairly optimal for my Rega Apheta's needs?

Thanks James, when you've got a chance.