[audiokiep]

I finally got a turntable and would like to decide on the cartridge to use. I have noticed some discrepancies between specs for the MC phono stage in the BP26 and those listed for the BP 1.5 module.
Earlier post from JT indicates that they should be identical.


Can Bryston clarify which are the correct specs, particularly the gains and sensitivities? 22dB for the MC seems very low. My guess this is an additional gain on top of the MM stage amp.


From BP26 manual:
" ...
Additional Specifications for BP26MC
Phono Inputs:
Distortion: <0.005%, 20-20kHz, with preamplifier driven to full rated output
Noise: Equivalent to approximately 1000 ohm metal film register (Thermal noise greater than 85dB below 0.6mV input, unweighted)
Gain: 16.5 or 22.5dB (internally reconfigurable)
Frequency Response: Below 5Hz to above 30kHz, within
less than +/- 0.5dB
Input sensitivity: 350uV (0.35mV)
..."

From BP1.5 data sheet
"...
High Level sensitivity    MM mode; 5 mV
MC mode; 500uV
Distortion     < .005% IM or THD, any frequency or combination of frequencies from 20Hz-20kHz at rated output
Rated noise
(with A Weighting filter)    MM mode; -80 dBA referred to an input of 5 mV RMS @ 1kHz

MC mode; -80 dBA referred to an input of 0.5
Gain     
MM mode; 35 dB or 41 dB (internally changeable). Factory set gain; 35dB
MC mode; 51.5 dB , 57.5 dB or 63.5 dB (internally changeable). Factory set gain; 57.5 dB
..."

and earlier post from JT:

...

The BP26 phono section is identical to the BP25 and the BP1.5.

The best option in my opinion would be the BP26 with the phono stage installed. That way you reduce wiring and connection issues and you get the advanatge of the MPS-2 power supply.

james

[James Tanner]

Hi;
 
The gain in the MC stage is normally 22.5dB, and is added to the 35dB gain of the MM stage, to obtain a standard gain of 57.5dB at midband.  The gain of the MM stage can also be increased by a further 6dB, to 63.5dB total, including the MC section. 

In Bryston's experience, the range of gain offered is appropriate for almost all MM and MC cartridges.  Most MC cartridges will work perfectly with the standard overall phono gain of 57.5dB, but if you need somewhat more, the optional 6dB increase will be more than sufficient.
 
cwr

[vegasdave]

I think I asked this before...but what is the capacitance of the phono stage in my BP6P?

[James Tanner]

I think I asked this before...but what is the capacitance of the phono stage in my BP6P?

220pf

james

[vegasdave]

Thanks, James. I have the Audio Technica AT150MLX cartridge. Others have said that 220pf is too high for this cart. True or not?

[vegasdave]

Also, is there an advantage to a higher capacitance?

The AT manual says loading from 100-200pf. Is the extra 20pf negligible?

[Toka]

Thanks, James. I have the Audio Technica AT150MLX cartridge. Others have said that 220pf is too high for this cart. True or not?

Ultimately its up to you to decide if its too much or not...from my experience that particular load will in fact give a tipped-up high end, but how that translates into what you actually hear has to do with everything else it is connected to.

[James Tanner]

Also, is there an advantage to a higher capacitance?

The AT manual says loading from 100-200pf. Is the extra 20pf negligible?

Hi Dave,

The higher the capacitance the more very top end frequency response roll-off there will be with a MM cartridge.  Remember the cable capacitance of the tonearm has to be considered and added as well to the 220pf.

Most tonearm cables we have tested are around 50pf.

james

[vegasdave]

James, thanks for the info. Well, I'm not sure of the tonearm capacitance of my turntable. I have a Technics 1210M5G.

Anyway, let's say it's 50pf...what would the total capacitance be?

[James Tanner]

James, thanks for the info. Well, I'm not sure of the tonearm capacitance of my turntable. I have a Technics 1210M5G.

Anyway, let's say it's 50pf...what would the total capacitance be?

270pf

james

[Toka]

James, thanks for the info. Well, I'm not sure of the tonearm capacitance of my turntable. I have a Technics 1210M5G.

Anyway, let's say it's 50pf...what would the total capacitance be?

According to KAB, the tonearm wire of the '1200 (MK2 at least) contributes 10pF, and the IC's add 90pF, for 100pF total on the TT end (not counting the phono stage, of course).

[vegasdave]

Thanks, Toka, and thanks again James.

[denjo]

Hi;
 
The gain of the MM stage can also be increased by a further 6dB, to 63.5dB total, including the MC section. 

In Bryston's experience, the range of gain offered is appropriate for almost all MM and MC cartridges.  Most MC cartridges will work perfectly with the standard overall phono gain of 57.5dB, but if you need somewhat more, the optional 6dB increase will be more than sufficient.
 
cwr

Hi James
My cart is a Dynavector 20 x High Gain, with specs at 2.8 mV. I have placed an order for the B100P/DAC.  I would like to have listening levels roughly equal between the phono and CD sources. Would the 6 dB boost and higher gain of 63.5 dB bring the sound levels to approximate sound levels at the same volume setting? This is important as I normally switch between sources.

Many thanks,

Best Regards
Dennis

[James Tanner]

Hi;
 
The gain of the MM stage can also be increased by a further 6dB, to 63.5dB total, including the MC section. 

In Bryston's experience, the range of gain offered is appropriate for almost all MM and MC cartridges.  Most MC cartridges will work perfectly with the standard overall phono gain of 57.5dB, but if you need somewhat more, the optional 6dB increase will be more than sufficient.
 
cwr

Hi James
My cart is a Dynavector 20 x High Gain, with specs at 2.8 mV. I have placed an order for the B100P/DAC.  I would like to have listening levels roughly equal between the phono and CD sources. Would the 6 dB boost and higher gain of 63.5 dB bring the sound levels to approximate sound levels at the same volume setting? This is important as I normally switch between sources.

Many thanks,

Best Regards
Dennis

Hi Dennis,

I will check with engineering on that. 2.8mv is reasonably high for a MC (high output) so you should be fine.  Do you know if the Dynavector wants to be loaded with 47,000 ohms?

Usually the CD player will have more overall system gain than the Phono section because of the substantial voltage out of the CD Player (2V or more).

What you have to think about is achieving the maximum noise floor in your system. So higher gain may fool you into thinking your getting a more 'dynamic' presentation but in effect you are also raising the noise floor of the overall system. I can see matching the gains as close as possible if you want to switch back and forth between CD and Phono and make comparisons but be aware of the potential compromises.

james

PS - Welcome sir to Bryston ownership!

[James Tanner]

Hi Dennis,

Engineering tells me the extra 6dB of gain in the phono stage would come close to balancing the levels between CD and Phono given the Dynavectors output.

james

[denjo]

Hi James

Thanks for the warm welcome to the Bryston club and for the quick responses.

The Dynavector website states that "(t)he recommeded load resistance for 20XH is over 1K ohms it means typical 47 Kohms for MM inputs is suitable." So I think the 47 Kohms sounds just fine!

As the excellent point you raised about the possibility of increasing the noise floor, would the 6 DB gain seriously compromise my vinyl playback quality?

Best Regards
Dennis

[James Tanner]

Hi James

Thanks for the warm welcome to the Bryston club and for the quick responses.

The Dynavector website states that "(t)he recommeded load resistance for 20XH is over 1K ohms it means typical 47 Kohms for MM inputs is suitable." So I think the 47 Kohms sounds just fine!

As the excellent point you raised about the possibility of increasing the noise floor, would the 6 DB gain seriously compromise my vinyl playback quality?

Best Regards
Dennis

Hi Dennis,

No I would not say 'seriously' as we have done it before but it is just something I felt you should be aware of. Like most things in life - it's a give and take.

james

[Gustavo]

Hi James,
I have been using another brand phono stage for a while but I’m considering an upgrade to the BP1.5, so let me ask you two questions about it.

1) I use a Benz Micro ace low output MC cartridge, the recommended load for this cartridge is 1000 ohms, Is it possible for the BP1.5 to provide this load? According to the manual, the higher load available for the BP1.5 is 120 ohms, so It is possible to customize the BP1.5 for higher ohms?.

2) Checking the BP1.5 from inside (audioadvisor web site), the left part of the BP1.5 has two rectangular metal parts, Are those Batteries? Is the BP1.5 battery operated?

Thank you for your time.

[James Tanner]

Hi James,
I have been using another brand phono stage for a while but I’m considering an upgrade to the BP1.5, so let me ask you two questions about it.

1) I use a Benz Micro ace low output MC cartridge, the recommended load for this cartridge is 1000 ohms, Is it possible for the BP1.5 to provide this load? According to the manual, the higher load available for the BP1.5 is 120 ohms, so It is possible to customize the BP1.5 for higher ohms?.

2) Checking the BP1.5 from inside (audioadvisor web site), the left part of the BP1.5 has two rectangular metal parts, Are those Batteries? Is the BP1.5 battery operated?

Thank you for your time.

From Engineering:


Hi James;

Yes, we can provide a 1000-Ohm input impedance at the MC inputs of the BP-1.5.  We would like to know the output Voltage of the Benz Micro. 

The two rectangular metal cans in the BP-1.5 are wideband step-up transformers for the MC inputs.  The BP-1.5 is not battery-operated.
 
cwr

[Gustavo]

Hi James,
I have been using another brand phono stage for a while but I’m considering an upgrade to the BP1.5, so let me ask you two questions about it.

1) I use a Benz Micro ace low output MC cartridge, the recommended load for this cartridge is 1000 ohms, Is it possible for the BP1.5 to provide this load? According to the manual, the higher load available for the BP1.5 is 120 ohms, so It is possible to customize the BP1.5 for higher ohms?.

2) Checking the BP1.5 from inside (audioadvisor web site), the left part of the BP1.5 has two rectangular metal parts, Are those Batteries? Is the BP1.5 battery operated?

Thank you for your time.

From Engineering:


Hi James;

Yes, we can provide a 1000-Ohm input impedance at the MC inputs of the BP-1.5.  We would like to know the output Voltage of the Benz Micro. 

The two rectangular metal cans in the BP-1.5 are wideband step-up transformers for the MC inputs.  The BP-1.5 is not battery-operated.
 
cwr

Thanks,

Benz Ace MC low output has the following specs.

Output voltage: 0,4 mV at 3,54 cm/s
Internal impedance: 12 ohms
Recommended loading 100 - 47.000 ohms (nevertheless this is not really true because best results are around 1000 ohms).

My other cardtridge is an ortofon MC3000, with the 63 db of the BP1,5 and 120 ohms should be work just fine (ortofon has 0,125 mV output).