Re: Trident Series 65 upgrades

[[email protected]]

Direct outs are unbalanced with a maximum output of +21 dbu. The master mix outputs are balanced with a maximum output of +26 dbu. Many pro converters require +20 dbu for 0 db digital. That means you need to adjust the converter's input sensitivity up or risk clipping the console. The TLO71 opamps used in the direct outputs are not capable of driving loads below 2 k ohms without rising THD. There are also no series resistors in the direct outputs so capacitive loads from cables, etc, will cause ringing and maybe oscillations. Install a 50~100 ohm resistor ( there is a jumper that can be pulled for this) to avoid loading problems, install a LME49710NA opamp to drive 600 ohm transformer input loads and lower noise as well.


Anyone has done this mod????

Best for all

[geoff]

On 9/08/2017 5:56 PM, wrote:
> Direct outs are unbalanced with a maximum output of +21 dbu. The master mix outputs are balanced with a maximum output of +26 dbu. Many pro converters require +20 dbu for 0 db digital. That means you need to adjust the converter's input sensitivity up or risk clipping the console. The TLO71 opamps used in the direct outputs are not capable of driving loads below 2 k ohms without rising THD. There are also no series resistors in the direct outputs so capacitive loads from cables, etc, will cause ringing and maybe oscillations. Install a 50~100 ohm resistor ( there is a jumper that can be pulled for this) to avoid loading problems, install a LME49710NA opamp to drive 600 ohm transformer input loads and lower noise as well.
>
>
> Anyone has done this mod????
>
> Best for all
>


Or a common-or-garden 5534/5534 . Dunno the LME49710NA, but a quick
glance looks like the dog's ********.

geoff

[Phil Allison[_4_]]

geoff wrote:

---------------------------
>>
> >
> > Anyone has done this mod????
> >
> >
>
>
> Or a common-or-garden 5534/5534 .
>


** An NE5534 or 32 has only slightly more output current than a TL071.

Negligible difference in audio in practice.


> Dunno the LME49710NA, but a quick
> glance looks like the dog's ********.
>

** THD and noise specs are exceptional, but the max output current is the same as an NE5534.

Much ado about SFA.


..... Phil

[Scott Dorsey]

geoff > wrote:
>On 9/08/2017 5:56 PM, wrote:
>> Direct outs are unbalanced with a maximum output of +21 dbu. The master mix outputs are balanced with a maximum output of +26 dbu. Many pro converters require +20 dbu for 0 db digital. That means you need to adjust the converter's input sensitivity up or risk clipping the console. The TLO71 opamps used in the direct outputs are not capable of driving loads below 2 k ohms without rising THD. There are also no series resistors in the direct outputs so capacitive loads from cables, etc, will cause ringing and maybe oscillations. Install a 50~100 ohm resistor ( there is a jumper that can be pulled for this) to avoid loading problems, install a LME49710NA opamp to drive 600 ohm transformer input loads and lower noise as well.
>>
>>
>> Anyone has done this mod????
>>
>> Best for all
>>
>
>
>Or a common-or-garden 5534/5534 . Dunno the LME49710NA, but a quick
>glance looks like the dog's ********.

I'd do the 5532/5534 myself. It is a remarkably good-sounding part and
it measures well and is very stable. It gets an undeservedly bad rap with
audiophiles but it is a good choice.

The TL071s were originally used throughout in order to keep power demands
down and reduce the cost of the power supply. It was a fair choice at the
time but a little more output current is a good thing.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[geoff]

On 9/08/2017 9:49 PM, Scott Dorsey wrote:

>>>
>>
>>
>> Or a common-or-garden 5534/5534 . Dunno the LME49710NA, but a quick
>> glance looks like the dog's ********.
>
> I'd do the 5532/5534 myself. It is a remarkably good-sounding part and
> it measures well and is very stable. It gets an undeservedly bad rap with
> audiophiles but it is a good choice.

Specifically designed to adequately drive a 600R load IIRC.

geoff

[Scott Dorsey]

In article >,
geoff > wrote:
>On 9/08/2017 9:49 PM, Scott Dorsey wrote:
>
>>>
>>> Or a common-or-garden 5534/5534 . Dunno the LME49710NA, but a quick
>>> glance looks like the dog's ********.
>>
>> I'd do the 5532/5534 myself. It is a remarkably good-sounding part and
>> it measures well and is very stable. It gets an undeservedly bad rap with
>> audiophiles but it is a good choice.
>
>Specifically designed to adequately drive a 600R load IIRC.

Yes, although just barely. It can benefit from a couple transistors on
the output if you are doing that. Still, it'll perform great into a
low-Z summing network... the busses on the Tridents were made comparatively
high-Z to keep power demands down, at some noise expense.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[[email protected]]

On Wednesday, August 9, 2017 at 12:56:54 AM UTC-5, wrote:
> Direct outs are unbalanced with a maximum output of +21 dbu. The master mix outputs are balanced with a maximum output of +26 dbu. Many pro converters require +20 dbu for 0 db digital. That means you need to adjust the converter's input sensitivity up or risk clipping the console. The TLO71 opamps used in the direct outputs are not capable of driving loads below 2 k ohms without rising THD. There are also no series resistors in the direct outputs so capacitive loads from cables, etc, will cause ringing and maybe oscillations. Install a 50~100 ohm resistor ( there is a jumper that can be pulled for this) to avoid loading problems, install a LME49710NA opamp to drive 600 ohm transformer input loads and lower noise as well.
>
>
> Anyone has done this mod????
>
> Best for all
Could you give me more info on which jumper on the channel module to remove and replace with the appropriate resistor? I have the schematics but don't recall any info there regarding this.

[[email protected]]

On Wednesday, August 9, 2017 at 7:58:03 AM UTC-5, Scott Dorsey wrote:
> In article >,
> geoff > wrote:
> >On 9/08/2017 9:49 PM, Scott Dorsey wrote:
> >
> >>>
> >>> Or a common-or-garden 5534/5534 . Dunno the LME49710NA, but a quick
> >>> glance looks like the dog's ********.
> >>
> >> I'd do the 5532/5534 myself. It is a remarkably good-sounding part and
> >> it measures well and is very stable. It gets an undeservedly bad rap with
> >> audiophiles but it is a good choice.
> >
> >Specifically designed to adequately drive a 600R load IIRC.
>
> Yes, although just barely. It can benefit from a couple transistors on
> the output if you are doing that. Still, it'll perform great into a
> low-Z summing network... the busses on the Tridents were made comparatively
> high-Z to keep power demands down, at some noise expense.
> --scott
> --
> "C'est un Nagra. C'est suisse, et tres, tres precis."

Scott Dorsey, how and where would someone wire in those transistors and which transistors?

[Scott Dorsey]

> wrote:
>On Wednesday, August 9, 2017 at 7:58:03 AM UTC-5, Scott Dorsey wrote:
>> In article >,
>> geoff > wrote:
>> >On 9/08/2017 9:49 PM, Scott Dorsey wrote:
>> >
>> >>>
>> >>> Or a common-or-garden 5534/5534 . Dunno the LME49710NA, but a quick
>> >>> glance looks like the dog's ********.
>> >>
>> >> I'd do the 5532/5534 myself. It is a remarkably good-sounding part and
>> >> it measures well and is very stable. It gets an undeservedly bad rap with
>> >> audiophiles but it is a good choice.
>> >
>> >Specifically designed to adequately drive a 600R load IIRC.
>>
>> Yes, although just barely. It can benefit from a couple transistors on
>> the output if you are doing that. Still, it'll perform great into a
>> low-Z summing network... the busses on the Tridents were made comparatively
>> high-Z to keep power demands down, at some noise expense.
>
>Scott Dorsey, how and where would someone wire in those transistors and which transistors?

I was referring to the idea of putting a push-pull pair on the output of an
opamp (but inside the feedback loop) to get more current drive capability than
is possible with just a monolithic chip.

Burr-Brown has a whole applications note on doing this, in
http://www.ti.com/lit/an/snoa600b/snoa600b.pdf and so does the competition
at http://www.linear.com/docs/4114 as well.

If you look at a lot of consoles from that era, many of them use booster
circuits like this both on the outputs (to drive 600 ohm loads easily) and
on the buss amplifiers (in order to reduce the summing buss impedance so
lower resistance summing resistors could be used, for lower noise). But
doing this is not cheap and Trident was very much built to a price point.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[geoff]

On 9/02/2018 9:28 AM, Scott Dorsey wrote:
> > wrote:
>> On Wednesday, August 9, 2017 at 7:58:03 AM UTC-5, Scott Dorsey wrote:
>>> In article >,
>>> geoff > wrote:
>>>> On 9/08/2017 9:49 PM, Scott Dorsey wrote:
>>>>
>>>>>>
>>>>>> Or a common-or-garden 5534/5534 . Dunno the LME49710NA, but a quick
>>>>>> glance looks like the dog's ********.
>>>>>
>>>>> I'd do the 5532/5534 myself. It is a remarkably good-sounding part and
>>>>> it measures well and is very stable. It gets an undeservedly bad rap with
>>>>> audiophiles but it is a good choice.
>>>>
>>>> Specifically designed to adequately drive a 600R load IIRC.
>>>
>>> Yes, although just barely. It can benefit from a couple transistors on
>>> the output if you are doing that. Still, it'll perform great into a
>>> low-Z summing network... the busses on the Tridents were made comparatively
>>> high-Z to keep power demands down, at some noise expense.
>>
>> Scott Dorsey, how and where would someone wire in those transistors and which transistors?
>
> I was referring to the idea of putting a push-pull pair on the output of an
> opamp (but inside the feedback loop) to get more current drive capability than
> is possible with just a monolithic chip.
>
> Burr-Brown has a whole applications note on doing this, in
> http://www.ti.com/lit/an/snoa600b/snoa600b.pdf and so does the competition
> at http://www.linear.com/docs/4114 as well.
>
> If you look at a lot of consoles from that era, many of them use booster
> circuits like this both on the outputs (to drive 600 ohm loads easily) and
> on the buss amplifiers (in order to reduce the summing buss impedance so
> lower resistance summing resistors could be used, for lower noise). But
> doing this is not cheap and Trident was very much built to a price point.
> --scott
>

Just drop in a 5532/5534 .

geoff