TSSA V1.7

[buzzforb]

I must admit, the Nano sounds interesting. Have you ever gone to the trouble of doing a comparison of through gain devices vs the SMD you currently use? The reason I ask about the output stage enlargement is my affection for the FE/driver stage you haev created. While my system will be semi HE, at 93dB, it is not a horn system and 50-100W amp is appealing. Another thing I have found is that i tend to like amps that are either bridged or ones that use higher rails. Seems to add a dynamic capabilty that pairs well with dynamic speakers. Balanced./bridged designs are a way to get this voltage headroom and still maintain higher bias, although it can also be achieved with SE designs and higher rails if you are willing to parallel outputs and create a FE that can drive the capacitance.
Sorry if I have cluttered the thread. Very much looking forward to the new designs. Have the fets here waiting

[Siberia]

What is the exact SMPS500R that was ringing? Very interested in 1.7v.

[sonnya]

Hi, i have added the schematic.

The Main difference on the TSSA V1.6 and TSSA V1.7 is the more "advanced" current generators which makes it possible to raise the gain by 15 times.

It depends on heavy use of multipacks transistors. So no matching is required.

The board uses BCM847/857 (Matched pairs) and THAT340S.

Secondly 1 trimmer is removed. The use of a JFET current source is hugely depended on the supply voltage . ... In other words .. worse than standard CCS with two BJT'S!!!

So trimming should be easier.

Added an ferrite bead (10Amp DC, Z=100R@100MHz) together with an 10uF 50V X7R to form an effective lowpass filter for noise from supply ... Main contributor is ringing from diodes.

Resistor added to bypass capacitors C8 and C9 to prevent ringing due to parasitic inductances.

Gatestoppers added to the mosfet, but it does not reduce performance regarding bandwidth and distortion.

The schematic show a 47pF millercap. This gives a bandwidth of ~2.7MHz.

So all in all a serious upgrade. And the people that have listened to until now is very happy with the result.

The updates are not cheap but effective.

Best regards

Sonny Andersen

[buzzforb]

How long before we can play?

[sonnya]

I expect 1 week, but I know later tonight.

[sonnya]

The boards will arrive in 7 work days.

Black, gold plated 60um copper.

[buzzforb]

I will be using it for the top end in an active two way, running in cooperation with a J2. I expect it to be the perfect compliment to the J2. It will be driving a Transducer Labs N26C in a waveguide.

[sonnya]

Pricing:

TSSA V1.7 will be priced at :

1 - 3 modules 115€/module.
4 - 10 modules 100€/module.

Old customers will receive an discount to the prices above. Please contact me at mail@mirand-audio.dk

I was asked if they could run bridged. It is possible and will with +/-32V supply produce in the order of 120 - 150Watt into 8R. But they will need a balanced source.

In an bridged stereo set you will need 4 modules.

We will post pictures of such an setup.

- Sonny

[buzzforb]

Is the module a complete working amp or do we have to add components on some level? I will probably want 4.

[sonnya]

I was not happy with the HV version I had designed. So this amp will be changed to be an dual TSSA V1.7 module running balanced with an optional discrete inverter onboard to make it possible to feed it from an single ended source.

The new TSSA V1.7 BL (HV is renamed to BL) will cost €200/module.

But the system voltage should be +/-32VDC. So it is possible to reuse powersupply from the TSSA V1.6.

- Sonny

PS: Below is the PCB design of the TSSA V1.7