900W H-class PA Amp with Limiter

Dear Sir,

is circuit description available ?

1...only 5 (10) Toshiba 2 Sc 5200 / 2 SA 1943 Output devices Rail 140 V +/- ?

.. 140 V rail with Toshiba 2 Sc 5200 / 2 SA 1943

how can this amp work stable if Vceo max. 230 V for this ttransistors ?

Vceo is 230 V for this transistors, rail should be max 115 V


How is it possibile this amp can work stable and not violate SOA from output devices and not get second breakdown?


sorry, for this question, but long time before have import from China 50 pcs. PA Amp with similar rail +/- 145 V

60% amplifier fail within few weeks after sold. second breakdown
Toshiba 2 Sc 5200 / 2 SA 1943

Maximum voltage on transistors can be 140+18=158V in non conduction rail side on other side emiter to colector voltage is 18V maximum.
Tracking Downconverter | Sunfire
 
ok thx for info


The basic amp schematic is popular class AB apexaudio 900 W class H PA amp,


1. but whats specification (output power( have this amp with TD Step ?

2. Is it possibile to add TD Step to any other class AB Amp ?


Finally: 900 W class H PA amp have 2 different high voltage Rails,


TD have 1 high voltage Rail 140V, + 18V standby


If I missunderstood something wrong, pleaae help to understand
 
Last edited:
ok thx for info


The basic amp schematic is popular class AB apexaudio 900 W class H PA amp,


1. but whats specification (output power( have this amp with TD Step ?

2. Is it possibile to add TD Step to any other class AB Amp ?


Finally: 900 W class H PA amp have 2 different high voltage Rails,


TD have 1 high voltage Rail 140V, + 18V standby


If I missunderstood something wrong, pleaae help to understand

Basic amp schematic is B500. B500 with class H is H900, with class TD is TD1800 and power will be double with same number of output devices.
This tracking downconverter can work only with B500 topology, for any other amp use Yamaha EEEngine or Sunfire by Carver or LabGrupen...TD converter
 
Basic amp schematic is B500. B500 with class H is H900, with class TD is TD1800 and power will be double with same number of output devices.
This tracking downconverter can work only with B500 topology, for any other amp use Yamaha EEEngine or Sunfire by Carver or LabGrupen...TD converter

Thx for Info

very good.....good news


This means, I can get 1800W @ 4 Ohm

with same number of output devices compare to H900 / B500

4 output devices per Rail = 8

without leave SOA oputput devices, no second breakdown ?


I think this trackinng downconverter can work with BGW 750B/C too

I want try
 
BGW 750B Bass Amp similar Apex B500

selected costumized 12 x SJxxx Motorola / RCA TO3 output devices very reliable PA Amp design

working 23 years 1978 - 2001 in High End PA Installation Frankfirt Airport Germany Disco Club Dorian Gray

To reduce heat I think can add TD1800 step down converter
replace original VI Limiter with Apex VI Limiter, amp should work stable
 

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BGW 750B Bass Amp similar Apex B500

selected costumized 12 x SJxxx Motorola / RCA TO3 output devices very reliable PA Amp design

working 23 years 1978 - 2001 in High End PA Installation Frankfirt Airport Germany Disco Club Dorian Gray

To reduce heat I think can add TD1800 step down converter
replace original VI Limiter with Apex VI Limiter, amp should work stable

BGW 750B Bass Amp is not similar Apex B500. B500 is CFA amplifier use OP amp as DC servo, BGW is VFA amp use OP amp for gain and NF fedback....
 
BGW 750B Bass Amp is not similar Apex B500. B500 is CFA amplifier use OP amp as DC servo, BGW is VFA amp use OP amp for gain and NF fedback....

Thx for Info

to learn and understand

If I design new BGW 750B PCB with small changes ( VI limter )

and add TD1800 step down converter,

can BGW 750B work ?

In this case compare to 500W before, now can get 1800 W

I remember some diy people add class H Stepdriver to old BGW, it works and heat decrease.