no , THF51-S are most probably all falling in "adequate" range
what I'm suspicious of are 2SK182
so , re-check them , if you have time , at 22Vdc and 2A
what I'm suspicious of are 2SK182
so , re-check them , if you have time , at 22Vdc and 2A
I am intending to build this amp for some low impedance speakers(3.4ohm the minimum impedance) and for this I want to paralel 2pcs of irfps for a bias up to 3.2amps(for both).
Is this possible?
Any chances that I will get the same thd spectrum as the original amp?
Is this possible?
Any chances that I will get the same thd spectrum as the original amp?
match them tightly , and include 0R1 source resistors for each mosfet
THD spectra will stay practically the same , but amount of THD will change , no doubt
THD spectra will stay practically the same , but amount of THD will change , no doubt
2SK2145BL is rated at 6~14mA per FET, max. dissipation 300mW for 2 FETs.
Assuming 10mA average, running them at 15V Vds means you are right on the absolute maximum rating (at 25°C).
Brave man !! 🙂
Cheers,
Patrick
Assuming 10mA average, running them at 15V Vds means you are right on the absolute maximum rating (at 25°C).
Brave man !! 🙂
Cheers,
Patrick
if that's the case , 2SK182 , at least some of them ..... are applicable in SissySIT circuit
though , still best to have them , test them , then everything is crystal clear
regarding final result - THD spectra and all ........ it must be sort of similar to THF 51-S ... but how much similar , I can't tell without actually having them
though , still best to have them , test them , then everything is crystal clear
regarding final result - THD spectra and all ........ it must be sort of similar to THF 51-S ... but how much similar , I can't tell without actually having them
Most of the big Tokins I've tried in the past exhibit 100uA or greater gate leakage current at the Drain currents mentioned, so the internal resistance of the Vgs source becomes a factor. 🙂
Yes, That was what troubled me and I thought ZM's SissySIT circuit was using it to set the bias voltage.
🙂
🙂
I mention it only because it's good to know when measuring your SITs, since they need to fall within a certain range of Vgs. 🙂
I ordered two pair of the THF51S from the recommended eBay source this past week along with a Sissy board package from ZM.
I’m educating myself by re-reading the related development threads that I just sort of checked in on previously to see what progress was being made.
I know at one point there was testing being done on the THF51S, albeit by members with high tech labs.
Is there a process that can be outlined for the less fortunate simple folk like myself that can help confirm basic operational integrity and parameter viability of these SITs using voltmeters and the like?
I’m educating myself by re-reading the related development threads that I just sort of checked in on previously to see what progress was being made.
I know at one point there was testing being done on the THF51S, albeit by members with high tech labs.
Is there a process that can be outlined for the less fortunate simple folk like myself that can help confirm basic operational integrity and parameter viability of these SITs using voltmeters and the like?
voltage source of some 20-25Vdc , capable of delivering at least 3A (you can borrow positive rail of your existing Papamp, if you have one ) ...... goal Iq is 2A
what the heck , you can use 19V power brick ,either from your ACA or your laptop
plain 9V battery for gate voltage (sonnested to gnd of above , to be negative)
10K pot or trimpot for setting that gate voltage
1K gate resistor
some kind of heatsink , best to have 8-12cm fan cooling it all the time of test ...... just to prevent temp. build up ..... you can use main rail for it , just reg it down to fan voltage .....or use 24V fan
ampermeter (one DMM)
gate voltage meter (second DMM)
have all that ?
if yes, I'll draw schm
what the heck , you can use 19V power brick ,either from your ACA or your laptop
plain 9V battery for gate voltage (sonnested to gnd of above , to be negative)
10K pot or trimpot for setting that gate voltage
1K gate resistor
some kind of heatsink , best to have 8-12cm fan cooling it all the time of test ...... just to prevent temp. build up ..... you can use main rail for it , just reg it down to fan voltage .....or use 24V fan
ampermeter (one DMM)
gate voltage meter (second DMM)
have all that ?
if yes, I'll draw schm
would highly appreciate that little schematic too 
btw, are normal FW heatsinks sufficient for sissysit?
best,
stefan
Until the smoke clears (for me) I am hesitant to order these SITs, as I don't know what measurement I need, or what is being supplied.
Are these still being manufactured? There seems to be several sellers on eBay...don't want to miss out.
Russellc
Are these still being manufactured? There seems to be several sellers on eBay...don't want to miss out.
Russellc