Hi Shaan,
I find 8 pairs TO-18 metal can transistor which is 2N2222A and 2N2907A in my drawer. Can i try use it in my second new V4H ? I mean i will try to replace original Q2 and Q1 (BC546 & BC556) with them. My AMP DC supply rails is +/- 35VDC.
Except Q1 & Q2, which important transistors i can also swap with this stuff ?
I just want to try something special :>
I find 8 pairs TO-18 metal can transistor which is 2N2222A and 2N2907A in my drawer. Can i try use it in my second new V4H ? I mean i will try to replace original Q2 and Q1 (BC546 & BC556) with them. My AMP DC supply rails is +/- 35VDC.
Except Q1 & Q2, which important transistors i can also swap with this stuff ?
I just want to try something special :>
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Hi CK.
I apologize I missed this post. 😱
Have you already tried the transistors you mentioned?
You'll be pleasantly surprised by the superb (and transparent) sound from these modules. Shaan's done an excellent job. I started with single 45v SMPS and then moved to 56v IIRC. I built the linear PSU, but have not tried it yet.
Have had these for many years but never used them. Have changed the output "no name" caps to better types just to be sure .
SMPS500QRv2 | Connex Electronic
Was originally planning +-60V linear (Shaans v4h psu) (with changed components that could handle that) but will try with smps first
Have a couple of more v4h populated boards also and might built another amp?
SMPS500QRv2 | Connex Electronic
Was originally planning +-60V linear (Shaans v4h psu) (with changed components that could handle that) but will try with smps first
Have a couple of more v4h populated boards also and might built another amp?
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Shaan I would like to know if it is possible and wise to build an amp with two bridged modules per channel and feed them with +-40V at the rails?
In that case will the amplifier be able to handle loads of 4 ohms and what would be the power output at 8/4 ohms? also in that case is a power transformer with 4X30Vac secondaries and 1.4KVA power enough to feed the rails?
In that case will the amplifier be able to handle loads of 4 ohms and what would be the power output at 8/4 ohms? also in that case is a power transformer with 4X30Vac secondaries and 1.4KVA power enough to feed the rails?
Hi.
Could be possible. Each amp will see 2ohm load and with 10V loss at clipping the two channels will put out ((30/1.4)*(30/1.4)/2)*2 = 441Watt into 4ohm.
But...
I have not tested the amps into 2ohm with 40V rails and can't say for sure that they will be happy with this combo of rails and load.
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Ok fired up and doing the procedure. VAS bias ok, offset ok but nothing when probing the rail resistors and turning VR3. No movement at all.
The AC side of the smps is connected directly to chassis gnd.
However the gnd from DC side of the smps is connected to PGND and SGND on the V4H modules.
It is 10kohm between AC gnd and DC gnd on the smps..
Does this make any sense?
The AC side of the smps is connected directly to chassis gnd.
However the gnd from DC side of the smps is connected to PGND and SGND on the V4H modules.
It is 10kohm between AC gnd and DC gnd on the smps..
Does this make any sense?
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Looks as if the output gnd on Connex smps is floating. It is where PGND and SGND is connected.
What would the best way connecting be?
What would the best way connecting be?
The ground node that connects to the amp modules needs a short connection to the chassis metal at high frequencies. The 10K resistance will prevent this and may cause oscillation in the amplifiers. You can try using a 10ohm resistor and a 100nF low voltage ceramic capacitor in parallel between SMPS DC ground node and mains earth connection on the chassis.
If mains earth is connected to the chassis then each SMPS's output ground should be connected to the chassis via the resistor+capacitor network as I mentioned.
These transistors are usable upto 35V but seems to have a low-ish hFE of 100-200 while the BC pair has around 350. The lower gain may introduce more distortion. Other than that there should be no problem.
Bests.
