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I just checked with Digikey.ca and both the devices in the BOM, the KSC3503 and the KSA1381 are shown as ‘Active’.
The KSC3503 is in stock with over 3,000 available for immediate shipment.
However, the KSA1381 is out of stock with a 6 week lead time indicated.
In looking for alternatives: the key specifications are:
1/ package and pin-out compatible, i.e. TO-126 or TO225 and e-c-b (or b-c-e if you flip it over) pin-out.
2/ maximum Vce to be at least 50% higher than the total rail voltage pos to neg, so +/-50V rails means > 150V
3/ for VAS duty I prefer low Cob (usually comes with high Vce rating) of < 10pF
4/ rated for collector currents of > 50mA
I do like the look of the KSA1142 and Digikey.ca shows it has stock.
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Hi,
Yes KSC3503 is stocked by both mouser.ee and digikey.ee, but KSA1381 isn't. And to be honest I use tme.eu usually if possible.
I figured that the MJE variants aren't well suited after glancing over the datasheets...
If I forgo packaging the PZTA42T1G and PZTA92T1G pop up. General purpose they say. Not very convenient but seem suitable?
Yes KSC3503 is stocked by both mouser.ee and digikey.ee, but KSA1381 isn't. And to be honest I use tme.eu usually if possible.
I figured that the MJE variants aren't well suited after glancing over the datasheets...
If I forgo packaging the PZTA42T1G and PZTA92T1G pop up. General purpose they say. Not very convenient but seem suitable?
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Hi - when I look at Digikey the PZT parts are surface mount, which are unsuitable for my PCB. I'm not sure, but I don't think these are available in TO-126 packages. The devices do not need to be from the same manufacturer and complementary parts are not really that close since NPN and PNP are different. Of course, you could buy extra parts and try matching them by hand for similar characteristics but I'm not convinced this is needed and I didn't try matching the devices in my build. So if you're not going to wait for re-stock of the KSA1381 I would simply use the KSA1142 which looks like a very nice device indeed.
Don't forget, you may also want to add an output inductor - I fit one in-line into the wire connecting the amplifier PCB to the speaker binding post. I pull my output inductors from an old home theatre receiver, got a bunch of them that way
Don't forget, you may also want to add an output inductor - I fit one in-line into the wire connecting the amplifier PCB to the speaker binding post. I pull my output inductors from an old home theatre receiver, got a bunch of them that way
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I used octopart.com to obtain the data below. Other diyAudio members prefer findchips.com ; to each her own.
Some might not know that Newark is the US member of the "Element14" electronic distribution alliance. I am guessing that if Newark has stock, so does every Element14 distributor around the world. Check whether your local Element14 distributor has parts on the shelf, ready to ship. They may be able to pull some devices from Newark if necessary.
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Some might not know that Newark is the US member of the "Element14" electronic distribution alliance. I am guessing that if Newark has stock, so does every Element14 distributor around the world. Check whether your local Element14 distributor has parts on the shelf, ready to ship. They may be able to pull some devices from Newark if necessary.
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update:
1/ 'maust' - paid for 1 pair
2/ 'maust' - paid for 2nd pair
3/ 'Selwe' - paid for 1 pair
4/ 'Selwe' - paid for 2nd pair
5/ 'Selwe' - paid for 3rd pair
6/ ‘bvtrinh’ - paid for 1 pair
7/ 'bullittstang' - paid for 1 pair
8/ 'bullittstang' - paid for 2nd pair
9/ 'Rhinobirds' - paid for 1 pair
10/ 'Rhinobirds' - paid for 2nd pair
11/ 'bsd04' - paid for 1 pair
12/ 'danielwritesbac' - paid for 1 pair
As of today, all the boards from the current batch are gone. And I was too lazy to make progress with my stereo build last night after attending a tube-amp listening session with a friend of mine. We were both rather surprised how well my Cellini (6H5C SET) amp performed up against an SV811-10 SET and a SIT amplifier. Sometimes cheap & simple can hold it's own!
1/ 'maust' - paid for 1 pair
2/ 'maust' - paid for 2nd pair
3/ 'Selwe' - paid for 1 pair
4/ 'Selwe' - paid for 2nd pair
5/ 'Selwe' - paid for 3rd pair
6/ ‘bvtrinh’ - paid for 1 pair
7/ 'bullittstang' - paid for 1 pair
8/ 'bullittstang' - paid for 2nd pair
9/ 'Rhinobirds' - paid for 1 pair
10/ 'Rhinobirds' - paid for 2nd pair
11/ 'bsd04' - paid for 1 pair
12/ 'danielwritesbac' - paid for 1 pair
As of today, all the boards from the current batch are gone. And I was too lazy to make progress with my stereo build last night after attending a tube-amp listening session with a friend of mine. We were both rather surprised how well my Cellini (6H5C SET) amp performed up against an SV811-10 SET and a SIT amplifier. Sometimes cheap & simple can hold it's own!
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Posting a Spice file for the amp where the parts have been renumbered to match the pcb schematic. I don't have spice models for some of the semiconductors so you'll find some of the parts values for the transistors aren't correct in the simulation - maybe we can find some better models. And now we can fine tune parts values if the tweakers are interested (one tweak I would look at is eliminated the gate zeners from the output MOSFETs, I think their junction capacitances make compensation more complex without adding enough value as protection).
I didn't have a chance to fire up my stereo box yet - the beast is sat waiting for me. I couldn't find my 30Vac transformer so I installed a version with dual 36Vac windings. I installed a bridge rectifier on each winding, i.e. one for the +ve supply and one for the -ve supply with a common 0V. I put some 10nF ceramic caps across each diode in the bridge and added a 10nF + 10R snubber across each secondary winding of the transformer for good measure. The rail voltages come up to +/-48.5V on the amplifier boards which is within the design range. After allowing for a good warm up period I checked the dc-offset on the output and low and behold it was sitting at 4.7mV and 1mV which means it hasn't drifted off since I built these amps a few years back.
(one tweak I would look at is eliminated the gate zeners from the output MOSFETs, I think their junction capacitances make compensation more complex without adding enough value as protection).I didn't have a chance to fire up my stereo box yet - the beast is sat waiting for me. I couldn't find my 30Vac transformer so I installed a version with dual 36Vac windings. I installed a bridge rectifier on each winding, i.e. one for the +ve supply and one for the -ve supply with a common 0V. I put some 10nF ceramic caps across each diode in the bridge and added a 10nF + 10R snubber across each secondary winding of the transformer for good measure. The rail voltages come up to +/-48.5V on the amplifier boards which is within the design range. After allowing for a good warm up period I checked the dc-offset on the output and low and behold it was sitting at 4.7mV and 1mV which means it hasn't drifted off since I built these amps a few years back.
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There used to be a miniaturized ferrite bead which could be installed onto the gate pin of the mosfet itself. After it was 'collared' then it was tame too.
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Ran out of boards so I've ordered another batch (it was 35% more expensive this time, I think they messed up last time, oh well):
1/ 'Scotty123' - paid for 1 pair
2/ available
3/ available
4/ available
5/ available
6/ available
7/ available
8/ available
9/ available
10/ available
1/ 'Scotty123' - paid for 1 pair
2/ available
3/ available
4/ available
5/ available
6/ available
7/ available
8/ available
9/ available
10/ available
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To collar the mosfet gate pin, these miniature ferrite beads seem similar to fb43-110: Ferrite Cores - Cables and Wiring | Filters | DigiKey
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