That's the same kit in #9178 but 3A bias current for each channel or both? I think 60W dissipation for one pair of genuine TIP 41spec. transistors would be too much and at >50C case temperature, derating should be applied anyway. https://datasheetspdf.com/pdf/1074675/ONSemiconductor/TIP41/1
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You know, I've seen some with four heatsinks smaller than credit cards with the original 69 diagram and in TO220, I think we're more like stupidity.
Agreed, but if those credit cards were attached to the heatsinks, they'd be bubbling blobs of plastic if the bias current was 3A or greater. 
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When I listened Jlh I heard piano passage has became pronounced at 4:23 of this part
Maybe I heard in the past too but it did not caught my attention that there was a piano with my Muse TA2020 amp.It is not a bad amp but Jlh is much more forward sounding and detailed amp. Dynamics are very good too.Maybe because of i connected JLH to 4 ohm with 2000uF caps bass is lowered and mid and treble details increased but I think i will not go back to TA2020 again.It is not as clear as Jlh
Yes will do. We already made short listening tests. It was just a trial amp and l already checked the heat.66C left transistors and 45c right ones approx.Trial Heatsinks approx 50c. Everything is under control 😉
I am just wondering if I change tip41c driver make a difference on sound now.
By the way, a basic advice regarding the placement of loudspeakers:
Regardless of the listening distance, size of the listening room and the size of the speakers: first of all, 50 cm to each other. And listen. After a while 60 cm. Listen. 70 cm. Listen. And so on. Until the sound image tears apart. For the vast majority, the distance (center - center) of the speakers will be less than one meter. For very large speakers, it will usually be a maximum of 1.5 meters.
Why? The vast majority of signals are mono. Contained on both channels, with mostly only a few level difference. The point is to combine these two almost identical "fixed images" into one, so that at all a physical, also spatially deep, in the most diverse rooms unproblematic sound comes together. The vast majority of "room problems" disappear with such a set-up.
Angle, alignment I have not yet uttered.
And: as soon as you change a device or a part of the chain, even if it's just different emitter resistors, consider correcting the position and alignment of the speakers;-)
Bad luck, who humped a pair of Consequence or Puppies into the joint, he does not need to lift his speakers off the lift trucks;-)
;-)
Regardless of the listening distance, size of the listening room and the size of the speakers: first of all, 50 cm to each other. And listen. After a while 60 cm. Listen. 70 cm. Listen. And so on. Until the sound image tears apart. For the vast majority, the distance (center - center) of the speakers will be less than one meter. For very large speakers, it will usually be a maximum of 1.5 meters.
Why? The vast majority of signals are mono. Contained on both channels, with mostly only a few level difference. The point is to combine these two almost identical "fixed images" into one, so that at all a physical, also spatially deep, in the most diverse rooms unproblematic sound comes together. The vast majority of "room problems" disappear with such a set-up.
Angle, alignment I have not yet uttered.
And: as soon as you change a device or a part of the chain, even if it's just different emitter resistors, consider correcting the position and alignment of the speakers;-)
Bad luck, who humped a pair of Consequence or Puppies into the joint, he does not need to lift his speakers off the lift trucks;-)
;-)
Hi Ian, your last comment is probably the most true and that is, the better it looks, the better it sounds. Take an amp with a meter, it is mesmerizing you see the bass whether you hear it or not.
When you consider any power device, you should consider the SOAR!
Do you think there will be any sound benefit if we use lower capacitance bjt and cool it very well?
Maybe because of it is driven easier there will be improvements in sound quality
Maybe because of it is driven easier there will be improvements in sound quality
The TIP31/32 SOAR indicate that these transistors will be marginal at 10 w and 22VDC. Thus they should not even be considered.
The 2N3055 seems to exactly match the SOAR requirement for this amp. Why mess with parts you have not researched.
MJE3281 would be a perfect match, even if you want to push 25 watt
The 2N3055 seems to exactly match the SOAR requirement for this amp. Why mess with parts you have not researched.
MJE3281 would be a perfect match, even if you want to push 25 watt
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I imagine that the only semis and components that will be available for many people here, will just be those in that mini JLH kit of 2 from Aliexpress. The total cost with postage can be as low as a very attractive US$3.50. There's likely a higher price hidden in some offers with higher postage charges but how
cheap is that?? https://www.aliexpress.com/item/4000143260291.html?spm=a2g0o.detail.1000014.3.5a81y15Fy15FEI&gps-id=pcDetailBottomMoreOtherSeller&scm=1007.40000.326746.0&scm_id=1007.40000.326746.0&scm-url=1007.40000.326746.0&pvid=712aef55-5d23-418a-9a76-9d699281164c&_t=gps-id😛cDetailBottomMoreOtherSeller,scm-url:1007.40000.326746.0,pvid:712aef55-5d23-418a-9a76-9d699281164c,tpp_buckets:668#2846#8112#563&pdp_npi=3@dis!AUD!3.62!2.34!!!!!@2101c5b116834206309955858ea955!10000000433606720!rec!AU!178186480
For any of you who are serious about getting your 10 Watts worth, the above version of the mini JLH'69 kit has a PCB with extra pads where you can alternatively fit 2SC5198 (very cheap TO3P version of 2SC5200) or probably any large, common plastic power transistor with an Ft of 4Mz or more. If you have 4 of them stored away somewhere, you can now have a full-blown JLH 10 watter for the price of a snack at a coffee shop!
cheap is that?? https://www.aliexpress.com/item/4000143260291.html?spm=a2g0o.detail.1000014.3.5a81y15Fy15FEI&gps-id=pcDetailBottomMoreOtherSeller&scm=1007.40000.326746.0&scm_id=1007.40000.326746.0&scm-url=1007.40000.326746.0&pvid=712aef55-5d23-418a-9a76-9d699281164c&_t=gps-id😛cDetailBottomMoreOtherSeller,scm-url:1007.40000.326746.0,pvid:712aef55-5d23-418a-9a76-9d699281164c,tpp_buckets:668#2846#8112#563&pdp_npi=3@dis!AUD!3.62!2.34!!!!!@2101c5b116834206309955858ea955!10000000433606720!rec!AU!178186480
For any of you who are serious about getting your 10 Watts worth, the above version of the mini JLH'69 kit has a PCB with extra pads where you can alternatively fit 2SC5198 (very cheap TO3P version of 2SC5200) or probably any large, common plastic power transistor with an Ft of 4Mz or more. If you have 4 of them stored away somewhere, you can now have a full-blown JLH 10 watter for the price of a snack at a coffee shop!
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I also have used 2sc5200 Toshiba transistors in shelf but I am afraid if they cause oscillation because of high fT. Maybe I can give a try?
I would, with one channel only but start with the present low voltage and current settings before raising them to the full ratings. You may get a fault whether it oscillates or not, so keep an eye on the current, an ear at the speaker and stay close to the power switch or DC connector.
For reference, this is an alleged specification of the mini JLH kits, as they come, correctly assembled and powered as suggested. It was posted at "Survy 2014" store:
1. Model: 1969 small group A
2. Tube Model: TIP41C
3. Output power: 5 W per channel
4. Power consumption: 20 W
5. Power source: DC 12-30V
6. Current Static: Standard 25 v DC to 0.8-0.9A
7. Board Sizez: 5x5cm
8. Resistance: Fully five-precision metallic film resistor ring
9. Adjust Resistance: Sealed multi-turn adjustable resistance
10. Input Capability: Farah Campaigns Promise
11. Electrolytic capacitor: high capacity
As you can see, this has differences to claims made by other stores and obviously to the original JLH'69 but it is more likely to be correct for these kits and should be adhered to for safety reasons. Note that 30V maximum supply voltage does not mean you can also use that voltage with a maximum bias current setting. That will overload those little TIP41s! Some advertisers are listing performance figures that refer to the original 10-15W design. That's misleading and potentially dangerous if you power the kits according to the wrong spec.
For reference, this is an alleged specification of the mini JLH kits, as they come, correctly assembled and powered as suggested. It was posted at "Survy 2014" store:
1. Model: 1969 small group A
2. Tube Model: TIP41C
3. Output power: 5 W per channel
4. Power consumption: 20 W
5. Power source: DC 12-30V
6. Current Static: Standard 25 v DC to 0.8-0.9A
7. Board Sizez: 5x5cm
8. Resistance: Fully five-precision metallic film resistor ring
9. Adjust Resistance: Sealed multi-turn adjustable resistance
10. Input Capability: Farah Campaigns Promise
11. Electrolytic capacitor: high capacity
As you can see, this has differences to claims made by other stores and obviously to the original JLH'69 but it is more likely to be correct for these kits and should be adhered to for safety reasons. Note that 30V maximum supply voltage does not mean you can also use that voltage with a maximum bias current setting. That will overload those little TIP41s! Some advertisers are listing performance figures that refer to the original 10-15W design. That's misleading and potentially dangerous if you power the kits according to the wrong spec.
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Completely agree with nico concerning the SOAR and something else not to be overlooked, it is the specific pairing of the power transistors, it is not for nothing that I end up with more than 500 TO3 from the 3055 15003 family and other exotic from Tesla and others, it's really important.
I repeat, a jlh69 will always produce a correct sound but to obtain the quintessence of it you must carefully choose the components according to the original document and the work of those who worked on it a few years later.
I repeat, a jlh69 will always produce a correct sound but to obtain the quintessence of it you must carefully choose the components according to the original document and the work of those who worked on it a few years later.
As I didn't want to die stupid and I have a lot of transistors, I bought a pair of these small modules (TIP41c) in England for 9$ delivered at home, we'll see...