Re: Heat Sink Potential?
Hey cantskienuf, thanks for posting this valuable information to the members working with this project
If your intention are to build mono blocks they fit perfectly for this application. You will need two heat sinks for each mono. And this is a very nice heat sink too.
If you want to see how they looks like you could follow this link to page 73-74 and have a look at post #1826 + 1826.
http://www.diyaudio.com/forums/showthread.php?s=&threadid=78129&perpage=25&pagenumber=73
If choosing those heat sinks there will be no need for a fan for cooling but remember, you could not build a stereo amp with only two heat sinks, either way you will end up with 4 heat sinks for a stereo amp.
Dont miss this opportunity to join this GB for the Conrad Heat Sink MF35-151
Regards
cantskienuf said:
Hey cantskienuf, thanks for posting this valuable information to the members working with this project
If your intention are to build mono blocks they fit perfectly for this application. You will need two heat sinks for each mono. And this is a very nice heat sink too.
If you want to see how they looks like you could follow this link to page 73-74 and have a look at post #1826 + 1826.
http://www.diyaudio.com/forums/showthread.php?s=&threadid=78129&perpage=25&pagenumber=73
If choosing those heat sinks there will be no need for a fan for cooling but remember, you could not build a stereo amp with only two heat sinks, either way you will end up with 4 heat sinks for a stereo amp.
Dont miss this opportunity to join this GB for the Conrad Heat Sink MF35-151
Regards
cantskienuf, Flodstroem,
Thanks for info!
Any GB for nice transformers with electrostatic screen? I've got a quote from Victoria Magnetics and toroid.com for about $280 for each monoblock transformer. Quote from toroid.com came without electrostatic screen on the specs. Victoria Magnetics can't do bifilar for 11+A.
Antek sells 1500VA transformers for $150. but no electrostatic screen. Is electrostatic screen important?
Which PSU capacitors are recommended? Spraque, BC or something different? Or something from different price range like Mundorf is really better?
I'm trying to have less headaches caused by question "what I've done wrong?"
Thanks for info!
Any GB for nice transformers with electrostatic screen? I've got a quote from Victoria Magnetics and toroid.com for about $280 for each monoblock transformer. Quote from toroid.com came without electrostatic screen on the specs. Victoria Magnetics can't do bifilar for 11+A.
Antek sells 1500VA transformers for $150. but no electrostatic screen. Is electrostatic screen important?
Which PSU capacitors are recommended? Spraque, BC or something different? Or something from different price range like Mundorf is really better?
I'm trying to have less headaches caused by question "what I've done wrong?"
Hi stolbovoy
I have got a price quotation from the Avel transformers and that was for an original KRELL mains transformer wound exactly as the original as they did those years they where the KRELL´s source and supplier of mains transformers.
I have got a price quotation for 6-10 units @ the price of £ 160 each, but this was a year ago and a guess the price is not the same for today?
Note, you will need the same quantity of transformers as in the original: 2 of those units for a stereo amp. Total price would then be £ 320. This is approx. $ 636, a difference of approx $ 76. Not much if looking at what you will get for those 76 bucks: Static shielding, magnetic shielding, enough power, all windings needed/voltage outputs, potted in a mild steel can (black color), universal mains voltage (110-240).
I didnt received any response from members for those KRELL transformers (except the positive responce from Mark, the tread starter
) and I didnt went further to order. 
Maybe the interest has change and I would be glad to start and admin. for a GB. in the same way I did for the Conrad Heat Sink in the 2007 GB (90 pcs of the MF-35-151)
Ok, Regards
I have got a price quotation from the Avel transformers and that was for an original KRELL mains transformer wound exactly as the original as they did those years they where the KRELL´s source and supplier of mains transformers.
I have got a price quotation for 6-10 units @ the price of £ 160 each, but this was a year ago and a guess the price is not the same for today?
Note, you will need the same quantity of transformers as in the original: 2 of those units for a stereo amp. Total price would then be £ 320. This is approx. $ 636, a difference of approx $ 76. Not much if looking at what you will get for those 76 bucks: Static shielding, magnetic shielding, enough power, all windings needed/voltage outputs, potted in a mild steel can (black color), universal mains voltage (110-240).
I didnt received any response from members for those KRELL transformers (except the positive responce from Mark, the tread starter
) and I didnt went further to order. Maybe the interest has change and I would be glad to start and admin. for a GB. in the same way I did for the Conrad Heat Sink in the 2007 GB (90 pcs of the MF-35-151)
Ok, Regards
Hi Doan,
you could choose either one of those trim-pots (Cermet, 1/2Watt) from Bourns (depending on stock holding etc.) :
Mouser parts number:
652-3299W-1-502LF
or
652-3299Y-1-502LF
The only difference are the leg configuration, both do fit to solder pads on PCB´s
Pricing approx $ 2.65 each
Hope this helps
Regards
you could choose either one of those trim-pots (Cermet, 1/2Watt) from Bourns (depending on stock holding etc.) :
Mouser parts number:
652-3299W-1-502LF
or
652-3299Y-1-502LF
The only difference are the leg configuration, both do fit to solder pads on PCB´s
Pricing approx $ 2.65 each
Hope this helps
Regards
Flodstroem said:Hi Doan,
you could choose either one of those trim-pots (Cermet, 1/2Watt) from Bourns (depending on stock holding etc.) :
Mouser parts number:
652-3299W-1-502LF
or
652-3299Y-1-502LF
The only difference are the leg configuration, both do fit to solder pads on PCB´s
Pricing approx $ 2.65 each
Hope this helps
Regards
Thank you very much flodstroem. I am ordering
Question about the Relays LY4-DC24
How many do I need, 1 for each channel and 1 in the Powercontrol, Total of 3 ?
Can't we use the LY1-DC24 if we not going to use more that one channel ?
As they are rated at 24DC maximum, why is there 62VAC into it.
I see the resistor on 250ohm, and the diode. Will I get 24DC then ?
How many do I need, 1 for each channel and 1 in the Powercontrol, Total of 3 ?
Can't we use the LY1-DC24 if we not going to use more that one channel ?
As they are rated at 24DC maximum, why is there 62VAC into it.
I see the resistor on 250ohm, and the diode. Will I get 24DC then ?
Could you elaborate on this? What do you mean by "provide the same capacitance for each winding for better balance at high frequencies"?pooge said:
What happens if windings are not identical? In traditional PSU with one rectifier charging pulses for the same rail will not be identical from different windings, but rails will be the same. Does it mean anything except higher 60Hz harmonic?
Bifilare winding technique has mostly been used in audio output transformers for a long time by now but it could also be used in production of high class and fully balanced main transformers for super quality audio amps.
The benefit by using a bifilar winding technique could be specified by:
provide the same resistance in both (e.g. all) secondary windings.
provide the same capacitance between secondaries and secondaries to primaries/ or earth if shielded.
provide the same Copper loss when driving high power speakers (e.g. low impedance)
provide the same inductance due to same length of copper wire and coil form.
this will give you a "silent" transformer that is fully balanced due to the ability to:
*damping out high frequency signals (HF) that could be picked up on mains
*damping out high transients (spikes) on mains
*prevent spikes in the speakers (could otherwise be very irritating)
*prevent asymmetrical clipping due to different copper losses because different length (e.g. different resistance) of copper wires and resulting in different voltage in DC-power rails
and finally:
*prevent different turn of copper wire due to "by mistake"
Regards
How does it work if capacitors on the rails have different capacitance (-10/+30% tolerance)?Flodstroem said:
....
this will give you a "silent" transformer that is fully balanced due to the ability to:
*damping out high frequency signals (HF) that could be picked up on mains
*damping out high transients (spikes) on mains
*prevent spikes in the speakers (could otherwise be very irritating)
*prevent asymmetrical clipping due to different copper losses because different length (e.g. different resistance) of copper wires and resulting in different voltage in DC-power rails
and finally:
*prevent different turn of copper wire due to "by mistake"
Regards
You will get the same voltage on + and - rail anyway in schema with one rectifier (like KSA100), because both windings work on both rails
Asymmetrical clipping will occur as a halve waves rectifier problem and lowering the useful power rail voltage and lowering the maximum clean output capability (as a "ripple-clipping"), including all other drawbacks.
The fact is, for a commercial standard power supply transformer used in a regulated power supply (most common) this will newer be a significant problem because these problems never show op due to sophisticated electronic filtering of DC voltage but in a Super Hi Fi amp. this is not the case due to there is no filtering in the power supply. Even if the filter capacitors value differ a lot this will not be a problem if the transformer is fully balanced. (but it will be even better if matching those caps.)
Worth case show up when both transformer and capacitor act together and when maximum unbalance ad a gain to the incoming distortion/spike/HF signals.
Regards
The fact is, for a commercial standard power supply transformer used in a regulated power supply (most common) this will newer be a significant problem because these problems never show op due to sophisticated electronic filtering of DC voltage but in a Super Hi Fi amp. this is not the case due to there is no filtering in the power supply. Even if the filter capacitors value differ a lot this will not be a problem if the transformer is fully balanced. (but it will be even better if matching those caps.)
Worth case show up when both transformer and capacitor act together and when maximum unbalance ad a gain to the incoming distortion/spike/HF signals.
Regards
I've got a quote from toroid.com:
With electrostatic shiels and magnetic shield:
2pcs - 316.06
5pcs-230.60
10pcs - 198.82
With electrostatic shiels and without magnetic shield:
2pcs - 299.96
5pcs-220.36
10pcs - 190.81
This transformer planed to be used with output stage only. It has 2 additional 10v windings to play with chokes in PSU
For everything else separate transformer will be used.
With electrostatic shiels and magnetic shield:
2pcs - 316.06
5pcs-230.60
10pcs - 198.82
With electrostatic shiels and without magnetic shield:
2pcs - 299.96
5pcs-220.36
10pcs - 190.81
This transformer planed to be used with output stage only. It has 2 additional 10v windings to play with chokes in PSU
For everything else separate transformer