HK compaired to Leach is no contest. The HK is a beautiful piece of art w/10 outputs per channel. One wonders why, with outstanding specs, it sounds as bad as it does. Its never been tweeked and is "as is" from the factory. Low level class A sounds OK, but as the volume goes up, it has the "transistor" sound to it.
Changing the caps may help the sound but I'll probably sell it before that happens.
Changing the caps may help the sound but I'll probably sell it before that happens.
Searching for components...
Hi everyone! I'm continuing the search for components for the gorgeous boards that Tad provided for us. So far, so good, but... does anyone have a manufacturer / model number recommendation for the bias trimpot?? That's the only part I'm having a problem finding.
I wanted to let people know that Digikey has the Mills resistors for the output stage emitters at a very good price ($1.89/ea), once you order more than 10 pieces. The secret seems to be that they are listed under the parent company's name, Huntington Electronics, instead of Mills Resistor.
Best wishes,
Keith
Hi everyone! I'm continuing the search for components for the gorgeous boards that Tad provided for us. So far, so good, but... does anyone have a manufacturer / model number recommendation for the bias trimpot?? That's the only part I'm having a problem finding.
I wanted to let people know that Digikey has the Mills resistors for the output stage emitters at a very good price ($1.89/ea), once you order more than 10 pieces. The secret seems to be that they are listed under the parent company's name, Huntington Electronics, instead of Mills Resistor.
Best wishes,
Keith
It's a staggered lead only layout. Bournes 3299Y-1-502LF works. Mouser has them http://www.mouser.com/Search/ProductDetail.aspx?qs=jqvwU7YSWc3/kZliMYJ/Uw==
Does anyone know if the Leach would work in balanced mode with 2 boards per channel. What I really mean is it a plausible project. I have this p1.7 all assembled and could use it for a good balanced input source. It is just kinda laying around with all the OTHER STUFF. I think most of you know what I mean. Tad
tryonziess said:
hello Tad, can't see why not....by operating in a balanced mode, you are effectively bridging your amp....
http://www.schuro.de/Daten/Burr%20Brown/DRV134.pdf
That's commonly known as bridging. Works great, I used a BOSOZ to do that for a while. With an appropriate PSU and enough heat sinking you're looking at around a kilowatt or more into 8 ohms. (Did I just increase demand for another buy?)
Keep eye on the effect bridging has on the apparent load impedance - an 8 ohm load on a bridged pair of amps presents an apparent 4 ohm load. This is because the load sees twice the voltage that either amp swings, therefore drawing twice the current.
With reduced rail voltage you could probably handle a 4R load on your bridged amps. I'd be leery of trying 4R bridged at much more than 60V rails.
Keep eye on the effect bridging has on the apparent load impedance - an 8 ohm load on a bridged pair of amps presents an apparent 4 ohm load. This is because the load sees twice the voltage that either amp swings, therefore drawing twice the current.
With reduced rail voltage you could probably handle a 4R load on your bridged amps. I'd be leery of trying 4R bridged at much more than 60V rails.
I got the Kapton tapes and will send out PM for the fellow members who expressed interested. For US, I will send priority mail + delivery confirmation. It is tight, but I think I can fit 2 packages into one priority mail envelop which only costs $4.80 up to one pound. Delivery confirmation is 0.65 which brings the domestic total to $5.45. Tony, I will need to bring your package to postal to get the estimate. We can discuss the type of mail that you want via PM. PM's followpchw said:
I was thinking of using 50 -55 volt rails on the bridge unit. I then could build with 63 volt caps in the psu and afford to buy some Rifa's or the like. Those 100 volt caps are NOT cheap. Hook up the regulators I got from Bob for the frontend and then see how it goes. Should be a worthwhile project. Would be a quite large item though. I guess it would be very useful for a power hungry set of speakers with all that available juice. A small fan might be a nice addition on this job.
Anyone know how the beta test on the Super Leach is progressing?
Is there any interest out there for a long board configured to hold TO-247 devices. Something with just the power, drive, output and could be used with any project. Maybe 6 inches long with space for 6 devices. You could pair them up as you need. It would make building simple layouts very neat. I have not seen this anywhere before and could use some.
Tad
Anyone know how the beta test on the Super Leach is progressing?
Is there any interest out there for a long board configured to hold TO-247 devices. Something with just the power, drive, output and could be used with any project. Maybe 6 inches long with space for 6 devices. You could pair them up as you need. It would make building simple layouts very neat. I have not seen this anywhere before and could use some.
Tad
IMHO, your RIFA caps are more likely to be noticed if you use the lower rail amps singly to drive mains (or mid/tweet). For home use, there isn't much need for 600+W headroom anywhere but the sub.
Your output board idea is interesting - perhaps an extender for the extended amp if you're driving really low impedance/reactive loads. It would also be nice for other designs.
A while ago I got some intended for an Aleph that have spots for 6 devices and can be cut in the center to make three device boards. Always a trade-off - spacing the devices a bit would provide better cooling, but make it harder to find suitable heat sinks.
Your output board idea is interesting - perhaps an extender for the extended amp if you're driving really low impedance/reactive loads. It would also be nice for other designs.
A while ago I got some intended for an Aleph that have spots for 6 devices and can be cut in the center to make three device boards. Always a trade-off - spacing the devices a bit would provide better cooling, but make it harder to find suitable heat sinks.
Dear Folks,
Just found a power AMP case from China's DIY site :
http://www.lite8.com/product.php?action=369
It's net weight is 15KG with heat sink and inside dimension is 480mm=W*135mm=H*420mm=D. Seems it is moderate for this project
CK
Just found a power AMP case from China's DIY site :
http://www.lite8.com/product.php?action=369
It's net weight is 15KG with heat sink and inside dimension is 480mm=W*135mm=H*420mm=D. Seems it is moderate for this project
CK
Trimpot advice
My thanks to Bob and Andrew for their help on the trimpot issue!
I think the case that CK mentioned looks really nice. Since any audio equipment can only be located in the family room with the approval of my wife Nancy, that kind of appealing case could be just the ticket. It's taken me years to teach her to appreciate Dynaco aesthetics! (She's a Pioneer pre-silver-era type of woman.....)
All the best,
Keith
My thanks to Bob and Andrew for their help on the trimpot issue!
I think the case that CK mentioned looks really nice. Since any audio equipment can only be located in the family room with the approval of my wife Nancy, that kind of appealing case could be just the ticket. It's taken me years to teach her to appreciate Dynaco aesthetics! (She's a Pioneer pre-silver-era type of woman.....)
All the best,
Keith
The website doesn't say in US dollars or Yuan. But I believe it is in China currency which is Yuan. That will be too expensive chasis if it's on dollar amount. If you convert it to dollars, then its approximately $ 95.00, which is not bad. That made me think of buying maybe two for my other amps.
TAD said, "Anyone know how the beta test on the Super Leach is progressing?"
I am the guy that is building and testing the Leach SuperAmp prototype. Sorry that it has been taking so long. It has been hard to find time to work on this.
STATUS REPORT: The PCBs are fabricated. I have all of the parts (most parts???) to build & test two channels with the exception of heatsinks and enclosure. I need to acquire a pair of heatsinks suitable for at least testing purposes. Anybody have a spare pair of heatsinks they'd like to sell?
I plan to assemble this beastie during the upcoming Holiday break. More to come, I promise!!
I am the guy that is building and testing the Leach SuperAmp prototype. Sorry that it has been taking so long. It has been hard to find time to work on this.
STATUS REPORT: The PCBs are fabricated. I have all of the parts (most parts???) to build & test two channels with the exception of heatsinks and enclosure. I need to acquire a pair of heatsinks suitable for at least testing purposes. Anybody have a spare pair of heatsinks they'd like to sell?
I plan to assemble this beastie during the upcoming Holiday break. More to come, I promise!!