Hi Schubert_dk,
mail me bobgroger_at_hotmail_dot_com
Lots of KSA50 boards left, KSA100 boards are gone. In fact I still have a GB member I need 2 boards for, if anyone has changed their mind about this project.
I guess at this point we should do a check for interest in another board GB? Should we move this to group buys or keep it here?
Bob G.
mail me bobgroger_at_hotmail_dot_com
Lots of KSA50 boards left, KSA100 boards are gone. In fact I still have a GB member I need 2 boards for, if anyone has changed their mind about this project.
I guess at this point we should do a check for interest in another board GB? Should we move this to group buys or keep it here?
Bob G.
Why so quiet
Harry
My intention was to build a No Hold Barred Ksa100 with a professional look to it. When I handed my expensive heatsinks to a metalshop to start with the case and the workmanship I got back was worse than a backstreet DIY job. That was a major dissapointment to me.
I then bought a broken KSA150 with the intention of replacing the innards with the KSA100 but it now working and sounding very good- possibly better (more detail and very fast) than my KSA100.2.
I then found new heatsinks for the KSA clone but they still have to be predrilled. This time I do it myself.
Rest assured I have not lost interest - it just that my strategy has taken a few unexpected turns and expenses.
Jozua
Harry
My intention was to build a No Hold Barred Ksa100 with a professional look to it. When I handed my expensive heatsinks to a metalshop to start with the case and the workmanship I got back was worse than a backstreet DIY job. That was a major dissapointment to me.
I then bought a broken KSA150 with the intention of replacing the innards with the KSA100 but it now working and sounding very good- possibly better (more detail and very fast) than my KSA100.2.
I then found new heatsinks for the KSA clone but they still have to be predrilled. This time I do it myself.
Rest assured I have not lost interest - it just that my strategy has taken a few unexpected turns and expenses.
Jozua
Good to hear from you Jozua and I am glad you are still working on the KSA100.
Mine seems to be taking forever to put together and I still haven't worked out how to place the 8 output pairs on the heat sink. I might need to design a PCB as I hate wiring.
Best regards to you and Pierre.
Andrew what's your progress?
Mine seems to be taking forever to put together and I still haven't worked out how to place the 8 output pairs on the heat sink. I might need to design a PCB as I hate wiring.
Best regards to you and Pierre.
Andrew what's your progress?
Hi,Harry3 said:
I put mine aside until more feedback comes through on other builds.
I'm beginning to wonder if my oscilloscope/signal generator were misleading me. But unfortunately after replacing both I still ended up with blowing fuses or ringing when adding caps in parallel to 8r0 loading.
Anyone interested in a Groupbuy on the original/similar heatsinks with a fan from Fischer Elektronik GmbH & Co. KG ?
I got a quote on €100 / each
* Heatsink for 8 TO3 (2 on each heatsink)
* Papst Fan @ 230v (guess they have 110v too..)
* Predrilled for the TO3's
(Complete)
I also have a quote on just the heatsink (1000mm) for about €50/each
Then you have to cut it and drill it and get your own fan..
- - -
http://www.fischerelektronik.de
Waiting for an answers for 10,25 and 50pcs
** Pictues is not showing the actual, just so you all can get an idea... **
I got a quote on €100 / each
* Heatsink for 8 TO3 (2 on each heatsink)
* Papst Fan @ 230v (guess they have 110v too..)
* Predrilled for the TO3's
(Complete)
I also have a quote on just the heatsink (1000mm) for about €50/each
Then you have to cut it and drill it and get your own fan..
- - -
http://www.fischerelektronik.de
Waiting for an answers for 10,25 and 50pcs
An externally hosted image should be here but it was not working when we last tested it.
** Pictues is not showing the actual, just so you all can get an idea... **
An externally hosted image should be here but it was not working when we last tested it.
Heatsinks (& Transformers)
Hi Fix,
I may be interested in your GB of the heatsinks (I have my own fans) if the carriage costs to the UK are reasonable. I would be looking for 5 units.
I continue to look for reasonable cost transformers so I can start this project but so far either the transformers and/or carriage costs break my budget whenever a find a candidate.....
Is anyone else in the UK/Europe suffering the same fate?
Hi Fix,
I may be interested in your GB of the heatsinks (I have my own fans) if the carriage costs to the UK are reasonable. I would be looking for 5 units.
I continue to look for reasonable cost transformers so I can start this project but so far either the transformers and/or carriage costs break my budget whenever a find a candidate.....
Is anyone else in the UK/Europe suffering the same fate?
I bought two transformers on Ebay.
each were 1kVA 74+74Vac.
I split each winding to give 37+37+37+37Vac and used parallel sets of windings to double the current capacity.
I could add extra windings to bring the voltage up slightly but decided after power and temperature testing that my DC voltage was high enough (453W into 2r0).
If you look long enough you can find bargains that are capable of good results even though they may need a bit of work.
each were 1kVA 74+74Vac.
I split each winding to give 37+37+37+37Vac and used parallel sets of windings to double the current capacity.
I could add extra windings to bring the voltage up slightly but decided after power and temperature testing that my DC voltage was high enough (453W into 2r0).
If you look long enough you can find bargains that are capable of good results even though they may need a bit of work.
using those 37Vac secondaries.
I've got quotes from toroid.com.
Quantity- Price ($) each
5- $302.32
10- $260.97
I plan to make an order next Friday, March 21st.
Please contact me if interested.
http://www.diyaudio.com/forums/showthread.php?s=&postid=1460757#post1460757
Quantity- Price ($) each
5- $302.32
10- $260.97
I plan to make an order next Friday, March 21st.
Please contact me if interested.
http://www.diyaudio.com/forums/showthread.php?s=&postid=1460757#post1460757
Re: Transformers
I also bought from Rapid when they were discounting their NON ROHS transformers. Again some great deals on wire and resistors as well as transformers.
I now have about 30 suitable transformers for any projects that I care to take forward.
I bought them as a batch of 6, about £20 each. The others were a bit smaller. But I have been patient waiting for the right deals to come along.barryblue said:
I also bought from Rapid when they were discounting their NON ROHS transformers. Again some great deals on wire and resistors as well as transformers.
I now have about 30 suitable transformers for any projects that I care to take forward.
Hi Fix,
a 900VA 38Vac transformer has an AC current rating of about 11.8A continuous.
If you use it to feed a capacitor input filter the maximum contiuous current rating falls to about 5.9Adc.
At this current the transformer will run hot and this may be the temperature rating that the manufacturer has found is critical for their design of transformer.
For a Class A amplifier drawing 2.6A of bias plus some other small current loads, the transformer will be running at about 46% of maximum rating. This is about the usual maximum for a transformer, leaving the remainder for short term peaks. (It's why Pass recommends transformer VA~=6 to 7times amp power rating)
Uprating to 1kVA and running two ClassA amplifiers from it will draw about 82% of maximum rating continuously.
The transformer will run HOT. Worse, the amplifier internal ambient temperature will be high due to the ClassA dissipation.
You have nothing going for your idea of running a single transformer KSA two channel amp except saving money and risking unreliability.
You might get away with 1.5kVA, but the allegedly low regulation of the Krell spec transformer indicates it had a large area core and a high copper content. Both these will result in a lower operating temperature for a genuine Krell transformer. It may be that building their Transformer this way resulted in their 900VA spec and that this may be more equivalent to other manufacturers rating of nearer 1.5kVA.
That may be the reason that Flod's Krell copy was so expensive.
a 900VA 38Vac transformer has an AC current rating of about 11.8A continuous.
If you use it to feed a capacitor input filter the maximum contiuous current rating falls to about 5.9Adc.
At this current the transformer will run hot and this may be the temperature rating that the manufacturer has found is critical for their design of transformer.
For a Class A amplifier drawing 2.6A of bias plus some other small current loads, the transformer will be running at about 46% of maximum rating. This is about the usual maximum for a transformer, leaving the remainder for short term peaks. (It's why Pass recommends transformer VA~=6 to 7times amp power rating)
Uprating to 1kVA and running two ClassA amplifiers from it will draw about 82% of maximum rating continuously.
The transformer will run HOT. Worse, the amplifier internal ambient temperature will be high due to the ClassA dissipation.
You have nothing going for your idea of running a single transformer KSA two channel amp except saving money and risking unreliability.
You might get away with 1.5kVA, but the allegedly low regulation of the Krell spec transformer indicates it had a large area core and a high copper content. Both these will result in a lower operating temperature for a genuine Krell transformer. It may be that building their Transformer this way resulted in their 900VA spec and that this may be more equivalent to other manufacturers rating of nearer 1.5kVA.
That may be the reason that Flod's Krell copy was so expensive.