Hi out there, waiting for a Groupbuy 
Let me start this way: I definitly do not start a Groupbuy! I want to keep it simple for me - and for you.
I'll order 20 to 50 pcbs depending on demand. 50 boards is my personal maximum. I would order them and send to anybody, who sent an email to me and money after I know exactly the cost.
50 boards would give 25 stereos. 2 stereos for me, 2 for friends. So the maximum I could give away would be 21 stereos. I would sell them for the money they would cost me plus package plus shipping.
The first 21 will be the ones to get a pair of.
I will order by end of August, maybe later. But be sure, I'll order.
I don't want to have too much conversation, too much requests.
Neither I want to hijack this thread, nor I'll open another one. Just email me.
Price? go some posts back.
Please do not email for pcbs, if you can't accept this.
Cheers Ernst
Let me start this way: I definitly do not start a Groupbuy! I want to keep it simple for me - and for you.
I'll order 20 to 50 pcbs depending on demand. 50 boards is my personal maximum. I would order them and send to anybody, who sent an email to me and money after I know exactly the cost.
50 boards would give 25 stereos. 2 stereos for me, 2 for friends. So the maximum I could give away would be 21 stereos. I would sell them for the money they would cost me plus package plus shipping.
The first 21 will be the ones to get a pair of.
I will order by end of August, maybe later. But be sure, I'll order.
I don't want to have too much conversation, too much requests.
Neither I want to hijack this thread, nor I'll open another one. Just email me.
Price? go some posts back.
Please do not email for pcbs, if you can't accept this.
Cheers Ernst
RMI-FC100 Boards set
Hi,
I must say, it took me the entire day to read all of the posts about the project of this amplifier.
I can only congratulate with Mihai, VERY NICE job.
Ivan
Hi,
I must say, it took me the entire day to read all of the posts about the project of this amplifier.
I can only congratulate with Mihai, VERY NICE job.
Ivan
This project is almost exactly what I've been pondering, with improvements..... Less the FET inputs.
I was thinking bjt inputs with bjt buffered inputs. Loop gain is very high then, like 77dB.
This looks to be a very cool design, and I'd love to get a pair or two of boards.
Portland Mike
I was thinking bjt inputs with bjt buffered inputs. Loop gain is very high then, like 77dB.
This looks to be a very cool design, and I'd love to get a pair or two of boards.
Portland Mike
Yet another Toriod house to consider
I find these to be decent cost effective and ship cheap at least in the US via USPS, like $10 for to 800VA ones.
More specs than most too.
http://antekinc.com/trans.html
tryonziess said:
DRZ1 said:
I find these to be decent cost effective and ship cheap at least in the US via USPS, like $10 for to 800VA ones.
More specs than most too.
http://antekinc.com/trans.html
One to many tracking diodes?
Hi,
I was just looking at the schematic for the amp, and I counted 5 bias diodes, and only 4 Vbe drops.
Is there intentionally an extra bias diode in the tracker, and if so, what was the rational.
Seems like it would defeat some of the benifit of having very fast tracking if the multiplier had 20% to much gain....
Thanks
Portland Mike
Hi,
I was just looking at the schematic for the amp, and I counted 5 bias diodes, and only 4 Vbe drops.
Is there intentionally an extra bias diode in the tracker, and if so, what was the rational.
Seems like it would defeat some of the benifit of having very fast tracking if the multiplier had 20% to much gain....
Thanks
Portland Mike
Re: One to many tracking diodes?
Hi Mike,
The TC of ThermalTrack transistor is different than the diode TC
http://www.diyaudio.com/forums/showthread.php?postid=1412728#post1412728
Portlandmike said:
Hi Mike,
The TC of ThermalTrack transistor is different than the diode TC
http://www.diyaudio.com/forums/showthread.php?postid=1412728#post1412728
PCB
Hi Ernest,
I would like to order 2 stereos for my biamped system.
I'm sorry to bother you this way, but I've currently no chance to send you an e-mail directly (??? - it seems to be impossible for new user on this forum).
Thanks
DeBe
Hi Ernest,
I would like to order 2 stereos for my biamped system.
I'm sorry to bother you this way, but I've currently no chance to send you an e-mail directly (??? - it seems to be impossible for new user on this forum).
Thanks
DeBe
If making new boards, why not modify them for the modifications?
I'd be interested in a couple.
Haven't looked back through the thread for a while. What is the recommended Idss for the FETs? There's a group buy in the WIKI
LSK170 group buy
There's also a group buy on the duals for these in the same group buy. Is the matching on these LSK389s tight enough, or should LSK179s be used and matched better?
LSK389 datasheet
Sorry if this has been discussed. The group buy looks to be winding up and no time to scan thread.
I'd be interested in a couple.
Haven't looked back through the thread for a while. What is the recommended Idss for the FETs? There's a group buy in the WIKI
LSK170 group buy
There's also a group buy on the duals for these in the same group buy. Is the matching on these LSK389s tight enough, or should LSK179s be used and matched better?
LSK389 datasheet
Sorry if this has been discussed. The group buy looks to be winding up and no time to scan thread.
OK, found the answer to Idss being greater than 9ma, so it looks like the right LSK170 in the group buy is the "C" grouping. Correct?
Also found the matching to be +/- 1mv. Wow. How many should be bought to hope to get this close?
As the LSK389 is matched to +/-20mv, they do not appear to be a good substitute. Correct?
Also found the matching to be +/- 1mv. Wow. How many should be bought to hope to get this close?
As the LSK389 is matched to +/-20mv, they do not appear to be a good substitute. Correct?
Is it possible to paralle the jfets?
Hi Mihai,
I like your amp. I’m going to study and build your amp. To be an audio fanatic, I want to try some mod first. For the input stage, I am thinking to parallel the jfets (i.e. a total of four jfets in the input stage) to increase the OLG for improving the THD. The THD improvement was confirmed by Ltspice. However, I could only successfully simulate parallel of BL grade 2SK170. For parallel V grade 2SK170, the simulation was failed. I followed the formulae in http://www.diyaudio.com/forums/showthread.php?postid=1574128#post1574128 for adjusting the CCS.
Can the ballasting resistor be omitted in paralleling the jfets? If yes, how close do I need to match the jfets in order to avoid ballasting resistor? How do you think in paralleling the jfets? Is there any stability problem? I’m not from the field of EE, please forgive me if I’m asking trivial questions.
Wai
Hi Mihai,
I like your amp. I’m going to study and build your amp. To be an audio fanatic, I want to try some mod first. For the input stage, I am thinking to parallel the jfets (i.e. a total of four jfets in the input stage) to increase the OLG for improving the THD. The THD improvement was confirmed by Ltspice. However, I could only successfully simulate parallel of BL grade 2SK170. For parallel V grade 2SK170, the simulation was failed. I followed the formulae in http://www.diyaudio.com/forums/showthread.php?postid=1574128#post1574128 for adjusting the CCS.
Can the ballasting resistor be omitted in paralleling the jfets? If yes, how close do I need to match the jfets in order to avoid ballasting resistor? How do you think in paralleling the jfets? Is there any stability problem? I’m not from the field of EE, please forgive me if I’m asking trivial questions.
Wai
Re: Is it possible to paralle the jfets?
What's the current do you want to run in the LTP? Maybe a V grade k170 is enough ...
I don't think that you can skip resistors if you want to put in parallel more jfets
Cheers,
M
wai235 said:
What's the current do you want to run in the LTP? Maybe a V grade k170 is enough ...
I don't think that you can skip resistors if you want to put in parallel more jfets
Cheers,
M
Roender,
looking at your PSU schematic, can I ask why you put caps across the rectifier diodes?
I did some work on this and one of the areas where you can actually make noise feedthrough worse is by using these caps.
you may have a different experience through.
looking at your PSU schematic, can I ask why you put caps across the rectifier diodes?
I did some work on this and one of the areas where you can actually make noise feedthrough worse is by using these caps.
you may have a different experience through.
Bonsai said:
In this particular case, FR106/107 and 10nF make a very good parallel combination from noise POV
Re: Re: Is it possible to parallel the jfets?
Mihai,
The LTP current calculated for paralleling V grade 2SK170 is 59mA.
I found that even small ballasting resistor, say 1R will ruin the benefit of paralleling BL grade 2SK170.
Wai
roender said:
Mihai,
The LTP current calculated for paralleling V grade 2SK170 is 59mA.
I found that even small ballasting resistor, say 1R will ruin the benefit of paralleling BL grade 2SK170.
Wai
Re: Re: Re: Is it possible to parallel the jfets?
? how did you workout/measure that?wai235 said:
Re: Re: Re: Re: Is it possible to parallel the jfets?
Hi Andrew,
From the simulation of single 2SK170V, I measured:
Id(J1) = 12.45mA
Id(J2) = 12.51mA
For paralleling 2SK170V
I5 = 2 x Id(J1) = 24.91mA
I6 = 2 x Id(J2) = 25.01mA
Adjusting I2 to 9.01mA with R19 = 22R
I1 = I2 + I5 + I6 = 58.93mA
I1 to I6 are variables of Mihai's formulae http://www.diyaudio.com/forums/showthread.php?postid=1574128#post1574128
Wai
AndrewT said:
Hi Andrew,
From the simulation of single 2SK170V, I measured:
Id(J1) = 12.45mA
Id(J2) = 12.51mA
For paralleling 2SK170V
I5 = 2 x Id(J1) = 24.91mA
I6 = 2 x Id(J2) = 25.01mA
Adjusting I2 to 9.01mA with R19 = 22R
I1 = I2 + I5 + I6 = 58.93mA
I1 to I6 are variables of Mihai's formulae http://www.diyaudio.com/forums/showthread.php?postid=1574128#post1574128
Wai