zeners
Hi All,
For the zeners, the issue is one of physical fit, if the devices mentioned in the datasheet will fit in the space, they should work perfectly...
The zeners only have to dissipate about 70mW, so pretty much anything at the correct voltage that will fit in the holes on the board will do...plus the 27v isn't absolutely critical, 26 or 28 would work perfectly too...
Stuart
Hi All,
For the zeners, the issue is one of physical fit, if the devices mentioned in the datasheet will fit in the space, they should work perfectly...
The zeners only have to dissipate about 70mW, so pretty much anything at the correct voltage that will fit in the holes on the board will do...plus the 27v isn't absolutely critical, 26 or 28 would work perfectly too...
Stuart
Rabstg
I wasn't trying to accuse, complain or anything. I just wanted to know if the Wattage was an issue but according to the Wiki it doesn't seem to be of any significant value.
I just want to know if it's ok to mix or f I should order all new zeners when i'm sending for other things as well.
Some other things:
*The big Wima, 0.1uF. where does that go?
*C104 and C109 are the same value but of different physical size. Any reason?
*The third pot (blue with the enlonged axel, not the two bournes 5K), which one is that? I can't seem to find a spot for it.
I wasn't trying to accuse, complain or anything. I just wanted to know if the Wattage was an issue but according to the Wiki it doesn't seem to be of any significant value.
I just want to know if it's ok to mix or f I should order all new zeners when i'm sending for other things as well.
Some other things:
*The big Wima, 0.1uF. where does that go?
*C104 and C109 are the same value but of different physical size. Any reason?
*The third pot (blue with the enlonged axel, not the two bournes 5K), which one is that? I can't seem to find a spot for it.
kmj said:
The 400VDC Wima is "extra" I threw it in as an AC mains filter cap... It is good up to 250AC or 400VDC.
104 and 109 are different pitch sizes.. One of the reasons it took sooo long to ge the parts. Even though they are the same value the same part will not fit in both spots. And neither of those will fit on Jan's boards...
The brds call for 2 pots.. I got the shaft pots and figured not everyone would like them so I got a third "conventional" pot. Pick and choose 2, but they are all "Name brand" pots...
Thyristors
Thanks Andrew....yes, I will be using either two 28v+28v 500VA toroids from Antek. or a single 28v+28v 2KVA toroid from AudioHobby....depending on which fits best in the case. I haven't received the big one yet.
Robert
AndrewT said:
Thanks Andrew....yes, I will be using either two 28v+28v 500VA toroids from Antek. or a single 28v+28v 2KVA toroid from AudioHobby....depending on which fits best in the case. I haven't received the big one yet.
Robert
rabstg said:
Didn't try those, but the 15030/1 certainly work, and I have used them successfully.
Those zeners will be fine, I actually put 24V ones in one of the prototypes, and it was only when measuring to find another problem that I noticed...
The big one sounds ALOT better! Worth waiting for.
Flodstroem
I still have to talk to the right guy at the parts place about how many caps they have left. He should be back from vacation this week so I will definately find out.
Mark
Hi Mark,
can you confirm your latest set up?
single transformer-dual secondaries?
twin rectifiers each with smoothing caps?
each channel fed from it's own rectifier/smoothing?
Nominal impedance of the speakers?
Can you describe the changes in sound, both for the better and for the worse?
can you confirm your latest set up?
single transformer-dual secondaries?
twin rectifiers each with smoothing caps?
each channel fed from it's own rectifier/smoothing?
Nominal impedance of the speakers?
Can you describe the changes in sound, both for the better and for the worse?
Andrew,
The KSA is the same except for the tranny change out. This KSA-50 is listed in the builders WIKI. Also, check the "Pass Shoot Out Version 2" in the Pass section for a description of the system and some photos.
The most apparent difference is in the bottom end. It is much tighter and cleaner at very low bass notes than it was with the two 400 VA transformers from ANATEK I had in the unit. The top end also seems smoother than it was although the bias and rail voltages remain almost exactly the same as before the switch out. There is definately someting good about having an overkill toroid in this amp. I would also suspect that it is capable of producing more power at lower (below 4 ohm) impedances although I have not conformed that.
Mark
25 ohms 2W where to find a supplier?
Hi
I have a problem to find a supplier of the emitter resistors R 127/128: cant find a decent supplier of those 25 ohms 2W resistors. In principle all of my supplier only have 22 ohm and the next value is 27 ohm. I WANT those 25 ohms and I am in the need of 35pcs. Anybody who have an overstocked 25 ohm? (I have a PayPal account)
Or, any tip for a decent supplier (metal film preferable) ?
Regards 😎
Hi
I have a problem to find a supplier of the emitter resistors R 127/128: cant find a decent supplier of those 25 ohms 2W resistors. In principle all of my supplier only have 22 ohm and the next value is 27 ohm. I WANT those 25 ohms and I am in the need of 35pcs. Anybody who have an overstocked 25 ohm? (I have a PayPal account)
Or, any tip for a decent supplier (metal film preferable) ?
Regards 😎
Hi,
if 25r 2W become impossible, then you might want to consider using a parallel pair of 1W resistors. Not as neat but will do the job.
47//47 =23r5
51//51 =25r5, These values may be difficult in 1W.
47//56 =25r6 but only 1.84W (close enough)
56//56 =28r
Lowering the driver Re value will increase the driver dissipation and conversely raising Re will lower dissipation.
if 25r 2W become impossible, then you might want to consider using a parallel pair of 1W resistors. Not as neat but will do the job.
47//47 =23r5
51//51 =25r5, These values may be difficult in 1W.
47//56 =25r6 but only 1.84W (close enough)
56//56 =28r
Lowering the driver Re value will increase the driver dissipation and conversely raising Re will lower dissipation.
Mouser has a 25R 3W wirewound that Terry used see his post
Terry's resistor
EDIT: looks like mouser only has 5 in stock at the moment, more on backorder.
Terry's resistor
EDIT: looks like mouser only has 5 in stock at the moment, more on backorder.
Driver emitter resistors
Hi All,
Since it has been said before this may be superfluous but...
The exact value of the driver emitter resistor is not critical from a functionality perspective, any of the values mentioned will work properly. I have used 22 and 27, since they were what I had at hand.
We'll probably never know why Dan chose 25r, it would have been an even weirder choice back then that it is now. While it could have been the sonically perfect value, occams razor would suggest it was more likely as trivial as getting a good deal on 100 000 resistors with a 'strange' value...
Stuart
Hi All,
Since it has been said before this may be superfluous but...
The exact value of the driver emitter resistor is not critical from a functionality perspective, any of the values mentioned will work properly. I have used 22 and 27, since they were what I had at hand.
We'll probably never know why Dan chose 25r, it would have been an even weirder choice back then that it is now. While it could have been the sonically perfect value, occams razor would suggest it was more likely as trivial as getting a good deal on 100 000 resistors with a 'strange' value...
Stuart
With these repeating questions and answers we can keep this thread alive till we are all in the retirement home.
Play it again, Sam:
Better to have a 22R metalfilm/metaloxide than a 25R wirewound there.
I used 22R 3watt metalfilm, 2% accurate.
And matched them to way under 1%. (this is where Upupa comes in to say i am a nut)
Play it again, Sam:
Better to have a 22R metalfilm/metaloxide than a 25R wirewound there.
I used 22R 3watt metalfilm, 2% accurate.
And matched them to way under 1%. (this is where Upupa comes in to say i am a nut)
The GB kits have 27 Ohm 2 watt Dale metal film.
I have some Dale RN60 1 Watt 49's if you wanted to parallel...
I ordered some to put those in the GB kits, but that was WAY TOO expensive.
I have some Dale RN60 1 Watt 49's if you wanted to parallel...
I ordered some to put those in the GB kits, but that was WAY TOO expensive.
Thank you all for your wise comments
At the Newark.com I found these: #94c2481 which is a Vishay BC Component: 2 W 24 ohm and a metal film resistor. (if 25 ohms is ±5% its resistans will span from 23.75 ohm up to 26.26 ohm)
I think this will suit the purpose well but I would like to ask you though, could this one be a substitute for the 25 ohms?
Price for 1-99: $0.32, >99: $0.181
Regards 😎
At the Newark.com I found these: #94c2481 which is a Vishay BC Component: 2 W 24 ohm and a metal film resistor. (if 25 ohms is ±5% its resistans will span from 23.75 ohm up to 26.26 ohm)
I think this will suit the purpose well but I would like to ask you though, could this one be a substitute for the 25 ohms?
Price for 1-99: $0.32, >99: $0.181
Regards 😎
Thanks Al
Regarding the front end: Whats the reason for changing the 2SA970/2SC2240, 120V low noise Toshiba to the MPSA42/92 300V nixie driver ONSEMI? Okay I admit I havnt search the thread for this. Any link?
Regards 😎
Regarding the front end: Whats the reason for changing the 2SA970/2SC2240, 120V low noise Toshiba to the MPSA42/92 300V nixie driver ONSEMI? Okay I admit I havnt search the thread for this. Any link?
Regards 😎