Ok, I've got 8 Aleph X boards, rev 1.0. I'd be willing to part with 6.
I've got some PM's from a few of you asking for two boards. What I may do to keep things simple is list them on eBay. It is easier to setup payment and shipping that way. Does anyone have any objections to that?
I've got some PM's from a few of you asking for two boards. What I may do to keep things simple is list them on eBay. It is easier to setup payment and shipping that way. Does anyone have any objections to that?
http://www.bcae1.com/
Thank you for this link guys. Its an eye opener to so much for me. It has not made me any electrical genius 🙂, but it is helping to take the fog out of many things.
Thank you for this link guys. Its an eye opener to so much for me. It has not made me any electrical genius 🙂, but it is helping to take the fog out of many things.
Guys, it would be nice to start a thread in Trading post or Group buys.
Let's keep this topic strictly technical.
/Hugo
Let's keep this topic strictly technical.
/Hugo
Netlist said:
Tried to do what you suggested, but the system won't let me start a new thread. So here it is:
Link to eBay listing: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=230243740837
P.S. Can the admins get rid of that ridiculous "Please Search the Thread before Posting" requirement? Or at least turn it off for the Trading Post section of the forum. 🙄
PCBs
Hm, for me (Germany) this information comes at 2:00am.
So all PCBs were sold.
Is there anyone , who is willing to send me a layout?
Hm, for me (Germany) this information comes at 2:00am.
So all PCBs were sold.
Is there anyone , who is willing to send me a layout?
Re: PCBs
Yeah, sorry about that. After they went so quickly I realized I should have given everyone a heads up as to when I'd post them. My apologies.
400 said:
Yeah, sorry about that. After they went so quickly I realized I should have given everyone a heads up as to when I'd post them. My apologies.
quick question, maybe more general class A question.
built an aleph XAJ ? more or less aleph X with jfet front end, 2sj74 and ztx550 current source. 8 output devices total, almost like alephJ - X. Bias at 1.1 amp per device, voltage 19.5 volts. During long running, get an intermittent hiss. Not sputtering but like a loud steady white noise. Hehe, have had the static spurts on other adventures where was killing the mosfet, not the same here.
Amp runs hot, but not as too hot i believe. Can touch hold for couple-few seconds.
Is a fet jxn overheating? Or can jfet input's start freaking out?...
built an aleph XAJ ? more or less aleph X with jfet front end, 2sj74 and ztx550 current source. 8 output devices total, almost like alephJ - X. Bias at 1.1 amp per device, voltage 19.5 volts. During long running, get an intermittent hiss. Not sputtering but like a loud steady white noise. Hehe, have had the static spurts on other adventures where was killing the mosfet, not the same here.
Amp runs hot, but not as too hot i believe. Can touch hold for couple-few seconds.
Is a fet jxn overheating? Or can jfet input's start freaking out?...
traw said:
one or both channels?
if both - somethng is wrong with PSU ( if is common for both channels)
if just one-
what's current through input jfets ?
what's dissipation for ZTX ?
anyway - try with bypassing ( after long warm up) both drain resistors on input differential with 100uF caps ; if hiss is gone , then somewhere in input stage is culprit
it's just one channel, however it's also dual mono so hard to tell there.
using 1k drain resistors, and a 2k pot to adjust ztx550 current source. think pot lands somewhere little over 1k, thus similar to aleph J setting. Will check reading across the drain resistors to see what current is. So try putting caps across the 1k (where traditionally 392 on other alephs) ? Will try this weekend. Imagine use low value like 10uf?
using 1k drain resistors, and a 2k pot to adjust ztx550 current source. think pot lands somewhere little over 1k, thus similar to aleph J setting. Will check reading across the drain resistors to see what current is. So try putting caps across the 1k (where traditionally 392 on other alephs) ? Will try this weekend. Imagine use low value like 10uf?
traw said:
just in case - replace ZTX , pot and zenner ;
proposed bypass with 100uF cap (elco) is for testing only ; it will kill any AC signal across input drain resistors and tell you is it noise originating from input stage itself
hello,
i have some problems with my alephX..
it clipped so bad / distort (i dont know what to call it in english lol) when i raise the volume into a little below or normal listening level..
that problems seems dont appear on very little volume..
btw, i use cayin CDT15A > Tandberg Preamp 4038>aleph X > diy proac 2.5
tried using 10K and 50K volume attenuator but its the same, so i guess problem is in my amp..
i will be gratefull if someone could told me what to do..
i attach some picture
i think it using karis pcb.. i
t use 8xIRP240/channel and +/- 22V supplies
and... anyone can enligthen me what this pot use for?
thanks
i have some problems with my alephX..
it clipped so bad / distort (i dont know what to call it in english lol) when i raise the volume into a little below or normal listening level..
that problems seems dont appear on very little volume..
btw, i use cayin CDT15A > Tandberg Preamp 4038>aleph X > diy proac 2.5
tried using 10K and 50K volume attenuator but its the same, so i guess problem is in my amp..
i will be gratefull if someone could told me what to do..
i attach some picture
i think it using karis pcb.. i
t use 8xIRP240/channel and +/- 22V supplies
and... anyone can enligthen me what this pot use for?
thanks
Ducky,
you've got a stereo Al-X board, the pot in each of the quadrants is for biasing the quiescent current and to zero in on relative DC.
Why not begin to read at the very start of this thread, instead of asking others to DIY a power amp you did not DIY yourself ?
you've got a stereo Al-X board, the pot in each of the quadrants is for biasing the quiescent current and to zero in on relative DC.
Why not begin to read at the very start of this thread, instead of asking others to DIY a power amp you did not DIY yourself ?
That is to adjust the offset.
I think your offset is up way to high and this voltage is subtracted from the amplifer voltage swing.
Just measure the output to ground and you will see a large voltage at turn on that will drift downward and go negative (as I recall).
When at working temperature aim for a voltage of not more than 2 volts +-
http://www.hifizone.net/upload/shop/p200762301129.gif
Its astereo pcb so you have the 6 irf9610 and 6 vertical trimmers for bias and offset.
*This site is an infringment of the Passlabs commercial domain for use the model brand descriptors. )
Ian
I think your offset is up way to high and this voltage is subtracted from the amplifer voltage swing.
Just measure the output to ground and you will see a large voltage at turn on that will drift downward and go negative (as I recall).
When at working temperature aim for a voltage of not more than 2 volts +-
http://www.hifizone.net/upload/shop/p200762301129.gif
Its astereo pcb so you have the 6 irf9610 and 6 vertical trimmers for bias and offset.
*This site is an infringment of the Passlabs commercial domain for use the model brand descriptors. )
Ian