Thank you. This is most useful to know. My parts are not from a GB. I ordered them solo and might have received devices with different characteristics than most.
Now, as you will understand, removing the pretty heat sink is not at the top of my list of things to try
. But if I have to, will do.Pierre
Should have written: they are the STMicroelectronics devices. Not the Fairchild.
Many thanks for you assistance. Much appreciated.
Regards - Pierre
New Prereg GB round - Final Deadline!!!
Hi Guys,
as we now reached a critical mass for a new GB for the Prereg (thanks Peter for doing it again), there will be a final deadline, next Wednesday, 30th of April 2014 at 11:37pm CEST!
https://docs.google.com/spreadsheets/d/1eA-F1Z3nZYQPkwdGa0nRqHP2hrClLh4kcjPRQnRiodE/edit?usp=sharing
is now locked. If someone wants to make an order for the GB, please send me an PM or E-Mail with the respective number of PCBs you want.
Everyone who has is listed until then gets further information from me via PM.
Price will be the same as last time: 44€ per Stereoset (=2 PCBs) + Shipping/Packaging (within Germany for 1 set: 4€, for 2 sets 4.60€, worldwide depends on country).
Cheers,
Walter
Hi Guys,
as we now reached a critical mass for a new GB for the Prereg (thanks Peter for doing it again), there will be a final deadline, next Wednesday, 30th of April 2014 at 11:37pm CEST!
https://docs.google.com/spreadsheets/d/1eA-F1Z3nZYQPkwdGa0nRqHP2hrClLh4kcjPRQnRiodE/edit?usp=sharing
is now locked. If someone wants to make an order for the GB, please send me an PM or E-Mail with the respective number of PCBs you want.
Everyone who has is listed until then gets further information from me via PM.
Price will be the same as last time: 44€ per Stereoset (=2 PCBs) + Shipping/Packaging (within Germany for 1 set: 4€, for 2 sets 4.60€, worldwide depends on country).
Cheers,
Walter
I removed the heat sink and replaced the stock power NPN and PNP BJTs by these Toshiba devices. Sadly, this did not fix the problem
.Well, the pinout/footprint of the block transformers is a UI39/xx. I guess every transformer with this core type should fit the board. In the german AAA forum, there is currently a GB for an custom made transformer from an austrian company and they offer this footprint.
Clearly, the discussion with the block transformers was not as it should have been!
Additionally, nothing speaks against puttin the transformer off the board, e.g. when you want to use an R-core or something else.
Just my two cents!
Cheers,
Walter
Some examples that i copied from the AAA forum:
http://www.conrad.at/ce/de/product/...-mA-14-VA-83265-Weiss-Elektrotechnik?ref=list
http://shc-gmbh.com/product.aspx?pn=SPF1031212&line=Spitznagel&ma=Spitznagel&lang=1
http://www.hahn-trafo.com/deutsch/flachtransformatoren-ui39.php
http://at.rs-online.com/web/p/leiterplatten-transformatoren/2075911/
Clearly, more european companies but you get the idea?!
Clearly, the discussion with the block transformers was not as it should have been!
Additionally, nothing speaks against puttin the transformer off the board, e.g. when you want to use an R-core or something else.
Just my two cents!
Cheers,
Walter
Some examples that i copied from the AAA forum:
http://www.conrad.at/ce/de/product/...-mA-14-VA-83265-Weiss-Elektrotechnik?ref=list
http://shc-gmbh.com/product.aspx?pn=SPF1031212&line=Spitznagel&ma=Spitznagel&lang=1
http://www.hahn-trafo.com/deutsch/flachtransformatoren-ui39.php
http://at.rs-online.com/web/p/leiterplatten-transformatoren/2075911/
Clearly, more european companies but you get the idea?!
Last edited:
Oh, i have looked for PCB mounted transformers with same pinout without finding anyone that fits the boards. And the second batch of block was more silent - but when mounted inside case and lid on - the hum is still there :-(
So, is it possible for a swede to also enter this groupbuy of transformers???
So, is it possible for a swede to also enter this groupbuy of transformers???
Hi all!
I need some help, please.
So, finally, after a year, I built my Paradise, installed in the cases and ran it. It started instantly, beautiful sounds coming out of my speaker.
Great, but I do have two boring problems.
1. HUM, no matter the distance between the prereg case and the preamp case. It's audible with the volume knob at 11 o'clock. This hum (or another hum!!!) increases a lot when I come closer with the prereg box to the other box.
Solution: I'll change the two transformers I use right now - Triads EI type with two encapsulated toroid. I fear that There are two types of hum hear: one from a ground loop, not being changed by the replacement of the transfromers, and the other, that it's generated by the magnetic field of the current transformers. I'll report back after the change.
2. HISS. Well that's boring. The hum man can probably get rid of, but the hiss, I don't know. That's why I really need help.
It's also audible with the volume knob at 11 o'clock. At normal levels of audition, (till 9 -10 o'clock) it's not possible to hear it.
Strange behavior of the preamp: each time I power on the preamp, a very strong hiss, like a strong wind, like a waterfall, very audible at low level, can be heard in the speakers. After a while, circa 2 minutes, these noises decrease, remaining only the hiss described above. Is this normal for this amplifier? It occurs only in the heat up period of the electronics, and the stabilization of the voltages?
Solution: If I can leave with the strong noise that disappears after two minutes, I find the hiss not be compatible with this fine preamp. Is this caused oscillations? The transistors are very well matched. Is the Calvin Buffer causing this? Or rather my bad implementation of this buffer?
So, please help!
Emil
I need some help, please.
So, finally, after a year, I built my Paradise, installed in the cases and ran it. It started instantly, beautiful sounds coming out of my speaker.
Great, but I do have two boring problems.
1. HUM, no matter the distance between the prereg case and the preamp case. It's audible with the volume knob at 11 o'clock. This hum (or another hum!!!) increases a lot when I come closer with the prereg box to the other box.
Solution: I'll change the two transformers I use right now - Triads EI type with two encapsulated toroid. I fear that There are two types of hum hear: one from a ground loop, not being changed by the replacement of the transfromers, and the other, that it's generated by the magnetic field of the current transformers. I'll report back after the change.
2. HISS. Well that's boring. The hum man can probably get rid of, but the hiss, I don't know. That's why I really need help.
It's also audible with the volume knob at 11 o'clock. At normal levels of audition, (till 9 -10 o'clock) it's not possible to hear it.
Strange behavior of the preamp: each time I power on the preamp, a very strong hiss, like a strong wind, like a waterfall, very audible at low level, can be heard in the speakers. After a while, circa 2 minutes, these noises decrease, remaining only the hiss described above. Is this normal for this amplifier? It occurs only in the heat up period of the electronics, and the stabilization of the voltages?
Solution: If I can leave with the strong noise that disappears after two minutes, I find the hiss not be compatible with this fine preamp. Is this caused oscillations? The transistors are very well matched. Is the Calvin Buffer causing this? Or rather my bad implementation of this buffer?
So, please help!
Emil
