Hi Morten,
You mentioned in the thread that a new revision of the board will be released with these changes,
1) Deleted the input coupling capacitor - it's now direct DC coupled
2) Added 2-stage internal split voltage power supply with SMPS 1st stage and linear 2nd stage (was previously a 10 V single linear supply)
3) Changed from 12 V to 24 V - 500 ma external power supply input
4) Additional power supply bypass capacitors - Elna Silmac II plus Vishay Polypropylene
- Will these changes flow on to the LDR3.v25?
- Can you wire output as buffered and the other without on the LDR300.V25? Reason is that I have a pair of active speakers which will need a 7-8ft pair of rcas, and the other to a power amp, which would only need a standard 3ft pair.
- Swappable output stage modules? Is this user replaceable as an upgrade in the future? I really hope this takes off.
Thanks in advance.
We just received blank circuit boards for the updated LDR300 buffer board yesterday so will be incorporating the new board into all new LD300's going forward.
The solid state buffer board does not have any relevance to the LDR3.V25 which is passive only preamp. On the other hand, incorporating the new SSB.V2 buffer board into the LDR3.V25 is essentially the definition of an LDR300.
The dual outputs on the LDR300 are the same buffered signal. Earlier on we tested having one output be optionally passive and the other active/buffered. However we found that the passive output had some unfriendly power on/off transients due to the interplay with the active buffer stage. This may be mitigated some or entirely with the updated buffer board design but have not tested that yet.
After extensive research on the output buffer design we've settled on the LSK170B for the buffer JFET. After much back and forth we decided to simplify the design and do away with the plug-in buffer module on the new buffer board. The LSK170 is a current production version of the old Toshiba 2SK170 JFET and it's hard to imagine a better performing transistor for this application. If we do find something superior we'll use that going forward but it won't be replaceable in existing units without a soldering iron.
