Hello TT-team,

It is good to see that now offer a complete kit to build a HIWATT DR103 clone. :bier: I've noticed that you designed a pre-amp with a mix of the original early 70's and the mid 70's schematic. Was this done on purpose? I also noted that you have changed the screen resistors for the output tubes from 100 Ohms into 1k5. What is the reason behind this mod? It might be worth to replace the 100k lin presence pot.meter by a tapered version. I've been informed that this change would be more effective. By deleting capacitor C10 the amp will sound more cleaner. Changing the master volume pot.meter for a tapered version would also be an option. It might be worth to experiment with an additional 220pf capacitor in parallel to C8. Let's :guitar:

Hi TT-team,

Adding an R/C combination in parallel to the stand-by switch will make the operation of that circuit more friendly too.

Hi TT-team,

Will you be offering the BIAS PCB as separate item in your webshop too?

Yes.

Regards, Dirk

Changing the screen resistors from 100ohms to 1k5 will effect the max. output power, but also extend the lifetime of these tubes. A value of 1k is often used too

He Kentuckytukker,

das wiederspricht aber der Auslegung auf maximalen Clean Headroom und wird deutlich mehr komprimieren.

Grüße Stephan

Hi Stephan, im original hat Dave Reeves 100 Ohm Wiederstände verwendet.
Gr, René

For Bass use the DR506 pre-amp in combination with the yah power amp. It is a small conversion