Hi!
I repeatedly get asked about the possibility to offer an integrated amplifier and also headphone amplifier based on the 300B and preferably in a single chassis.
So I decided do develop one and see if there really is demand. I mocked up a test circuit using a new Lundahl output transformer with a new high bandwidth winding technique and which has optimum values to be used with Elrog ER300B.
Above the bread boarded test circuit, one channel completed. To fit all into a single chassis no interstage transformer and no transformer volume control. Volume control is done via a DACT stepped resistive attenuator (not seen in the pic above yet)
I selected the 6DN7 as driver tube. The two systems offer the right amplification factors and plate resistances for this job.
Initial measurements and listening tests with a bunch of lab supplies gave very good results. So time to bread board a power supply as well.
Some older metal plates got recycled for the test. The result is very pleasing. A headphone version of this will be offered as well with selectable impedances for 32/150/600 Ohm. Now everything will be fitted into a single box and the metal plates for that have to be designed.
Drop me a mail if you are interested to become one of the first owners of a 300B integrated amplifier or headphone amplifier. Other tubes will also be possible.
Best regards
Thomas
Wow. Very nice development!
ReplyDeleteThe headphone community should be looking out for this for sure.
Is it too early to describe the sonic differences between this amp and the 10Y line stage as hp amp?
This integrated and the 10Y are very different. The integrated can drive low impedance headphones and the 10Y is a preamp which can only drive high impedance headphones. The 10Y is transformer coupled with transformer volume control and the integrated is RC coupled with regular, resisitive volume control. Ids not really fair to compare
DeleteHallo Thomas,
ReplyDeletereicht der Netztrafo für eine Stereoausführung mit der 300B?
Ich frag deswegen weil ich so einen noch zu Hause habe.
Grüsse Hannes
Für den Testaufbau ok, aber für Dauerbetrieb mit 2 300B zu knapp. In der finalen Version ist was anderes verbaut
DeleteDanke für die Info, also eher der Trafo aus dem 6CB5A Stereoamp?
ReplyDeleteGrüsse Hannes
Der würde wohl passen. Das kommt auf Deine Schaltung an und Deinen gesamten Strombedarf wie der Netztrafo zu dimensionieren ist
DeleteHi Thomas - can you estimate the asking price for the Headphone amp described in the post?
ReplyDeleteIntroductory price will be 7150 Euros (export) / 8500 Euros (including sales tax). The price includes Elrog ER300B tubes. I will also offer it without tubes. price will be raised by 500 Euros after introduction phase
Delete