vintageHIWATTconvention.com

Hi
i have a DR 405 for changing tubes on my bench. I`m a little confused about the preamp tubes.
V1= ECC83
V2= ECC83
V3= ECC83
V4= ECC81
V5= ECC83
Is that correct or ? or is there a mistake on marks Website?

Gunter

I can check what mine is when I'm home tomorrow.

Unfortunately I won't be much help. In looking at the amp from the front, my leftmost preamp tubes have the silk screens work off. Center, and two right tubes are ECC83s.

Thanks for your help!
The only question is , V5 must be an ECC 83? It`s the middle tube of the row.

Yes, the middle tube is an ECC83 in mine,

Actually, both the PI and the output stage driver should be ECC81. Starting from the input side, it should be 83, 83, 81, 83, 81.

Hi Mark

are you sure? I think it must be 83,83,81,81,83

Thanks BOSSCO
i know this schematic, but in this amp was an ECC83 as V5

Anything can happen I suppose, however 99.9% sure that from Hylight your amp would have shipped out with an ECC81/12AT7 in the phase inverter position. Perhaps previous owner was a Marshall fan & chose ECC83/12AX7 like a Marshall would have...? Lots of opinions on the subject posted in various forums. My favorite source on the subject: http://www.guitaramplifierblueprinting. ... verter.pdf

ECC 81 for PI is correct. But after the PI must be additionel tube (V5). it`s a driver or impedance converter.

hiwattguenni wrote: ECC 81 for PI is correct. But after the PI must be additionel tube (V5). it`s a driver or impedance converter.

Perhaps I misunderstand your comment, however V5 is the phase inverter (PI) which is last before the power tubes. note: last does not mean last in the row physically/visually, but last in the signal chain before power tubes.

Hi BOSSCO

we talking about the preamp from a DR 405. I know V4 is always the PI, but next tube in the signalflow is there V5. In Pittman`s schematics you can see an ECC83 ( V5 ) . It`s working as an impedance converter for the 6 KT88.

The third tube from the input end is the PI on all Hylight amps. The 4th is the voltage reference. Only 405s have a 5th, and that's the driver.

but which is the right one for V5? ECC 81 or ECC 83 ?