DR 405 V1-5

[hiwattguenni]

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

[Zentner]

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

[Zentner]

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.

[hiwattguenni]

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

[Zentner]

Yes, the middle tube is an ECC83 in mine,

[mhuss]

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.

[hiwattguenni]

Hi Mark

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

[Bossco]

http://hiwatt.org/tech2.html

[hiwattguenni]

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

[Bossco]

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

[hiwattguenni]

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

[Bossco]

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.

[hiwattguenni]

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.

[mhuss]

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.

[hiwattguenni]

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