A question about valves

[krispn]

So I had a chance to test out some old mullards today in my Aguilar DB659 preamp.

I have to say that initially I was a little surprised as I tried my normal settings and i could barely hear anything - power amp was up full, volume around 1 pm and master volume/output at 9am on the preamp

I had to really push the preamp volume to around 3pm amd drivd the output to around 3 or 4pm to get sufficient volume for what would be gig levels.

The sound i was getting was a good one and i was half expecting I'd have too push the valves more to get the sound i was after.

What i'd like to know is what other ppl's experience is with vintage or old vavles. Is it normally to have push them so much to get the tone or even the actual output volume or does it sound like the valves are past their best?

Its my first time really trying out different valves in this preamp.

[Mr. Foxen]

What valve was it? If you have an ECC81 or 82 instead of an 83 you'll lose a bunch of volume.

[geoffbyrne]

ECC83=12AX7 - supposed to be 100% gain
ECC82=12AY7 - supposed to be 40% gain
ECC81=12AU7 - supposed to be 19% gain

A handy one is the 5751 which is about 70% gain - gives you greater headroom at the cost of a little top-end volume.

Your amp shouldn't have dropped that much volume unless it was a 12AU7 type you put in.

G.

Edited August 2, 2010 by geoffbyrne

[krispn]

Thanks guys

I think they were ECC83 but one of them has the majority of the printed info on the valve worn off. It still has the mullard emblem part intact but I can't be sure. The other is an ECC83.

I knew the other valves gave less gain but as little as 19% !!!! I guess with only two valves in the preamp the effect is quite noticeable.

I'll get back to the guy and see if I can try two ECC83's

I have to say the tone was great - warm and round and with more extreme settings on the EQ I could get many great sounds or at least great to my ear.

Thanks again guys very helpful


gavin

[Alien]

[quote name='geoffbyrne' post='912304' date='Aug 1 2010, 10:16 PM']ECC83=12AX7 - supposed to be 100% gain
ECC82=12AY7 - supposed to be 40% gain
[b]ECC81[/b]=12AU7 - supposed to be 19% gain[/quote]

Got that for ya

A

[Mr. Foxen]

Thought the ECC81 was 70%, I had one in a DHA dual pedal, for the cleaner side, was not loads quieter.

[geoffbyrne]

[quote name='Alien' post='912321' date='Aug 1 2010, 10:39 PM']Got that for ya

A[/quote]


Oooopps!!!!!! Ta!!!!

G.

[geoffbyrne]

[quote name='Mr. Foxen' post='912344' date='Aug 1 2010, 11:10 PM']Thought the ECC81 was 70%, I had one in a DHA dual pedal, for the cleaner side, was not loads quieter.[/quote]

Depends which site you look at - some say the ECC81 is the equivalent of the 12AT7, while others say the 12AU7 - there's quite a bit of difference.

I've always worked as its being the 12AU7 equ.

Of course, a lot of these figures depends on the individual valve & where/when it was manufactured. If you look at Myles Rose's stuff:

[url="http://www.guitaramplifierblueprinting.com/index2.html"]http://www.guitaramplifierblueprinting.com/index2.html[/url]

there's a whole world of information there. You can contact Myles directly by going through the MusicPlayer's Guitar Forum.

G.

Edited August 2, 2010 by geoffbyrne