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Author Topic: NAD  (Read 4144 times)

Dmoney

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NAD
« on: May 04, 2010, 02:06:06 PM »
So today I swapped my Uberschall for a Decatone.
I got the Uber because I wanted some flexibility with my live sound. More flexibility than the Avenger could give me.
I liked the Uber but never fully got on with it. Always prefered my Avenger.
This is partly the reason I built my own 2 channel SLO-ish beast. That amp has something up with it (hum) and currently, Frank JPF is taking a look.

I didn't really want to get more amps, well, technically I have the same amount of amps as I did before!
These two will be getting used at my bands final show, unless Frank fixes my clone by then... may 29th!

Obviously this fella needs recovering Orange. I already spoke to Paul @ Zilla about that. I also swapped the grills for some spare avenger grills I had. So eventually I should have matching headshells for the Avenger and the Deca.

Now my first thoughts are EL34 conversion and FX Loop bypass switch.
Detailed tone report later I guess...






AndyR

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Re: NAD
« Reply #1 on: May 04, 2010, 04:46:19 PM »
It's, umm, got more knobs on it :D (ya can tell I'm expert in this area... :lol:)

Congrats - hope it does a better job for you than the one it's replacing.

Although I have to admit, I'm hoping more that JPF sorts out your build - I'm still highly impressed at what you've achieved in that :D
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Jonny

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Re: NAD
« Reply #2 on: May 04, 2010, 05:47:35 PM »
Reading your post I felt no "Woo!" or "I just had to have it", etc.

But then again I don't expect it to be a Jane Austen novel either.

Congrats.
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Dmoney

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Re: NAD
« Reply #3 on: May 04, 2010, 06:06:02 PM »
Woo!

haha

Nah its pretty cool.
I've not had chance to play it much cos my land landy was having a meeting in my house. It's better than the Uberschall (for me anyway).

I guess it's what I expected, so it hasn't reeeally blown me away. The gain channel is awesome. actually, the crunch channel is REALLY good. my Avenger is cool and can do a lot of sounds but you have to stop and re-dial the amp to get them, with this... even though its a shared EQ... you can set the EQ as you like and flick between clean, crunch, and overdrive and it all sounds pretty cool. its got the Depth control that I really like too.

So yeah, one channel Avenger to a 3 Channel Decatone. It's very versatile. which is what I was after when I got the Uberschall. I got the Uber because I didn't want to go back to Soldano and deal with Sounds Great again.

The Decatone has a valve buffered loop in it too, which is handy in case I ever want to use pedals. In the SLO, the loop is just between two cathode followers and BEFORE the tone stack. Its also +4 dB so some pedal have issues with it.
The Decatone Loop is AFTER the tone stack and has a level control. It's a more complicated loop. I like my Avenger and the Clone I built with No Loop, which is why im already fancying a loop bypass switch in this. if possible.

There is also a strange relationship between the channel volumes and master volume, The guy who dropped it off said to run it with the master at max and just get the level using the channel volume. I did that, it sounded ok, but you get some different tones depending on how you use those bits... maybe because the channel volumes are just before the valve loop, and the master volume is just after, before the phase inverter.

The amp I built myself that frank now has is pretty cool. I like that a lot too. But it has 2 channels and no loop. The Decatone is now the most versatile amp. It's also cool knowing that in future if i need an amp that has certain features, this should probably has it covered.

dave_mc

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Re: NAD
« Reply #4 on: May 05, 2010, 12:19:50 AM »
nice! :D

38thBeatle

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Re: NAD
« Reply #5 on: May 05, 2010, 06:25:20 AM »
That looks like an amp and a half.
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Dmoney

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Re: NAD
« Reply #6 on: May 05, 2010, 11:58:11 AM »
Did some A/B'ing just before work between the Avenger and the Decatone.

The Avenger has a bit more low end and punch. just a touch. The Deca has a bit more sizzle depending on where you sit the Master Volume.

They are very similar, I prefer the Avenger for the higher gain stuff but the difference is subtle so I can't complain.
Remeber the Avenger has EL34's and the Decatone has 5881's.

I'm wondering if this subtle difference is down to the valves.

I have been trying to get some information together to get this amp running EL34, but im slightly tempted to try KT66. I've never used KT66 before though. maybe i'd use them a bit and then still want to try EL34. hmmm.

EL34 vs KT66 anyone?

Dmoney

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Re: NAD
« Reply #7 on: May 07, 2010, 04:53:38 PM »
YO!

Did some more this this today.
I've been on a quest to find out if the PT in the amp can handle the extra filament current draw from EL34's and so far it been a mixed of people saying "I've done it without any trouble" and "It can probably run like that for a thousand hours before turning into a Darwinian Selector"

I played about with the preamp valves. got JJ's in there with a Philips in V1.
the FX loop mix level control effects the tone. towards 'dry' adds fizz and towards 'wet' makes it sound fuller but slightly less focused.
the big thing I did find, was that the Sovtek 5881's had idle current of around 60mA and over, while the amp has a plate voltage of 510V. This seemed high to me! One of the 5881's had no idle current. It wasn't arc'ing but wasn't working. The headshell was full of cobwebs so I don't know what the valves where last changed.
I took two valves out and set the bias and I've been running the amp set 8ohm's into my 16ohm cab.

Sounds a bit better. I'm guessing the 5881's remaining are worn out. Especially if they've been in there for 5 years.
I've ordered some JJ 6L6GC's to try in hear before I mess about with EL34's. Hopefully that'll breathe some new life into it!


 

HTH AMPS

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Re: NAD
« Reply #8 on: May 07, 2010, 06:56:43 PM »
I'd find out the PT's spec to be sure - you're asking a lot of extra heater current from the PT changing from 6L6s to EL34s.

One way to indicate whether the PT will cope is to bias the EL34s up and see if the heater voltage has dropped considerably.  Also, monitor how hot the PT gets compared to with 6L6s - if its too hot to touch, chances are that you're pulling more current than the PT can handle.


Dmoney

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Re: NAD
« Reply #9 on: May 07, 2010, 07:16:06 PM »
I have some spare EL34's.
I sat them in the amp with the standby on. so they are heated and getting bias but I haven't set the bias. wasn't sure about kicking it on with 500ohm screen grid resistors.

It's on like that for almost an hour and its only warm to touch. no bad smells etc.

what's funny, is that my actual other stock EL34 soldano amp, the PT gets MUCH hotter than this, and that was factory built EL34, not a mod.
Deca has the Merc Magnetics PT and the other hotter amp is Onetics. Made to the same spec I believe.

Still no answer from Soldano, but I've had a lot of help from other people. I know the OT will handle EL34's and how the Onectics is designed around the MM tranny. No definitive answer as yet though, but I'm being really careful.


Until I'm sure about stuff I won't use the EL34's. New 6L6's will probably have an impact on the Deca as it is.

HTH AMPS

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Re: NAD
« Reply #10 on: May 07, 2010, 07:58:34 PM »
If the Deca has a Mercury Magnetics PT, give them a call (or email) and ask for the specs.

Alternatively, give me the part# and I'll ask my contact at Mercury.


Dmoney

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Re: NAD
« Reply #11 on: May 07, 2010, 08:40:31 PM »
It's an sca100 x:01b
I tried mm right after soldano. They wouldn't give me the spec as the spec is owned by soldano. Same deal with getting the onetics spec from onetics.

I found 3 bad power valves today. Sucks

Heritage Softail

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Re: NAD
« Reply #12 on: May 08, 2010, 11:11:53 AM »
Nicely Done!  I am a Soldano fan.  Great set-up you have going. 
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Dmoney

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Re: NAD
« Reply #13 on: May 08, 2010, 11:22:55 AM »
cheers man!

when my Sloclone is 100% working I'll be set.
I'm a bit disappointed that over 2 weeks I couldn't get an answer from them about the transformers.

The sound is just right for me.

I need new valves all round now!

in the Deca I found a 5881 with no idle current at 500+V on the plate. The rest had over 60mA Idle.
I found an arc'ing EL34 in some spares I had... not good!

Then last night I was showing my girlfriend my amp because she liked the look of the lit up valves and one flashed and took out the HT fuse. I was running at noon on the master vol. so not pushing so hard. So I've thrown out all my spare EL34's. Just have the Ruby set left.

Yes... showing your girlfriend lit up EL34's is a winner!

Heritage Softail

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Re: NAD
« Reply #14 on: May 08, 2010, 11:46:21 AM »
You know far more about the innards of amps than I.  Quite out of my depth there.  I do like to dabble in tubes a bit.  You seem to be quite enamoured with the EL34's.  I have a few amps and have tossed them in and out.  The EL34's smoothed out the Mesa MKV and made it a better lead type amp IMO.  Frankly, I am happy with my SLO and will not be doing any tinkering.   It is tempting.  Maybe an amp clone build project would be best.  Seems you have really gotten to know the nuts and bolts of things.   Although I would like to keep my relationship with the 460V at bit distant, if you know what I mean.

Peace out.

Softail
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