Re: Ok.. here's a guy who was thinking what I was thinking *epi vj*
- From: Jim <askme@xxxxxxxxxxxxxxxxx>
- Date: Mon, 30 Apr 2007 11:10:12 -0700
Twang wrote:
At every step of deciding on my mods..I have been balancing choices..
thinking I'd have to test them one at a time.. and then decide on
which to keep.
But I also have been thinking.. can I use a switch here and there, or
otherwise install choices permanently.
And that is definately my next bit.. to go through each mod and see if
I can, and if it would work well, --be smart-, get options on the
front or rear panels.
So Ebay ad Item number: 140112519976 caught my eye.
for starters:
The 'Voice' Group
The 'Bias' Switch allows you to Voice the Amp to your Particular
Liking. With 3 Settings to choose from and used in Conjunction with
the 'Boost' Switch, you should be able to 'NAIL' the Sound You Want.
1. - Position '1' is Very Clean, Crisp and Bright, This Sound is
Enhanced by the Hammond 125DSE Output Transformer. Much like an Amp
made by a well known Company starting with 'F'.
2. - Position '2' is still Clean and Bright but Starts to Break-up as
the Volume is Raised. Like an old 'V' AC30 Amp.
The VJ is a single ended EL84 amp. You will not get an AC30 push/pull tone out of it.
3. - Position '3' is the Much loved 'M' Sound. The Harder you drive it
the Better it Gets.
Same comment as above, but modify it to "you will not get a push/pull EL34 tone out of it."
See.. I'm not far along enough to know about each mods physical data..
room. size of parts. noise relationships. *like how close they can
be .. using sheilded wire.. etc.*
So I find this kind of stuff very interesting.. someone has done some
thinking for me.*S*
Though I will NOT be changing the transformer.. at least not this
first one
and then we come to:
In Addition - The 'Boost' Switch Now has 3 Settings.
4. - The 'Boost' Switch. - Set to 'Off' (Centre Position) the Amp is
Fairly Tame. All of the other Controls still work, but do Not Have the
'EDGE'. Switch it 'On' to Position 1 or 2 and the Amp Sparkles and
Comes to Life. The Depth, Dynamics and Detail are Superb - Beautiful
Smooth Creamy Sustain just Flows.
Position '1' is Half Power Boost.
Centre Position is 'Off'.
Position '2' is FULL Power Boost.
I'd like to know a bit more about that one.
I have no idea what he's doing, unless it's just messing with the attenuation in the preamp.
and:
The 'Amplifier Gain' Group
Because Everybody has a Different Idea of a 'Great' Sound, the 'Gain'
Group Caters for Individual Requirements. You can 'Dial In' The Type
and Level of Harmonic Valve Sound that you want. These Controls are
Interactive - So the Setting on One will effect the Setting of the
Next.
1. - The 'Drive' Control. Sets How Hard the Preamp is Driven. This is
where you will Get 'YOUR' Sound.
Probably adding resistance to the first resistor to ground.
2. - The 'Master' Control. Sets How Hard the Power Amp is Driven. It
is Very Interactive with the 'Drive' Control.
More messing with the preamp attenuation.
again. good idea.
this one.. I'm really not sure. Frankly, I can run my amp as loud as I
want anytime I want.. so I don't need less power at all. though it
does offer another sound.. this guy didn't note that it's also a mod
that many others have said produces more hum and noise.
The 'Power' Group and 'Mains' Switch
1. - The 'Standby', 'Triode' and 'Pentode' Switch. All Valve
Amplifiers 'NEED' a Standby Switch. It is a Requirement of the Valves
in the Amp. The Valves need to 'Warm Up' Before they are 'Started'
When the 'Mains' Switch is turned 'On', the 'Power' Switch should be
at 'Standby' (S/B) (Center Position) for at least 30 seconds.
2. - Select 'Triode' or 'Pentode'? This is another Little 'Hot Rod'
Trick that makes this Amp Sound so Great. The Output Valve in this Amp
is Classified as a Pentode. This is its Normal Mode of Operation,
Producing about 5 Watts of Audio Output Power. However - The Valve can
be Forced to operate as a 'Triode' Producing 1.8 Watts of Output
Power. Not only does it more than Half the Output but it Totally
Changes the Sound Characteristics of the Valve making it Warmer and
Smoother Sounding. Believe me, it's Still LOUD if thats what you want.
Ok - There you have it - A completely different Amp at the Flick of a
Switch. 'Triode' or 'Pentode' - It's your Choice.
I may try a triode switch for kicks. But it's warm enough without it.
as to the next mod.. I also begin to lose some interest. though it's
ok for an idea and all..
but for me, that attenuation is just not something I care about.
but a line out/headphone jack.. hmmm!
On The Rear Panel
The 'L-Pad' or Variable Speaker Power Attenuator. It will allow the
Volume of the Speaker to be adjusted from 'Max' down to 'Zero'. Once
you have Got the Sound you want from the Amplfier, if its too loud,
you just turn the Speaker Volume Down. Simple and VERY Effective.
There is a Down side to the L-Pad. The Speaker itself is part of the
overall sound heard, so by reducing the power delivered to it you are
changing the sound properties. Keep in mind that with the Amp Set to
'Triode' you may well be able to achieve the Desired Sound and Volume
Level you want - without having to use the L-Pad. The L-Pad works only
with the 8 Ohm Output.
I did this, but I used a 16 ohm L pad with a switch that takes an 8 ohm resistor in and out, for use with 8 or 16 ohms.
Also on the Rear Panel you will find the The Speaker Outputs - One
each for 4, 8 and 16 Ohms. There is a 'Line In' Socket - This Gives
Direct Access to the Final Output Stage, any Line Level Unit such as a
Pedal Board or CD Player can be Connected, Volume can be adjusted
using the 'Master' Control. There is a 'Line Out' Socket for Direct
Connection to a Mixing Desk or Recorder. Mono Headphones can be
Connected to the 8 Ohm Speaker Output and the L-Pad will Control Their
Volume.
I don't recommend this unless you start with the L-pad at full attenuation, then ramp up SLOWLY. Plus, your headphones are most likely not 8 ohms, but it won't mess with the amp at low output levels.
of interest to me, though it's the vjs brightness that is most often
talked about as to improving.. is this:
2. - HUGE Smoother Capacitors - This Eliminates ALL Hum and
Substantially Enhances Bass Response
IMHO, NOT NEEDED. The new series adds a filter cap.
I have my EQ bass set to 10.. and it's just not right.. this amp is
not producing the lows I need.
Still have the Sovtek tube? Upgrade and it may help a bit. But don't forget, this is a single ended EL84 amp. You need brute power for convincing bottom end.
Also, you may try changing coupling caps to .05 (or .047) all the way up to .1.
I have no problem at all with my Fender tone stack. Bigger value coupling caps would give me more bottom yet.
They aren't thick enough, not enough emphasis.
I have to EQ like crazy to get it to sound the way I want.
(ymmv)
this I like.
9. Input Impedance Corrected - The Standard Factory Input Network
causes over Half of the applied Signal to be 'LOST to EARTH' as soon
as it Enters the Amp. Not any more.
Half, not over half. But yes, this is the first mod that most people do.
this part.. wowzers.. I guess that's why it's 450.00 us dollars..
Damn, I'd sell mine for that price. And I have real Mullards, a tone stack, and line level output.
10. - Both Valves Re-Biased and Calibrated to work within their
Prescribed Design Parameters. More than 50% of the Components on the
PCB have been changed in order to Accomplish this.
You don't have to change over 50% of the components. You change three cathode resistors.
I dont think anyone needs to go that far.. and I doubt most of us
will.
that is.. I wont be replacing so much, or demanding so much of the
amp. the transformer is only about 40.00 by the way.
All the gain switches are nonsense. Dial in gain to your ears.
(but it may not fit... there seems to be some argument about this*
no dobut on this next one:
11. - HT Fuse and Holder Mounted on the PCB. A 'MUST' for Safety
Reasons.
No, better yet mount it on the back where you can get to it. That's what I'm doing. But that's more work and more money.
and cheap, too.
and:
14. - Ultra Fast Switching Rectifier Diodes - STOPS any Residual 100Hz
Buzz on the HT Line.
Considering I'm not hearing buzz, I don't feel a need to change this.
http://i20.ebayimg.com/05/i/000/9b/c6/f62c_3.JPG.
http://i13.ebayimg.com/01/i/000/9b/c6/fa79_3.JPG
http://i12.ebayimg.com/03/i/000/9b/c6/fea5_3.JPG
still sorting through all the ideas.. it's not easy getting all this
information straight in my old hippie head.
But I'm making progress.
and mowing the stupid lawn.
TWANG
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