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My latest gear experiment...

Back to the Gear Room

ron a
Aug 13, 2010 6:22 PM GMT

Was a smashing success! I'll talk you through it and if anybody expresses interest i'll post a couple of pictures after I get off night shift for a couple of days.

I have a valve junior head, unmodified except for a mullard 12ax7 and a groove tubes el84 siver series. I absolutely am satisfied with the tone through any speaker, especially any 12 inch or pair of 12 inch speakers I have tried. I have compared vintage alnico jensens to newer Jch series Jensens and find them all very usable and hardly detectable in tone differences once I started using a crystal mic. For me, with this amp and my style, the mic is unquestionably the bigger issue, but I was looking for a way to preserve my tube tone without lugging a dual 12 inch cabinet everywhere. In the order of gear and what makes tyhe most difference to me, i did extensive tests and recordings and arrived at the following order of improvement:

1. Microphone, by a wide margin, makes the most audible difference on my digital recordings under carefully controlled conditions for comparison, using headphones for playback reference, then monitor speakers and finally my PA system for comparisons.

2. The amplifier and various settings of the single volume knob make more difference than any speaker swap, until the speaker is less than 8 inches in diameter.

3. The difference in tone and volume between an 8 inch speaker and a 12 inch one is quite audible and measurable on my spl meter, but correctable and usable with EQ in many cases if you are micing the cabinet. If you are not, there is a clear advantage to the 12 and an even bigger one with two 12s. I did not test more than one 10 inch vintage speaker, so i didn't think it was fair to comment, other than it was usable and i'll leave it at was a weber alnico recone.

So, what was the latest experiment? simple. I mounted a 4x6 inch 8 ohm TV speaker inside the cabinet of the valve junior head, facing downward into the plywood on the bottom opposite the tubes. The back of the speaker is the only surface radiating into the cabinet and out the grille on the back panel, which I have also switched to the front panel. The back is now open.

Why do this? I found my amplifier's tone translates VERY well into the PA when attenuated by an active DI. The amplifier still requires a load to keep it from burning out, so the 8 ohm 5 watt speaker does the trick. I run the amp into the Di, put the DI on 20dB attenuation, in link mode and the speaker plugs into the channel 2 link ouput often used to run a bass amp, for example.

Now I have valve junior tone options and the power of the biggest amp in the house...the PA system. The effect is like using a line out, with a small monitor speaker that doesn't put out much volume to generate feedback, since the back of the cone is the radiating surface and out of phase with the mic. I am very pleased with the recordings compared to the actual amp and speaker cabinet. Playing into the room to jam tracks can now be done at lower volumes with the tone of the amp preserved as well. Very tweakable setup!

The added benefit is one briefcase of harps, mics and connectors and one small amp head to carry to the gig or jam speakers!


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Comments (13)

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Aug 13, 2010 6:25 PM GMT
ron a Replied:

Disclaimer: I realize there is no possibility I tested every possible efficiency or size of speaker. My results are based on several speakers of very similar eficiency and different cone sizes only. The experiment was intended to see if my amp can be used without a speaker cabinet with great tone and the answer is yes.

Aug 15, 2010 10:00 PM GMT
Bulldog B Replied:

So, if I had no equipment and was was starting from scratch, it sounds like the most bang for the buck would be: 2 mikes - one a Green Bullet or something similar for Chicago Blues and one a clean mike (SM57) for everything else; and a pre-amp/amp simulator (Harp Commander, Tech 21 Sans Amp, etc.) that I could plug directly into the PA (using a direct box of some kind). Later I could add a delay pedal and/or reverb pedal. My idea is to carry as little gear as possible while having as wide a range of sounds as possible.

Aug 16, 2010 12:48 AM GMT
Chris C Replied:

Bulldog- Thats exactly what I have done.

1. Lucky find at a second hand shop harp mike (Loud Bark Low Z) AUS$65

2. Cheap DI box from JayCars for impedence matching AUS$24

3. Behringer 8Band EQ - Feed back control - AUS$70

4. Behringer Vintage Delay - AUS$85

5. ART MP Tube Preamp - AUS$100 - Recently replaced the Tube for an RCA 12AU7 great improvement.

Total AUS$344 = Aprox US$300 = Excelent results.

Aug 16, 2010 1:50 PM GMT
ron a Replied:

Yes, and the astatic roadhouse is a good value for only $70. There are many other vocal mics for greater savings if money is tight and the $100 sm57 is too much. Pedal into the PA is what i have been doing with a digitech rp80. The valve junior via di to the PA is true tube tone, where the digitech is all modeled. There is undoubtedly a tone difference, but the audience may not care. The tube preamp to PA is a good idea too, but you will need a DI anyway if you are very far from the mixer...unless the preamp has a built in DI. I also like to use the pedal for eq and slight delay for variety, even with my valve junior. Personally, I like to keep it as simple as possible and use the pedal less now that i have a volume control on a mic. I was using it for that too before i got the astatic roadhouse.

Aug 17, 2010 8:19 AM GMT
Chris C Replied:

I find the EQ helps drive the Valve in the peamp abit and sculpt the sound a little as well. Everything in moderation I guess.I used to use a damn Pod but now would not go back from valves. I say that now but thechology keeps getting better smaller and cheaper. I like the idea of the Blues Junior head. I have had some realy goodresults before with a small Line 6 Microspider amp which has a DI. It can be used straight and is very loud for the size, miked up or DI. Great for partys.

Aug 17, 2010 5:36 PM GMT
ron a Replied:

for dirt cheap startup amp'd tone...provided you can go to a jam with a PA...Behringer DI20, Astatic roadhouse jt30 and a mic cable if you think they won't have one for you. Add the honeytone amp if you want...still dirt cheap and let's you work on your amp'd tone.

DI20 $29.95

jt30rh $69.95

cable $10-50 depending on how long and what quality.

Honeytone belt amp $19.95

You can plug the jt30 into the honeytone belt amp for practice and run it (alone or from the honeytone earplug jack..need another cable and adaptor for that)) into the DI20 at the jam

I think this would be my minimum starter rig and I truly believe the honeytone is optional if you have a place to play through a PA or own one...which I do, both. The jt30 straight into the pa via the DI20 is a nice sounding mic and very similar in concept to what the old guys were doing anyway..Crytal mic into a PA. I have clips here somewhere of how that sounds if you can stand my playing. I have tested this extensively using various mics and speakers and even playback media. The mic made the biggest difference in tone of anything I tested, hands down. I guess this explains the fascination with mics, but it doesn't explain the need for a harp-specific amp..not to may anyway. Tone is subjective and that's the key to all the questions and all the answers.


A comparison of a vocal mic, a homemade pill biottle mic and the jt30 roadhouse..all straight into the board with appropriate impedance matching. Tell me if you can't tell which lick is which mic..or at least hear the differences.

Aug 17, 2010 11:38 PM GMT
ron a Replied:

here's the audio in the room with a jam track and my valve junior di into the PA as outlined about: boogie shuffle i guess.mp3

Aug 24, 2010 12:23 AM GMT
Broke Leg J Replied:

Interesting thread. I'm just starting to consider how I might modify my tone for different genres of music. As Bulldog suggested, I am considering a POD orBehringer V-amp amp modeler. I'm also interested to hear what a guitar amp modeler does for tone variety without changing mics. In any case, don't you guys want to lug an amp along anyway for stage volume / monitor purposes?

Aug 24, 2010 4:24 AM GMT
Maka M Replied:

Amp modellers are really interesting, but the more options an amp modeller provides, the more time it takes to investigate them all. Some program a lot easier than others (like through a computer vs punching codes into the modeller).I took the ‘easy out’.The Digitech RP series offer some pretty neat modelling capabilities.The 350/355 offer a huge amount of capability that would probably take me a lifetime to figure out.So I ‘buy’ the brains of Richard Hunter, who has written hundreds of model variations specifically for harmonica (for $25!).Most are designed for use with a clean mic (Richard H recommends an Audix Fireball V – I use a homemade mic based on the iMic design from Planet Harmonica or an SM58 clone), but he also has some designed to provide effects for ‘dirty’ mics.

I use my iMic, a rat tail DI, an RP350 (eBay second hand) with the RH patch set straight into the PA.That can go from clean to just reverb (pedal controlled!) to dirty Chicago to heavy metal to full psychedelia, just by selecting the correct patch.Lots of options (some of them very strange and quite good fun to scare an audience with), not much weight and not too expensive (compared to a boutique amp anyway).

I’ve got a little 35W Realistic mono PA amp and a 4 x 8” quadbox if I need to provide my own PA and that works fine for a small – medium room.It’s also the ‘house PA’ for parties at home.

Modellers are a very real option, particularly if you want more options than just that dirty Chicago blues sound.


Aug 24, 2010 8:00 PM GMT
ron a Replied:

i have a modeler clip that shows acoustic at the desk here followed by wireless mic into a digitech modeler into the valve junior and twin 12 cab... blues jam track_minor blues jamtrack.mp3

The tone isn't really that much different when i use it into the PA.

Aug 28, 2010 12:51 PM GMT
Broke Leg J Replied:

Thanks for the feedback. I just ordered a Behringer V-Amp 2 on ebay for cheap. I'm hoping this guitar amp modeler will get me some of the same kind of tone from Ron's latest clip.I'll let you know how it works out. I'm hoping to either play it through the PA or through an amp and then into the PA when I need stage volume to hear myself amongst my band mates.

Sep 01, 2010 10:15 PM GMT
Broke Leg J Replied:

I got the Behringer V-Amp 2 and played around with it a VERY little bit. The sound being produced is pretty easy to modify. Not sure yet whether it will produce a good Chicago Blues overdriven tube amp sound, but realize much of that sound is on me. I'll post more as I experiement with the modeler.

Sep 04, 2010 4:20 PM GMT
ron a Replied:

The only thing my modeler doesn't give me is what i call "gravel" or the tone. even with tongue blocking and different double stops , etc, it doesn't add that little "garlgling" sound my tube amp and jt 30 roadhouse give me. The roadhouse into the modeler really sounds good, but there is that extra little crunchy gravelly grit from the tube amp...more so than from a speaker swap, BTW. I have tried an alnico vintage speaker and the added "tone" had too much cone cry in it for me. Regular oem jensen chicago series 12's sound just fine to me. Actually, straight into the PA with the crystal mic/DI is so easy it's hard to beat with a little sacrifice in the gravel. "tone is in the player" is true, to a degree, but it is incorrect to assume ANY tone is available to a player with ANY equipment. ACCEPTABLE, even excellent tone is certainly available with anything, but they don't all sound the same...there would be no gear market if they

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