chrishlp

Hi,

There is a lot of misinformation in this thread. The HD master volume now works with the DT25 to allow you to adjust your overall HD preset volumes to match unity with the DT preAmp volume. This is useful if you are using your recording presets which need to be lowered as a group to match the DT preamp volume. Best way to set this up is to choose 1 on the DT and adjust the HD master volume on the same amp sim to get unity between the two preamps. Driving the DT harder will increase tube saturation to the rectifier tube but this has some serious headroom so you probably won't see a lot of benefit doing this as you will simply have to turn the DT master down to get the desired output volume, loosing both power tube and speaker distortion.

the DT master volume, and only this control, determines how hard you drive the DT power amp stage (assuming you have unity gain between the HD and DT preamp stages). The resistor forming the DT master volume controls current draw from the power transformer which drives the speaker, not voltage, which remains largely constant.

As to Carl's custom attenuator, forget it, this has no effect on the power amp stage as it only affects the preamp volume. It is a useful tool on Fender and Peavey amps where it is hard to set the master volumes as these use linear not log pots. the DT uses a log pot taper so is capable of fine tuning the volumes itself.

If you can't run the DT at high enough volumes to drive the power amp tubes, then your best option (which is very effective) is to use full amp models to simulate power amp saturation. If you are at very low volumes then using the studio preamp sim at the end of your HD patch chain, is a good way to rebalance those lost low and high frequencies.

Hi Innovine,

You have some serious scientific experiments planned, so would love to know the results!

The basis for my view ties in with your comments on input gain.  My understanding is that the DT Master Volume attenuates gain to the Phase Inverter valve not the Power Valves.  Driving the PI valve delivers part fo the classic 'power amp' tone along with speaker distortion (see this link - http://www.guitaramplifierblueprinting.com/files/Phaseinverter.pdf ).  If the input signal is too low to drive the PI valve then the power amp will not compress/distort, nore will the speaker.

Crank the DT MV but then feed a low input signal to it will give you a poor signal to noise ratio increasing the sense of noise in the heard sound (interestingly I just did this on my DT25 and biy the amp has a really good S/N ratio, a lot better than some other serious $$ amps out there!).

The headroom issue is simple.  Provided you are not clipping your preamp stage, then maximum MV should always give you more headroom on a clean tone and more dynamics.

HI,

If you want your DT to sound like a Marshal stack then you you have to model the input from the cab to get the sound you are looking for, otherwise it would be a JCM800 through a 1x12 cab!! 

Line 6 has been smart in allowing us to add the effect of cab/mic selection to our tones, I think this is why they have a custom speakerin their DT25 combo which offers a fairly neutral response.  Best way is not to think of cab.mic solection not in the physical sense but to listern to the impact they have on your tone. 

TONE RULE No.1 - WHAT SOUNDS RIGHT, IS RIGHT!

PS 

Tthe only 'active' preamp control on the DT when connected to a POD HD is the reverb!  Not sure why, and I think LIne 6 need to update the DT firmware to mute this when a POD HD is connected via the L6 Link.

Think about the signal chain.  A power amp will only respond to the signal fed to it.  Low signal means low power amp output/distortion, high signal means high output/distortion.   Anyone who has fed a high gain signal into a mixing desk will know that the desk will distort if the signal is too high regardless of the output gain setting, a tube amp behaves in a similar way only the valve/tube distortion is more desirable/musical.

If you want playing dynamics, then keep the DT master volume up and contol overall volume using the POD HD channel volume as the POD HD Master Volume is constant where as the channel volume can be adjusted per patch to achieve a common gain.  This will allow you to drive the preamp stage without being constrained by the DT Master Volume setting.  This is what the guys are hearing.

Hi,

set the master volume on the POD HD as high as you can, this will deliver the maximum input signal to the DT and, along with your channnel volume, will allow you to drive both the PI and the power amp valves. 

Cranking the DT master volume allows for more headroom (only really required on clean tones) but if your preamp (POD) input volume is low then you will not see any real benefit from this but may experience increased noise and hum (typical wen you turn the master volume on any amp to 11!).

If you are useing the DT at low to medium volumes (not driving the power amp tubes) the use full POD amp models and set the amp sim Master Volume, Sag, Resonance, Thump, Bias and the preamp drive to get the tone yo want (Preamp drive vs power amp compression) This is a very powerful tool in the POD/DT setup and can give you a a wide range of different tones

Enjoy

Try the gibson EH-185.  It runs Class A so tends to be responsive.  I run full model sims from my HD500 and adjust the sim drive and master volume to get the right balance between preamp drive and power amp saturation.  Have a play around with the sag control as well.  Goes great with a strat!

Spend the money on the 500 it will be a lot more expensive to findout you needed it later on.  It also works better as a recording platform.

Hi,

I use a DT25 in the house and am very pleased with its tone and dynamic feel.  I tehnd to run full amp sims with full power (not LVM) as I think this give a more valve/tube feels. 

I've found that adjustign the amp sim master volume and gain on the POD allows me to get any tone I want, with the Tweed and 185 tones being my favourate for low gain/crunch tones with plenty of feel.

The DT25/POD HD combo is really powerfull but it does require some time to get the sound just right depending on how high your DT25 master volume is set.  However it is well worth the effort!

Thanks MartinDorr,

There is a lot of info in the FAQ and the various manuals, I had to read them all before I started t understand how the amp works.  I am currently playing around with using the POD HD amp model master volume (not the POD MV) to get different tones and dynamics.  I'm finding this a really good way of matching the amp sim to my different guitars.

With all respect, have a look at the Line 6 software for the FBV. It is definately MIDI and the manual talks about using it as a MIDI controller for various software packages.

If so that is a shame, Line 6 should provide a contoller for the DT amps especially now you can have the 8 preset tones.

You can get USB to MIDI cables and the edit sotware runs on MIDI control CC parameters, are you 100% certain it does not work??

Hi,

Anyone used the FVB Express Mkii pedal as a MIDI controller to change between channels A/B and select Voicings on the DT25/50?

Looking at the manual, this should work using a USB to MIDI cable and the LIne 6 FVB edit software.

Chrislp

Hi edstar1960,

There is no need (or ability) to rebias the 12AX7 tube, so you only have to replace the tube.  Make sure your amp has been off for some time (I did mine in the morning after the amp had been off all night and the power tuned off at the mains). Make sure you don't touch anything other than the tube. 

Remove the stock and insert the new tube using a clean soft cloth so you don't get finger marks on the glass. 

Hope this helps.

Hi, I replaced the Chinese 12AX7 phase inverter valve with a Tung-Sol Reissue unit selected for the PI location from HotRox (uk).  The PI valve is often overlooked, but plays a key role in setting the tone and dynamic response of the power amp tubes.  

What I found was interesting; 

1. the hum I was getting from the amp (not out of the speaker) largely went

2. Bass response was tighter 

3. High response was smoother and less brittle

Overall a very worthwhile upgrade which has improved the musicality of the amp as well as dealing with the hum.

Hi, I recently swapped out the 12AX7 in my DT25 on the basis that it was the 'weakest link' in the 3 valves.  As this is a phase inverter I spoke to HotRox Valves (uk) about what might be the best replacement and they recommended the TungSol Reissue valve, which has an option to select a valve for the PI position. 

After installing the new valve the most immediate benefit was that the amp hum I was getting (not speaker but amp) disappeared.  As to the impact on tone?  The bottom end tightened up, the tope end smoothed out, the dynamics increased and the overdrive sounded more natural.  These changes (except for the hum) were subtle rather than extreme which means the stock Chinese valve is not too bad; however the TunSol is a worthwhile upgrade.

As to changing the power valves, I'll think about this at some stage but for now I'm enjoying the DT25/HD500 combo as is!

Hi, had the same happen to me with my HD500 and had to reload the latest firmware.  Seems OK not, not sure what is going on but suggests problem with Monkey.

Guys, are you talking about the HD master volume or the amp model master volume?

I've recently have been using the amp master volume on full amp sims and low volume to get greater headroom and dynamics out of the DT tube power stage.

Hi,  I got this from the DT50/DT25 Knowledge Base FAQ on the lIne 6 site.  I've reporduced it below, hope this helps. Have a go at crnking low volume mode with the same model setting and it is still very loud, there is no power amp in the DT25 so it is using the tubes. 

Q: How does the modeling of the DT50/DT25 contribute to the overall tone?
A: In the DT50/DT25's "normal mode", the modeling performs the function of the preamp: mating the digital preamp with the analog power amp so the whole system creates the sound of the amp modeled. This is different than our previous Spider Valve amps, where we modelled the entire amp model (pre-amp and power amp) and then fed that signal through the output tube power section.

In "low power mode" (pulling the master volume switch out on the DT50 or on the DT25 flipping the switch on the back panel), the digital modeling section will assume duties for the power amp section and the Master Volume has been scaled so that you can have the sound of a driven power amp at lower monitoring volume levels. If you turn the master volume knob all the way up in this mode, you will have Spider Valve-like tones behavior (where the pre and power amp software modeling signal is pushing the EL34 or EL84 tubes).

In both Normal and Low Power modes, cabinet modeling is applied to the output signal fed to the power tubes. When using a POD HD device connected via L6 Link, you must use the default cabinet model that is recalled on the POD HD 'pre' amp model when using the L6 Link connection with the DT amp to get the same type of sound as using the DT amplifier by itself with the same amp model.

Lastly, when using Low Volume Mode on the DT amp with a POD HD connected via L6 Link, the sound of a 'Pre' amp model selected on the POD preset will sound slightly different if an identical amp model is selected on the DT amplifier (on Channel B ). This is because when using the Low Volume Mode on the DT amp with L6 Link, Channel A on the DT amp with the POD modeling is still using the just the PRE amp model with the scaled Master Volume knob, whereas Channel B on the DT amp uses the preamp AND power amp modeling with the scaled Master Volume. The inclusion of the power modeling is what makes it sound differently. You therefore are better off using full amp models at low volumes and it does not matter if you are using Normal or LVM as in both the power valves are not working hard enough to get real power amp distortion and sag as well as speaker distortion.

Not sure where Line 6 is going with this????

An all plastic case (it looks like) means it won't be as sturdy as a Spider amp; however 75/150 watts is not a home practice amp!

Add to this the use of X3 modelling and it is not aimed at the higher market.

I'll have a go of one out of curiosity but would not swap my DT25/HD500 at the moment.

The LVM still uses the tube power amp stage but with a reconfigured volume taper. It does not reduce the overall volume of the amp.

Use LVM when plugged direct into your DT and it uses full amp modelling. Use LVM with a POD HD connected and you will need to use the full amp modelling (not preamp) to get the right tone. If you then crank the DT master volume you will add Power amp distortion to modelled power amp distortion.

A lot of users seem to get confused by the DT amps, treating them as if they are solidstate amps where the level of distortion is set by the gain pot and the mater volume only adjusts overall volume. The DT should be treated as a true valve amp where overall distortion is determined by a combination of preamp and power amp gain.

To pick the right model (pure/full) you need to think about how the digital amp model will work with the real valve power amp in the DT25. At low volumes the pre combined with the DT power stage lacks the power amp distortion and compression. This is not a problem on clean tones but is not going to work for crunch and distorted tones, you are better off using the full amp models in these cases.

As you increase the master volume on the DT you reach a point where the valve power section is working hard and producing the distortion you need. At this point you are better off using the pure amp model.

At volumes in between low and high, you can use the full amp model but reduce the HD amp master volume to reduce the modelled power amp distortion.

What this does mean is that if you are using your POD HD / DT for both gigging then you will probably need two sets of patches. the only way around this is to ditch the DT and go for a Stage line or the new amplifier.

Hi Melissiah,

I don't think taking one tube out is a good idea, you may cause damage to your amp and that would be an expensive repair! 

Further more, if you read the Line 6 Connectivity Guide it tells you that for Class A/B it uses both tubes, so as a minimum you won't be able to use that topology.

If you are trying to get low volume power amp sag and distortion, then use the Low Volume setting and edit the parameters.  If you are linking a POD HD, then you have the option to use either normal power or Low Volume with a full amp model, the only difference will be a different response to the Master Volume.

Have fun!

Hi,  I've experienced similar differences where the gain from the HD500 preamps is not the same as you get from the DT25.  I've used the 4 cable method to link the HD500 to other amp and the same thing happens.  I think there is a difference in the hardware preamps between the HD and DT sereis.  One option is to add a Studio EQ (flat EQ/increased gain) or Vetta Juice (low compression/increased gain) to the front of your HD preamp patch and use this to achieve the same gain response with you plug direct into the DT. 

Hi, I recently got a Blackstar ID60 1x12 combo for use as home.  I was looking for an amp to run my HD500 though for those times when I can let it rip!  The ID60 tones are really good and the MIDI input allows you to use the POD HD500 as a patch selector.  I tried the 4 cable method (5 cables if you include MIDI) but the ID60 lost some of its dynamic response when the giutar was plugged into the HD500, so a reverted to plugging my guitar direct into the amp.

I also tried running the ID60 Emulated Ouptut back into the POD and using the speaker sims to improve the tone through my headphones and when recording.

After  a week of playing around with the ID60  I decided to take it back and changed it for a Line 6 DT25.  Why?

1. The background noise levels were too high for close playing at low volumes.  Fine for live gigging but when you are sitting 2 to 3 ft away from the amp you hear everything!

2. The output signal from the Emulated Output is really low.  Even with the gain and channel volume at full I still had to add about 30dB gain from a mixer to bring the signal to unit gain.  This just added noise to the signal. 

3. Getting equal volume between patched was not easy especially if you want to use the channel volume to get  power amp daming and sag as Blackstar suggest. 

Those are the main negatives on the ID60; however there are a lot of positives to using the DT25 and HD500 combo.  These being: 

a. Broader amp tone options

b. reduced noise on amp and through HD500 for headphones and recording

c. Balancng patch volumes is easier.

d.  Using full HD amp models with cab off, allows you to warm the tone up using the sag, bias, resonance and thump controls whilst at low vonlumes (IMO a better solution to using the DT25 low volume switch).

e.  pick dynamics are maintained. 

f. The full HD500 suite of comp, boost, vol, wah, distortion, O/D modules can be used so no need to buy additonal pedals.

IMO the DT25 may be several £100 more than the ID60 but that is money well spent if like me you already have an HD500.