oscarguitar

I can’t say for certain but I don’t think there is any modelling after the power amp. All the modelling and reverb is done in the pre amp.

Long time since I started this thread! Since then I’ve been gigging the DT25 about 75 times and have built up a pedal board over the years with poly tuner, XP comp, hoof, D&M drive, Black Country Custom TI boost, mini TS in front with chorus, delay, reverb and clean boost in the loop. All true bypass. I have 3x20 ft cable and the guitar cable. After feeling that the amp sounded increasingly like it had a blanket over it, and thinking a Hot Rod Deluxe might be the answer to my problems, I have been reading up about buffers. So far I have switched my reverb (hall of fame) to buffered bypass and added an Emerson Concord buffer as the first box after the guitar. The difference is astonishing! I’m still playing around with the position of the Emerson and may move it to after the hoof, but in terms of attack, dynamics, clarity and tone it’s a revelation. The British Crunch is finally crunchy! I have been able to turn the treble and presence down and lose the ice pick that could dominate my sound making it harsh. The mids are layered with harmonics and the bass tighter and better defined. I did loads of a, b testing and compared with plugging straight into the amp, and I’m convinced it’s better than straight in. (Which is v odd). I think, but have no evidence for this, the the digital preamp in the DT25 needs a ‘full’ signal (100mv?) to work at its best, and even straight in with a 10 ft cable from single coils and a variety of humbuckers the amp wasn’t getting the best signal to do its stuff. Most boss pedals are buffered, their tuners certainly are, so if you are running boss (or Ibanez) you shouldn’t have a problem. But If like me you’ve gone down the true bypass route and you’re suffering from thin muffled tone, try a buffer. It might save you buying a new amp!

Great, just checking. I gig using L6 extension cab and combo, with analogue pedal board which even after 100’s of outings still surprises me just how good it can sound

Which outlets did you have them plugged into?

You can get 8 Amps. 4 on channel A and 4 on channel B using DTEdit

Just swapped the tubes out again on my DT25. 4th set of EH replacements. I gig regularly and I was disappointed with the sound of the amp recently, volume and bass was down, and wondered if a new set of tubes would make a difference. I checked the bais of the old tubes before swapping. 24.9 mV and 34.6 mV. So something was clearly not right. New ones biased to 25mV, gig last night and order is restored. Checked the bias again this morning and made a minor tweak. But the tone is back. That Laney 30BL is gonna have to wait.

I thought I recognised the rubber band!

Don’t change the tubes without biasing. It’s not difficult but you need to have your wits about you as it can be dangerous. If you are unsure take it to a pro. Where did you get your tubes from?

Some DT50 had duff transformers. Do a search on here for details. But it sounds like it’s not a home fix.

Mine did that in rehearsal, new tubes and the tube protection fuse was the cure. Hopefully some for you.

Check the tube protection fuse before you get it checked by a tech. If the tubes go they often take the fuse out. Mine certainly has/ does. It's a weird fuse so be prepared to search around for it. Remember to have it re-biased as well. Otherwise the tube will just go again.

That's the one. Same as DT 25 but I wasn't sure about the DT50.

Try a reset. If the amp was used when you got it, there could be some old settings stored. I'm not sure how to do that on a DT50. And a 50 as a bedroom amp! Unless you blow the doors off you will never hear how good that amp can sound. I Gig regularly with a DT25 combo and extension cab and rarely get it in the sweet spot above 50% master volume. But it sounds stunning when I do.

Oh dear, take cover. Probably need a valve change back to the EH originals and a re-bias. Plenty of threads on here about the subject. The DT 25 will pop when changing to Class A but generally if the valves are good it's a pretty quiet amp.

Does it crackle without anything plugged in? I had similar issue and found out it was a dodgy instrument cable.

I thought he had the head. So no internal speaker just the 112 extension cab 8 ohms and the Marshall cab 8 ohms. So just plug 'em both in the middle pair (B) and play.

Read the back of the amp. It's as easy as A, B, C. If plugging in two 8 ohm speaker cabs use the left hand pair marked A. 1 x 4 ohm or 2 x 8 ohm cabs If a single 8 ohm cab, use one of the middle pair marked B (or two x 16 ohm). If using a single 16 ohm cab, use the right hand single socket. Marked C

Fender Delux Reverb for clean. Works brilliantly with pedals, and the JCM 800 for the rest. But I love the Treadplate, the Soldanos, etc. But for gigging the fender and the JCM seem to cover the bases, and cut through the mix nicely.

Thanks for the advice. I've read everything I can find about the biasing of these amps. Have done it several times now and always check again after a few days. The gig went really well, the amp sounded fantastic and I had some great feedback.

I managed to get a couple of Fuses from Allparts. Fantastic service. Arrived the next day. Replaced the power tubes re-biased and working better than before. Sounds a bit creamier/smoother. I had to turn the bias down a bit as the first reading was 32mV. I know the old tubes were biased at 25mV as I checked them a couple of times since I put them in. The old tubes have been from a 'higher' batch. Fingers crossed for the gig tonight.

Thanks, I'll give him a try first thing tomorrow.

Does anyone know where I can get my hands on a Valve protection fuse in U.K. before Saturday? At rehearsal last night my DT 25 112 died. The valve protection fuse has gone so I suspect the tubes need changing. I have tubes in stock but no fuse. I have a gig on Saturday so I need a fuse in a hurry. No problem I think. Ring Line 6 (E&M Electronics in the U.K.) who will be bound to have some. They pass me on to Sontec Electonics who supply the spares. However I was told this morning that SONTEC ELECTRONICS are not able to deal with my enquiry because the parts manager is on holiday!! I rang again this afternoon and while they do have a parts department they don't keep even fuses in stock and have to order from Germany and can't get any to me before Saturday. I reckon this is pretty poor customer service from Line 6, E&M and Sontec Electronics in particular. The Sontec Electronics website is full of content about customer service and getting you up and running as soon as possible but seems not in this case. A dedicated spares supplier Lee like Sontec Electronics should surely keep some of the more disposable spares in stock otherwise they are just a middle man taking a cut but not holding any stock. I accept I should have anticipated this but after 3 years faultless service it didn't seem necessary. Really very poor all round.

I have the DT25 combo with a DT extension cab. Best of both worlds. Either or both. Small gigs, just the combo, bigger gigs full rig. I also have an anologue pedal board using the 4 cable hook up. (5 if you count the channel switch). Very versatile, change on the fly, no endless tweaking (did that with the Flextone III) and easy to adapt for each venue. Easily loud enough for medium sized (300 pax) pubs if you want to actually hear the music, not just make a lot of noise. If the venue is bigger, hook up to the pa.

I have never biased an amp before, but I've done the DT twice now. It's really not a problem. Very straightforward provided you are sensible and don't rush it. The key seems to be very gentle, small moments of the bias pots.

Thank for the replies, I think I understand how it works now.