DHA

[quote name='danlea' post='259558' date='Aug 10 2008, 09:41 PM']Hey fellas, I've attached a schematic I've drawn up for a hot-rodded p-bass. It's a Fender Japan with a Seymour Duncan SPB-2 (hot precision) and I'm getting it routed to add a STK-J2 (hot stack jazz) at the bridge, making it rather like the backup Squire Precision Special I've loaded with the same (only the jazz is single coil). Anyway, I'll get to the point. I never dial down the precision, so that doesn't need an individual control, but I do need a volume control for the jazz and want a master volume for fading in and out where necessary. I almost always have the tone control fully in, occasionally dialling it down either half-way (once in a while) or completely (once in a blue moon). I plan on sticking in a mini-switch for this, and as they only have on-off-on toggles in Maplins (£2, just up the road from me) and I'd rather not order a more expensive three-way on-on-on switch from the internet and have to pay postage, I've implemented a slightly round-about way of controlling the treble leakage. Switch centred (off) is no cut (~250k), down is moderate cut (~23k) and up is proper dub. Aside from this, it's exactly as the recommended Seymour Duncan wiring, [i]except[/i] for the lack of a pot, or even a dedicated resistor for the p pickup since the pickup is already loaded with both the Jazz and master volume pots I figure another would only serve to cut the output further - in fact I'm considering changing the pots to 500k for this reason, but Seymour Duncan don't say anything about using higher values for any of their bass pickups, or for any configuration. Ok, enough from me. Any thoughts? Dan.[/quote] Hi Dan, I am not sure that your circuit diagram is correct? If you explain in words what each switch position does and how then I may understand. Dave

[quote name='Sean.Robinson' post='257574' date='Aug 7 2008, 08:51 PM']Hi, i fixed the prior issues with the amp head, changed the switch and the fuse (which i had to import from america (a cooper bussman gma-2.5a)) and the amp was working perfect all yesterday, the sound was amazing. This said i came to turn it on this morning and nothing. The mains switch lights up, but non of the other lights come on, the tubes do not light up and absolutely no sound is being outputted from the amp not even a slight amount of noise. I have no idea what could be wrong and any help would be much appreciated[/quote] Could be anything but if the valves are not getting warm then there is no heater supply. Check if there is a heater supply fuse. After that I am not willing to help as the risk of killing yourself if high, even after the amp is switched off the voltages remain inside. You must get a techie invloved. If I remember correctly you applied 240V when it was set to 110V? If so all the voltages inside would have been twice what they should for a while and this may have taken out a few components which have now stopped working after time. My guess would be the power transformer, as I say get a techie involved. Dave

[quote name='Sean.Robinson' post='254159' date='Aug 4 2008, 09:50 AM']Hi, the fuses from maplin dont provide the voltage drop info and while some other quick blow glass fuses do, the ones that do provide the info dont provide the required voltage drop, so i have just chose to import the fuse from america now. As for the switch the front had melted a little when i got it and it ended up giving me an electric shock so it has to be replaced, however the fast-on connectors that are attached to it are ridiculously tight and i cant seem to pull them off to replace the switch Thanks[/quote] I would suggest you take it to a tech as it's mains you are playing with. If you are getting shocks then DO NOT SWITCH IT ON UNTIL IT IS CHECKED OUT - you can DIE! Dave

[quote name='Sean.Robinson' post='253899' date='Aug 3 2008, 08:12 PM']Hi, continuing with my VT-.40 I'm going to change the fuse and half it in rating. To do this the ideal fuse would be a Cooper Bussman GMA-2.5A with the following spec from the Cooper Bussman website: Unfortunately unless ordering in bulk (100+) obtaining one of these seems near impossible so can anyone point me in the direction of either an identical fuse but from a different manufacturer or someone in the UK selling the fuse in single units. Also i'm looking to change the front switch which just seems to be a simple rocker switch, my question however with regards to this is how do i disconnect the cables from the existing switch is it a matter of just pulling them really hard or is there a trick to it, or does it require some tool, this can be seen a little in the picture below: Thank you in advance for any help[/quote] I am sure Maplin will have a fuse that will do the job. The connectors on the mains switch will just pull off but why change it? Dave

[quote name='warwickhunt' post='250663' date='Jul 29 2008, 06:06 PM']Unfortunately Geordies only come in one size... large [/quote] I'am a Geordie!, right about the size.

[quote name='BassManKev' post='244984' date='Jul 22 2008, 12:55 AM']BUMP haha! in my knowledge of DHA bass valvetones, any pedal that doesnt have switch for fat, has it hard wired[/quote] Correct!

[quote name='Maxcat' post='244977' date='Jul 22 2008, 12:46 AM']Dave can I presume that the VT2 has the fat hard wired as well?[/quote] It depends on the model. It's either hardwired or switchable but never not there at all. Dave

[quote name='jhk' post='244627' date='Jul 21 2008, 05:49 PM']Is there a simple test for relative non experts to find out whether the horn in a peavey 4X10 tvx bass cab is not working or the attenuator?pot does not work,resulting in same thing. I don`t want to replace the wrong piece is the real crux of the matter. I have a small circuit tester ............ will that be of any use? all answers welcome![/quote] Put a 9V PP3 battery across the terminals of the speaker or horn, if it moves and or makes a noise then it's most likely okay. Dave

[quote name='BassManKev' post='242503' date='Jul 18 2008, 11:01 AM']no idea about di's tbh i have a cable which is xlr one end 3.5mm jack the other, so i just connect di out of the dha to the line in of my laptop. despite this as i say its not noisy so whether its missin the point of di or not it does the job for me [/quote] If it's a mono jack at one end then it's not a balanced i/p. It's still DI but there is no noise reduction circuit being used. If you get into PC recording in a big way then you might want to look at external soundcards designed for the job. The difference in sound quality is huge. Dave

[quote name='BassManKev' post='242267' date='Jul 17 2008, 11:30 PM']agree with pretty much all that is said here however i have never found the DI to be noisy, recording wise anyways, its been great glad your clearly enjoying it as much as i am![/quote] Hi Kev, The DI is a balanced XLR type and requires the connection at the other end to also be a balanced DI. Most PC soundcards are not balanced and hence there will be noise. Not sure how you are doing the recording but please check it is a balanced i/p as even if it's an XLR connector it may not be. The way balanced DI's work is that two signals plus a ground are sent to the desk. One signal is the main one and feeds the non-inverting op-amp input on the desk, the other signal is subject to the same conditions and hence the same induced noise as the main signal but it is fed into the inverting i/p of the op-amp which will mean the noise is cancelled. To save money some desks and soundcard manufactures just use one side of the op-amp which means that there is no gain in terms of noise reduction. Dave

[quote name='mr.sibs' post='242273' date='Jul 17 2008, 11:41 PM']yeah i think it was caused by a noisy power supply further back in the chain, and ive since had better results, yeah its a great pedal for sure[/quote] Thanks for the review, I hope the review in next months BassPlayer mag is as good On the DI subject it might be that the some of the noise is coming from the overdrive part of the circuit as it is a valve after all. Try the bass into the pedal and the DI into the desk but switch the effect into by-pass. Any noise you get then will be down to the DI, desk and cables. It is also important to get the DI levels correct, I found that the i/p level on the desk was very important to the noise level and setting it around the middle (0dB) and then adjusting the DI level on the pedal so that there was not an overload gave the best results. As you also say any noise generated in the chain before the pedal will all add up. Dave

[quote name='bassbonehead' post='236240' date='Jul 10 2008, 01:24 AM']Hello, Looking for some help with PA setup. I'm new to this so haven't a clue. We have 2 peavey 800x power amps. One powers some bose speakers, the other powers a bose bass bin. We also have a 16ch mixing desk. Problem is speakers work fine, but we are getting next to no sound through through the bass bin. (signal is there) The bass bin is plugged directly into the peavey with a DI and an audio jack. Both amps have been checked and work fine. Any help greatly appreciated [/quote] Is the bass bin active? I ask as you say there is a DI connector. If it is active it means that it has a built in power amp and will not need the Peavey to drive it just a line feed from the desk. If it has a mains power connector then it's active. Dave

[quote name='Silent Fly' post='234446' date='Jul 7 2008, 07:59 PM']Hi Dave/DHA, Do you have anynews about these pedals? Silent Fly[/quote] Hi, Didn't get much of a response so will most likely stick with the VT1-EQ-Bass-Drive design and add the headphone amp and maybe the stereo line in/out when it goes to PCB. I might use the same PCB without the valve drive part as a lower cost SS EQ/DI with headphones at a later date. Dave

[quote name='Silent Fly' post='230825' date='Jul 1 2008, 07:45 PM']It sounds interesting. I assume that by "3 channel active EQ" you actually mean "3 band active EQ" unless I am wrong and the pedal has 3 separate channels with EQ for each one (which would be very cool). I would have liked a mini-jack stereo input to play along mp3 players but I could live without it. With a simple DI, you are in the same territory of other DIs that cost around the same money. I think that to be interesting it has to sound exceptionally well (which I am sure it will be the case).[/quote] Yes, sorry 3 band. I will have a look at the iPod input but as that is a new design I don't want to commit until I have tried it. Dave

[quote name='rayfw' post='230658' date='Jul 1 2008, 04:38 PM']The EBS is >£200[/quote] But I guess that is nearer my VT1-EQ-Bass-Drive in spec anyway which is now £149.99. Once this goes to PCB it will also have a headphone amp. So a DHA-EQ/DI will have 3 channel active EQ with mid range Q, balanced XLR DI and 1/4" jack line out, 1/4" jack in, DI level, i/p pad, output level, toggle switch to by-pass the eq, 9-12VDC connector, Stereo headphone jack with level, DI ground lift, bright switch, tuner mute footswitch and 1/4" tuner jack. Could have a PP3 battery but not sure how long it will last due to the headphone amp. No phantom power as it will require a fair amount of current and most desks will not supply it. Cost will be £75 + P&P A DHA-DI will have a balanced XLR DI and 1/4" in and out, DI level, phantom power and switch, PP3 battery and 9-12VDC power connector. Cost will be £45 + P&P What you think? Dave

[quote name='dannybuoy' post='230600' date='Jul 1 2008, 03:09 PM']Dave, what do you have to say on the matter of active vs. passive DIs in the chain I was talking about above? I thought I would be best off with a passive DI like the Radial JDI or ProDI.[/quote] My design is active but I do have a design for a transformer passive DI as well but I have not built one yet.

[quote name='dannybuoy' post='230562' date='Jul 1 2008, 02:24 PM']I'm looking at DIs at the moment; I intend to get a VT Bass as an amp modeller going into some kind of stereo modulation and was looking at the Radial ProD2 passive stereo DI box. A headphone amp would also be very useful in this kind of setup, so I'm watching to see what you come up with![/quote] Looking for a home for the prototype if you are interested? Dave

[quote name='johnnylager' post='230563' date='Jul 1 2008, 02:26 PM']And the price! [/quote] How much is the ebs?

[quote name='Mr Cougar' post='230351' date='Jul 1 2008, 10:33 AM']Thanks Clauster dude, your search-fu is strong. It seems from general reviews that the one tone you struggle to get out of the DHA amps is the Hi-fi ultra clear tone you get from a solid state; would you say this is a fair assesment Dave? Since this is a tone I do need to use I'm not sure if I'd be better off looking at something else with maybe one of DHAs switchable pre-amps to augment the sound and get the valvey goodness.[/quote] I have been looking at making the valve power stage switchable by it's fair to say the tone is still very valvey given the pre-amp is valve as well. The is a VTX-Bass version which is a valve pre-amp with a 2-3W power stage so you still get the output valve tone as well. It's really a VTX-400 or VTX-700 without the power stage. Or we do valve pre-amps without the valve power stage. You could use these as switchable pre-amps with a super clean power amp. Dave

[quote name='clauster' post='230324' date='Jul 1 2008, 09:55 AM']Well this was fifth in the list - [url="http://basschat.co.uk/index.php?showtopic=6172&hl=DHA+400"]http://basschat.co.uk/index.php?showtopic=...&hl=DHA+400[/url][/quote] There are a couple of reviews in that thread but please bare in mind they are early prototype models. We have made improvements after talking to the first few owners and we are upgrading their amps in return. The production models are now hitting the streets and the first VTX-700-Bass is in the final stages of production. I am still offering a discount on the first five production models sold, 3 sold so 2 left at the old price in return for reviews, etc. Dave

[quote name='Silent Fly' post='230031' date='Jun 30 2008, 08:44 PM']I was thinking to something slightly different: solid state and transformerless. Nothing against valves but I think DHA production has enough products valve-based. What do you think about our ideas so far DHA?[/quote] It's a SS design I have in mind. If you want valves and a DI then buy the VT1-EQ-Bass-Drive. Dave

[quote name='BassBod' post='229177' date='Jun 29 2008, 06:52 PM']I'm always keen to try any new or different DI/EQ. I currently use an LR Baggs or Orchid DI(for upright) and Sansamp/Aguilar DB924 depending on the gig. They all sound different. I've yet to track down a Demeter or Sadowsky. On functions, I think the Sadowsky is ahead of the pack (EQ bypass, tuner send and mute..so useful) but it really comes down to a musical eq and a great sounding DI output. Running on phantom power is a nice touch, but I understand it has limitations (limited current?). I sometimes only use a DI (no amp) and I can see this happening more often, as PA's get better and transport get harder, so the more options the better. BB[/quote] Useful info. Can do phantom power as there is no valve to power and the tuner mute is a good idea. Thanks Dave

As our VT1-EQ-Bass-Drive is really a VT1-Std-Bass with an EQ and a DI on the end of it I was thinking I could offer just the EQ and DI in a seperate pedal for those who already have a VT1 or VT2? Or for those that want just an uncoloured EQ/DI. It will be a solid state pedal so will have a battery and 9V connector and in a small box. There will be a 3 channel active EQ with a mid frequency Q, an i/p pad, level and DI Level. The DI will be a balanced XLR with a ground lift switch. There will be an in and out 1/4" jack as well. Could add a by-pass switch as well if people think it's required? Might also do just an Eq and just a DI if it make sense. Target prices would be EQ/DI £55 - EQ £45 and DI £35. Could add a headphone amp as well as an option for an extra £15? What you think? Dave DHA

[quote name='BassManKev' post='228428' date='Jun 28 2008, 09:03 AM']after a bit more experimenting this morning, the hum cant be heard with the odb-3, and the hum is REALLY pronounced in the headphones compared to the amp, i turned up the amp to max output (gigging volume) and it wasnt that loud at all, but thru headphones its about half as loud as the bass. pretty much cant be heard out the amp at bedroom volume. annoying as hell.[/quote] Sounds like you have just found the "noise floor". All amps and pedals have some noise at very low level and the more you have the more it adds up. Putting some effects in a loop will help.

[quote name='BassManKev' post='227608' date='Jun 26 2008, 09:00 PM']ye id like to give JJs a go, as well as a cheap sovtek valve 12ax7wb, they both interest me, tis indeed fun![/quote] Sovtek is EH. EH purchased the old Sovtek site 2 years back. Fender, Mesa, Marshall and few others are rebranded Sovtek. So you already tried a Sovtek! The 12ax7EH is a high gain version of the 12ax7WB. Don't bother with any valves from China, they are rubbish. Try looking for NOS Siemans, RCA, GEC, Brimmer, Mullards, Mazda, etc. and you can't go wrong. Also 12at7, 12au7, ECC81, ECC82 work very well with less gain but great tone. Dave