DHA

[quote name='wazz' post='150236' date='Mar 3 2008, 11:44 AM']Hi Dave, Just wondering if my amp would have the new Q control and if its going to be front mounted? Cheers Warren[/quote] Yes and yes. Dave

[quote name='karlbbb' post='148353' date='Feb 28 2008, 12:30 PM']I was just wondering if DHA offered customizing options to the VT2 Bass RM? Come summer I'm looking at getting a rack together, and I planned on it being quite a basic rack, with a tuner, pre-amp (hopefully DHA) and a power amp. I was wondering if it was possible to add a switchable output to a tuner, that would also mute the main output, and be switchable from the pedal? How much would this add to the cost? Thanks in advance for any help! Karl[/quote] Hi Karl, It sounds like a good feature so I will add it to the design at no extra cost. Dave

[quote name='Mr. Foxen' post='147681' date='Feb 27 2008, 10:43 AM']I was passing a charity shop, and there was an old valve radio in there. Had a look in the back and it had what looked roughly like a 12AX7 with Mullard written on it. What are the chances of that being a useable valve for my DHA pedal? Will the fact its been used in a radio for ages mean it probably won't be very good, or is the low power use in there going to mean its a good score? Being a charity shop the whole thing was cheaper than a NOS Mullard. Oh, and might it not have actually been an ECC85/12AX7?[/quote] It won't be a 12ax7 and most likely an RF valve, in fact there will be no valves in there which be any use to you. But, why not buy it anyway and use it as a radio, they sound great and are becoming collectors items. I have an old GEC radio I did up and got working. dave

[quote name='stevebasshead' post='147297' date='Feb 26 2008, 03:53 PM']No probs, Dave, it'll only be a minor inconvenience compared to the bonus of having it Just out of interest what's the frequency range that the mid sweep covers? Oh, and what centre frequencies did you decide on for the bass and treble? Regards, Steve.[/quote] Hi Steve, Bass 30Hz, Mid (Q in mid position) 1Khz, Treble 10KHz. There is about a 15-19dB cut and boost at each frequency. It's what called a Baxendall design and considered by many to be the best active eq there is. I have not worked out how much sweep the Q adds yet, but its a fair bit if my ears tell me right. Dave

[quote name='Voodoosnake' post='147192' date='Feb 26 2008, 12:07 PM']If your in the market for a high quality unit, the price become less of an issue. Id most certainly want the blend. I'll be watching this space as I'm looking for an unit like this. Keep posting developments. What sort of timescale are we looking at as I could hold all my GAS for one of the first units. Cheers Col[/quote] Hi Col, I could make some pre-production models now to test the market before going to PCB. Dave

[quote name='OldGit' post='147107' date='Feb 26 2008, 09:35 AM']Dave, May I suggest you put all the knobs on the top. The DHA compressor was hard to use with the i/p knob on the front. It's vunerable there too. Also if it has a battery, use a quick release battery holder such as found in basses. Also how about a rechargable, stock size, battery that recharges itself when the unit is plugged in but which can be replacable with a Duracell if needed.[/quote] Won't have a battery as it's a valve pedal and current drawn would flatten it in no time. Dave

[quote name='stevebasshead' post='147262' date='Feb 26 2008, 02:43 PM']Perfect!![/quote] Hi Steve, I tested the design on your VT5-Bass but there is no room on the front panel for the new Q control as yours is already drilled, marked up and 3/4 wired so I will fit it on the back. The production models will have the Q control under the mid eq pot. Dave

[quote name='Voodoosnake' post='147075' date='Feb 26 2008, 08:15 AM']How about a Blend control? Seems lots of bassist want this in an overdrive. On a pedal of this caliber Im sure it would make a very attractive proposition. Col[/quote] I would only add a valve driven active blend so the price just went up £80. Dave

[quote name='sk8' post='147061' date='Feb 26 2008, 07:17 AM']how about a DI too?[/quote] maybe

I am thinking of doing a new pedal for bass players. Needs a name but something like the DHA VT1-EQ-Drive might work? It's a 3 channel active tone control with Mid Q sweep and valve overdrive. It's a VT1 overdrive with active tone controls really. It will have to go in a larger VT2 box and have i/p pad, gain, level, boost, treble, mid, bass, Q controls and fat, bright and boost switches plus a true by-pass footswitch. Price will be £130-£140 I think. Comments welcome please. Dave

[quote name='DHA' post='139468' date='Feb 13 2008, 01:25 PM']We are now taking orders for the production DHA VTX range of Bass power amps. As many of you know we have been developing these over the last 6 months and we are now happy with the design and going to PCB. The range has 4 models. 1. VTX-Bass - £599+P&P - this is the all valve 4W version with DI and Line out to feed existing power amps, PA and direct recording. 2. VTX-400-Bass - £799+P&P - All valve pre-amp and 4W power stage feeding a Class D 400W Solid State amp. 3. VTX-700-Bass - £999+P&P - All valve pre-amp and 4W power stage feeding a Class D 700W Solid State amp. 4. VTX-400x400-Bass - £1199+P&P - All valve pre-amp and 4W power stage feeding a 2 selectable Class D 400W Solid State amps. Switching options for 2x400W, 1x400W or none. All have the same following specifications, it's just the SS power section that changes. 1. 2U 19" rack mount with silkscreen or DHA custom paint. 2. Three 12ax7 pre-amp valves and one 4W EL90 power valve. 3. Two stage pre-amp, clean and overdrive selectable via front panel or footswitch. 4. Valve driven FX loop with blend. Selectable via front panel or footswitch. 5. Active tone controls with 15dB cut and boost. 6. LED VU meters on input and output. 7. Tuner mute, selectable via front panel or footswitch. 8. i/p pad. 9. Line out with level. 10. DI out with level. 11. Mains operation. 12. Valve drive control (sets valve output distortion) 13. Master level control (sets SS power amp level) 14. SS power stage peak led. 15. SS power amp select switch. 16. Standby and mains on. 17. SS power amp DC speaker protect. 18. Valve stage speaker out jack with 4, 8 and 16R select switch. The valve pre-amp and low wattage power stage with output transformer drives an internal dummy load or speaker cab. The signal at this point is used to drive the DI, line out and the SS power stage so that the tone is not just pre-amp distortion but also valve power amp overdrive. Options include the footswitch at £35 and flightcase or amp sleeve (POA) I will offer any BC member any of the above with free footswitch and amp sleeve as way of a discount. I will also a limited number of these at a discount in return for reviews, endosements, etc. first come first serve. I am interested in your comments on the pricing, options, range, features, etc and how they compare to others out there. Dave[/quote] I have added a new feature to the active tone controls, it's a Q control. It works on the Mid range and allows you to select the frequency at which the Mid control cuts or boosts. You will be able to pick the sweet spot for your bass. This will be standard on the VTX range and the VT2-Pre-amps from now on. Dave

[quote name='Chopthebass' post='145958' date='Feb 24 2008, 12:38 PM']Why is there a switch to select the speaker load being used? I thought this was just on valve amps, not SS. I'm curious as my Mesa Titan V12 has a switch that you engage when going down to 2-ohms. I thought if an amp can handle a 2-ohm load there's no need for a switch. No doubt there is a technical explanation! Thanks[/quote] It is a valve amp and the switch is for the valve amp speaker selection. The SS power stage will work fine at anything down to 4 ohm. dave

[quote name='DHA' post='139468' date='Feb 13 2008, 01:25 PM']We are now taking orders for the production DHA VTX range of Bass power amps. As many of you know we have been developing these over the last 6 months and we are now happy with the design and going to PCB. The range has 4 models. 1. VTX-Bass - £599+P&P - this is the all valve 4W version with DI and Line out to feed existing power amps, PA and direct recording. 2. VTX-400-Bass - £799+P&P - All valve pre-amp and 4W power stage feeding a Class D 400W Solid State amp. 3. VTX-700-Bass - £999+P&P - All valve pre-amp and 4W power stage feeding a Class D 700W Solid State amp. 4. VTX-400x400-Bass - £1199+P&P - All valve pre-amp and 4W power stage feeding a 2 selectable Class D 400W Solid State amps. Switching options for 2x400W, 1x400W or none. All have the same following specifications, it's just the SS power section that changes. 1. 2U 19" rack mount with silkscreen or DHA custom paint. 2. Three 12ax7 pre-amp valves and one 4W EL90 power valve. 3. Two stage pre-amp, clean and overdrive selectable via front panel or footswitch. 4. Valve driven FX loop with blend. Selectable via front panel or footswitch. 5. Active tone controls with 15dB cut and boost. 6. LED VU meters on input and output. 7. Tuner mute, selectable via front panel or footswitch. 8. i/p pad. 9. Line out with level. 10. DI out with level. 11. Mains operation. 12. Valve drive control (sets valve output distortion) 13. Master level control (sets SS power amp level) 14. SS power stage peak led. 15. SS power amp select switch. 16. Standby and mains on. 17. SS power amp DC speaker protect. 18. Valve stage speaker out jack with 4, 8 and 16R select switch. The valve pre-amp and low wattage power stage with output transformer drives an internal dummy load or speaker cab. The signal at this point is used to drive the DI, line out and the SS power stage so that the tone is not just pre-amp distortion but also valve power amp overdrive. Options include the footswitch at £35 and flightcase or amp sleeve (POA) I will offer any BC member any of the above with free footswitch and amp sleeve as way of a discount. I will also a limited number of these at a discount in return for reviews, endosements, etc. first come first serve. I am interested in your comments on the pricing, options, range, features, etc and how they compare to others out there. Dave[/quote] I have ordered the first batch of 5 PCBs for this, they should be here next week. As already stated I will let this first pre-production run go a little cheaper, 3 have already been ordered so that's 2 left. Dave

[quote name='otis_spunkmeyer' post='136593' date='Feb 8 2008, 02:40 PM']I just thought I'd reseerect this topic by adding a little review of this amp: Construction: This amp feels very solid and well put together. It’s not just the fact it’s in a metal casing but the overall feel of the various knobs and switches which do not feel at all loose in the way that many cheap products do. Add to this the fact that this is meant to be rack mounted and the level of protection should be enough for even the most active gaggers. Ease of use: There’s no manual for this as of yet but I believe Dave is in the process of writing one and he emailed me when the amp was shipped with a nice guide to getting started. Overall it’s fairly simple to get the amp up and running- you just need to work out which direction is on or off for the various switches (it’s generally up) as they are not labelled. However, once you get used to it I particularly like the fact that the start up sequence is more reminiscent of a pilot starting up a plain than a muso firing up his amp. The only complicated thing about this amp is the way in which the various features interact with each other. For example the distortion switch that flips between Si Ge and off, has a noticeable affect on the volume depending on which you choose as does the fat boost. This is not a big problem as these are not designed to be switched on the fly, but it does mean you find yourself having to tinker with the levels a lot more when trying out a new sound. Features: The amp has all the basics you need to get a vintage tone. Usefully it features a bendable valve driven fx loop which allows you to control the ratio of wet to dry signals. I haven’t personally used this too much as yet, but it’s a really good idea and seemed to work well even when I tested it using a borrowed cheapo mutlifx. There is also a built in compressor, however as meantioned in other reviews this proved far too noisy to be of much use. It might be possible to get a usable sound from it by cutting levels elsewhere such as the gain and eq sections, but the way I have tended to set up the amp makes using the compressor a big no no. Sound: Definitely the best part of this amp is the sound. I haven’t yet succeeded in getting an entirely clean sound out of it, but then if that’s the tone you want you’ll probably be better off with a solid state amp anyways. Nonetheless, the sounds you can get out of the amp are extremely versatile; it does every form of distortion you’re likely to use except for hi gain fuzz. However for these sounds its probably bets to use some form of pedal and on a similar note I have to say the amp does sound very nice when I run my Tech 21 XXL in front. As you would effect from an (almost) all valve amp the sound is pretty vintage. I’m no expert on the all valve sounds of ampeg etc but to my ears it definitely sounds much more like an all valve than a hybrid amp. Even it you can tell the difference when using the solid state power amp, keep in mind that this probably won’t show through in a live context and in the studio you can use the 3 watt output and have an all valve sound anyway. My version also has the new valve driven eq circuit. Apparently the previous passive design didn’t have much effect on the tone. I’m happy to report that I found the current system very usable. Although its all variations on a theme it was certainly possible to tweak my sound to add a bit more bass and treble when I needed to (the amp naturally has a very clear mids which is a definite plus when sitting in the mix). Overall impression: I’ve had this amp for just over a month now and its definitely not going anywhere soon. I’m still getting used to the whole valve thing, having previously only owned a trace hybrid amp. I still love my trace but currently find myself torn between its ultra clean solid state sound and the warmth of the DHA, but I guess that sums up the debate between valve and solid state which has been raging in the bass world for many years. I would definitely recommend at least trying this amp out to anyone looking to break into the valve amp route. Lets not forget that for an all valve jobby this amp is actually at the budget end of the price bracket- not bad for something which sounds amazing and is built like a nuclear submarine![/quote] Thanks for the review. The production versions of this amp are now available and I have changed a few things on them after the comments from the first few owners. The gain and overdrive switching has changed, same tone and drive but the new design makes it easier to dial in a cleaner tone. The production version has an switchable overdrive channel instead of the 1+2. The DI and Line out signals now both have level controls. The compressor is removed. There are different power stage options available. Dave

[quote name='Machines' post='139497' date='Feb 13 2008, 01:59 PM']I'd love to do a review for you Dave, the VTX-400 would probably suit me best. I'm not in a buying position at the moment but it would be a bit of an insight for people who are. Let me know if you're interested. Matt[/quote] I am going to build one as a demo version which I shall offer to the bass magazines first. Might be something we could let out to the BC bashes and a few select members. Dave

[quote name='clauster' post='139502' date='Feb 13 2008, 02:03 PM']Am I missing something or is the compressor not there anymore?[/quote] Compressor is removed. It just didn't work out in the chain when at higher gains plus the front panel is fully loaded with other bits and bobs and it brings the price down. Dave

We are now taking orders for the production DHA VTX range of Bass power amps. As many of you know we have been developing these over the last 6 months and we are now happy with the design and going to PCB. The range has 4 models. 1. VTX-Bass - £599+P&P - this is the all valve 4W version with DI and Line out to feed existing power amps, PA and direct recording. 2. VTX-400-Bass - £799+P&P - All valve pre-amp and 4W power stage feeding a Class D 400W Solid State amp. 3. VTX-700-Bass - £999+P&P - All valve pre-amp and 4W power stage feeding a Class D 700W Solid State amp. 4. VTX-400x400-Bass - £1199+P&P - All valve pre-amp and 4W power stage feeding a 2 selectable Class D 400W Solid State amps. Switching options for 2x400W, 1x400W or none. All have the same following specifications, it's just the SS power section that changes. 1. 2U 19" rack mount with silkscreen or DHA custom paint. 2. Three 12ax7 pre-amp valves and one 4W EL90 power valve. 3. Two stage pre-amp, clean and overdrive selectable via front panel or footswitch. 4. Valve driven FX loop with blend. Selectable via front panel or footswitch. 5. Active tone controls with 15dB cut and boost. 6. LED VU meters on input and output. 7. Tuner mute, selectable via front panel or footswitch. 8. i/p pad. 9. Line out with level. 10. DI out with level. 11. Mains operation. 12. Valve drive control (sets valve output distortion) 13. Master level control (sets SS power amp level) 14. SS power stage peak led. 15. SS power amp select switch. 16. Standby and mains on. 17. SS power amp DC speaker protect. 18. Valve stage speaker out jack with 4, 8 and 16R select switch. The valve pre-amp and low wattage power stage with output transformer drives an internal dummy load or speaker cab. The signal at this point is used to drive the DI, line out and the SS power stage so that the tone is not just pre-amp distortion but also valve power amp overdrive. Options include the footswitch at £35 and flightcase or amp sleeve (POA) I will offer any BC member any of the above with free footswitch and amp sleeve as way of a discount. I will also a limited number of these at a discount in return for reviews, endosements, etc. first come first serve. I am interested in your comments on the pricing, options, range, features, etc and how they compare to others out there. Dave

[quote name='sk8' post='138244' date='Feb 11 2008, 03:59 PM']is there much of a difference powering it with 9 instead of 12 volts?[/quote] Yes, there is less output at 9V and the tone is a little thinner. dave

[quote name='presoulnation' post='138126' date='Feb 11 2008, 01:03 PM']I have just bought one of the slightly older SVT3 heads from a very pleasant young chappy on this forum. Now on receiving said amp, I plugged it in to find that it was VERY quiet. Having the volume and gain on half and the eq volume on pretty much full gave me sufficient volume to play along to a cd. Now I have since discovered that the cab is a 4ohm jobby which is even more alarming because that should mean I am louder?! Also the tube gain knob makes some rather odd crackly noises when turning it and when i turn it right down the sound actually cuts out altogether for a brief second then comes back. I don't want to have to send the amp back but I aint so keen on the idea of having an amp that I have forked out for which needs lots of repairs so if anyone can give me any idea what it could be that would be great =) The chap I purchased from informs me the tubes are all in working order......[/quote] It could many different things that would cause that problem. But, the tube gain knob would explain a lot if it is not working correctly, try pushing and pulling it. It will need replacing anyway but that little test might help make sure you change the correct bit. It could be a valve problem but even if you change them then it will need to be re-biased anyway by a techie. Dave

[quote name='Buzz' post='137366' date='Feb 9 2008, 11:02 PM']Ask DHA (check the other sub-forums) He might be able to source a bigger power section for his new amps, granted they're hybrid, but it's a more valvey hybrid.[/quote] Hi, There are a few ways to do this. We do a VTX-400-Bass that has a valve pre-amp and low wattage valve power section to generate the real valve pre-amp and output distortion of an all valve amp. We then feed the signal taken after the valve power section as it drives a dummy load into a 420W Class D solid state power section. So the super clean SS amp just amplifies the valve sound a bit like a PA. We have plans for a 750W version of the above which will be called the VTX-750-Bass. Or, we do a VTX-Bass which is the above but without the SS power section, I am working on one of these for a BC member now. The output signal once again taken after the valve output transformer is supplied as DI and line for feeding an external power amp. I hope that helps. Dave

[quote name='shesmyrushmore' post='134987' date='Feb 6 2008, 01:40 PM']Hello, I've posted this topic in the technical section of the forum but not had much help. Basically, I have a Ampeg SVT 3 Pro head and i've lost the fuse/fuseholder out of the back of it. I've been trying everywhere I know in England for the replacement parts but no one seems to want to help as they will only be making about £1 out of sourcing the parts for me haha. I've found this page... [url="http://www.tubeampparts.com/Merchant2/merchant.mv?Screen=CTGY&Store_Code=A&Category_Code=FH"]http://www.tubeampparts.com/Merchant2/merc...ategory_Code=FH[/url] I don't know which, if any of those parts will fit my head. Also, what type of fuse would I be looking for to replace the old one. Thanks in advance for any help you can offer![/quote] Try my mate Barry at [url="http://www.torresamps.com/"]http://www.torresamps.com/[/url] tell him I sent you. He has lots of old bits and might have the very thing. Dave

[quote name='shesmyrushmore' post='134987' date='Feb 6 2008, 01:40 PM']Hello, I've posted this topic in the technical section of the forum but not had much help. Basically, I have a Ampeg SVT 3 Pro head and i've lost the fuse/fuseholder out of the back of it. I've been trying everywhere I know in England for the replacement parts but no one seems to want to help as they will only be making about £1 out of sourcing the parts for me haha. I've found this page... [url="http://www.tubeampparts.com/Merchant2/merchant.mv?Screen=CTGY&Store_Code=A&Category_Code=FH"]http://www.tubeampparts.com/Merchant2/merc...ategory_Code=FH[/url] I don't know which, if any of those parts will fit my head. Also, what type of fuse would I be looking for to replace the old one. Thanks in advance for any help you can offer![/quote] Could be that you may have to swap to another make of Fuse holder if you can't find it anywhere. Did you contact Ampeg UK? Dave

[quote name='sk8' post='134932' date='Feb 6 2008, 12:19 PM']so could i say have channel 1 set for tube warmth fo rthe amp and use channel 2 to get my distortion?[/quote] yes, spot on Dave

[quote name='BassBalls' post='134671' date='Feb 5 2008, 09:38 PM']Have you used an active bass with this peal, if so how does it sound?[/quote] The trick is to have an input pad which all my bass effects and amps have. Dave

[quote name='GremlinAndy' post='134782' date='Feb 6 2008, 01:26 AM']Thats an interseting concept mate, and one which I may well need to know more about (in practical terms) once my coffers are high again. It sounds like it might be just the ticket. Thanks[/quote] The first few are out there now and reviews have and will be posted by the owners. I am just about to press the button on the PCB version which will mean we can make them a lot quicker. Dave