DHA

[quote name='BassKS' post='429798' date='Mar 9 2009, 08:37 PM']Hi Dave, I bought a bass purist mk1 from someone in this forum and cant wait to get it. I was also thinking, instead of buying a sansamp, id get your bass drive/eq vt-1 jobbie. Now, combined with the purist, will one be able to achieve the crazy stuff that your dual valve does? od, distortion through to fuzz and all things in between? Or have I missed something very fundamental and some circuitry boffin is laughing in his sleeve.[/quote] Yes, using a VT1 to drive another VT1 will be great. In fact a VT2 is really two VT1's in the same box.

[quote name='Leowasright' post='420965' date='Feb 27 2009, 02:52 PM']Dave, I made the repairs this morning, replacing the big caps. I have to say that when turning it on after the work, it was so quiet I thought it had totally died! New caps has eliminated virtually all of the noise in the circuits. It sounds like it always did, but with less backround noise than it ever had. Tight, bell like, but a different bell to say a Hiwatt. Oh, and bass is good as well! There is clearly still some valve microphony going on in the preamps, but I will address this by replacing them all (6L6s as well) after I come back from 1 week of holiday. I think job nearly done. Many Thanks for the advice thus far. NB, Do you know of someone that fixes valve amps around Southampton? I used to get Mick in MM music to do it, but they have long since sold the shop and retired. I suppose I ought to get the bias looked at once new valves are in. David Hare[/quote] Hi David, Good news. Sorry I don't know anyone that repairs amps near Southampton and yes you must get the bias checked if you change valves. Dave

[quote name='Leowasright' post='417821' date='Feb 23 2009, 08:36 PM']I must say it is getting better as it recovers (drys out) from it's garage storage. I am currently waiting for the replacement big caps to arrive. Ta, David H[/quote] Keep us posted on progress please.

[quote name='silverfoxnik' post='412623' date='Feb 18 2009, 12:20 AM']Hi Dave Just bought this pedal of yours from aphook and I have to say it's absolutely brilliant! Cheers Nik[/quote] Nice one, have fun. Dave

[quote name='TenLetters' post='410618' date='Feb 15 2009, 11:38 PM']I have an old style Hartke HA3500 which has been well used for a good 6-7 years with no trouble at all. I have owned it for 5 of those but knew the previous owner and there were never any problems untill recently.... Basically when i turn the amp on everything powers up fine but the output is barely audible and sounds farty. Turning up the master has little to no effect on the volume of the 'noise'. If I give the head a good bang it seems to work fine for the rest of the day even after being turned off and on again. It seems to happen after being left for a while unplayed which at the moment is quite often as i dont use it as my main practice amp. I assume from this that it is some kind of loose solder or something but really dont have the minerals to go snooping around when electronics really are not my thing. I change the tube in the pre-amp not so long ago and that didnt do a great deal not that i really expected it too. I dont really want to go on banging my amp every time I have a rehersal that requires it as im sure thats not going to do it a lot of good in the long run. Any ideas or advice/ things for me to check would be much appreciated. Cheers, Adam[/quote] Hi Adam, Yes I would say it's a dry joint. Find a techie near you as it should not cost that much to fix. Dave

[quote name='Leowasright' post='406327' date='Feb 11 2009, 02:26 PM']DH, I tried it (Bassman) this morning again, and it was better behaved, though still noisy. The plan to let it dry out may be working. When you talk about the caps, one assumes you mean the big mains supply ones under the pressed cover on the outside of the chassis. These must be original, they are brown cardboard covered ones, and look like nothing I've seen made in the last 20 years. I don't think it's a hard job to renew them. The other plan is to change the valves. The preamp ones are possibly the ones in it when I got it in 1987. I don't know if the 6L6s in there have ever been changed, but the driver valve has changed in the last 15 years, there is a "Groove Tube" in there. Apart from that, get the damp out......[/quote] Yes I mean the big ones but they may just get better the longer the amp is left on. The problem with elect caps is they don't store well and stop being elect caps and turn into standard ones, but sometimes they turn back. I would leave the amp on with the volume turned down for a day or two and see if it gets better. I would swap and rebais the valves anyway. Dave

[quote name='Leowasright' post='404376' date='Feb 9 2009, 03:25 PM']The Hartke question was just out of interest, really, and one wonders if they bothered to spec two different PSUs. As for the Fender Bassman, I have to say that the paper-fibre tag boards were not the shape I remember the last time I saw inside it 20 years ago. My friend, who has had custody of it for the last 15 years, has stored it in a garage next to a working tumble dryer for the last 10 years....I think it has got damp. I tried it at home, and it makes an alarming humming boom, the power valves glow blue and get hot. But it does just make a sound when an instrument is plugged in. I think I'll have to dry it out before trying again. Ta.[/quote] Glowing blue output tubes is fine, is red plates that is not. Sounds like the power supply caps are shot and drying it out is a good idea. There are kits to replace the boards from people like my mate Barry at Torries. Let us know how you get on.

[quote name='Leowasright' post='402202' date='Feb 6 2009, 05:40 PM']Now, I have just nailed a Hartke HA3500 at a price well below the hikes filtering through at the minute. I'm more than sure it'll be loud enough anyway, but the rush in which I hit the buy it now button eliminated any consideration of the HA5500. I suspect that the 3500 and 5500 probably share a common PCB. That means I reckon that the only probable real difference is the number of MOSFET power transistors in the output section of the amp. Anybody out there able to confirm my thoughts, or even actually done such a mod to their amp? Apart from that, I'm also picking up from an old friend my Fender Bassman 100 head I bought 21 years ago, and sold to him 15 years ago for £70. I'm buying it back for £100(!) Only thing is, it's a bit sick, lots of noise when used. Resistors in preamp section?[/quote] It's going to need a power supply modification as well. The bassman problem could be a number of things. A common problem with older Fenders is that if they are stored in a damp place the paper tag broad sucks in water from the air! This means the component values change and then there are problems. If it's not been used for a number of years then a good few of the caps will need changing. sounds like a project to me but one worth doing for such a great amp. Dave

[quote name='babaseen' post='401705' date='Feb 6 2009, 02:42 AM']Looking for a warmer tube tone for my sound and have become interested in the DHA pedals. I'm considering the dual tube as it seems to have more overdrive capability. I was hoping that someone may have experience using the VT2 Dual Bass either as an overdrive pedal into a preamp (Acoustic 360 clone) or as the preamp right into the Bergantino IP112. Thanks for any assistance. Cheers, --Tom[/quote] I make a rack mount version that has a balanced DI and active tone controls which is designed to drive a power amp. The Dual pedal will work as well but you will need to switch the boost on and line out is not balanced. The VT1-EQ-Bass-Drive does have a DI as well as active tone controls but is only a single channel. Lots of guys have used my pedals and rack mounts to drive amps so hopefully someone will also add a comment or two. Dave

[quote name='thedonutman' post='387795' date='Jan 21 2009, 05:46 PM']I have a pair of these, have no idea if they work. Somebody on a different forum pointed out that a few of the capacitors looked leaky. No idea if it's in working condition, but I don't feel like it's a good idea to power it up and see without having a tech look over it. What do you guys think?[/quote] Nice! May be wise to get them checked out and it could be that some caps will need replacing. Most likely the valves will have to be replaced and rebiased anyway which needs to be done by a tech. Dave

[quote name='jkedinburgh' post='384237' date='Jan 18 2009, 06:43 PM']Hi I have a Fender Pro Junior with a US voltage mains transformer, any ideas where could I get a UK transformer for this amp apart from Fender who want more money for the transformer that the amp cost me, it gives a great sound but hums a lot on the step down transformer I'm using? Appreciate the assistance John[/quote] Hi John, Fender maybe your best option as the voltages will have to be 100% correct. You should not have a hum with a step down transformer unless there is no earth, which is very unsafe! Dave

[quote name='Bassmanc' post='376206' date='Jan 10 2009, 03:26 PM']Hi, I'm currently trying to sell a load of equipment, but amongst the list is a Trace Elliot Preamp. It's got damage to 4 of the 11 graphic faders after a guitar fell against it some years back. As the faders all still work (they're just a bit fiddly to adjust) I never got around to the repair. I even ordered replacement faders, but I have no idea where these are now. Assuming that the faders are still an off-the-shelf item, could you give me some idea of the likely cost of a repair without seeing the unit? - It's not going to be worth a great deal even with the faders repaired, but if it's relatively economic to do it I would have it sorted. Many thanks![/quote] You would be much better off getting a quote from a local technie as postage cost alone would write off me doing it. Also I don't have the time anymore for general repair work. Sorry i can't help

[quote name='Pentode' post='375112' date='Jan 9 2009, 01:55 PM']Ooooops... So what gave? [/quote] quicker to reply what didn't! burnt out wiring and resistors.

[quote name='Pentode' post='367469' date='Dec 31 2008, 10:10 PM']Hi Dave, I've got a nice little Ampeg B25 currently running with 6L6GC's - I thought it might be fun to try popping a couple of 6550's in there to see how it sounds.... I'm a bit concerned about the screen voltage being a little high for the 6550 and maybe the heater current a bit heavier on the transformer. Whaddya think? Cheers Grahame [/quote] Just remember an old Fender Twin I had in to repair years ago, the owners dad swapped the 6L6s for KT66's - took forever to repair. dave

[quote name='Pentode' post='367469' date='Dec 31 2008, 10:10 PM']Hi Dave, I've got a nice little Ampeg B25 currently running with 6L6GC's - I thought it might be fun to try popping a couple of 6550's in there to see how it sounds.... I'm a bit concerned about the screen voltage being a little high for the 6550 and maybe the heater current a bit heavier on the transformer. Whaddya think? Cheers Grahame [/quote] It will vary a little betwwen manufactures but a 6550 has a load resistance of about 4K and a 6L6 about 3K8-6K6 in class AB push-pull so if should be okay on that side of things. a re-bais will be a must. 6L6 heater current is 0.9A - 6550 = 1.6A so unless the amp has an overspec'd heater supply then it's not going to work. A KT88 and 6550 are almost the same thing so KT88's will not help. regards Dave

[quote name='ferguswads' post='373211' date='Jan 7 2009, 04:30 PM']I have recently acquired a new 75 Reissue jazz. It came with the pickup covers and I'm thinking of just adding the rear one so my questions is two fold. What difference will it make to the sound? What would you advise is the best way to fit them/get them fitted? Thanks Ferg x[/quote] Hi Freg, you asking the wrong guy, this is a effects, amps and valves forum. regards Dave

[quote name='redzombie' post='373069' date='Jan 7 2009, 02:10 PM']I'm seriously close to picking one of these up. What I'm looking for is an overdrive pedal, that wont lose any bottom end, or add or take any other frequencies for that matter. Basically, something that will be totally transparent and not colour my tone, apart from the glorious amounts of overdrive that are being added. Think the flat voicing of a Barber LTD SR, this is what I'm after, but with some real tubey goodness. Does the VT1 Std Bass fit this description? EDIT: Nevermind, I should find out for myself soon enough, won one 2nd hand on eBay last night [/quote] let us know how you get on. Dave

[quote name='Pentode' post='367469' date='Dec 31 2008, 10:10 PM']Hi Dave, I've got a nice little Ampeg B25 currently running with 6L6GC's - I thought it might be fun to try popping a couple of 6550's in there to see how it sounds.... I'm a bit concerned about the screen voltage being a little high for the 6550 and maybe the heater current a bit heavier on the transformer. Whaddya think? Cheers Grahame [/quote] Hi Grahame, I will check the figures and get back to you. I would think it should be fine but I would be more interested in the output transformers load impedance, I think they are near each other but best to check. Dave

[quote name='hatori' post='359579' date='Dec 20 2008, 01:57 PM']Like a fool I sold my Marshall superbass 100 5 years ago and now desperately want another. Prices on Ebay reflect their collectability and are sadly out of my reach. I have read that there is not a great deal of difference between the Superbass and Superlead head. Is this correct and, were I to use a superlead would it damage it in any way? Ive been checking out the Vintage modern 2466 which is more affordable. What do you think?[/quote] The difference between the two amps is one cap which makes the superlead a bit brighter. A superlead will work great for bass. My fav amp BTW. Dave

[quote name='The Burpster' post='349516' date='Dec 9 2008, 11:13 AM']Dave... Sorted it thank you.. The pup has a central blade that can be removed from teh plastic housing. This blade had a sliver of the earth brading from the shielded wire runnig up inside the cavity and sat between teh magnet and blade. This was causing the two parts to rock... So took out both parts of the blade and stuck them together with very thin double sided tape and soldered a piece of copper foil to the shielding and that sits alongide the blade in the cavity now..... Job sorted, two very happy non microphonic humbucking pups now. Thx for putting me on the right track..! [/quote] good news

[quote name='The Burpster' post='341050' date='Nov 30 2008, 12:33 PM']Dave, What is the cause of microphony on single coil pups? can it be rectified? Is it amplifed by a pre-amp (proprtianally) or does it just make the problem louder? Is there a test I can preform to identify if this is the problem as opposed to just very sensitive pick ups....? Help please.... (cant find any tech reading on this!) Bob[/quote] Very good reply from ahpook on this. microphony in valves and pick ups is caused by something moving that should not be. Not sure how to test a pick up but it might be the same as a valve, just tap it with something wooden, lolly-stick that sort of thing. If you hear the tap via the amp and it rings then all is not well.

We are seeing a big increase in sales at the moment and it will only be a matter of days now before we can no longer commit to deliver some pedals before Xmas. So, not pushing for more sales but if anyone was after anything from us before Xmas then don't hang about. Some pedals are easier to build than others so please check delivery with us first. Dave

[quote name='karlbbb' post='330932' date='Nov 17 2008, 07:27 PM']D'oh! Yes it is! I blame the lack of food... I'm just thinking in terms of getting a bigger rig together, and was hoping to be able to just buy a power amp (Behringer/Peavey) and get a 410 cab etc, and run straight from the DHA to a power amp.[/quote] The DI is designed to drive a power amp but the normal instrument out will as well but you may need to have the boost on. Dave

[quote name='agoulding' post='324984' date='Nov 8 2008, 08:40 PM']is there any soundclips for the vt1-std?[/quote] There are a few been posted on this forum in the past plus on our websites - www.davehallamps.co.uk and www.davehallampsusa.com - Worth looking at the VT2 soundclips when it's in channel 1 only mode as it's the same thing. Dave