Leowasright Posted February 6, 2009 Share Posted February 6, 2009 (edited) 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? Edited February 11, 2009 by Leowasright Quote Link to comment Share on other sites More sharing options...
Mottlefeeder Posted February 6, 2009 Share Posted February 6, 2009 [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] Putting more MOSFETS on the output will increase the current an amplifier can produce, which would possibly enable you to use an extra cab, if the power supply could supply the extra current. To get more power into an 8 ohm load, you have to have more voltage to drive the extra current around, so one of the main differences between the 3500 and the 5500 will be the internal supply voltage to the amplifiers. A retrofit upgrade to the power supply to provide say 10% more volts is unlikely to be a realistic proposition. Quote Link to comment Share on other sites More sharing options...
DHA Posted February 7, 2009 Share Posted February 7, 2009 [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 Link to comment Share on other sites More sharing options...
Leowasright Posted February 9, 2009 Author Share Posted February 9, 2009 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 Link to comment Share on other sites More sharing options...
DHA Posted February 10, 2009 Share Posted February 10, 2009 (edited) [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. Edited February 10, 2009 by DHA Quote Link to comment Share on other sites More sharing options...
Leowasright Posted February 11, 2009 Author Share Posted February 11, 2009 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 Link to comment Share on other sites More sharing options...
DHA Posted February 14, 2009 Share Posted February 14, 2009 [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 Link to comment Share on other sites More sharing options...
Leowasright Posted February 23, 2009 Author Share Posted February 23, 2009 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 Link to comment Share on other sites More sharing options...
DHA Posted February 25, 2009 Share Posted February 25, 2009 [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 Link to comment Share on other sites More sharing options...
Leowasright Posted February 27, 2009 Author Share Posted February 27, 2009 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 Link to comment Share on other sites More sharing options...
DHA Posted February 27, 2009 Share Posted February 27, 2009 [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 Link to comment Share on other sites More sharing options...
bumnote Posted March 1, 2009 Share Posted March 1, 2009 [quote name='Leowasright' post='420965' date='Feb 27 2009, 02:52 PM']Dave, 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] Try the noizyboys who are christchurch way 01202 490110 07780 605058 i dont know if they can help with a valve amp but we have taken a studiomaster desk and one of our pa amps in the past, and they have been prompt reasonable and professional I dont know anyone reasonable in portsmouth, Steves amps in godalming are good but its a fair way from you. Quote Link to comment Share on other sites More sharing options...
umph Posted March 5, 2009 Share Posted March 5, 2009 [quote name='DHA' post='405011' date='Feb 10 2009, 08:17 AM']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] +1 on barry at torres Quote Link to comment Share on other sites More sharing options...
Leowasright Posted March 17, 2009 Author Share Posted March 17, 2009 I dont know anyone reasonable in portsmouth, Steves amps in godalming are good but its a fair way from you. [/quote] This guy is near my friend who lives near Aldershot, so may be the #1 option. Good news overall, the Bassman now seems to be in a stable condition to now be usable. Better news, I got a 1981 MV Marshall 100 from my friend for £200 as well..... Now to a Hiwatt.... Thanks to Dave Hall. Quote Link to comment Share on other sites More sharing options...
DHA Posted March 18, 2009 Share Posted March 18, 2009 [quote name='Leowasright' post='436904' date='Mar 17 2009, 09:11 AM']I dont know anyone reasonable in portsmouth, Steves amps in godalming are good but its a fair way from you. This guy is near my friend who lives near Aldershot, so may be the #1 option. Good news overall, the Bassman now seems to be in a stable condition to now be usable. Better news, I got a 1981 MV Marshall 100 from my friend for £200 as well..... Now to a Hiwatt.... Thanks to Dave Hall.[/quote] You are welcome Quote Link to comment Share on other sites More sharing options...
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