Hi Matt , adjusted the Bias and the amp sounds great but it's just not that loud . Got a 50W transistor amp that's louder than the 100W tube so somethings going wrong somewhere , convinced it's something to do with that first gain stage!!
As regards to the build quality of the hammond it's really good and am quite impressed with it. Getting about 440V rectified out of it which drops to about 410-15 when the tubes warm up. This is a bit more than it should be when you work out the values on paper. So there is some extra oomph in them.
Jim
As regards to the build quality of the hammond it's really good and am quite impressed with it. Getting about 440V rectified out of it which drops to about 410-15 when the tubes warm up. This is a bit more than it should be when you work out the values on paper. So there is some extra oomph in them.
Jim
Hello Jim,
Ok. I usually work backwards from output to input when designing or fault finding.
If you stick a signal in at the phase splitter/driver whats it like?
Also dont forget that all your voltages have changed so you may need to recalculate all the resistors in each stage.
Cheers Matt.
Ok. I usually work backwards from output to input when designing or fault finding.
If you stick a signal in at the phase splitter/driver whats it like?
Also dont forget that all your voltages have changed so you may need to recalculate all the resistors in each stage.
Cheers Matt.
Regarding the 50W amp that "sounds louder" . . . sometimes the perception of being "loud" has more to do with the onset of distortion than the actual sound pressure level. The higher power amp may not sound as loud because it may not be distorting as much. Try observing and comparing the amplitude of your output waveforms on a scope, just prior to the onset of clipping. Even if you don't do the math, it will allow you to view which has greater output while simultaneously making your subjective assessment.
Hello Glassguy,
Spot on, I have been wondering if the whole loudness issue is just a distortion thing (which I guess Jim wants) . The transistor amp is probably well into class B at this level and sounding harsh, hence the "loudness".
Jim, how far into Wales are you? Im only just over the border. We should hook up. I can bring my scope, signal gene. and a dummy load, plus probably a load of bits and bobs and see if we can get it sorted. Mail me off the forum and we can arange to meet, maybe have a couple of pints aswell.
Cheers Matt.
Spot on, I have been wondering if the whole loudness issue is just a distortion thing (which I guess Jim wants) . The transistor amp is probably well into class B at this level and sounding harsh, hence the "loudness".
Jim, how far into Wales are you? Im only just over the border. We should hook up. I can bring my scope, signal gene. and a dummy load, plus probably a load of bits and bobs and see if we can get it sorted. Mail me off the forum and we can arange to meet, maybe have a couple of pints aswell.
Cheers Matt.
Hi Matt , sorry I haven't been posting for a while had to go away with work.
I think I sorted the problem with my amp Basically I've done 2 things , I've taken off the 22uf cap I had on the cathode. This has dropped the gain and the bass in the amp. Also I've used the graphic eq on the pod to cut certain bass frequencies. The amp now sounds great and loud.
What I think basically was happening is that the POD is very bass heavy sending a signal into an already bassy amp. This was just trying to amplify pure bass and too much of it and woofing at high volumes. By cutting all this back the mids and the highs are comming through loud with enough acceptable bass.
I've only tried the amp out in my house so will be taking it to band practice to see if its going to be loud enough.
Thanks for your kind offer of help Matt. I'll let you know how it goes at band practice next week. But I think I've nailed it!!
cheers
Jim
I think I sorted the problem with my amp Basically I've done 2 things , I've taken off the 22uf cap I had on the cathode. This has dropped the gain and the bass in the amp. Also I've used the graphic eq on the pod to cut certain bass frequencies. The amp now sounds great and loud.
What I think basically was happening is that the POD is very bass heavy sending a signal into an already bassy amp. This was just trying to amplify pure bass and too much of it and woofing at high volumes. By cutting all this back the mids and the highs are comming through loud with enough acceptable bass.
I've only tried the amp out in my house so will be taking it to band practice to see if its going to be loud enough.
Thanks for your kind offer of help Matt. I'll let you know how it goes at band practice next week. But I think I've nailed it!!
cheers
Jim
Let me know how it goes.Hi all tried the amp out last night in practice and it sounds great and is loud enough , but just!! I'm still going to have a play around with the first pre amp section to see if I can get some more volume. I can get more volume by turning the POD up but then the sound overdistorts. If I can up the gain slightly on that first section hopefully i can get some more volume without over distorting the sound.
Thanks for all your help everyone
appreciated
James
Thanks for all your help everyone
appreciated
James
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