Andrew, I've been reflecting on the heating of my 300Bs; I think I should go for the full eight modules, just in case. What transformer voltage will I need for 5V output for a 300B?
Ray
DHT Heater using VCCS - PCB or Kit (Possible Group buy)
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Dave the bass
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#288
Kent Massiff update Pt2.
Our-Thomas passed your pair of proto kits onto me to have a play with. I've duly fitted them and played with 1st stage anode current to 'spice' up the drive to the 300B as the hear-through quality of the DC heater supply revealed a lack of tinkle on my amp last week. Last session we used Thomas's mega 300B amp as Test-mule, this time we thought we'd try my Owston 300B amp as the test bed.
Thomas kindly hosted the 2nd sesh again so could we could use the same yummy mega revealing set up and music as last week as a form of control.
This time we used my amp with 'natty' fast changeover clipleads to A/B the AC and DC filament supplies. We also had a few pairs of 300B's between us to compare using BOTH types of heating. Its a lorra lorra testing but the results were repeatable and showed everytime that....... <drum roll> .... suspense.... "Oooooooooooo"'s from the audience.... (etc) ..... that ...... your DC supplies just lets the amp get on with it! We had repeatable Soundstage expansion then contraction when going from DC back to AC. On my amp thatwe all heard at Owster's using a seperate PSU for each stage the effect was obvious each time. Also (and this isn't exactly surprising as we found it last week too) the HF extension ("air"?) was heightened using DC over the AC supply. Detailing was just easier to hear on DC rather than the 'hum-haze' of the AC which I didn't 'get' at Owston but others did hear. It really showed on JM's mad strangled distorted guitar solo in the middle of 'Hurt in you Heart', with AC heaters the solo was just 'there' but on DC heaters itwas a major attention-seeker! I know it sounds odd but thats what we both heard. Maybe MrT can add summat a bit more eloquent, he's posher than me!
I think you've got a winner there MrL. Well done fella. If you can somehow get them to 'do' 2A3 levels of current aswell as 300B's even more so.
Kent Massiff signing off.
R'spek.
Our-Thomas passed your pair of proto kits onto me to have a play with. I've duly fitted them and played with 1st stage anode current to 'spice' up the drive to the 300B as the hear-through quality of the DC heater supply revealed a lack of tinkle on my amp last week. Last session we used Thomas's mega 300B amp as Test-mule, this time we thought we'd try my Owston 300B amp as the test bed.
Thomas kindly hosted the 2nd sesh again so could we could use the same yummy mega revealing set up and music as last week as a form of control.
This time we used my amp with 'natty' fast changeover clipleads to A/B the AC and DC filament supplies. We also had a few pairs of 300B's between us to compare using BOTH types of heating. Its a lorra lorra testing but the results were repeatable and showed everytime that....... <drum roll> .... suspense.... "Oooooooooooo"'s from the audience.... (etc) ..... that ...... your DC supplies just lets the amp get on with it! We had repeatable Soundstage expansion then contraction when going from DC back to AC. On my amp thatwe all heard at Owster's using a seperate PSU for each stage the effect was obvious each time. Also (and this isn't exactly surprising as we found it last week too) the HF extension ("air"?) was heightened using DC over the AC supply. Detailing was just easier to hear on DC rather than the 'hum-haze' of the AC which I didn't 'get' at Owston but others did hear. It really showed on JM's mad strangled distorted guitar solo in the middle of 'Hurt in you Heart', with AC heaters the solo was just 'there' but on DC heaters itwas a major attention-seeker! I know it sounds odd but thats what we both heard. Maybe MrT can add summat a bit more eloquent, he's posher than me!
I think you've got a winner there MrL. Well done fella. If you can somehow get them to 'do' 2A3 levels of current aswell as 300B's even more so.
Kent Massiff signing off.
R'spek.
"The fat bourgeois and his doppelganger"
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IslandPink
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#291
!Maybe MrT can add summat a bit more eloquent, he's posher than me! Smile
+1 Wot he said!
Relative to ac, your dc modules 'sort out' soundstage, voices and instruments like cymbals, in a very good way, and this effect subjectively seems to extend down several octaves too. Excellent work!
T
#292
I really don't care if nobody listens to me.....
http://www.audio-talk.co.uk/phpBB2/view ... 6&start=19
but seriously, If I didn't already have a spare coleman 2A3 supply I would hang out for Andrew's higher current version
No hum rools!
http://www.audio-talk.co.uk/phpBB2/view ... 6&start=19
but seriously, If I didn't already have a spare coleman 2A3 supply I would hang out for Andrew's higher current version
No hum rools!
There's nowhere you can be that isn't where you're meant to be
#293
If its any consolation, I believed you Ed....ed wrote:I really don't care if nobody listens to me.....
http://www.audio-talk.co.uk/phpBB2/view ... 6&start=19
No hum rools!
Analogue, the lost world that lies between 0 and 1.
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Dave the bass
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- Joined: Tue May 22, 2007 4:36 pm
- Location: NW Kent, Darn Sarf innit.
#294
We DO listen!ed wrote:I really don't care if nobody listens to me.....
Its sooooo much easier to hear you now you don't Hum!!!DTB
"The fat bourgeois and his doppelganger"
#295
Thanks Andrew. All the positive feedback is feeding my enthusiasm to try your modules; what plans are there for testing higher current draw?Andrew wrote:Don't worry just yet Ray, let's see how the testing goes at higher currents.
Andrew
I'm planning to get my amp builds finished and tested over the Christmas break so might be able to offer to assist in the new year?
What voltage transformer will be required for 5V >=2.5A output?
Ray
#296
Pa! I fart in your general direction...Pa!Dave the bass wrote:We DO listen!ed wrote:I really don't care if nobody listens to me.....
DTB
hum rools is just like fight club rools...rool 1 of hum rools is..we don't talk about hum
There's nowhere you can be that isn't where you're meant to be
#297
I am reworking the PCB to use a double sided process and to handle the higher current requirements at different voltages, the plan is to make them flexible and cost effective for current draw from 300B up to 2A3 levels (which will help you Ray as you should only need 4 of them not 8 ).All the positive feedback is feeding my enthusiasm to try your modules; what plans are there for testing higher current draw?
I will get these made up by a PCB prototyping shop; the same one Nick uses for small runs. I will then test these at the various voltage and current configurations.
If all goes well I will make an order for the final PCB soon after that.
Andrew
Analogue, the lost world that lies between 0 and 1.
#298
Thanks Andrew, really appreciate your work on these boards...
I've just ordered replacement plugs/sockets for the off-board heater supply connections; six pin connectors to facilitate the max. possible connections in the schematic you sent me.
Ray
I've just ordered replacement plugs/sockets for the off-board heater supply connections; six pin connectors to facilitate the max. possible connections in the schematic you sent me.
Ray
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IslandPink
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#299
This is certainly true, Ed, but maybe the reason I was not so 'Swift'ed wrote:I really don't care if nobody listens to me.....
http://www.audio-talk.co.uk/phpBB2/view ... 6&start=19
but seriously, If I didn't already have a spare coleman 2A3 supply I would hang out for Andrew's higher current version
No hum rools!
to agree with you, is that low hum in itself is not enough . Where we began with these DHT boards, the hum was very low, but the performance in the low bass and the treble was not good . It took us a long while and numerous iterations to everything correct. The 'air' and spacious feel that Dave/Thomas have been appreciating did not appear properly until we used certain types of non-inductive caps in the control loop for the current source. In this respect your Coleman supplies are not as good as they should be - in the treble - though they are as good as anything from the low bass through to the mids.
Definitely low hum will bring out tone from the bass right though the mids though , no question.
"Once you find out ... the Circumstances ; then you can go out"
#300
it was actually meant to be humorous Mark.
although
although
is way way way beyond my hearing or requirement.The 'air' and spacious feel that Dave/Thomas have been appreciating did not appear properly until we used certain types of non-inductive caps in the control loop for the current source.
There's nowhere you can be that isn't where you're meant to be