MYSTERY?... NO!
Hi,
'Course not. How could it? But the xformer pulled it of though.
Mind you, choosing either one of the proposed outputs didn't change the sonic result much on my 90dB+ speakers...
Odd enough I prefered the capcoupled output...go figure.
There should be plenty of EL86s floating around....I buy mine from Halfin in Belgium.
It's simple enough, Einsteinian if you like...
I should have the full schematic on one the HDDs, I'll post it asap.
Cheers,
Hi,
'Course not. How could it? But the xformer pulled it of though.
Mind you, choosing either one of the proposed outputs didn't change the sonic result much on my 90dB+ speakers...
Odd enough I prefered the capcoupled output...go figure.
There should be plenty of EL86s floating around....I buy mine from Halfin in Belgium.
It's simple enough, Einsteinian if you like...
I should have the full schematic on one the HDDs, I'll post it asap.
Cheers,
Going off at a slight tangent
That reminds me !
I have a pair of 7mH double c-core chokes that have 0.1 ohm DCR , rated at 5A . Do you think these will be a good cathode load for 3 x parallel SE 6C33 a side running at 1A ? I was thinking zero feedback , OTL , OCL with the 6C33 running fixed bias at 40w dissipation per valve . Surely with a choke with such low DCR I can lose the output coupling cap as the DC offset will be very low ? I hate large coupling caps , especially electrolytics : they sound AWFUL! . Chokes may be a bit low in value for full range usage in this application though . Or am I completely wrong ? 
316a
That reminds me !
I have a pair of 7mH double c-core chokes that have 0.1 ohm DCR , rated at 5A . Do you think these will be a good cathode load for 3 x parallel SE 6C33 a side running at 1A ? I was thinking zero feedback , OTL , OCL with the 6C33 running fixed bias at 40w dissipation per valve . Surely with a choke with such low DCR I can lose the output coupling cap as the DC offset will be very low ? I hate large coupling caps , especially electrolytics : they sound AWFUL! . Chokes may be a bit low in value for full range usage in this application though . Or am I completely wrong ? 316a
But 316a's point is that with only 100mV offset, it might not be worth worrying about it.fdegrove said:Hi,
I thought as much...
And if you are going to use a bipolar supply for the CF you may have a chance of nulling DC at the cathode.
I haven't seen it done before but it may be worth looking into.
Cheers,
Cheers,
Of course there is not an AC powered amp in existance that does not have a power supply in series with the load (by whatever circuiticious route).fdegrove said:Hi,
Yes.*
Now show us how smart you really are and find us an OTL that has NO caps in the signal path.
Just kidding Tim, but I think you see my point?
*Only for designers designing for the fun of it...
Hit me with a rithm stick...
In fact I can deliver on one without a cap in the signal path:
On one of Steve Bench's pages, there is a cap-less amp, and that includes the power supply!
Here's the power supply:
An externally hosted image should be here but it was not working when we last tested it.
Cheers,
Hi,
Sure. 100mV into an 8 Ohm load would only slightly pull the woofer out of center position.
No big deal, give it your best shot.
You can always capcouple the output initially, monitor it for a while and once you're confident enough you can bypass it.
The only trouble that could potentially arise is at start up so, careful.
Cheers,
Sure. 100mV into an 8 Ohm load would only slightly pull the woofer out of center position.
No big deal, give it your best shot.
You can always capcouple the output initially, monitor it for a while and once you're confident enough you can bypass it.
The only trouble that could potentially arise is at start up so, careful.
Cheers,
hmmm.......
Capcouple the output , pah !!! Saying that I do have 200 LCR 10uF motor runs to parallel up I may just build this amp for fun Fullrange or not . I'm guessing here but say for instance the choke is rated at 7Mh at 5A : surely I would have more inductance available if running far less current through the thingies ? Methinks with the DC offset , it would be best to take the speaker connections from directly from across the choke to minimise the offset instead of 0V and cathode . I have some B&W DM12 as test speakers , these have cap coupling even to the bass driver , probably ideal for testing this type of thing 
316a
Capcouple the output , pah !!! Saying that I do have 200 LCR 10uF motor runs to parallel up
I may just build this amp for fun Fullrange or not . I'm guessing here but say for instance the choke is rated at 7Mh at 5A : surely I would have more inductance available if running far less current through the thingies ? Methinks with the DC offset , it would be best to take the speaker connections from directly from across the choke to minimise the offset instead of 0V and cathode . I have some B&W DM12 as test speakers , these have cap coupling even to the bass driver , probably ideal for testing this type of thing 316a
Hi,
Hey, burn away all those sucker B&W speakies you like...just don't pin it on us.
OTLS can deliver mucho amps so I would'nt bet my speakers x-overs' caps to stop it from biting right through it.
On a more serious note, draw up some diagram and I may be able to point to some caveats...
Cheers,
Hey, burn away all those sucker B&W speakies you like...just don't pin it on us.
OTLS can deliver mucho amps so I would'nt bet my speakers x-overs' caps to stop it from biting right through it.
On a more serious note, draw up some diagram and I may be able to point to some caveats...
Cheers,
Hallo,
can you please attach photo and dimensions for Ad3800AM in OB configuration and also a schema for triode connection you used?
Thank you
Bye
The transental 1.5w se otl amp schematic was posted here a couple of years ago.
It used 2 cascoded triode stages for voltage amplification, 4 6c19pi tubes in parallel with a choke load for the output. Most of the bias voltage was supplied from a -12v bias supply. But it sure looks like the amp might have been inspired by this old design that used parallel 6as7's .
A few years ago another seotl amp was offered from ARG Audio Labs it was rated at 3.5W and only used 2 tubes a 6ch6 ? and a 6c33c-b. I think
they went out of business. Fikus Lampizator says he will post the schematic one of these days when he has time .....
It used 2 cascoded triode stages for voltage amplification, 4 6c19pi tubes in parallel with a choke load for the output. Most of the bias voltage was supplied from a -12v bias supply. But it sure looks like the amp might have been inspired by this old design that used parallel 6as7's .
A few years ago another seotl amp was offered from ARG Audio Labs it was rated at 3.5W and only used 2 tubes a 6ch6 ? and a 6c33c-b. I think
they went out of business. Fikus Lampizator says he will post the schematic one of these days when he has time .....
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