There must be already 50-75pF of Miller (kept there thanks to the cascode), plus 150pF from TT cable. Extra capacitance additions must mind that residual.
Varying the ohmic load does a lot too. Has been discussed here before but here it is again http://www.tnt-audio.com/sorgenti/load_the_magnets_e.html
Hummmm
... eated up all my diy time in the last ten days. No time to build the Salas shunt regulator V1.2 psu.
Why?
I was still working on replacing a bottleneck in my audio chain: the active crossover.
And I had a longtime project, reported earlier in this thread:
Rod Elliott opamp based crossovers (P09) and two t-amps in two 3-way monoblock enclosures.
And, as I also reported here: hum problems.
So, I removed the t-amps. Working well.
I added the needed power up delay, shorting the outputs to ground.
Hummmmmm.
I tried all different kinds of grounding.
Till I began, to make a drawing of my whole audio chain, including the grounding connections.
This is the block schematics without ground connections. Just draw it by yourself and think about!
Horror, a lot of ground loops! Why dont I have balanced cabling for a long time???
I tried bus grounding through my whole audio chain. No real success. Hum or buzz.
I realized, the main problems are:
- the point to connect the audio chains ground to safety earth
- splitting up the stereo chain into two mono-xover and then going to three stereo amps
O.K.
Different tries showed me, that the central grounding point should sit in the xover, not in the preamp.
I quickly made a MDF enclosure to include both channels xovers in one enclosure, together with one psu. I also added the two delay circuits.
Hum.
This time, I quickly identified the problem as an input loop problem, between the preamp and the xover. Simply disconnected the ground on one channel:
I finally got it.
The enclosure is big enough to replace later the opamp circuit by a fine FET thing...
For me it was urgent to finish ONE project (soon), including enclosure (O.K., MDF is not perfect).
Soon, I can proceed to the V1.2 psu for the phono pre.
And later, one (first) Pass F5 (no MDF), to replace one of the t-amps.
But: next problem will arise: how can I drive 6 channels of F5's to drive my speakers? In winter season, it will be O.K, but in summer?
Franz
... eated up all my diy time in the last ten days. No time to build the Salas shunt regulator V1.2 psu.
Why?
I was still working on replacing a bottleneck in my audio chain: the active crossover.
And I had a longtime project, reported earlier in this thread:
Rod Elliott opamp based crossovers (P09) and two t-amps in two 3-way monoblock enclosures.
And, as I also reported here: hum problems.
So, I removed the t-amps. Working well.
I added the needed power up delay, shorting the outputs to ground.
Hummmmmm.
I tried all different kinds of grounding.
Till I began, to make a drawing of my whole audio chain, including the grounding connections.
This is the block schematics without ground connections. Just draw it by yourself and think about!
An externally hosted image should be here but it was not working when we last tested it.
Horror, a lot of ground loops! Why dont I have balanced cabling for a long time???
I tried bus grounding through my whole audio chain. No real success. Hum or buzz.
I realized, the main problems are:
- the point to connect the audio chains ground to safety earth
- splitting up the stereo chain into two mono-xover and then going to three stereo amps
O.K.
Different tries showed me, that the central grounding point should sit in the xover, not in the preamp.
I quickly made a MDF enclosure to include both channels xovers in one enclosure, together with one psu. I also added the two delay circuits.
Hum.
This time, I quickly identified the problem as an input loop problem, between the preamp and the xover. Simply disconnected the ground on one channel:
I finally got it.
An externally hosted image should be here but it was not working when we last tested it.
The enclosure is big enough to replace later the opamp circuit by a fine FET thing...
For me it was urgent to finish ONE project (soon), including enclosure (O.K., MDF is not perfect).
Soon, I can proceed to the V1.2 psu for the phono pre.
And later, one (first) Pass F5 (no MDF), to replace one of the t-amps.
But: next problem will arise: how can I drive 6 channels of F5's to drive my speakers? In winter season, it will be O.K, but in summer?
Franz
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Riaa upgrade
@Rcruz
The last buy to upgrade RIAA:
0.047uF / 1000VDC Obbligato teflon
@Rcruz
The last buy to upgrade RIAA:
An externally hosted image should be here but it was not working when we last tested it.
0.047uF / 1000VDC Obbligato teflon
@Rcruz
The last buy to upgrade RIAA:
0.047uF / 1000VDC Obbligato teflon
Is that SCR Teflon & tin foil, or just Teflon?
Hi Merlin..... I am looking forward to read your comments on this upgrade
FS: 2 caps silver mica 47nF 500V news 16€00 special offer 8€00 each + paypal + shipping fees
Blue are teflon metallized, now mine foils are in break-in process, it's really a different animal: nothing to compare vs Obbligato polypropypelene aluminium foil, I suppose teflon foil break-in is very similar to BG: initially a lot of difused bass & final break-in dep & tight bass & ultra hig-resolution mids & highs, all film & foil caps as experienced needs a very long break-in process I assume it's due to itself construction, Obbligatos polypropylene aluminium foil the break-in was also very long but the sensations was opposite to teflon foil so without mid-lows & lows & only giving mid-highs & highs extra smooth so was the initial reason that disagree, now are after the break-in sounding vey well but isn't teflon. I chosed Obbligato because are 1000V with very good relation quality-price I bought in Teflon Tin Foil 0.047uF 1000V | Diy HiFi Supply 35$ each the Reliable TFT Capacitors only arrives till 600V.
Do you know RIAA cap 47nF the frecuency range because it seems I hear changes in lows, mids & mids-highs so I suppose affect till 4.000Hz or a little more....
Resuming teflon film & foil is like BG the big difference is the mids & lows without loses highs resolution, nothing like human voice to test the differences between BG & teflon foil & the others lytics & films & foils.
Mine first choice for teflon was copper foil but V-Cap 101.03$ each it's a lot expensive, also are expensive the V-Cap teflon & tin foil 69.28$ each, I don't know Aura teflon from Auricap if are metallized or foil, I suppose are metallized like polypropylenes.
One question for the other RIAA cap will be enough 15nF? V-Cap have teflon tin foil at 58.78 $ each a little bit expensive, Aura have a teflon at 26.92 $ but I don't know if are metallized or foil if are foil will be mine 1st choice.
Do you know RIAA cap 47nF the frecuency range because it seems I hear changes in lows, mids & mids-highs so I suppose affect till 4.000Hz or a little more....
Resuming teflon film & foil is like BG the big difference is the mids & lows without loses highs resolution, nothing like human voice to test the differences between BG & teflon foil & the others lytics & films & foils.
Mine first choice for teflon was copper foil but V-Cap 101.03$ each it's a lot expensive, also are expensive the V-Cap teflon & tin foil 69.28$ each, I don't know Aura teflon from Auricap if are metallized or foil, I suppose are metallized like polypropylenes.
One question for the other RIAA cap will be enough 15nF? V-Cap have teflon tin foil at 58.78 $ each a little bit expensive, Aura have a teflon at 26.92 $ but I don't know if are metallized or foil if are foil will be mine 1st choice.
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Thanks is where are more difference between SM & teflon film & foil.
What about to use 15nF for the other RIAA cap?
I'm looking for a USA surplus teflon & foil caps I will let us know because the price is very good 15$ each 15nF 200V 1% hermetically sealed metal case non-inductive extended foil with glass ends seals, I am waiting an answer about kind of conductor: aluminium, tin, copper, etc.
What about to use 15nF for the other RIAA cap?
I'm looking for a USA surplus teflon & foil caps I will let us know because the price is very good 15$ each 15nF 200V 1% hermetically sealed metal case non-inductive extended foil with glass ends seals, I am waiting an answer about kind of conductor: aluminium, tin, copper, etc.
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Oooopa, ultra-nice
I would like have a friend like Mike to help me drilling stuff.Only one reg & one Tx, sounds rare
?PSU caps: manufacturer, capacitance & voltage value
?
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