Just checked. Hiss at full volum is very low, audible only at the horns. At the listening position you are hard pressed to hear something. of course DCB1 has no gain. Pot is a DACT 10K.
Merlin, transformer is a custom toroidal 310x2 150VA (Don't go lower on VA rating. You can use lower voltage though). Filtering is LCLC and then two Salas HV shunts. Heating with 2 EI 30VA 2x6 transformers and coleman's regulator. For output and anode load LC or LL1660. Haven't decide yet, as I have the anode chokes, but want the lower output impedance of the transformer. Tubes from ebay. Most of the parts are from my previous 12b4a pre.
Regarding 901, I like it very much. Much better than a Denon 103 with wooden body I have. Also from my distant memory compared with Lyra Helicon, Lyra was a little bit more airy but Shelter had more weight.
Merlin, transformer is a custom toroidal 310x2 150VA (Don't go lower on VA rating. You can use lower voltage though). Filtering is LCLC and then two Salas HV shunts. Heating with 2 EI 30VA 2x6 transformers and coleman's regulator. For output and anode load LC or LL1660. Haven't decide yet, as I have the anode chokes, but want the lower output impedance of the transformer. Tubes from ebay. Most of the parts are from my previous 12b4a pre.
Regarding 901, I like it very much. Much better than a Denon 103 with wooden body I have. Also from my distant memory compared with Lyra Helicon, Lyra was a little bit more airy but Shelter had more weight.
Tango are big word & expensive, if you will use SSHV you don't need the choke for B+ & I think that Rod's Colleman filament CCS don't need the choke....BTW for Tango main Tx wich model exactly must be for #26 pre & where you will buy to be cheap?
Tango and cheap do not go together! You could try EILF in Japan.
I was using LL1667 anode chokes and was happy with them.
Even with SSHV you need either a resistor, choke or transformer load.
I was using LL1667 anode chokes and was happy with them.
Even with SSHV you need either a resistor, choke or transformer load.
Tango TC-160-15W (160 H, 15 mA, 1160 ohms) anode choke is just enough. 116USD ea. + shipping at Eilf
O/p xfrms are >50% more expensive. Pw xfrm has to be custom IMO.
O/p xfrms are >50% more expensive. Pw xfrm has to be custom IMO.
@vgeorge
Acoustic Dimension in The Netherlands also have Tango, link: Acoustic-Dimension, high-end audio and components for tube audio
@massimo
Tango choke cost in Acoustic Dimension 155€00 taxes included & not shipping included.
For mains wich Tango I need?
Acoustic Dimension in The Netherlands also have Tango, link: Acoustic-Dimension, high-end audio and components for tube audio
@massimo
Tango choke cost in Acoustic Dimension 155€00 taxes included & not shipping included.
For mains wich Tango I need?
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what Power and gain in the Power amps?
I'd guess that a 10W amplifier will give peaks around 110dB @ 2.5m listening distance.
You could just about manage with a low gain headphone amp capable of driving 8ohm speakers.
What does the output noise measure with the gain set to zero and at maximum? Use an ordinary DMM set to 200.0mVac for reference to what most DIYers have available.
As I said before, I am using DCB1 and F5, so total gain 15dB (My tube pre is undergoing magor reconstruction now). The problem - for a headphone amp - is that I have around 4 ohm below 1kHz in my speakers. As the woofers are wired in parallel. If I wire them in series I get around 16 Ohm, but around 101dB sensitivity. Plan is to make a low watt tube power amp a for next year.
I will measure later when I can and let you know.
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Is it achieving room filling power as a system with the TT and its now total gain structure? How many m2? Do you have a full room pic?
My room is 7,3 x 5,50 m, so around 40 sq m.
Right now I have much more power than I need. I would prefer a ittle more gain on the pre. Not that run out of it with DCB1, but is marginal.
I think I can get away with 2 watts with a SE tube, but with the right output transformer.
Let me take some better pictures later to show you.
Right now I have much more power than I need. I would prefer a ittle more gain on the pre. Not that run out of it with DCB1, but is marginal.
I think I can get away with 2 watts with a SE tube, but with the right output transformer.
Let me take some better pictures later to show you.
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Better a custom wound power xfrm as stated. Secs depends on what you would like to use as rectifier and then CRC, CLC or....
I still have to do some math, but roughly I think about a 5 V/2 A and 190-170-0-170-190/150-200 mA. Then 2 xfrm 6 V/5 A for Rod's regs.
Too much OT..... somebody might write a post starting with a cop icon. 😉
Try to avoid much more line pre and power amp voltage gain especially with tubes in the future IMO. Since you got enough SPL with unity line gain and insensitive F5 already, some possible future excess It will only shorten your volume pot useful rotation area and add hiss from the horns. Maybe some medium gain in the line preamp and a 15-18dB SE low Watt amp. Will wait for pics. Thanks.
That is what I am thinking. With the #26 tube and ll1660 on the output to reduce gain and output impedance, but a little bit more gain than now.
Its not easy to say without knowing the bandwidth of the DVM or the real max voltage that the F5 can do on your 4 Ohm speakers with this system's drive. You can also be measuring mainly a narrow band peak like hum. To take a crude attempt, 105dB/2.83V speakers will do 130dB with 25W (assuming F5's 8 Ohm power spec at least sustainable). 14mV is 0.00005W on 4 Ohm. 2.83V is 2W on 4 Ohm. That is 46dbW lower from your 105dBSPL. 105-46=59. 130dBSPL (your assumed max) - 59dBSPL= 71dBSPL SNR. If F5 does 30-40W on 4 Ohm add the difference. You cover even DMM vinyl spec in any case. Change DCB1's input from phono to shorted, to see how much you can measure also for a check. Should be less if the DVM actually shows something valuable.
Thanks for the explanation!
I think could go lower if I take more care about grounding on the dbc1. It was just a quick project.
I have some shorting plugs to test.
Tomorow I will finish my #26 pre. Rod' s heaters working fine and your regs. Choke anode load. Just to adjust and connect output caps.
Maybe will posy at the 26 thread the results.
Have a wife to take care now....
I think could go lower if I take more care about grounding on the dbc1. It was just a quick project.
I have some shorting plugs to test.
Tomorow I will finish my #26 pre. Rod' s heaters working fine and your regs. Choke anode load. Just to adjust and connect output caps.
Maybe will posy at the 26 thread the results.
Have a wife to take care now....
14mVac is astronomic for ordinary sensitivity speakers.
For speakers with 10 to 15dB more sensitivity, you should be looking for <<1mVac at the power amp terminals with the volume gain at maximum and the pre-amp input shorted.
For speakers with 10 to 15dB more sensitivity, you should be looking for <<1mVac at the power amp terminals with the volume gain at maximum and the pre-amp input shorted.
Preamp inputs were not shorted. This is with the RIAA combined.
At the levels I listen, I am hard pressed to hear any noise. And my room is very silent.
I will try to change the grounding tomorow. This will help.
At the levels I listen, I am hard pressed to hear any noise. And my room is very silent.
I will try to change the grounding tomorow. This will help.