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Old 4th February 2005, 02:14 AM   #101
joe3rp is offline joe3rp  Philippines
diyAudio Member
 
Join Date: Apr 2004
Location: Makati City
Thanks guys for the gain clarification.

But how will paralleling triodes affect the sound? Doesn't Conrad Johnson do a lot of this type of design in their pre-amps?

Anyway my main question was about the replacement of tha passive RIAA component of the ecc83/ecc88 dc phono with the S&B 10k "canned" riaa module that I think Mr. Kuei Yan Wag is familiar with. So is it a simple drop in ?


Joe
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Old 4th February 2005, 08:18 AM   #102
ThorstenL is offline ThorstenL  Germany
Previously: Kuei Yang Wang
 
Join Date: Nov 2002
Konnichiwa,

Quote:
Originally posted by joe3rp
Can I remove the RIAA network in your ecc83/ecc88 circuit and drop in a S&B 10k RIAA Can?
No.

Quote:
Originally posted by joe3rp
Can I parallel triodes in the ecc88 for more gain
No.

Quote:
Originally posted by joe3rp
Can I parallel triodes in the ecc88 for lower ouput impedance?
Yes, but I doubt the neccesity of lowering much more than it is already.

Sayonara
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Old 4th February 2005, 11:55 AM   #103
ThorstenL is offline ThorstenL  Germany
Previously: Kuei Yang Wang
 
Join Date: Nov 2002
Konnichiwa,

Quote:
Originally posted by joe3rp
Anyway my main question was about the replacement of tha passive RIAA component of the ecc83/ecc88 dc phono with the S&B 10k "canned" riaa module that I think Mr. Kuei Yan Wag is familiar with. So is it a simple drop in ?
I have already noted a NO for that, however your post prompted me to write a few short notes of how to approach making a phonostage with the 10K RIAA here:

Designing a Phonostage with the S&B 10K LCR RIAA Module

Sayonara
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Old 5th February 2005, 03:31 AM   #104
Kofi Annan is offline Kofi Annan  United States
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Join Date: Jan 2004
Location: US
I've never quoted myself before, but...

Quote:
I'll have two ground lugs, one for each stage. The grounds of each stage will connect to their respective lugs, but then the each ground lug will be connected together, right?
Sorry, but I need to know about the grounding.

Also, what's your recommendation for wire?

Frugal wire.

Frugal.

Cheap.

Kofi
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Old 5th February 2005, 11:14 AM   #105
ThorstenL is offline ThorstenL  Germany
Previously: Kuei Yang Wang
 
Join Date: Nov 2002
Konnichiwa,

Quote:
Originally posted by Kofi Annan
Sorry, but I need to know about the grounding.
Apply the usual methode. Each stage receives a local "star" ground where the PSU Filtering capacitors and all other current loops drawing current around this stage are returned. So for example the RIAA "ground" is returned to the first stage star ground.

In fact, the best thing to do is to forget anything about "ground" and remember that ground is actually the Signal (return) shared with the Powersupply (return).

Quote:
Originally posted by Kofi Annan
Also, what's your recommendation for wire?
Bare solid fine silver wire, ideally goldplated in ovesized PTFE Sleeving, Litzwire from Nebraska Surplus, Enameled copper wire, in order of preference.

Any of three are quite cheap. Goldplated 0.2mm Silver Wire from wires.co.uk is around 5 for 10m with the PTFE sleeving costing around the same.

Sayonara
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Old 5th February 2005, 04:50 PM   #106
clivetjm is offline clivetjm  United Kingdom
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Join Date: May 2003
Location: UK
My implementation of Kuei Yang Wang's low-cost phono stage is still in it's infancy, the caps will probably improve and I have yet to install my preferred Jupiter's in the output position, at the moment they are in another phono stage.

I'm feeding the phono stage with a "Gyrorbe" SE, OL Encounter, Ortofon KB, TX103 stepups and the phono stage runs into a TX102 TVC. The PS is a based on a WAD PSU-II that is silicon rectified CLCRCRCRC.

I've perfromed a quick comparison of the phonostage with the Cornet2 and WAD Phono-II. All were using NOS tubes, mainly various Mullards.

The ECC83 / 12AX7 based WAD is a very "pleasant" performer but ultimately it's rather laid back. The Cornet2 is a much more upfront, indeed it some respects it presents almost a CD sound, which is not meant as an insult!

Thorsten's phono stage immediately sounds well balanced, possibly due to the ECC83 and ECC88/6922 etc being an excellent match.

The sound is fluid in the mid with no harsh elements, it is certainly more forgiving than the Cornet2. Bass and timing is easily the best of the bunch. There is an ease of presentation coupled with a bouncy sound and fluidity to the music that I reckon over time will mean this will be my 1st choice phono stage out of these 3.

Cheers,

Clive
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Old 7th February 2005, 09:02 PM   #107
clivetjm is offline clivetjm  United Kingdom
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Join Date: May 2003
Location: UK
Having spent a little more time with Thorstens low-cost phono stage I find it gets better the more I listen, it probably is getting better with time.

What I really mean is that the Hagerman Cornet2 is good and initially impressive, whereas Throrsten's unit becomes more impressive over time. My vinyl is sounding so good.....I know this is "value engineered" compared to the LCR circuit but it's damned good. Depth, control, articulation are all very good.

Currently I have CV4004 and CV2493 fitted. I'm surprised it is this good.
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Old 10th February 2005, 08:34 AM   #108
bucurb is offline bucurb  Romania
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Join Date: Sep 2004
Location: Bucharest
Thumbs up Thorsten's low-cost phono stage

Thank you Thorsten for this low-cost phono stage project, it really sounds absolutely great!

More I listen music using this stage; more I like it. It sounds better and better using my old Thorens 160BC, and makes me happy.

I did use 6N1P Russian tube (filament current is about 650 mA), because I don't have 6DJ8, and tube based +B PSU (EL86 as serial regulator, and ECC 83 error amplifier) I already had.

Filaments are feed from separated secondaries of mains transformer, rectified and well filtered just near the mains transformer, and then local (near the tubes) regulated using well known solid state LM7812 (ECC 83) and LM7806 (6N1P).
I feel that it helps making the sound less influenced by mains (5oHz) noise.

I would ask Thorsten opinions about (possible increasing cost) modifications of his marvellous low-cost phono stage:

-Using parallel sections of ECC83 on the input stage;
(Would make this stage less noisy, increasing input capacitance - quite positive fact for MM RIAA stage-, and increasing gm of first tube - positive fact, also);
-Using CCS on both tubes.
(it would make both tubes working with less distortion, amplification made mostly on their internal impendence parallel with the load, all stage will be less influenced by the PSU noise, and +B value could be around 100V, actually being 250V).

Mr. Thorsten I wish to thank you again for this phono project!

Warm regards,

BBB
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Old 10th February 2005, 10:52 AM   #109
ThorstenL is offline ThorstenL  Germany
Previously: Kuei Yang Wang
 
Join Date: Nov 2002
Default Re: Thorsten's low-cost phono stage

Konnichiwa,

Quote:
Originally posted by bucurb
I did use 6N1P Russian tube (filament current is about 650 mA), because I don't have 6DJ8,
That will make the output impedance a little higher, otherwise you'll be fine.

Quote:
Originally posted by bucurb
I would ask Thorsten opinions about (possible increasing cost) modifications of his marvellous low-cost phono stage:

-Using parallel sections of ECC83 on the input stage;
(Would make this stage less noisy, increasing input capacitance - quite positive fact for MM RIAA stage-, and increasing gm of first tube - positive fact, also);
The ECC83 is part of the RIAA (with the large value unbypassed cathode resistor, so any changes there and your RIAA response (Low frequencies) will be off. If you can re-tune it it would be easy to use two sections of the ECC83 in parallel.

If you use 51K load and 91K +B Dropper and seperate cathode resistors for the ECC83 sections you will probably need around 270K in the place of 215K for the RIAA EQ.

Quote:
Originally posted by bucurb
-Using CCS on both tubes.
(it would make both tubes working with less distortion, amplification made mostly on their internal impendence parallel with the load, all stage will be less influenced by the PSU noise, and +B value could be around 100V, actually being 250V).
You can easily change the Output stage to CCS, the Input stage would (again) require the RIAA series resistor to be adjusted, this time downwards. As the input stage drops a lot of the +B Voltage anyway you could use a lower +B decoupling resistor for the first stage and leave it otherwise as is and add a CCS to the output stage. The input stage is pretty linear (at the voltages it is likel to see anyway) as is.

Sayonara
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Old 10th February 2005, 09:26 PM   #110
bucurb is offline bucurb  Romania
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Join Date: Sep 2004
Location: Bucharest
Default Thank you!

Thorsten,

Thank you.
I appreciate your kind answer.

Have a nice day!

Warm regards,

BBB
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