Hi,
Gain (maximum) from the phonostage + linestage is 35V out for 0.5V in @ 0.05 % distortion.
Cheers,😉
Gain (maximum) from the phonostage + linestage is 35V out for 0.5V in @ 0.05 % distortion.
Cheers,😉
Thanks
I'm thinking to build it!But with simpler PSU.
I'm thinking to use yours PSU for each channel.
One for phono line L channel and one for phono line R channel.
What do you say?I know that it's better to use four.Maybe in the future.
Regards
I'm thinking to build it!But with simpler PSU.
I'm thinking to use yours PSU for each channel.
One for phono line L channel and one for phono line R channel.
What do you say?I know that it's better to use four.Maybe in the future.
Regards
Hi,
What can I say?
It was designed like that for a reason, namely to reduce IMD between stages...
I do realise it's not a cheap project but I do know it's one of the better phono preamps money can buy.
In fact, with the advent of more affordable high value filmcaps available and BG caps it still has the potential of being one of the best preamps ever.
Actually with all necessary attention to detail where it matters such as wire, PS caps and cathode decoupling caps it should be so good that it'll put CD to shame for a few decades to come.
If you have a substantial record collection and a good TT, arm and cart and love your music, I wouldn't hesitate one second...
Keep in mind I'm not saying this because it's my brainchild, I only want you to discover what your records can really sound like.
In all modesty, 😉
What can I say?
It was designed like that for a reason, namely to reduce IMD between stages...
I do realise it's not a cheap project but I do know it's one of the better phono preamps money can buy.
In fact, with the advent of more affordable high value filmcaps available and BG caps it still has the potential of being one of the best preamps ever.
Actually with all necessary attention to detail where it matters such as wire, PS caps and cathode decoupling caps it should be so good that it'll put CD to shame for a few decades to come.
If you have a substantial record collection and a good TT, arm and cart and love your music, I wouldn't hesitate one second...
Keep in mind I'm not saying this because it's my brainchild, I only want you to discover what your records can really sound like.
In all modesty, 😉
Hi Frank
You said that the input sensitivity of the phono stage is 2mV with 47K and 100pF in //.This is wrong right?
And If I'll use a simple volume like alps,panasonic,e.t.c. will I have any problem that the resistance of the pot doesn't stay constant ?
An other problem is that I can't find a pot with 1M resistance(like alps,panasonic,etc).What can I do?
The gain of the phono+line stage is 35V out with 0,5V in @ 0.05% distortion!!!(Very nice,bravo)
This means that the phono stage by itself has 35/0,5=70 gain.The line stage has gain about 0.97 ~ 1 as a buffer.
So If my MM cartridge has output about 4,5mV .I'll have an output from my phono about 4.5mV * 70 = 315mV.This overloads all the tube amps,both SE and P-P.Right?
I'm writing all these to be sure that with this preamp I will not have any problem to drive any amp.
You said that the input sensitivity of the phono stage is 2mV with 47K and 100pF in //.This is wrong right?
And If I'll use a simple volume like alps,panasonic,e.t.c. will I have any problem that the resistance of the pot doesn't stay constant ?
An other problem is that I can't find a pot with 1M resistance(like alps,panasonic,etc).What can I do?
The gain of the phono+line stage is 35V out with 0,5V in @ 0.05% distortion!!!(Very nice,bravo)
This means that the phono stage by itself has 35/0,5=70 gain.The line stage has gain about 0.97 ~ 1 as a buffer.
So If my MM cartridge has output about 4,5mV .I'll have an output from my phono about 4.5mV * 70 = 315mV.This overloads all the tube amps,both SE and P-P.Right?
I'm writing all these to be sure that with this preamp I will not have any problem to drive any amp.
SRPP Preamp
I have find this preamp in a magazine. They call it SRPP (Shunt Regulated Push-Pull), design used by the japanese Anzai at the end of the 60's.
I've got almost all the components, so maybe I'll try to do it. ¿What is your opinion?
The specs are:
Gain: 44dB (22 dB at the ECC82 line output)
s/n: 78 dB (63 dB at the ECC82 line output)
RIAA deviation: 0,3 dB
Distor: 0,01% (1V, 20Hz - 20 kHz)
Cheers
I have find this preamp in a magazine. They call it SRPP (Shunt Regulated Push-Pull), design used by the japanese Anzai at the end of the 60's.
I've got almost all the components, so maybe I'll try to do it. ¿What is your opinion?
The specs are:
Gain: 44dB (22 dB at the ECC82 line output)
s/n: 78 dB (63 dB at the ECC82 line output)
RIAA deviation: 0,3 dB
Distor: 0,01% (1V, 20Hz - 20 kHz)
Cheers
Attachments
Hi,
Yes, that's wrong.
Input sensitivity for MM is 1.2mV into 47k/100pF.
No, total resistance as seen by the previous stage will still be 1M.
The only thing I can think of is to move the volume pot behind the buffer.
Say you have a 100K ALPS or Pana, you remove the 100K bleeder resistor and put the pot there instead.
I have not tried this but it should work.
No, not at all.
Think about a CDP that puts out 2V RMS, that's 6V peak to peak.
I understand. Don't worry it will work with all commercially available amplifiers.
Cheers,😉
Yes, that's wrong.
Input sensitivity for MM is 1.2mV into 47k/100pF.
No, total resistance as seen by the previous stage will still be 1M.
The only thing I can think of is to move the volume pot behind the buffer.
Say you have a 100K ALPS or Pana, you remove the 100K bleeder resistor and put the pot there instead.
I have not tried this but it should work.
No, not at all.
Think about a CDP that puts out 2V RMS, that's 6V peak to peak.
I understand. Don't worry it will work with all commercially available amplifiers.
Cheers,😉
I can't understand the 1,2mV of the input sensitivity.My cartridge has an output of 4,8mV.This means that I'll have a problem??😕
What is a CDP?
Isn't better to put the pot behind the buffer?Even if the pot is 100K?
How much current can the PSU delivers to the circuit?I'm asking 'cause at the beginning I'll use only two PSUs.One for each channel for both phono and line.
What is a CDP?
Isn't better to put the pot behind the buffer?Even if the pot is 100K?
How much current can the PSU delivers to the circuit?I'm asking 'cause at the beginning I'll use only two PSUs.One for each channel for both phono and line.
Hi,
No. Don't worry it's just a standard specification norm : IHF 0.5V.
A CD-player.
I don't think so but you could argue both ways...
More than enough, you won't see the B+ sag.
Cheers,😉
No. Don't worry it's just a standard specification norm : IHF 0.5V.
A CD-player.
I don't think so but you could argue both ways...
More than enough, you won't see the B+ sag.
Cheers,😉
With my bad english I can't explain sometimes what I want to say. 
When I said that the preamp should overload both SE and P-P amps,I ment that I'll not have any problem to overload any amp.
Acommon tube amp has an input sensitivity about 250mV or lower,right?
With my cartridge (output 4,5mV) or any other MM cartridge,I'll have an ouput (of the phono+line) about 315mV.So if I wish to overload the amp ,I can.
When I said that the preamp should overload both SE and P-P amps,I ment that I'll not have any problem to overload any amp.
Acommon tube amp has an input sensitivity about 250mV or lower,right?
With my cartridge (output 4,5mV) or any other MM cartridge,I'll have an ouput (of the phono+line) about 315mV.So if I wish to overload the amp ,I can.
Hi Frank,
Am I right in assumming that you used a rotary switch for the 1M pot? If so, do you prefer any particular switch and/or resistor combo? And while I'm here asking you questions anyway, is the preamp voiced for any particular parts. What I mean is, did you design it to be used with a certain brand cap/resistor/etc?
Thanks and cheers,
Mats
Am I right in assumming that you used a rotary switch for the 1M pot? If so, do you prefer any particular switch and/or resistor combo? And while I'm here asking you questions anyway, is the preamp voiced for any particular parts. What I mean is, did you design it to be used with a certain brand cap/resistor/etc?
Thanks and cheers,
Mats
Hi,
Mats,
Yes, I do. This was an upgrade from the original Alps pot.
For the switches, the best ones IMO are made by ShallCo (US), Seiden (Japan), Blore Edwards (UK).
More affordable is the (Taiwanese?) Elna, this is what I used.
For positions 10 and 11 (most often used setting) I used Vishay S102, best quality available in those days) the others are Holco H4 (the old non-magnetic ones)
It was designed to use off the shelf parts and at first I used Corning resistors, Roederstein Resistas, some Philips depending on wattage requirements and application.
Caps were originally Nichicon 85 degrees for the PS, Roederstein MKP 1842 as coupling caps and some Philips styrenes for the RIAA correction.
The cathode decoupling caps were two blocks 10 * 4.7 µF/63V glued together and hardwired.
Years later I upgraded the coupling caps to MIT film & foil polysterenes, replaced most resistors with Holcos except for the RIAA correction were I used Vishay bulkfoils.
All signal path wiring was upgraded with 99.999 % pure PTFE insulated silver wire of 0.6 mm dia.
It was an expensive upgrade but well worth the outlay especially as I applied the same updates to the OTL amps and speaker x-overs.
Cheers,😉
Mats,
Yes, I do. This was an upgrade from the original Alps pot.
For the switches, the best ones IMO are made by ShallCo (US), Seiden (Japan), Blore Edwards (UK).
More affordable is the (Taiwanese?) Elna, this is what I used.
For positions 10 and 11 (most often used setting) I used Vishay S102, best quality available in those days) the others are Holco H4 (the old non-magnetic ones)
It was designed to use off the shelf parts and at first I used Corning resistors, Roederstein Resistas, some Philips depending on wattage requirements and application.
Caps were originally Nichicon 85 degrees for the PS, Roederstein MKP 1842 as coupling caps and some Philips styrenes for the RIAA correction.
The cathode decoupling caps were two blocks 10 * 4.7 µF/63V glued together and hardwired.
Years later I upgraded the coupling caps to MIT film & foil polysterenes, replaced most resistors with Holcos except for the RIAA correction were I used Vishay bulkfoils.
All signal path wiring was upgraded with 99.999 % pure PTFE insulated silver wire of 0.6 mm dia.
It was an expensive upgrade but well worth the outlay especially as I applied the same updates to the OTL amps and speaker x-overs.
Cheers,😉
This is my first post here.
I would love to have the final schematics of Frank's Ultimate tube preamp.
Thanks
I would love to have the final schematics of Frank's Ultimate tube preamp.
Thanks
Hi,
Welcome to the forum, Fastback.
As I'm the Frank you're looking for:
Scematics of the project can be found in following post #s on the previos pages:
# 75 Line stage, buffer circuit.
# 74 PSU except for regulated 12V heater circuit.
# 86 MC prepreamplifier to be built in a separate box.
# 112 Phono MM preamplifier with active RIAA, the one I use myself.
# 145 Same as above but with passive RIAA correction as suggested by Planet 10.
Any questions you may have just ask away.
Cheers, 😉
Welcome to the forum, Fastback.
As I'm the Frank you're looking for:
Scematics of the project can be found in following post #s on the previos pages:
# 75 Line stage, buffer circuit.
# 74 PSU except for regulated 12V heater circuit.
# 86 MC prepreamplifier to be built in a separate box.
# 112 Phono MM preamplifier with active RIAA, the one I use myself.
# 145 Same as above but with passive RIAA correction as suggested by Planet 10.
Any questions you may have just ask away.
Cheers, 😉
fdegrove
Thanks for the info got it.
hope to build one soon, have to complete the parts first.
and this will be my first tube project ever, If I have a question I know where to go.
You have been very helpfull thanks again.
Thanks for the info got it.
hope to build one soon, have to complete the parts first.
and this will be my first tube project ever, If I have a question I know where to go.
You have been very helpfull thanks again.
fastback, you've come to the right place. frank also has a 12BH7 buffer preamp on post #75 as frank mentioned, which is what i'm recommending to you.
it will be simple to build and cheap (wait, i didn't see the PSU of that, so i might be wrong 🙂)
it will be simple to build and cheap (wait, i didn't see the PSU of that, so i might be wrong 🙂)
Hi guys,
The preamp uses four times the same regulated PS. So two per channel.
So that makes for 4 * 3 tubes = 12 for the PSU only...
Just be glad I haven't released the tube rectified, penthode as choke, ripple killer input version yet or you'd be facing a gas factory....😀
So the linestage uses also 300VDC as B+ for the White cathode follower.
If you don't intend to use it in conjunction with the active RIAA phono stage you can use a 50K log pot as volume control, followed by, say, a 100nF coupling cap and 1M gridleakresistor.
As for the PS proper, anything stable and ripple free of good quality ought to work just fine. The better the PS, the better the final sound.
Another member, Erikdebest, has finished it and seems pleased with.
I haven't had the chance to ask him how he built it though.
Hope this helps,😉
The preamp uses four times the same regulated PS. So two per channel.
So that makes for 4 * 3 tubes = 12 for the PSU only...
Just be glad I haven't released the tube rectified, penthode as choke, ripple killer input version yet or you'd be facing a gas factory....😀
So the linestage uses also 300VDC as B+ for the White cathode follower.
If you don't intend to use it in conjunction with the active RIAA phono stage you can use a 50K log pot as volume control, followed by, say, a 100nF coupling cap and 1M gridleakresistor.
As for the PS proper, anything stable and ripple free of good quality ought to work just fine. The better the PS, the better the final sound.
Another member, Erikdebest, has finished it and seems pleased with.
I haven't had the chance to ask him how he built it though.
Hope this helps,😉
hi frank, oh that PSU 
i hope your 12BH7 is PSUD friendly if we decided to make a 'simpler' one, he he 😀 fastback is lucky to have a bunch of them 12BH7 for free 🙂
i hope your 12BH7 is PSUD friendly if we decided to make a 'simpler' one, he he 😀 fastback is lucky to have a bunch of them 12BH7 for free 🙂
Hi,
I don't know to what point you want to minimalise it but, by nature stacked triode designs such as the SRPP, cascode followers, WCFs etc. don't have great PSRR.
As you know me well enough by now I suspect you also are aware of the fact that I always try to emphasise the importance of a good PS.
How that is achieved is rather irrelevant to me but every PS recipe still has its' own sonic fingerprint.
Of course that doesn't mean you can't start with something within your budget and take it from there, moving up the scale as budget allows.
The 12BH7A is still made by EI but it's still overpriced...
If, however the 6C19-P would become easily available one day, I'll certainly consider tinkering with it.
In the meantime there's still plenty of cheap 12B4As and there's the new but expensive (relatively speaking) ECC99, all of which should be great candidates for this stage.
BTW, it's not hard to convert/expand it into a nice headphone amp although driving a set of AKG 1000's (?) may be asking a little too much of it.
Enjoy the building and watch where the hands go,😉
I don't know to what point you want to minimalise it but, by nature stacked triode designs such as the SRPP, cascode followers, WCFs etc. don't have great PSRR.
As you know me well enough by now I suspect you also are aware of the fact that I always try to emphasise the importance of a good PS.
How that is achieved is rather irrelevant to me but every PS recipe still has its' own sonic fingerprint.
Of course that doesn't mean you can't start with something within your budget and take it from there, moving up the scale as budget allows.
The 12BH7A is still made by EI but it's still overpriced...
If, however the 6C19-P would become easily available one day, I'll certainly consider tinkering with it.
In the meantime there's still plenty of cheap 12B4As and there's the new but expensive (relatively speaking) ECC99, all of which should be great candidates for this stage.
BTW, it's not hard to convert/expand it into a nice headphone amp although driving a set of AKG 1000's (?) may be asking a little too much of it.
Enjoy the building and watch where the hands go,😉