I haven't read the app note but will. S&B seem to owe an awful lot to TL (or not 🙂)
I have lots of good quality switches and an attenuator is thus always easy to assemble. Will probably buy into the TVC sooner rather than later.
Thanks for the info
peter
I have lots of good quality switches and an attenuator is thus always easy to assemble. Will probably buy into the TVC sooner rather than later.
Thanks for the info
peter
Peter,
I think Thorsten did a lot of the design work on the TVC, as well as some of their other products, and I remember reading somewhere that he was now a consultant engineer for them.
Cheers
I think Thorsten did a lot of the design work on the TVC, as well as some of their other products, and I remember reading somewhere that he was now a consultant engineer for them.
Cheers
Brett,
Wondefull roudup on line stage configurations, the best i'v read so far.
Two question, What sort of CCS do you use? and, are you using 6922 or 5842 on your preamp?
Wondefull roudup on line stage configurations, the best i'v read so far.
Two question, What sort of CCS do you use? and, are you using 6922 or 5842 on your preamp?
Thanks, glad you liked it.apassgear said:
The CCS is a Gary Pimm <a href="http://home.pacifier.com/~gpimm/Battery_biased_ccs.htm">BBMCCS</a> and the tube is a 12B4A. Later I'm going to try the 6C19pi, but I need to get some more from Gintaras when he gets back online. The few I have are going in to my tweeter amps. The 12B4A stage isn't a linestage per se, because I don't have one, but the last stage of my RIAA amps. Think if them as really grunty buffers with a bit of gain.
Since everyone keeps telling me how "SS" these sound, I might buy some LL1667/7.5mA chokes later and sub these for the CCS's. <G>
Cheers
CCS
Hi Brett,
Some people may take that as a compliment....😉
It seems that once again our findings concur.
I need to do some research on it but I'm very tempted to study a CCS using valves only.
After all you don't need complimentary sand pairs and if it can be done with a fet or two I don't see why it wouldn't work with valves.
That may just as well remove the sonic signature from the CCS (SS) without having to spend hard earned cash on iron.
Moreover I think the valved CCS would be more linear at audio frequencies than a choke.
Cheers,😉
Hi Brett,
Some people may take that as a compliment....😉
It seems that once again our findings concur.
I need to do some research on it but I'm very tempted to study a CCS using valves only.
After all you don't need complimentary sand pairs and if it can be done with a fet or two I don't see why it wouldn't work with valves.
That may just as well remove the sonic signature from the CCS (SS) without having to spend hard earned cash on iron.
Moreover I think the valved CCS would be more linear at audio frequencies than a choke.
Cheers,😉
Frank,
I was being sarcastic. The FET based CCS's I've tried haven't sounded SS at all. They just sound very clean and un-tubey.
Cheers
I was being sarcastic. The FET based CCS's I've tried haven't sounded SS at all. They just sound very clean and un-tubey.
Cheers
Brett
But have you tried replacing them with a plate choke?
Frank
I've tried pentode based current sources, nice but doesn't beat a nice plate choke.
regards
peter
But have you tried replacing them with a plate choke?
Frank
I've tried pentode based current sources, nice but doesn't beat a nice plate choke.
regards
peter
VALVED CCS
Hi Peter,
Just curious,can you tell us more?
You wouldn't happen to have a circuit diagram you can post here or e-mail me?
Did you use it together with a valve regulator?
As you see I am rather very curious.🙄
Thanks,😉
Hi Peter,
Just curious,can you tell us more?
You wouldn't happen to have a circuit diagram you can post here or e-mail me?
Did you use it together with a valve regulator?
As you see I am rather very curious.🙄
Thanks,😉
Nope, but I have used a number of choke and IT loaded stages before. It's a $A340 experiment when the quad of CCS's cost me $A25. Got the new horns to pay for in a couple of weeks, and they'll have a couple of orders of magnitude more impact on the system's sound than plate choke vs CCS. Maybe later.analog_sa said:
Cheers
I'l try some plate chokes hopefully this weekend over my 6DJ8.
Found some C cores on my junk box that are winded for another purpose and took one apart, these cores look prety nice finished on the partition, they where gapped with .060" spacers.
The section of the core is 0.490 X 0.770" = 0.377"2 , total lengh of 3" and window of 0.550". It looks OK for a choke but not enough size for a Tranny. I calculated that the numbers of turns for 100H (with no DC present) it will be 18,750, I dought that i need that much. Be using 35 Ga. wire that I have. I will not use a gap at the first trial, if it gets to hot I'l use a very thin spacer, since I will limit current to 6 mA.
Have not started because I need to do some mods to my hand winder in orde to accept the necesary mandrel.
One question:
On testing, would I need to change the Rk to limit current?
Never tested before a plate choke.
Found some C cores on my junk box that are winded for another purpose and took one apart, these cores look prety nice finished on the partition, they where gapped with .060" spacers.
The section of the core is 0.490 X 0.770" = 0.377"2 , total lengh of 3" and window of 0.550". It looks OK for a choke but not enough size for a Tranny. I calculated that the numbers of turns for 100H (with no DC present) it will be 18,750, I dought that i need that much. Be using 35 Ga. wire that I have. I will not use a gap at the first trial, if it gets to hot I'l use a very thin spacer, since I will limit current to 6 mA.
Have not started because I need to do some mods to my hand winder in orde to accept the necesary mandrel.
One question:
On testing, would I need to change the Rk to limit current?
Never tested before a plate choke.
apassgear
Easy with the winding machine. There was some discussion on the Joe list once re winding geometry of plate chokes. It seems to be far from trivial. If you just wind them as normal bobins there'll be no highs. Will do some digging and try to give you some winding pointers. If you really want to hear what plate chokes sound like, use the primary of an o/p transformer, even a p/p, provided it's of decent size and you don't go overboard with the current. Use a triode with low Rp if you have any doubts about the primary's inductance.
Btw Aquablue seem to offer Lundahl products at a much better price than Lundahl themselves. Will try ordering some stuff on Mon.
cheers
peter
Easy with the winding machine. There was some discussion on the Joe list once re winding geometry of plate chokes. It seems to be far from trivial. If you just wind them as normal bobins there'll be no highs. Will do some digging and try to give you some winding pointers. If you really want to hear what plate chokes sound like, use the primary of an o/p transformer, even a p/p, provided it's of decent size and you don't go overboard with the current. Use a triode with low Rp if you have any doubts about the primary's inductance.
Btw Aquablue seem to offer Lundahl products at a much better price than Lundahl themselves. Will try ordering some stuff on Mon.
cheers
peter
Thankx Peter, it will be nice if you could find something on winding bobins for chokes.
I have the Radiotron Handbook to which I usally refer for these matters and don't mention any special winding technic, of course this is an old manual.
I have the Radiotron Handbook to which I usally refer for these matters and don't mention any special winding technic, of course this is an old manual.
Paul Joppa/ Dave Slagle are the only one i recall having successfuly wound a plate choke. No idea how to get in touch though.
Here's the beginning of a thread i found. If this gets annoying to other members we can possibly continue with emails
Date: Sun, 09 Apr 2000 22:28:12 -0400
Subject: Re: [JN] Iron Age (was Kurts crazy amps and a little PF talk)
From: "Dave Slagle" <dslagle@earthlink.net>
To: sound@lists.io.com
Sender: owner-sound@lists.io.com
Content-Length: 2485
martin...other ironfolk...
> I would be very grateful for some pointers - just how much inductance does
> this take? More is obviously better (I think) but 10K plate load for -3
> dB at 10 HZ is 159 Henries. Is this practical -? What gap?
well practical is a matter of opinion... luckily you will be only drawing
6ma, and it is an early stage so you won't be swinging much AC...so you can
get away with a small core which will help you on the high end... but the
160 hy's you spec are gonna take a lot of turns of wire... particularly on a
small core... which adds up to DCR... but ime the one place dcr helps you is
in a plate choke...
> I just want to buy some parts and get winding so a full recipe including
> size of laminations/ stack /bobbin / wire gauge would be most welcome and
> I'll worry about the sums later.
not to make this overly simple... but buy some EI-75's of M-6 and some 36ga
wire and a bobbin... fill the bobbin, and gap it with a piece of typing
paper, then check to see what your inductance is... you can do this in
circuit loading the tube you plan on using it with... the minus 3 db point
on the low end will roughly tell you the inductance, and on the top end it
will alert you wo your winding capacitence... chances are at 160hy's they
both will be a problem... but armed with those results you can address the
compromises and move on...
need more bass? shrink the gap... if it gets worse you are saturating, and
need a bigger core, or more turns of smaller wire....
this will kill your top end... so you have to start looking at methods to
reduce capcitence... smaller cores... smaller wire... you eventually find a
balance of compromises...
> This choke load is going to have to be good to match the Black Art occult
> iron, but enticing the Dark Lord himself from the Halls of St Kilda can be
> tough...
well you have a reference to better... wind the choke and if it beats the
resistor... you did good... if it doesn't .... try again...
> I've been headsctatching about this cap coupling to a grid load choke
> business - when you sketch it down it's just the old parafeed again - 'cept
> you separate the cap and the choke by a length of interconnect. And the
> choke is a 1:1 Autoformer.
exactly! the cap provides the isolation, so you don't need the transformer
to do it... so why use a bandwidth robbing device if it provides no other
benefits?
the autoformer will match impedance too if thats what you tell it to do...
dave
Date: Sun, 09 Apr 2000 22:28:12 -0400
Subject: Re: [JN] Iron Age (was Kurts crazy amps and a little PF talk)
From: "Dave Slagle" <dslagle@earthlink.net>
To: sound@lists.io.com
Sender: owner-sound@lists.io.com
Content-Length: 2485
martin...other ironfolk...
> I would be very grateful for some pointers - just how much inductance does
> this take? More is obviously better (I think) but 10K plate load for -3
> dB at 10 HZ is 159 Henries. Is this practical -? What gap?
well practical is a matter of opinion... luckily you will be only drawing
6ma, and it is an early stage so you won't be swinging much AC...so you can
get away with a small core which will help you on the high end... but the
160 hy's you spec are gonna take a lot of turns of wire... particularly on a
small core... which adds up to DCR... but ime the one place dcr helps you is
in a plate choke...
> I just want to buy some parts and get winding so a full recipe including
> size of laminations/ stack /bobbin / wire gauge would be most welcome and
> I'll worry about the sums later.
not to make this overly simple... but buy some EI-75's of M-6 and some 36ga
wire and a bobbin... fill the bobbin, and gap it with a piece of typing
paper, then check to see what your inductance is... you can do this in
circuit loading the tube you plan on using it with... the minus 3 db point
on the low end will roughly tell you the inductance, and on the top end it
will alert you wo your winding capacitence... chances are at 160hy's they
both will be a problem... but armed with those results you can address the
compromises and move on...
need more bass? shrink the gap... if it gets worse you are saturating, and
need a bigger core, or more turns of smaller wire....
this will kill your top end... so you have to start looking at methods to
reduce capcitence... smaller cores... smaller wire... you eventually find a
balance of compromises...
> This choke load is going to have to be good to match the Black Art occult
> iron, but enticing the Dark Lord himself from the Halls of St Kilda can be
> tough...
well you have a reference to better... wind the choke and if it beats the
resistor... you did good... if it doesn't .... try again...
> I've been headsctatching about this cap coupling to a grid load choke
> business - when you sketch it down it's just the old parafeed again - 'cept
> you separate the cap and the choke by a length of interconnect. And the
> choke is a 1:1 Autoformer.
exactly! the cap provides the isolation, so you don't need the transformer
to do it... so why use a bandwidth robbing device if it provides no other
benefits?
the autoformer will match impedance too if thats what you tell it to do...
dave
And some more
Date: Mon, 10 Apr 2000 08:51:59 -0400
From: John Levreault <jlevro@mediaone.net>
Organization: Orvelle Technologies
X-Accept-Language: en
To: Dave Slagle <dslagle@earthlink.net>
CC: sound@lists.io.com
Subject: Re: [JN] Iron Age (was Kurts crazy amps and a little PF talk)
References: <200004100228.TAA13896@goose.prod.itd.earthlink.net>
Sender: owner-sound@lists.io.com
Content-Length: 753
Dave Slagle wrote:
>
> this will kill your top end... so you have to start looking at methods to
> reduce capcitence... smaller cores... smaller wire... you eventually find a
> balance of compromises...
I know very little about plate choke construction, but the RF guys have
a way for dealing with the distributed capacitance of plate chokes used
in wideband amplifiers. What they do is break the winding up into
several smaller windings on a common core/former and then connect
everything in series. You could do something similar at audio: Use a
bobbin core with several sections, wind up each section, and then
series-connect them all. If your bobbin has 4 sections, wind 1/4 of the
total into each section and then connect them all in series.
JL
Fortunately, the choke is not interleaved and can be made with much
less capacitance than an equivalent transformer primary winding. In my
(admittedly limited) experience, capacitance is important. In theory,
if the inductance is 100H and the capacitance is 633pF (and there are
no other significant resonances etc) then the choke's impedance will
remain large relative to the load impedance over the 2-200kHz
bandwidth. The capacitance and inductance resonate at 632Hz. But in
practice it is better to have that resonance above 3kHz, which would
require 28pF of capacitance. That is quite difficult to achieve!
Date: Mon, 10 Apr 2000 08:51:59 -0400
From: John Levreault <jlevro@mediaone.net>
Organization: Orvelle Technologies
X-Accept-Language: en
To: Dave Slagle <dslagle@earthlink.net>
CC: sound@lists.io.com
Subject: Re: [JN] Iron Age (was Kurts crazy amps and a little PF talk)
References: <200004100228.TAA13896@goose.prod.itd.earthlink.net>
Sender: owner-sound@lists.io.com
Content-Length: 753
Dave Slagle wrote:
>
> this will kill your top end... so you have to start looking at methods to
> reduce capcitence... smaller cores... smaller wire... you eventually find a
> balance of compromises...
I know very little about plate choke construction, but the RF guys have
a way for dealing with the distributed capacitance of plate chokes used
in wideband amplifiers. What they do is break the winding up into
several smaller windings on a common core/former and then connect
everything in series. You could do something similar at audio: Use a
bobbin core with several sections, wind up each section, and then
series-connect them all. If your bobbin has 4 sections, wind 1/4 of the
total into each section and then connect them all in series.
JL
Fortunately, the choke is not interleaved and can be made with much
less capacitance than an equivalent transformer primary winding. In my
(admittedly limited) experience, capacitance is important. In theory,
if the inductance is 100H and the capacitance is 633pF (and there are
no other significant resonances etc) then the choke's impedance will
remain large relative to the load impedance over the 2-200kHz
bandwidth. The capacitance and inductance resonate at 632Hz. But in
practice it is better to have that resonance above 3kHz, which would
require 28pF of capacitance. That is quite difficult to achieve!
Thanks Peter for all the information and think that that will do for the moment.
I read for a second time the Radiotron in relation to chokes and transformers. As you know this is a bag of compromises so just for the fun and testing I decided on some parameters and will try a transformer on my small C cores and see what happens.
Calculated Parameters (design, ja ja...)
Primary inductance: 55H (or somewhat more with luck)
Prim turns 9,560 -more if it fits
prim impedance 2500, secondary 600 X 2 Ohms
This parameters (if achived) will put me on 20 Hz -3 dB, and low capacitance may get 25K hz. the trouble with these C cores is that they are small for the task.
i have finish the mandrel that will go on the manual winding rig and it's already installed, Now I'm making some fish paper bobins, all this is very time consuming, but having a lot of fun! You bet.
Will do only one transformer first and test... if it works will do the second.
I read for a second time the Radiotron in relation to chokes and transformers. As you know this is a bag of compromises so just for the fun and testing I decided on some parameters and will try a transformer on my small C cores and see what happens.
Calculated Parameters (design, ja ja...)
Primary inductance: 55H (or somewhat more with luck)
Prim turns 9,560 -more if it fits
prim impedance 2500, secondary 600 X 2 Ohms
This parameters (if achived) will put me on 20 Hz -3 dB, and low capacitance may get 25K hz. the trouble with these C cores is that they are small for the task.
i have finish the mandrel that will go on the manual winding rig and it's already installed, Now I'm making some fish paper bobins, all this is very time consuming, but having a lot of fun! You bet.
Will do only one transformer first and test... if it works will do the second.
Brett said:
Should I use a floating symetrical output?
Or are you thinking of creating a ground with two shunting resistors?
I thought it should be referenced to ground, I might even like to try some NF.
In any case there is no problem adding a tap on the secondary.
Hello,
Here is also one example of Valve (ECC88/E88CC/6DJ8/6922)
Line Preamplifier that I found.
Does anyone tried it, and is there any comment on sound quality ?
Best regards,
Kristijan Kljucaric
http://web.vip.hr/pcb-design.vip
Here is also one example of Valve (ECC88/E88CC/6DJ8/6922)
Line Preamplifier that I found.
Does anyone tried it, and is there any comment on sound quality ?
Best regards,
Kristijan Kljucaric
http://web.vip.hr/pcb-design.vip
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