Well I tried to run the sub with the output from the volume control with a parallel connection to the sub but it kills that channel.

Now I guess I could run it in series but think I better wait for some professional forum members input!!!

I think you're misunderstanding me.
What I'm talking about only applies when you're using an external source for audio
(iPod or PC or something),
and only if you have a separate subwoofer that has it's own
built in amplifier and RCA mono input.


So no messing about inside the Kriesler at all:
Image Link

Thanks for the diagram!

I wasn't misunderstanding you I was just hoping to use a subwoofer with the Kriesler existing audio sources.

Do you think this isn't possible?

If I have to connect external source then with your diagram I presume the subwoofer ground is just the common ground too?

Would really like to have a subwoofer working with the Kriesler turntable though thats the main reason I wanted to connect one - lacking a bit of bass from my vinyls.

Your valve amplifier and output transformers will fall short there.
You need to take the signal from the phono cartridge then, and start there,
probably before that filter you described as couple of capacitors and resistors on a small PCB of it's own.
The powered subwoofers have their own low pass filter.

You can treat the phono as the source, and use the same method, the two 10K resistors to get the extra channel at
low level, but you will still need a different amp to do the low frequency.

I'm not sure about the level coming from the phono cartridge,
you might need to experiment with the resistor values.
You can start with higher values and work lower,
but keeping them both the same.
The penalty for getting the values too low for the source you're providing is losing stereo separation.

I use one of these:
Image Link

Thanks for that il try it out - I was originally going to tap into phono wires but thought I'd get clever and tap into volume pots! I'm still not sure why that didn't work altho maybe I did it wrong.

The pre-pre amp signal from phono may be a bit too low for sub to do much with but il try! Sub had its own powered amp but not as big as yours!!!

How old are you if you don't mind me asking?
I'm having trouble figuring you out with a valve amp and vinyl, but want a sub for bass.
ie. young person likes old music? or you got the likes of
Pearl Jam on vinyl or Faith No More, etc. ?

Haha yep 30 but love antiques, love vinyl (with bass!) and like tinkering so the Kriesler is perfect.

Now I think I have a 11-77 in the storage container, with its circuit.

I am not familiar with that Sub woofer. I have an amp here that has a single sub woofer speaker albeit the amp is stereo. I likely have that amps circuit?

If Sub, is mono? One normally took two 47K resistors, one from each channel of the turntable and took the feed from the centre of them.

More info needed.

Marc

Hi Marc thanks for that. My sub has its own amp and has left and right line level RCA ins as well as left and right high level ins. However I'm hardly getting bass at all with high level ins.
So you think there is enough voltage from the cartridge to tap in there?
I was hoping to tap onto volume control pots but doesn't seem like that is going to work.
I was actually trying to connect it to my 11-97 but there isn't much difference with respect to hooking up a sub.
Ps. Ur 77 is that to do up or u interested in selling some parts off it?

If you want to arrange and pay for courier,
or if anyone here does a regular commute, that Sony sub is yours.
Brisbane is a bit of a distance from you tho.

Thanks Art but I meant Marc re his 11-77 since there are a cpl of parts I could be interested in!

I just had a thought I wonder if the reason the sub is hardly picking anything up from the high level ins is because it expecting much lower impedance? Given the 11-97 i've got it connected to is 15ohm impedance and the sub is probably expecting 4 or 6, could that explain why it is so quiet? I was reading here about making a line out from speaker connection (http://www.singlecoil.com/docs/out.pdf) maybe i'll try that and use the line in on the sub and see how I go! Otherwise I may need a small amp connected between the speaker and high level ins. This is much harder than I thought!

The low end frequencies have been dropped by the time your Krielser speakers see them is the problem when it comes to picking up a signal after the valve amp.
There are hi-fi audio output transformers that do the low end,
but they are crazy expensive.

Wow I think iv fixed the problem; grabed a speaker to line level converter using the RCA connectors on sub....wow wouldn't believe the bass now the floor is vibrating!!! This is exactly what I was aiming for....purity of the tube amp combined with some heavy solid state bass I'm rapt!!!

Are you getting the input for the sub from the Kriesler speaker outputs?
Maybe compression in the valve amp is lifting some low end frequencies.