PPP KT66, Jensen P15N, Hammond PowTran 378CX/193L Choke

[Layberinthius]

I know I can use the Hammond 378CX (400-0-400 465mA) for Power Transformer and Hammond 193L (5H 300mA) choke...but.

http://www.triodeel.com/acpppar.gif

What OPT can I use with this schematic?

I've looked at Hammonds 1650K OPT capable of PPP however it is off by about 400 ohms in respect to the original design, IS this going to affect the operation of the amplifier to an extent that I should be worried and what can I do to counteract it?

And how does it affect the design?

Is there any other OPT's available from someone else?

Can you provide any further advancements to the original schematic's design?

The idea is to construct two 19x19 inch floorstanding boxes and install a pair of bell-cover Jensen P15N's into either one, Then incorporate the quad KT66 into either one with power unit at the bottom and amplification unit at top with upside down KT66 tubes.

This way I can build seperatley the all important midrange/top-end amps later down the track when I'm more keen with tubes but for now "practice" and get the bugs out of my system with the bass..

Improving on the bass amplifier later on.

Cheers!

[Layberinthius]

I've also found a close Sowter OPT, 3700 ohms 200w 275mA, but for 6 tubes, not 4 and "only" for EL34 pentode. KT66 in this schematic is a tetrode...

[Layberinthius]

Originally posted by Layberinthius
I've also found a close Sowter OPT, 3700 ohms 200w 275mA, but for 6 tubes, not 4 and "only" for EL34 pentode. KT66 in this schematic is a tetrode...

Can I still use it with the schematic above? If so, how?

Sowter U060

[Brett]

Originally posted by Layberinthius
I've looked at Hammonds 1650K OPT capable of PPP however it is off by about 400 ohms in respect to the original design, IS this going to affect the operation of the amplifier to an extent that I should be worried and what can I do to counteract it?

I presume you mean that the OPT's primary Z in the original design is 400 ohms different from the Hammond. Not enough difference for me to worry about.

The idea is to construct two 19x19 inch floorstanding boxes and install a pair of bell-cover Jensen P15N's into either one

Why are you using guitar speakers with an Fs of 77hz, an octave above E1? You'll get MUCH better sound from proper bass drivers.

[Layberinthius]

Originally posted by Brett
I presume you mean that the OPT's primary Z in the original design is 400 ohms different from the Hammond. Not enough difference for me to worry about.Why are you using guitar speakers with an Fs of 77hz, an octave above E1? You'll get MUCH better sound from proper bass drivers.

Oh please recommend recommend!


Lately I've been listening to rock a lot however..I'm an odd ball, I like both contemporary psychadelic and classic rock, either rarely come together.

I know that the circuit won't do my sources justice, and the output tranny won't either, but what choice do I have when it comes to a KT66 Push pull parallel? That's what this thread is for.

[Brett]

Originally posted by Layberinthius


Can I still use it with the schematic above? If so, how?

Sowter U060

Not directly. The Sowter doesn't have UL taps and the Acro is a UL amp.

Besides, do you really want to spend UKP237 + shipping etc on an OPT? As against $A182 for the 1650K?

I don't want to rain on your enthusiasm, but you have no idea what this amp will sound like, ie will you even like it, so I'm really against a novice builder spending large sums of money up front. Having it not work out the way you want is an even bigger enthusiasm killer.
If you're only going to use this in your bedroom, then it's too much power and expense, for most stage work or jamming with a drum kit it's too small but it might be OK for studio.

FWIW, I play bass, and I build amps on a semi-commercial basis.

[Layberinthius]

Originally posted by Brett

Not directly. The Sowter doesn't have UL taps and the Acro is a UL amp.

Besides, do you really want to spend UKP237 + shipping etc on an OPT? As against $A182 for the 1650K?

I don't want to rain on your enthusiasm, but you have no idea what this amp will sound like, ie will you even like it, so I'm really against a novice builder spending large sums of money up front. Having it not work out the way you want is an even bigger enthusiasm killer.
If you're only going to use this in your bedroom, then it's too much power and expense, for most stage work or jamming with a drum kit it's too small but it might be OK for studio.

FWIW, I play bass, and I build amps on a semi-commercial basis.

Thanks for the advice!, Would you consider 6L6 to be a good mid-bass contender? I already have the powtran and tubes...

http://www.triodeel.com/ac6l6280.gif

[Brett]

Originally posted by Layberinthius
Oh please recommend recommend!

Budget? Used OK? What are you planning on using this rig for?How low do you want it to go?

Lately I've been listening to rock a lot however..I'm an odd ball, I like both contemporary psychadelic and classic rock, either rarely come together.

I like both at times. Had the Who blaring most of today.

I know that the circuit won't do my sources justice, and the output tranny won't either,

Dunno what you mean by that. Is your bass and playing, superb? The Hammond will be fine and it's probably a better OPT than is in most bass amps.

but what choice do I have when it comes to a KT66 Push pull parallel? That's what this thread is for.

According to the GEC KT66 datasheet, in UL at 450VB+, you're going to get 60W from the PPP KT66's and be running them quite hot doing so. If it were me, I'd go with a pair of 6550, tetrode and a 1650R.

If you're not prepared to experiment a lot, and deal with the expense that involves, copy an existing, known good design (preferably one you can try first like an Ampeg). Just building any amp design and throwing it into a box with a couple of speakers isn't going to get what you want, unless you're extremely lucky.

[Brett]

Originally posted by Layberinthius
Thanks for the advice!, Would you consider 6L6 to be a good mid-bass contender? I already have the powtran and tubes...

http://www.triodeel.com/ac6l6280.gif

I was typing when you replied so some of what I said above may not apply.

If you have the PT, what are it's specs?
6L6's are good tubes and can sound great in the right circumstances.
If you can deal with 30W then the second Acro design is better looking. Built plenty of similar stuff. Hammond 1650H ($A178) would work well here.

You'll also need a preamp section. Try the one I've linked below as I know it sounds good as a basis to start from. Tweak the B+ voltages to the pre section with some extra RC sections from your poweramp PSU.

[Brett]

This might help