• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Poll..anyone interested in an Aikido linestage PCB group buy?

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#624
Bas Horneman said:

That's ok..but you are right..some say DC sounds worse (regulated or not) but when you have Hedlunds you might have to.

Can you measure ripple on the b+ with your scope? Maybe an extra RC network could do the trick as well.


Do you have a picture of your build? That way we might be able to see the grounding setup.
Click to expand...

When I disconnect the pre I have the same noise also the few seconds the caps last drying, so i assume it is a GND problem, not noise injected from the PSU

I have not camera here (snip!). GND arrangement is done with a thick copper wire where I connected the GND of each channel, the in and out rca connectors gnd, the PSU gnd and the pin of the pot. I assume the case must not be connected to this GND bus, maybe here is the fail because although I didn't connect the case I have a contact anywhere (I suspect in the rca inputs.
 
#625
Bas, have you tried the Dave Slagle AVC's with the Aikido? I have a pair I was going to try with it, but was wondering if it'd be better before or after the Aikido. Also I was wondering if it is best to load the secondaries with a 50K R resistor in the case where it is before the LS, providing the 50K R load.
 
#626
sourcing the transformers

New to DIY here, so this may be a dumb question, but I'm still coming up to speed on PSUs and transformers:

For the power supply, previous posts suggest a single transformer with 250V+ on the B+ and 6.3V for the filaments.

However, my Grounded Grid has 3 transformers...2 120V mains and 1 12V filament. From Bas's picture...it also seems his has 3 as well...

If I want to build regardless of cost, is it better to have separate transformers or a single integrated transformer?

Are there advantages/disadvantages?

Thanks,
Jayme
 
#627
jayme


I built a Bas Aikido line stage 6fq7/5687 with two separate transformers and two power supply boards for the dual mono approach. I believe that seperation is better as is detail. I happened to have two identical power transformers and that is the main reason I went that way. I didn't use a separate 6.3 transformer to feed the heaters.

I believe somewhere in this thread you will find a picture of a grounding scheme with a Hammond 369JX used. Note* This transformer will not supply enough filament current so a 6.3v or 12.6 v transformer will have to be used in addition to the power transformer.

I also built a P-P 6SN7 Aikido line stage and used a single transformer. I prefer the dual mono supply.
 
#629
Hi again,

Bas, sorry to bother you with more questions!
I revised the gnd setup of my Aikido getting really less noise, but still noticeable: perfect 60hz hum, not too loud but easy to listen from audition position with no tracks playing. I know that speakers with more than 98db and with all that gain -btw I changed the 50k for a lower value and now it is usable- it's easy to get some hum, but maybe I can (I'd like to) improve it.
Concerning gnd and enclosure: I have an aluminium enclosure and connected the gnd (thick copper wire tied to psu gnd, input and output gnd and VC gnd) to the enclosure. is this ok?
Concerning the DC on heathers as you suggested me: I'd like to try before the extra RC network trick, how would be the better way to implement it? I have now two trafo: one for the 6x5 heather and another for the 4 tubes in the boards.

Thanks again!

JL
 
#630
dual-mono

Dual-mono is indeed the way I am hoping to proceed.

But: couple more questions there. If I am using Bas's PSU board and only using half of it for a side, then only half of the 6x5 is used.

Can I swap out the diodes and use the other half of the 6x5 instead?

Is there a better rectifier tube to use in the dual-mono situation?
 
#632
Hi all again,

I found the solution: it was not hum due bad ground arrangement, after putting the trafo far from the Aikido boards hum is almost gone. I have a bit yet, but I have to be really close my Hedlunds to notice it. Assuming I have yet too much gain maybe this noise figure is ok, although I have not heard other's Aikido. Is already good enough? can I expect to be dead silent with >96db speakers?

ah! Sound is amazing! Best improvement here since I built these speakers 🙂

Thanks!

JL
 
#633
Aikido Balance Preamp & PSU PCB

Hi diyer,

Is there any one still have and sell the PCB of (2x Balanced Aikido + 2x PSU)?

I want to order PCB (2x Balanced Aikido + 2x PSU) and make dual mono for Aikido Balanced Preamp.

If yes, can you post some picture and schematic of Balanced Aikido Preamp & PSU? Or show me the final version link.

Thank you.

Dominic
 
#634
If yes, can you post some picture and schematic of Balanced Aikido Preamp & PSU? Or show me the final version link.
Click to expand...
Hi Dominic,

I have not had time to respond to your email. But now that you are in this thread, the following: Pictures of the schematic used for the boards, the psu schematic, pictures of the octal and noval boards...naked and populated can all be found in this thread. Also typical values and where and the amount orderable can be found in this thread.

But the Aikido is not a balanced pre-amplifier in itself. You can make it balanced if you like but you'd need 4 boards for 2 channels. This can also be found in this thread, with a drawing of how it can be done.

Boards can be ordered from me if you like. (Or if you have patience from John Broskie himself (I think), or from e-Bay by this one guy from Germany)

If you'd like to order from me, you can see how and how much the price is...also in this thread.

Regards,
Bas
 
#635
I see that the 6N1P/5687 schematic has these tubes in this VA/CF order. As the 5687 is lower gain (and there is too much already) why isn't it 5687 for the VA and 6N1P for the CF?

Is it to do with the overload characteristic of the 5687? I believe the 6N1P overloads at 2.3V but with all this gain I can't see overload being an issue. Of course 6CG7 offers even lower gain.

Clive
 
#637
aikido psu help

i just purchased the R0080-036 r-core power transformer from: http://www.vt4c.com/shop/program/main.php
to use for my 2 Aikido octal boards.

the specs are as follows:
100W power tranformer 0-115V, 0-115V, International version.
260-230-0-230-260V 200mA Full-wave rectification
0-5V 3A with CT
0-6.3 3A with CT
0-6.3 3A with CT
Grounding/Screen wire

i'm still learning what changing various parts in a power supply does to the B+.
i appreciate any input and help anyone with a little patience can offer.

i have 2 ASC 40uf/450v caps i'd like to put to use.
so all i need is a choke and since the PT is 200mA am I correct to assume that i'll need a choke that is 5-15H in the 200mA range like the Hammond 193J?

when I draw up a schematic like the one attached, what's the best way to determine what my B+ will be. is there an equation? can you guys take a look at the schematic to make sure i'm on the right track? sorry for such basic questions, trying to become a better DIYer.

Max
 

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#640
e if a member of diyaudio..and you have given up your name in the list below...mention your username as well...

bas.horneman-at-gmail.com

replace the -at- with @

PSU boards 9.00 US$
Octal 9.50US$
Noval 9.50 US$
Adapter boards 2.75$

NB. The adapter boards only "work" with the octal boards.

Shipping <= 4 boards 3.50US$
Shipping > 4 and <= 8 boards 5US$


I found it...........................................................
 
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