Buzzing usually has two sources.
-inadequate post rectifier filtering.
-to large charging spikes caused by oversized transformers or oversized filter caps. This can cause radio pick up of those spikes anywhere in the circuit and is very difficult to solve. If it is this it will appear as a small spike on the leading edge of the residual PS hum. Introducing some resistance post transformer can cure it. If it is this problem increasing the PS filtering caps will make it worse.
If you are using DC heaters with large capacitor banks for filtering this will cause the second problem. A way to decide is to hook up the heaters AC (should be adequate for quiet operation) with a +20VDC reference.
Most other things will cause a hum rather than a buzz.
Shoog
-inadequate post rectifier filtering.
-to large charging spikes caused by oversized transformers or oversized filter caps. This can cause radio pick up of those spikes anywhere in the circuit and is very difficult to solve. If it is this it will appear as a small spike on the leading edge of the residual PS hum. Introducing some resistance post transformer can cure it. If it is this problem increasing the PS filtering caps will make it worse.
If you are using DC heaters with large capacitor banks for filtering this will cause the second problem. A way to decide is to hook up the heaters AC (should be adequate for quiet operation) with a +20VDC reference.
Most other things will cause a hum rather than a buzz.
Shoog
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I had really bad buzz on a Broskie PSU and it ended up being the transformer shield wire. When tied to the CT pad of the heater circuit buzz was gone. I won't begin to try and understand exactly why but it worked.
I was using a separate filament transformer with my Hammond tranny so I can slow start my amp so I reconnected the filament wires from the Hammond and the buzz mostly went away. weird! The filament tranny is brand new.
Anyone have a schematic or is it even possible to have a switchable heaters voltage between 12.6 and 6.3?
I actually have an unused circuit board that I bought from Broskie that has provisions to switch between 6.3 and 12 volt heaters. Absolutely nothing wrong with doing it that way as it provides a variety of different tubes to play with. Check his site and you will find many nice schematics for the Aikido.
Yes, you can do that. It's just a couple jumpers on the PCB that switch between parallel 12.6v or series 6.3v.
I haven't put a switch on mine, but it was a really quick job to switch from 6 to 12v when I used different tubes.
I have almost every brand of 6sn7 tubes. Except the Holy grails 1940's Tung Sol black glass round plates. Average price? $600 a pair if you are lucky. Well, after doing some research. I found out that the 12sn7 are exactly the same in sound quality with the only different being the heater voltage at 12.6v. I have 4 NOS Tung sol black glass round plates ready to pop its cherry. Hopefully the 12sn7 lives up to the legendary 6sn7.
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Great. I have completely forgot everything i did to build this. in one ear-out the other. I have to go back and learn everything again. Thanks
I am an electronics newbie so I've been talking to another forum member over the years and I'm about to start a Tubelab amp...but last year he offered to build a Tube Buffer to use as a 'preamp' for me to use with my VTA ST-120 and then with my Tubelab amp once that's completed. The Tube Buffer he built also has an ALPS potentiometer for gain as well as a selector switch for 3 sources. With the VTA ST-120 amp it sounds very nice with 12AU7's. With 12AX7's it sounds even more open and 3 dimensional. There is no noise or hum. To be honest it sounds even better than my Cary SS preamp which was the main reason I started looking at the Tube Buffer.
Another side to the story. I had originally gotten a VTA SP10 preamp from the Roy Motram side of Tubes4HiFi. It had hum. Roy's first statement was that it's was due to the wiring in my house. I ended up returning it with the idea that Roy was going to build me an SP12 with better transformers that we're going to eliminate the hum. The hum wasn't as bad but still there. Eventually I did plug the preamp into a line conditioner that eliminated the electrical hum but now mechanical hum was noticeable. Mottram told me to put some rubber washers between the transformers and chassis. The noise was still there. I have to finish this post when I get back but the story is scary.
Another side to the story. I had originally gotten a VTA SP10 preamp from the Roy Motram side of Tubes4HiFi. It had hum. Roy's first statement was that it's was due to the wiring in my house. I ended up returning it with the idea that Roy was going to build me an SP12 with better transformers that we're going to eliminate the hum. The hum wasn't as bad but still there. Eventually I did plug the preamp into a line conditioner that eliminated the electrical hum but now mechanical hum was noticeable. Mottram told me to put some rubber washers between the transformers and chassis. The noise was still there. I have to finish this post when I get back but the story is scary.
I'll have to look at it and see how to wire it so I can used a toggle switch. I'll figure it out but Anyone with a schematic to do this on a octal all in one lsa/hpa board would be much appreciated. Always like other people opinions and ideas before I blow this thing up. As I remember hum was a bitch for me to track down and now if I add more wires to it. 😱
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Frequency = 159155/C/R
What size are people using for their Coupling Capacitors? I have 2 different power amps and all of them have different input impedance. For example:
Sony tan220es Input: 50K
Denon Poa 1500 Input : 18K
159155/1uf/50 =3183
159155/1uf/18 = 8841
What size are people using for their Coupling Capacitors? I have 2 different power amps and all of them have different input impedance. For example:
Sony tan220es Input: 50K
Denon Poa 1500 Input : 18K
159155/1uf/50 =3183
159155/1uf/18 = 8841
I assume a lower limit of about 5k load so I use a 4uf polycarbonate cap.
However when I build it for a 32 ohm load I use 470uf bypassed by 4uf.
What sources your music? I have two Aikidos and they are very flexible in build and use, but you probably don't need a preamp for ST 35 or ST 70 unless you are listening to vinyl and need a phono. You may look into a buffer or low mu preamp, like something based on 12B4. The latter is what I've been using to great satisfaction.
Hi!
I am sorry to start with my poor English language skills!
Here is my Aikido All In One preamp. The same box features Boozhound Riaa, Twisted Pear Audio 4: 1 Mux / Demux digital switch module, Pro-Ject Dac Box S2+ and engine-powered volume : D
I am sorry to start with my poor English language skills!
Here is my Aikido All In One preamp. The same box features Boozhound Riaa, Twisted Pear Audio 4: 1 Mux / Demux digital switch module, Pro-Ject Dac Box S2+ and engine-powered volume : D
Attachments
Has anyone compared a VTA SP9 preamp with the Aikido 6SN7 octal preamp?
I'm currently using the VTA with both Telefunkin and Sylvania 12AX7 tubes and it sounds wonderful.
I have an early Aikido 6SN7 kit that has been on the back burner for some time now. It is an early kit with all 6SN7 tubes in one straight row.
I'm curious if there is a big difference between the two.
Thank you
BillWojo
I'm currently using the VTA with both Telefunkin and Sylvania 12AX7 tubes and it sounds wonderful.
I have an early Aikido 6SN7 kit that has been on the back burner for some time now. It is an early kit with all 6SN7 tubes in one straight row.
I'm curious if there is a big difference between the two.
Thank you
BillWojo
Here's an aikido phono stage I built. It's powered from 12V by a boost converter.
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Thanks!
It sounds very good, I had a bit of grounding problems, but now the device is okay.
The power amplifier I have a Hypex UcD 700 HxR and as speakers are Finnish 15" "Piste"-coaxial-Diy-speakers