Wow Thank you very much for sharing. Look simple and very nice. However for me 6 watts A2 is enough. I prefer your 6 watts version.
Anyway the 9 watts version is superb. Thumbs up!!
6 watts A2 version use 3.5K OPT but 9 watts version us 600R OPT, Why OPT need to be change so much value?
The first inter-stage transformer is 100 : 900 (1 : 9) What is the value of Henry and DC impedance? Thank you.
The first inter-stage transformer is 100 : 900 (1 : 9) What is the value of Henry and DC impedance? Thank you.
Lot's of interesting versions of 6e5p amps. What's the chassis of the latest one made from? Not the wood top but the rest. Got any under-chassis pics of it? I'm always interested in construction methods that are atypical.
I have some 6e5p tubes that I bought a while back but haven't tried them in anything.
It's probably too late for you change the title of the thread, but I would point out that it's misleading since none of your designs are SPUDs.
As I understand the term, a SPUD only uses a single tube per channel, although tubes with more than one section in a single bottle seem to qualify. The only amp in this thread that meets the definition is the one posted by @nikon f , although in use it may not be a SPUD either.
In another thread, he mentioned that he uses a preamp with it. As I see it, if you're using an additional gain stage I don't think it can truly be considered a SPUD. It shouldn't matter if the additional gain stage is on a separate chassis or not, or if it's a tube, an opamp or a step up transformer.
Strictly speaking, if it can't be used with only a line level signal it's not really a SPUD.
As I mentioned in that other thread, I've never set out to build a SPUD, but it turns out that I inadvertently built one.
I modded a little Voice of Music SE 6BQ5 amp that normally uses a 12AX7 input tube that's mounted on a separate chassis. I eliminated the connection to the 12AX7, along with the global NFB, so that I could use the amp section with whatever preamp I wanted.
I left it in pentode to maximize the power output and added local NFB. I have no way to measure the power output but I assume it's probably in the 3 to 4 watt range. Whatever it is, it's enough for me using speakers that are probably ~92db.
When used as I intended, with a preamp, I would not consider it to be a SPUD.
What surprised me is that the amp works very nicely with no preamp - either a "passive preamp" (simple volume control) or using the volume control on my computer to stream to the amp using an Airport Express.
I would not have thought that a 6BQ5 / EL84 could be used to build a SPUD but it sounds wonderful.
I use for output transfmer what i have on hand. This 600R is wired to 4, and speakers are 8ohm. So it acts like 1200R x 6 - every tube see transformer like 7200Ohm.
Input transformer ratio is 1:3 (impendance is 100:900).
I use for source cd player connected to DAC ASUS Xonar Essence One. I use DAC for volume control. It is much better than any pot.
Input transformer ratio is 1:3 (impendance is 100:900).
I use for source cd player connected to DAC ASUS Xonar Essence One. I use DAC for volume control. It is much better than any pot.
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1200R OPET is about 10Henry on primary, right?
6E5P Anode resistance is 8K ohms
parallel 6 tubes 1.33K ohms anodes of 6 tubes
1.33K ohm / (2 x Pi X 10Henry) =21.21 Hz -3db
if we lower OPT from 1200R, will the frequency cutoff will be lower such as 10hz -3db?
6E5P Anode resistance is 8K ohms
parallel 6 tubes 1.33K ohms anodes of 6 tubes
1.33K ohm / (2 x Pi X 10Henry) =21.21 Hz -3db
if we lower OPT from 1200R, will the frequency cutoff will be lower such as 10hz -3db?
If it is irrelevant to topic, need to apologized in advanced. (please delete if consider irrelevant)
1st question:
- for 2 parallel of 6E5P tubes the OPT is 3.5K : 8 (each tube see OPT like 7.K)
- for 6 parallel of 6E5P tubes why the OPT is 1.2K : 8? (each tube see OPT as 7.2K)
Why need to add more 0.2K when add more 4 tube.
2nd question:
2.1 Instead of using OPAMP why replace by Step-up 1:3 interstage transformer?
2.2 I think nowsaday many people use "gyrator" to driver tube in replacement of 1:3 interstage transformer. If capable of using gyrator with tube to drive 6 x 6E5P what tube and MU need to drive them at 9 watts.
1st question:
- for 2 parallel of 6E5P tubes the OPT is 3.5K : 8 (each tube see OPT like 7.K)
- for 6 parallel of 6E5P tubes why the OPT is 1.2K : 8? (each tube see OPT as 7.2K)
Why need to add more 0.2K when add more 4 tube.
2nd question:
2.1 Instead of using OPAMP why replace by Step-up 1:3 interstage transformer?
2.2 I think nowsaday many people use "gyrator" to driver tube in replacement of 1:3 interstage transformer. If capable of using gyrator with tube to drive 6 x 6E5P what tube and MU need to drive them at 9 watts.
1 - Ogonowski selling transformer 600:4 (1200:8). Maybe he could wind for you the transformer 1.166,66666:8.
But when you will build 10 or 20 different amps, you will see that with tubes even 10% diference does not mean nothing.
2 - I have transformer in stock and no opamps. And I have only 1 day to build amp.
Of course, you can use anything you want.
But when you will build 10 or 20 different amps, you will see that with tubes even 10% diference does not mean nothing.
2 - I have transformer in stock and no opamps. And I have only 1 day to build amp.
Of course, you can use anything you want.