Well if i was super broke and wanted a simple SE:
el34 winged "c" = $30 pair on ebay, less if you want others or used
10 watt gxse= $26.10 (output transformers make the most improvement to sound)
Solid state rectifier= save $10-20
no choke= save $20 or more
no motor run cap= save $20 or more
antek AN-2T350 700v ct 240ma = $35.00
el34 winged "c" = $30 pair on ebay, less if you want others or used
10 watt gxse= $26.10 (output transformers make the most improvement to sound)
Solid state rectifier= save $10-20
no choke= save $20 or more
no motor run cap= save $20 or more
antek AN-2T350 700v ct 240ma = $35.00
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That pretty much sums it up........
really broke....use the XSE series transformers
kinda broke....use the GXSE and a choke
Couple of questions before I decide which way to go. I'm broke but not too too broke otherwise I would be looking at building a transistor radio.
I have a co-worker who apparently is a knowledgeable older gentleman, who used to rebuild tube tv's, radios, but really loved building and rebuilding guitar amps. Great to know in case I get into some real trouble. He is the one who keeps pressuring me to use the 6V6. He is eccentric so I may do 6V6 to keep him in a good mood to help me. He also tells me to get a 4ohm output on the transformer. Any reasons to follow this or not? He says it will be a great sound.
Also, it seems like all I would have to do is swap out the transformers and tubes if I wanted to upgrade.
Now for the questions:
Do the power tubes have to be a matched set? Since they are on separate channels I didn't know if it mattered. I am trying to find a datasheet on the 6V6 to see what the mA required is to know whether the Edcor or the Allied transformer will work. The allied is only 120mA and the Edcor @550VCT is 200mA. I will look at Antek as well. But I lean towards Edcor because they seem to have a good review from Tubelab.
I will do the GSXE15-4/8-5k depending on your thoughts. What is the difference in the input impedance?
If I don't need a matched pair, the local tube store has like 15 used 6V6 tubes that are guaranteed to work. GE, JAN, Tung-Sol and others for $10 each.
This is making me exercise my brain, I like it.
Sgregory: I know you what you meant, they just thought I had said it. I understand your point.
Can this amp be used for a guitar as well? Just out of curiosity.
Edit: Antek has one for $40 for 550VCT 500mA or $29 for 500VCT 200mA. I haven't heard anything about these transformers, but I don't know enough to know what effect these values will have on 6V6.
I have a co-worker who apparently is a knowledgeable older gentleman, who used to rebuild tube tv's, radios, but really loved building and rebuilding guitar amps. Great to know in case I get into some real trouble. He is the one who keeps pressuring me to use the 6V6. He is eccentric so I may do 6V6 to keep him in a good mood to help me. He also tells me to get a 4ohm output on the transformer. Any reasons to follow this or not? He says it will be a great sound.
Also, it seems like all I would have to do is swap out the transformers and tubes if I wanted to upgrade.
Now for the questions:
Do the power tubes have to be a matched set? Since they are on separate channels I didn't know if it mattered. I am trying to find a datasheet on the 6V6 to see what the mA required is to know whether the Edcor or the Allied transformer will work. The allied is only 120mA and the Edcor @550VCT is 200mA. I will look at Antek as well. But I lean towards Edcor because they seem to have a good review from Tubelab.
I will do the GSXE15-4/8-5k depending on your thoughts. What is the difference in the input impedance?
If I don't need a matched pair, the local tube store has like 15 used 6V6 tubes that are guaranteed to work. GE, JAN, Tung-Sol and others for $10 each.
This is making me exercise my brain, I like it.
Sgregory: I know you what you meant, they just thought I had said it. I understand your point.
Can this amp be used for a guitar as well? Just out of curiosity.
Edit: Antek has one for $40 for 550VCT 500mA or $29 for 500VCT 200mA. I haven't heard anything about these transformers, but I don't know enough to know what effect these values will have on 6V6.
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For quick 6V6 info, look here: TDSL Tube data [6V6]
In class A single ended with a plate voltage (Va) of 250V, you'd like to be drawing about 45 mA per tube (Ia). That's 90 mA for the pair, plus add another 16~20mA for both sides of the 12AT7 (roughly 8~10mA per side). That's a whopping total of 110mA.
If you intend to go with the 6V6, you might be able to get away with the Edcor GXSE5-8-5.5K. The 5.5K load impedance is a pretty good match for the triode strapped 6V6, assuming your speakers are roughly 8 ohms. The XPWR009 could probably work for the power transformer, but double check the specs carefully. I think it will give about 325 volts or so with a 5AR4 rectifier, or 345 volts if you try solid state rectification. The 5Y3 might work too, but has a lot of voltage drop - I'm guessing you'd end up somewhere around 260 VDC.
In class A single ended with a plate voltage (Va) of 250V, you'd like to be drawing about 45 mA per tube (Ia). That's 90 mA for the pair, plus add another 16~20mA for both sides of the 12AT7 (roughly 8~10mA per side). That's a whopping total of 110mA.
If you intend to go with the 6V6, you might be able to get away with the Edcor GXSE5-8-5.5K. The 5.5K load impedance is a pretty good match for the triode strapped 6V6, assuming your speakers are roughly 8 ohms. The XPWR009 could probably work for the power transformer, but double check the specs carefully. I think it will give about 325 volts or so with a 5AR4 rectifier, or 345 volts if you try solid state rectification. The 5Y3 might work too, but has a lot of voltage drop - I'm guessing you'd end up somewhere around 260 VDC.
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The output transformer just reflects the speaker load impedance to the output tube anodes, so for example connecting a 4 ohm speaker to 8 ohm taps with a 5K transformer makes it a 2.5K transformer. Conversely, connecting an 8 ohm speaker on a 4 ohm tap on a 5K transformer will make it a 10K load to the output tubes.
So.....long story short, it's best to connect the correct speaker impedance to the output taps, to assure that the output tubes see the correct load. If you get a transformer with 4 ohm secondaries, you'll need 4 ohm speakers for proper operation.
I wouldn't. If anything, I'd rather go smaller, rather than larger. There are enough problems reported with rectifiers arc'ing. Some will survive, but you're just asking for trouble.
Thanks SGregory and Ty.
Is it just the capacitance before the choke or resistor that matters for the max 60uF? I know 120uf is recommended to follow the 47uf and choke, so the rectifier won't be affected by this larger cap later in the circuit (or the optional motor cap?). Just trying to understand how the PS works.
Is it just the capacitance before the choke or resistor that matters for the max 60uF? I know 120uf is recommended to follow the 47uf and choke, so the rectifier won't be affected by this larger cap later in the circuit (or the optional motor cap?). Just trying to understand how the PS works.
Or just go solid state for the rectifier. The the cap size doesnt matter. He even has an option for it.
You are correct. The tube rec cant handle more then 60uf right off the bat. It would arc at turn on. Down the way you can add more capacitance, but with diminishing returns. You could always just pop the 68uf where the motor run cap should be and install R1 or a choke.
You are correct. The tube rec cant handle more then 60uf right off the bat. It would arc at turn on. Down the way you can add more capacitance, but with diminishing returns. You could always just pop the 68uf where the motor run cap should be and install R1 or a choke.
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FWIW, I've played with all the common tubes in my SSE, using Edcor XSE OPT's. All sound good in but the KT-88 definitely shines in UL mode when the program material demands higher volume settings. I suspect that the GX transformers would be a little bit better, but just enough to justify the extra $25 per pair. That said, most of my listening is, for reasons of domestic harmony, done at lower levels and the tubes that spend the most time in the amp are my EL-34's. This setup sounds good, so good that I've not even considered upgrading the OPT's.
I had considered using the large Edcors but I do not need an amp that goes down to 20Hz. The middle of the road GXSE series reach down to 40Hz which is a bit lower than the full range drivers (CSS EL -70)I bought for the amp reach. It struck me lately that using the X series might be great for a dedicated mid/tweet amp for bi amping an appropriate speaker set up. Going to build a set of Coniston^2's for my simple se. http://www.planet10-hifi.com/boxes-CSS.html
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just about any edcor will play down to 20-30hz regardless of model. However if you get the cheap 70hz ones, they will only play a few watts before distorting. diyaudioprojects measured the 70hz models way down since he was only pushing 1 watt
Poddwatt Class-A Stereo EL84 (6BQ5) Vacuum Tube Amplifier
Poddwatt Class-A Stereo EL84 (6BQ5) Vacuum Tube Amplifier
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