I hope this will be my first tube amp build. I have limited experience in modding crossovers and playing around with SS amps. I would like to build a good amp not the cheapest not the most expensive and I am thinking on just going for the EL34.
It appears that the transformers are the biggest expense and I do not know anything about the Transformers and I am going to rely on everyones input as to what transformers work best at a reasonable price point.
Thanks for any input.
Scott
It appears that the transformers are the biggest expense and I do not know anything about the Transformers and I am going to rely on everyones input as to what transformers work best at a reasonable price point.
Thanks for any input.
Scott
I assume you mean El84?
The 6CW5 PP would be a bit cheaper if you wanted to go that route. Those tubes run around $5 each compared to the El84s run around $10 each. You would also not need to purchase a rectifier tube and the power transformer should be a bit cheaper too. Just something to think about if you are really looking to go the cheaper route.
The 6CW5 PP would be a bit cheaper if you wanted to go that route. Those tubes run around $5 each compared to the El84s run around $10 each. You would also not need to purchase a rectifier tube and the power transformer should be a bit cheaper too. Just something to think about if you are really looking to go the cheaper route.
$400 Total. Working amp less chassis. I will build that from stuff i have laying around.
I guess I would like to see a spread sheet type set up with different output tubes and Transformers and approximate cost for each variant in a general sense.
EL 84 Transformers# Cost 6CW5 Transformers# Cost
Cheap
Mid
$$$
I am a newbee just trying to learn and at this stage all the different transformer # and voltage rating for this and that make my head spin.
I think I just need a starting point to start understanding everything and I can take it from there. I am greenhorn in the tube amp building arena.
Thanks
Scott
I guess I would like to see a spread sheet type set up with different output tubes and Transformers and approximate cost for each variant in a general sense.
EL 84 Transformers# Cost 6CW5 Transformers# Cost
Cheap
Mid
$$$
I am a newbee just trying to learn and at this stage all the different transformer # and voltage rating for this and that make my head spin.
I think I just need a starting point to start understanding everything and I can take it from there. I am greenhorn in the tube amp building arena.
Thanks
Scott
Well the component cost will be almost identical if you go with the el84 amp or the 6cw5 with the exception of some diodes otherwise the cost there should be the same.
The power transformer for the 6cw5 is $30 plus I think it was $10 shipping from antekinc.com
Output transformers would be $47.13 each from edcor plus shipping. You would have to find out which would be the prefered transformer but I think the CXPP25-16-7.6K would work with an 8ohm load. I could be wrong.
The power transformer for the 6cw5 is $30 plus I think it was $10 shipping from antekinc.com
Output transformers would be $47.13 each from edcor plus shipping. You would have to find out which would be the prefered transformer but I think the CXPP25-16-7.6K would work with an 8ohm load. I could be wrong.
For the EL84 build...
Scott, you should be able to do it for under $400. So far, for an EL84 version with tube rectifier, this is what I can work out. For a 6CW5/EL86 build, the tranny choices here do not apply.
PCB, $43. Parts for PCB, around $100 or less, including sockets and 5AR4 rectifier tube. Less if you use parts from your stash.
Possible power tranny choices:
Edcor XPWR131, 120Vrms, 60Hz. 660V(330-260-0-260-330)@175mA, 6.3V@4A & 5V@3A, $61.89 USD
Edcor XPWR008, 120Vrms, 60Hz. 600V(300-0-300)@200mA, 6.3V@4A & 5V@3A, $53.77 USD
Edcor XPWR066, 240Vrms, 50/60Hz. 600V(300-0-300)@200mA, 6.3V@4A & 5V@3A, $63.36 USD
Hammond 372HX, universal primary, 300-0-300@230mA, 6.3V@6A, 5V@3A, USD$120 Angela.com.
Hammond 372FX, universal primary, 300-0-300 @ 173mA, 6.3V@5A, 5V@3A, USD$105 AES, USD$83 Triode Elec.
Magnetic Components, 2 x 120V primary, 355-305-0-305-355@200mA, 6.3V@5A, 5V@3A. Triode Elec P/N 40-18029 for Fender Twin guitar amp, USD$80.
Antek 2T300, 2 x 115V primary. 2 x 300V@300mA, 2 x 6.3V@4A, $35 USD. No rectifier winding, but maybe we can fix this, read below.
Possible output tranny choices:
Edcor CXPP25-MS-7.6K, 4-8-16 ohm taps, $57, or USD$47 for a single output tap. 5.25lb.
Dynaclone Z565, 8K primary, 4-8 ohm taps, $79. 4lb.
Electraprint, 7K6 primary, UL taps, max DC 40mA, 20W, 4-8 ohms secondary, USD$95.
Hoping Bud from O'netics will come back with a quote next week.
There's also Hashimoto HWC-30-8 30W for $180 each, or Silk P-60-15A 15W for approx $100 (but George recommends 20-50W). I would love to spring for the Hashi but it sort of destroys the budget.
Have a read of Georges tubes and transformers pages here, this is what we should be going by to make the decisions.
So with Edcor $47 output trannies and Edcor power tranny (say $60) we are up to around $300, so there is still room to move, but we are not there yet, and no shipping has been included. I have no idea of internal USA shipping costs. If you need to buy EL84 tubes I think a matched quad of JJ EL84 is around $60 or less, I have heard nothing but good things about these tubes and the guitar guys testify they can handle 350V to 400V reliably. Plus George put a set through the torture rack and they survived...one started glowing a bit at 420V.
This hypothetical $300 does not include: IEC inlet, power cord, fuse, power switch, RCA sockets, banana sockets, EL84 tubes, chassis or volume pot. This stuff can add up and the stash box comes in handy to reduce costs. There may be other stuff I've missed. I will be using some Russian 6P14P as I already have some, they are cheap and plentiful. If the B+ is too hot for them, I'm thinking of lowering the screen grid voltage to make them comfortable, or get some JJ EL84.
There's many ways to go about this. This is also my first build and man its agony making these decisions on iron. Keep in mind these examples of iron are simply what I have been looking at and is by no means what someone else may call a good choice. I am not ready to pull the trigger on any iron yet, but have all the rest on the way.
I am thinking of using the Antek 2T300 power tranny and modifying one of the 6.3V windings for 5V or make a new winding for 5V for the rectifier. I am not sure if this is a good choice. George recommends a 320-0-320 tranny. So proly best to find one like that. It's early days and we will find out more as the beta builders complete their building/testing/fine tuning.
Ian.
Scott, you should be able to do it for under $400. So far, for an EL84 version with tube rectifier, this is what I can work out. For a 6CW5/EL86 build, the tranny choices here do not apply.
PCB, $43. Parts for PCB, around $100 or less, including sockets and 5AR4 rectifier tube. Less if you use parts from your stash.
Possible power tranny choices:
Edcor XPWR131, 120Vrms, 60Hz. 660V(330-260-0-260-330)@175mA, 6.3V@4A & 5V@3A, $61.89 USD
Edcor XPWR008, 120Vrms, 60Hz. 600V(300-0-300)@200mA, 6.3V@4A & 5V@3A, $53.77 USD
Edcor XPWR066, 240Vrms, 50/60Hz. 600V(300-0-300)@200mA, 6.3V@4A & 5V@3A, $63.36 USD
Hammond 372HX, universal primary, 300-0-300@230mA, 6.3V@6A, 5V@3A, USD$120 Angela.com.
Hammond 372FX, universal primary, 300-0-300 @ 173mA, 6.3V@5A, 5V@3A, USD$105 AES, USD$83 Triode Elec.
Magnetic Components, 2 x 120V primary, 355-305-0-305-355@200mA, 6.3V@5A, 5V@3A. Triode Elec P/N 40-18029 for Fender Twin guitar amp, USD$80.
Antek 2T300, 2 x 115V primary. 2 x 300V@300mA, 2 x 6.3V@4A, $35 USD. No rectifier winding, but maybe we can fix this, read below.
Possible output tranny choices:
Edcor CXPP25-MS-7.6K, 4-8-16 ohm taps, $57, or USD$47 for a single output tap. 5.25lb.
Dynaclone Z565, 8K primary, 4-8 ohm taps, $79. 4lb.
Electraprint, 7K6 primary, UL taps, max DC 40mA, 20W, 4-8 ohms secondary, USD$95.
Hoping Bud from O'netics will come back with a quote next week.
There's also Hashimoto HWC-30-8 30W for $180 each, or Silk P-60-15A 15W for approx $100 (but George recommends 20-50W). I would love to spring for the Hashi but it sort of destroys the budget.
Have a read of Georges tubes and transformers pages here, this is what we should be going by to make the decisions.
So with Edcor $47 output trannies and Edcor power tranny (say $60) we are up to around $300, so there is still room to move, but we are not there yet, and no shipping has been included. I have no idea of internal USA shipping costs. If you need to buy EL84 tubes I think a matched quad of JJ EL84 is around $60 or less, I have heard nothing but good things about these tubes and the guitar guys testify they can handle 350V to 400V reliably. Plus George put a set through the torture rack and they survived...one started glowing a bit at 420V.
This hypothetical $300 does not include: IEC inlet, power cord, fuse, power switch, RCA sockets, banana sockets, EL84 tubes, chassis or volume pot. This stuff can add up and the stash box comes in handy to reduce costs. There may be other stuff I've missed. I will be using some Russian 6P14P as I already have some, they are cheap and plentiful. If the B+ is too hot for them, I'm thinking of lowering the screen grid voltage to make them comfortable, or get some JJ EL84.
There's many ways to go about this. This is also my first build and man its agony making these decisions on iron. Keep in mind these examples of iron are simply what I have been looking at and is by no means what someone else may call a good choice. I am not ready to pull the trigger on any iron yet, but have all the rest on the way.
I am thinking of using the Antek 2T300 power tranny and modifying one of the 6.3V windings for 5V or make a new winding for 5V for the rectifier. I am not sure if this is a good choice. George recommends a 320-0-320 tranny. So proly best to find one like that. It's early days and we will find out more as the beta builders complete their building/testing/fine tuning.
Ian.
I have a quad of Sovtek EL84Ms, which are 6P14P-EVs and can supposedly take more plate voltage and have longer life than the regular 6P14P. They don't like more than about 310V across them and start to glow around 320V, which is about what you will get with a 650VCT transformer. I was able to get them up to 330V by lowering the screen voltage to around 250V, but this had a very noticeable effect on the distortion spectra. The higher-order harmonics became much more apparent.
I recently got a quad of JJs and they can take it. Very nice spectra too. In fact, I had trouble with one of the Sovteks and talked to Brian at TubeDepot.com about EL84 choices. As you might suspect, all of the New Sensor EL84s are slightly modified 6P14Ps and none of them can really take these bent operating conditions well. He more or less said that JJs are the best and they are the cheapest to boot.
Not saying the New Sensor EL84s are bad tubes. They just won't like having more than 300V across them, so choose your power transformer accordingly. 600VCT should keep your Sovteks happy.
I have some NOS Reflector 6P14P-EV from 1986. Thanks for the heads up on different distortion characteristics with lowered screen voltage, if I use the Antek with 600V CT I should be OK. There will be less power due to lower B+, but I will be happy with 10-12W or whatever it makes. It is interesting that George also commented on the low distortion of the JJ's. I could buy another Antek AN-0225 toroid with 2 x 24V windings at 230mA each that could be put in series with the power tranny giving approx 650 CT, for $11. Shipping will be free with the main tranny for an international order (up to 20lb is a flat rate). That would give a degree of flexibility.
Ian.
Ian.
I plan to offer the board AND the parts kit for $100 to $110. They can both be stuffed into a small flat rate box, so shipping is the same price as the board alone, until the USPS changes the rules again as they lost several BILLION dollars last year. The parts kit includes all of the small parts that go on the PC board, caps, resistors, tube sockets, screw terminals, and the diodes for 6CW5 builds. It does not include any tubes.
There is some work going on that may lead to a change in some resistor values. I have not verified the exact cost of some components in my latest spreadsheet since some of the vendors (Digikey) show no stock on some parts. After the values and costs are confirmed I will have an exact cost for the parts kits and offer them for sale.
I have both of these and they work.
I have a 2T300, a 3T325 and a 2T350 on order. They will be tested upon arrival.
I haven't tried any of these OPT's and I don't see it happening due to lack of funds. I bought a good supply of cheap OPT's that work well here, so that is what I use. My power recommendation is based on the fact that there is so much "interpetation" in OPT power specs. I will restate my recommendation in a more realistic manner. If you want an OPT that can deliver full power over the entire audio range (20Hz to 20 KHz) in this amp it should weigh at least 5 pounds. It takes that much iron to deliver 20 watts at 20 Hz. I have seen tiny OPT's that claim to handle 50 watts and big ones that are rated for 15, size matters.
Does anyone have a schematic for the simple p-p? I'm having a problem with the plates on the outputs, they have a slight glow and the 150ohm resistor in the power supply gets so hot that it melts the solder. Caps are all good and the right polarity.
Checked all the resistors and they are all in the right places.
Checked all the resistors and they are all in the right places.
Some links to schems here - http://www.diyaudio.com/forums/tubelab/167250-sp-p-final-connections.html#post2195794
Are you using 270 ohm cathode resistors on the output tubes and what is the B+?
Ian.
Are you using 270 ohm cathode resistors on the output tubes and what is the B+?
Ian.
i used a hammond ao29 amp that u can get for like 100$ at most or any hammond with that amp . built a 5e3 from it . used 90% of it and cost me 30$ . or if your bent on el84s i just picked up ( off the side of the road) a hammond L111 with a ao43 witch uses el84s in a pp that i will be converting . happy hunting
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.