| Coulomb |
I am considering the dual Mono EICO partial kit from diytube.com this is thier blurb.
The design closely resembles the Eico HF-series which used a modified Mullard 5-20 circuit. The Eiclone (pronounced ‘eye-clone’) uses the 12AX7 as the voltage gain stage tube, as did the classic Eico HF-87 and HF-89. This gain stage DC-couples to a 6SN7 long-tail pair phase splitter driving a pair of push-pull EL34 tubes. The bias supply and grid resistors in the standard design are compatible with alternate power tubes such as 6550s and KT88s.
It is a PARTIAL kit meant for experienced tube hobbyists, and it includes:
two ultra-heavy duty PCBs with silkscreen on both sides - 50% thicker and with 100% more copper than your average PCB
new 'Rev B' design allows the experienced DIYer many undocumented options (eg 6SL7 sub for the 12AX7, CCS for the LTP, etc.)
robust 16-page manual containing: straight-forward instructions, detailed schematics, assembly artwork and templates - see here (~500k PDF)
parts list w/ Mouser.com part numbers and BOM support
email support provided
a growing community forum and tons of project pictures on diytube.com
Most parts can be purchased easily through Mouser, and vendors are suggested for the others (ie transformers, tubes, and tube sockets). This design is intended for all new construction using Hammond transformers: 274BX power transformer and 1650N outputs. Pictures showing completed projects are not indicative of auction contents. Design is to be oriented for a tube out construction.
Go to diytube.com for more info and pictures.
Anyone tried this kit or this topology?
Regards
Anthony |
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| SHiFTY |
Would probably work fine. You might want to use 6SL7s in the front end though, would sound better. Use KT88s for max power. Dont solder sockets to the board but run wires instead to a large chrome chassis with sockets & trannies mounted on top.
I actually wish I had seen this kit before i started point-to-point wiring- would probably have halved the time to finish my amp, not to mention made it a lot neater!
So yeah probably a good idea eh. |
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| Coulomb |
Hello SHIFTY, Thanks for the tip on the tube selection.
Regards
Anthony |
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| anatech |
Hi Anthony,
I am a happy owner of an HF-87a. Uses 6SN7's, 6CA7's for outputs and 12AX7A for input. The output iron is larger than normal on a real HF-87A. (larger than other amps that power rating)
Build it and be happy.
-Chris |
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| KBK |
| I need some tube amps..but I'm short on free time! Rotac used to have the 'passion' kits, which were kinda cool. They gave up on that. darn. |
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| Coulomb |
Well I bought a pair of these boards from Shannon of tubediy.com, now I am just waiting for thier arrival. I think I am going to try the 6SL7 input as suggested. The Output Transformer is a Hammond 1650N good for 60 watts PP, I would like to investigate one of the bigger 1650 transformers as a possible replacement.
Regards
Anthony |
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| anatech |
Hi Anthony,
Those xformers should do fine. If you leave extra room on the chassis you can try the other ones later.
Are you going to use EL34's or 6CA7's ?
-Chris |
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| Coulomb |
| quote: | Originally posted by anatech
Hi Anthony,
Those xformers should do fine. If you leave extra room on the chassis you can try the other ones later.
Are you going to use EL34's or 6CA7's ?
-Chris |
Well I was thinking KT88's as suggested by SHIFTY,
Regards
Anthony |
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| anatech |
Hi Anthony,
I was just curious. The project power has gone up a fair bit with the KT-88's. I thought you were still down in EL-34 / 6L6 power ranges.
-Chris |
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| Coulomb |
Hello Chris, I ended up getting the Eico boards instead of the ST35 boards. The Eico uses a 1650N output transformer which is rated at 60 Watts as opposed to the much smaller transformer of the ST35 which develops 17.5 Watts.
Am I on subject here? Is that what you were referring to Chris?
Regards
Anthony |
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| anatech |
Hi Anthony,
That sounds good. I think we are on the same topic.
The larger iron will give better sound. Higher power also requires a higher B+, so if you don't increase the B+, the KT-88's may be a waste of tube and heater power.
The original Eico HF-87a is rated at 35W/ch. This seems to be ample power. I am toying with the idea of building a 50~70W/ch unit with a pair of KT-88's since I have many KT88's sitting around doing nothing (yet).
-Chris |
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| Coulomb |
| quote: | Originally posted by anatech
Hi Anthony,
That sounds good. I think we are on the same topic.
The larger iron will give better sound. Higher power also requires a higher B+, so if you don't increase the B+, the KT-88's may be a waste of tube and heater power.
The original Eico HF-87a is rated at 35W/ch. This seems to be ample power. I am toying with the idea of building a 50~70W/ch unit with a pair of KT-88's since I have many KT88's sitting around doing nothing (yet).
-Chris |
Thanks for the tip on the KT88, I may have to up the power transformer.
Hummm a plethora of KT88's eh, maybe we could work something out?
Regards
Anthony |
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| burnedfingers |
Quote:
I have many KT88's sitting around doing nothing (yet).
Please let me send you my address. I could help get rid of some of those KT88's. |
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| Coulomb |
Anyone have an opinion about the "Sound" of a KT88, 6550 or EL34? Any particular brands that have a place in your heart?
Regards
Anthony |
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| anatech |
Hi Anthony,
Possibly trade for something. Transformers maybe. I have quite a few tubes. Most are National branded. Some are 6550A from National.
The sound difference will depend on the circuit. The junk ones will blow up (arc). Early Chinese are famous for this.
-Chris |
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| Coulomb |
| quote: | Originally posted by anatech
Hi Anthony,
Possibly trade for something. Transformers maybe. I have quite a few tubes. Most are National branded. Some are 6550A from National.
The sound difference will depend on the circuit. The junk ones will blow up (arc). Early Chinese are famous for this.
-Chris |
What Transformers do you need Chris? I am also in the midst of refurbushing several Tube testers.
Regards
Anthony |
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| anatech |
Hi Anthony,
I would be interested in outputs and power for 6L6GC types, ultralinear around 50 - 60W. The amp would run around 40W. I haven't had any time to research this, it's just a wish list kinda thing. The other alternative would be power and outputs for an amp using one pair of KT-88 per channel.
I am in the Toronto area, so PM me if you are interested.
Thanks Anthony,
-Chris :D |
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| Coulomb |
| quote: | Originally posted by anatech
Hi Anthony,
I would be interested in outputs and power for 6L6GC types, ultralinear around 50 - 60W. The amp would run around 40W. I haven't had any time to research this, it's just a wish list kinda thing. The other alternative would be power and outputs for an amp using one pair of KT-88 per channel.
I am in the Toronto area, so PM me if you are interested.
Thanks Anthony,
-Chris :D |
Hello Chris, I have been silent for a few days, kind of busy. I am busily sorting through some equipment from an aquaintenance's father in law's estate.
Any Ideas what a Grid Dip meter is? I have one in excellent condition with a bunch of interchangeable probes. I thought it might be for shoving into the core of a coil to measure inductance.
BTW I have a whack load of tubes myself, including some Tung Sol 6SN7, you mentioned that make a nice output tube?
Regards
Anthony |
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| anatech |
Hi Anthony,
I have a broken grid dip meter. They are used to measure the tuning of IF and RF coils. Mostly in old radios (another hobby).
6SN7's are good signal tubes. You will use these.
Regards, -Chris |
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| Coulomb |
| quote: | Originally posted by anatech
Hi Anthony,
I have a broken grid dip meter. They are used to measure the tuning of IF and RF coils. Mostly in old radios (another hobby).
6SN7's are good signal tubes. You will use these.
Regards, -Chris |
Thanks Chris, any idea of the price range I can expect if I post it on ebay?
Regards
Anthony |
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| anatech |
Hi Anthony,
Highly variable. I'm guessing the grid dip meter is what you are talking about. What's the make and model? What were you thnking $$?
I bought my last one for $15.00 (working). Heathkit HD-1250 in box with coils. I am interested in picking up another one.
-Chris |
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| Coulomb |
| quote: | Originally posted by anatech
Hi Anthony,
Highly variable. I'm guessing the grid dip meter is what you are talking about. What's the make and model? What were you thnking $$?
I bought my last one for $15.00 (working). Heathkit HD-1250 in box with coils. I am interested in picking up another one.
-Chris |
I posted it on ebay here;
http://cgi.ebay.com/ws/eBayISAPI.dl...me=STRK:MESE:IT
If you are interested send me an email with your offer, please do not be concerned with the buy it now price, I can change it for you. I just want a fair price, so please make an offer.
Regards
Anthony |
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| Coulomb |
| quote: | Originally posted by anatech
Hi Anthony,
Highly variable. I'm guessing the grid dip meter is what you are talking about. What's the make and model? What were you thnking $$?
I bought my last one for $15.00 (working). Heathkit HD-1250 in box with coils. I am interested in picking up another one.
-Chris |
Chris, I also have a Test Oscillator for sale on ebay.
Regards
Anthony |
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