I have digested oodles of info, and come up with three candidates for my first pre-amp kit:
Foreplay III from Bottlehead http://www.bottlehead.com/et/adobespc/foreplay3/foreplay3.htm
Magic 5 SE from Mapletree http://hollowstate.netfirms.com/magic5.htm
AE-3 from audioelectronicsupply http://www.audioelectronicsupply.co...etail&dept_id=2&aisle_id=22&prod_num=AE-3_KIT
I just finished my first diy project, a Cmoy headphone amp that actually worked first time out of the gate. Feel confident to step up to a pre-amp, but also convinced a kit would probably be a sane choice for a beginner. (The temptation to move up from 18V dc to a couple hundred is too much).
Any sage advice or opinions from those who have heard or built more than one of the above? Santa is bugging me to make a decision.
Any help would be very kind. Thanks in advance.
Foreplay III from Bottlehead http://www.bottlehead.com/et/adobespc/foreplay3/foreplay3.htm
Magic 5 SE from Mapletree http://hollowstate.netfirms.com/magic5.htm
AE-3 from audioelectronicsupply http://www.audioelectronicsupply.co...etail&dept_id=2&aisle_id=22&prod_num=AE-3_KIT
I just finished my first diy project, a Cmoy headphone amp that actually worked first time out of the gate. Feel confident to step up to a pre-amp, but also convinced a kit would probably be a sane choice for a beginner. (The temptation to move up from 18V dc to a couple hundred is too much).
Any sage advice or opinions from those who have heard or built more than one of the above? Santa is bugging me to make a decision.
Any help would be very kind. Thanks in advance.
You could build Franks 5692 line stage at a fraction of the cost of those on your list. Franks line stage will out perform them also.
Why not make it a true DIY project instead of someone elses borderline kit?
Why not make it a true DIY project instead of someone elses borderline kit?
I have not heard any of them , I have built a few Bottlehead kits and can say that they are a pleasure to do business with. The general word is that the Foreplay III sounds as good or better then the II with all the usual mods ( CCS 's ,DC heaters, stepped antunators, designer output caps, PDMPS ) . There is an upgrade kit coming for the III so if you like to tinker , then you have a clear path. And then there is the Bottlehead Forum , one of the most civil places on the web. You may like one of the other choices better , but you won't go wrong with the bottlehead.
Have big fun building
Celeste
Have big fun building
Celeste
I'd echo the DIY idea instead of a cheap kit. You'll spend less money, and have a better linestage when you're done.
The Guinevere linestage discussed at Audio Roundtable is a good and fairly simple start. It is quite versatile. Pick your gain requirement and go from there. Need a gain of ~20? try a 6SN7, want a little less, go 5687, less still, 7AH7, still less? 12B4 comes to mind at mu=6.5.
The schematic is here:
http://audioroundtable.com/GroupBuild/Projects/
I drew it, got some help from a few members, and there are more than a dozen of them around by now in one form or another. You're looking at ~$200 in parts, and your own labour. there is nobody to pay for the design, so your parts bill is the end of it.
cheers,
Douglas
The Guinevere linestage discussed at Audio Roundtable is a good and fairly simple start. It is quite versatile. Pick your gain requirement and go from there. Need a gain of ~20? try a 6SN7, want a little less, go 5687, less still, 7AH7, still less? 12B4 comes to mind at mu=6.5.
The schematic is here:
http://audioroundtable.com/GroupBuild/Projects/
I drew it, got some help from a few members, and there are more than a dozen of them around by now in one form or another. You're looking at ~$200 in parts, and your own labour. there is nobody to pay for the design, so your parts bill is the end of it.
cheers,
Douglas
Hi,
if you don't mind spending more money go for the kit option. You don't need to search for a schematic( which one is better? there are hundreds....), you don't need to search for parts and the manual is dumb proof. But, on the other hand, you could easily have one better for half of the price.
If you go the DIY route just don't choose a complicated design, a simple line stage is SO easy to do and , generally, sound great.
if you don't mind spending more money go for the kit option. You don't need to search for a schematic( which one is better? there are hundreds....), you don't need to search for parts and the manual is dumb proof. But, on the other hand, you could easily have one better for half of the price.
If you go the DIY route just don't choose a complicated design, a simple line stage is SO easy to do and , generally, sound great.
I would (and did) personally build a 12b4a linestage. gain of about 5, simple, GREAT sounding, and fun!
You can cearch the schematic on this site...
You can cearch the schematic on this site...
You might want to add the Transcendent Grounded Grid to your list to consider. At $499, not too far outside the price range you are looking at. A completely different approach than the other kits you list in that it uses a PCB instead of point to point.
Grounded Grid
The new foreplay looks really nice from a build perspective. I gave up rebuilding my foreplay 2 when I saw the 3 had come out. In any case I'm happy with my grounded grid.
Grounded Grid
The new foreplay looks really nice from a build perspective. I gave up rebuilding my foreplay 2 when I saw the 3 had come out. In any case I'm happy with my grounded grid.
The Guinevere looks interesting, and isn't that different conceptually from Brant's 12B4 -- the SS loading bits could probably be added to it from the Guinevere and you'd have another version...
The Foreplay & the AES are 2 faces of the same topology, as is one of the Maple Tree modes. I've heard so many JoeListers comment on how their cicrcuit sounded better after converting an SRPP to common cathode that i'm leary of that.
For a kit in that price range, i vote for... The Grounded Grid.
dave
The Foreplay & the AES are 2 faces of the same topology, as is one of the Maple Tree modes. I've heard so many JoeListers comment on how their cicrcuit sounded better after converting an SRPP to common cathode that i'm leary of that.
For a kit in that price range, i vote for... The Grounded Grid.
dave
The 12B4 with a resistive plate load can be done very easily. The Guinevere plate loads will drop its output Z from ~1kOhm to less than 100R which is a nice low number for driving almost *ANYTHING* and making cable salesmen poor.
If you want to play with the Grounded grid, you can adjust gain by putting a plate load onto the input section. You don't have to do anything with it, and if you have too much gain, you can increase it up to and past the value on the amplifying section. Think Schmitt inverter/Lont-tail-pair sort of thing.
cheers,
Douglas
If you want to play with the Grounded grid, you can adjust gain by putting a plate load onto the input section. You don't have to do anything with it, and if you have too much gain, you can increase it up to and past the value on the amplifying section. Think Schmitt inverter/Lont-tail-pair sort of thing.
cheers,
Douglas
amperex said:
I think you should get out more🙂
The DIY most are proposing have features like choke input PS design, all film caps, valve rectifiers and other things that seriously push up a kit's price.
if a materials cost/economics lecture is required, look elsewhere...not my 'sponsibility.
What it boils down to is that at comparble money input, there is no beating DIY if the design is good, and there are a lot of good designs, and even a few great ones.
cheers,
Douglas
I built a Foreplay as my first DIY project and found it to be a remarkably positive experience. I can't speak for the more knowledgable folks here, but if you are just starting out on DIY projects, getting a kit makes good sense so long as it comes with clear directions and great support (should you need it). At $149 (the price I paid), the Foreplay was considerably cheaper than the highly-touted $499 Grounded Grid. Over time, I added over $300 worth of additions to my Foreplay (DACT attenuator, rack mount chassis, pseudo-dual mono power supply, both snubbers, Greyhill selector, CCS, etc). All resulted in noticeable sonic improvements, which taught me a number of important lessons. By the time I was done upgrading my Foreplay, it cost about what a stock Grounded Grid would have run me. I can't speak to the differences between the two preamps, but I do know that I learned a lot more building and tweaking my Foreplay than I would have learned simply building the Grounded Grid.
Amps are easier to build than preamps. My advice: buy a preamp kit and learn from an experienced designer. Experiment from a proven preamp design by tweaking. Get your sea legs. Then build an amp from scratch.
Regards,
Scott
Amps are easier to build than preamps. My advice: buy a preamp kit and learn from an experienced designer. Experiment from a proven preamp design by tweaking. Get your sea legs. Then build an amp from scratch.
Regards,
Scott
SRMcGee said:
Now at $399 with lots of the extra bits included, your journey would have to be taken via diy...
Attached is a pair of schematics Frank de Grove posted which are the essential elements of the AES (ir RC coupled) & ForePlay (direct coupled) using a 6SN7 or 5692,
dave
Attachments
I am always amazed at the responses I see on this Forum. Thanks so much for all of your inputs. If anyone would like elective root canal therapy give me a buzz.
If I continue on my original bend to build a kit, consensus seems to be either the foreplay or grounded grid. I think I could make that decision.
Douglass, you made me burn lots of brain cells trying to decipher schematics off of napkins. Many schematics are challenging for me as a beginning DIY. Can you give me any direction to a schematic with ps, that is obvious even to the electronically challenged? I am willing to go from scratch, but I also would need it be fairly clear.
Here is a link for a very clear 5687. Opinions? I only have had trouble trying to find a transformer that could be substituted.
Thanks for your encouragement. I feel like I am writing in crayon on a forum full of techs from the enterprise. Beam me up.
If I continue on my original bend to build a kit, consensus seems to be either the foreplay or grounded grid. I think I could make that decision.
Douglass, you made me burn lots of brain cells trying to decipher schematics off of napkins. Many schematics are challenging for me as a beginning DIY. Can you give me any direction to a schematic with ps, that is obvious even to the electronically challenged? I am willing to go from scratch, but I also would need it be fairly clear.
Here is a link for a very clear 5687. Opinions? I only have had trouble trying to find a transformer that could be substituted.
Thanks for your encouragement. I feel like I am writing in crayon on a forum full of techs from the enterprise. Beam me up.
Sorry, forgot to paste that link.
http://diyparadise.com/preamptutorial.html
Need to get that I.V. of coffee in.
http://diyparadise.com/preamptutorial.html
Need to get that I.V. of coffee in.
cryo said:
Indeed it is. Those same instructions would pretty much covr off Brett's 12B4 (2 tubes instead of dual triode thou) and would be a good basis to the Guinevere.
Transformer should be fairly easy to find... (i know i could go down to my "junk box" and find at least a half-dozen suitable (note the one he used is overkill size),
dave
On the grounded grid circuit, there is no need for a matching pair of triodes per channel. Run what ever triode you wish as the amplifier.
For the cathode follower, get a high-gm pentode. It will of course dictate the grid bias on the amplifier section. However, since we're only looking for a little bit of output voltage, it is not going to cause any troubles.
The pentode, say a 12GN7 offers output Z of 1/gm or ~30R to drive the cathode of the amplifier triode. We would want a cathode input Z of a few times this amount if we're keeping to the traditional, 'load is large compared to output Z'. Triode's cathode Z is R_p/(mu + 1) IIRC. With identical triodes, we're looking at 1:1 output Z:load ratio.
There's a few other benefits to this scheme. The plate Z is lowest at higher grid bias points, so the amplifier triode is going to have better drive for its amp and cable load. Tweak the pentode by playing with its g2 voltage.
cheers,
Douglas
For the cathode follower, get a high-gm pentode. It will of course dictate the grid bias on the amplifier section. However, since we're only looking for a little bit of output voltage, it is not going to cause any troubles.
The pentode, say a 12GN7 offers output Z of 1/gm or ~30R to drive the cathode of the amplifier triode. We would want a cathode input Z of a few times this amount if we're keeping to the traditional, 'load is large compared to output Z'. Triode's cathode Z is R_p/(mu + 1) IIRC. With identical triodes, we're looking at 1:1 output Z:load ratio.
There's a few other benefits to this scheme. The plate Z is lowest at higher grid bias points, so the amplifier triode is going to have better drive for its amp and cable load. Tweak the pentode by playing with its g2 voltage.
cheers,
Douglas
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