[88Sound]

Gilmore Class A Kit Review

It’s been nearly 20 years since I’ve done a DIY project. My last DIY project was a Hafler 220 power amp and Hafler Pre-amp in 1983. If anyone remembers these kits they were supplied with finished and tested circuit boards and only required mounting them in the chassis and wiring the jacks with some minimal additional soldering.

In anticipation of the Gilmore arrival I picked up some new tools, a Panavise electronic work center (vise for holding circuit boards, soldering station, a neat little spring like thing for holding wires) heat sink, and desoldering tool (in the unlikely event any mistakes were made). These Items along with my trusty Weller soldering iron would give me the greatest chance at success with my upcoming project.

My kit arrived 5 days before the New Year and I was ready. This amplifier has a separate power supply making this like two separate projects. All the components were nicely packaged with everything I needed for assembly except tools, solder, and hook up wire. All the individual components were in their own nicely labeled plastic bags. These small bags were then placed in larger bags labeled for Power Supply, Amp, or Misc. A check off sheet with a listing of all the items in the kit is provided to make sure you aren’t missing anything. The biggest shock of all is that no instructions are provided for assembly, zero, zip, nada.

I was quite shocked at the missing instructions but after looking at the very nicely stenciled circuit boards and well labeled components I thought…maybe it’s self-explanatory. I am a meticulous trained monkey solder slinger who can follow directions perfectly but have no practical knowledge of circuit design. This coupled with a fool’s go where angels fear to tread attitude gave this project an air of DANGER.

Between posted pictures of a similar amp and the excellent labeling I was able to solder on all the components for both power supply and amp boards. After puzzling and puzzling until my puzzler was sore an e-mail cry went out to antness (the board designer). I was not about to attempt any hookup wiring without some instructions. Antness promptly responded with very detailed instructions on the power supply assembly with promises of amp assembly instructions to follow.

After a look at the power supply instructions I had done some things wrong! Two heat sinked components were in backwards, two capacitors had to have one leg each removed and a resistor inserted, and a jumper to select the voltage for the amplifier had to be installed. I thought that desoldering tool might come in handy! After making the changes I wired up the Power Supply, powered it up and voila’ the blue light came on!

Now it was off to the amplifier. I received an e-mailed diagram from antness for the wiring of the amplifier back panel. This was a good start but still left several decisions up to me, generally a bad idea in my case. I did not know exactly how the Alps Blue pot should be wired but fortunately had the same pot in a META42 to do a stare and compare. After completing the amp I powered it up with the power supply and another blue light! Success, or so I thought.

I hooked up a portable source and took my Grado 325’s and the sound was weak, distorted, and the left and right channels were blended. Thinking I may have reversed some wiring somewhere I went through everything and it all look perfect. More e-mail cries for help with immediate responses came back and through a series of exchanges the problem turned out to be in the power supply. Remember those reversed components…one of the points on the board had been damaged on the underside and the soldering needed to be done from the top. After this the amp now sounded great.

To make sure there were no other components damaged they were all checked for excess heat and measurements were taken across all the 25 Ohm resistors and the Vout DC voltage to ground. This last measurement is important because if it’s high it can damage your headphones. Every thing checked out perfectly and that last measurement was between .2 and .3 mV per channel. Success at Last! All wiring was dressed everything was buttoned up and the units look perfect inside and out.

The operation of the amp is flawless. Complete silence with the volume control at zero. With no source you can barely tell the amp is on only perceiving a slight noise floor at ¾ volume. If you were to play music into a Grado with this thing at ¾ you’d need a catchers mitt to catch the voice coil flying out of the headphone. The switches work perfectly allowing you to hook up two sources simultaneously and instantly switch between them. You can also switch the amp out from the headphone to a pair of RCA’s for use as a preamp.

IT TOOK THIS LONG TO GET TO THE SOUND!… Hey give me a break it’s DIY.

So far I’ve tried the Gilmore with three Grado phones, the 325, RS-1, and HP-2. The sound can be described as powerful, punchy, dynamic, exciting. Instrument separation and sound staging are excellent. The timbre of each instrument seems accurate also; nice tight bass with power to spare.

I have been asked how this compares with my solid state reference amp the Grace 901. First of all the Gilmore has been on a total of 12 hours and on for 9 hours playing music continuously before the test. The Grace and Gilmore are hooked up identically. Both are using Virtual Dynamics Power 3 Cryro cords with Outlaw interconnects out of a Pioneer DV47A that are all broken in. Until the Gilmore the Grace was the only amp I own that can supply all the current necessary for the Grado’s to sound their best. Without the proper current the bass starts to loosen up, among other nasties. The Gilmore is definitely in the category of an amp that can supply a lot of current and as such is an excellent choice for low impedance phones.

The Gilmore is a powerful amp and extremely fun to listen to, but the sound of the Grace is more refined and controlled. This is evident at the frequency extremes. The Gilmore is ever so slightly ragged by comparison, at the top a little raw, at the bottom very powerful but slightly less controlled (it still has nice tight bass but the Grace is tighter). Please remember these observations are only apparent by direct comparison to the Grace. The Grace is approximately three times more expensive than an assembled Gilmore and near four times the Gilmore Kit price.

So what do I really think after all this? The Gilmore was incredibly fun to build, I’m as proud as a new father is to have actually built something that sounds and looks this good. The cost of an assembled Gilmore is an excellent deal. The sub $400 price of a kit is an absolute steal. So far I have not encountered anything remotely near this price that sounds this good...go get one…now.

FINAL THOUGHTS

I’d like to thank Kevin Gilmore for sharing his gift of circuit design with everyone, this is an incredibly generous thing he’s doing and an incredible asset to this site and the DIY community.

I’d like to thank Justin Wilson (a.k.a. antness) for his excellent board design, very well organized kit, and being there when I needed him for help over and over again.

I’d like to thank Jude for maintaining this excellent site…. The quality, talent, humor, honesty, and generosity of the people that post to this site on a daily basis never ceases to amaze me.

 

[grinch]

Quote:

Originally posted by 88Sound I’d like to thank David Gilmore for sharing his gift of circuit design with everyone, this is an incredibly generous thing he’s doing and an incredible asset to this site and the DIY community.

somebody's been listening to too much pink floyd.. the designer of the amp is Kevin Gilmore. (we Kevins tend to stick together!)

great review 88sound. i think it's very interesting to hear a good comparison to the grace. however, i bet with some premium parts, the gilmore could kick its ass.

were you using the dac in the grace when you reviewed at all?

 

[88Sound]

Quote:

[size=xx-small]Originally posted by grinch[/size] somebody's been listening to too much pink floyd.. the designer of the amp is Kevin Gilmore. were you using the dac in the grace when you reviewed at all?

Thanks grinch, post has been edited, or I don't know what you're talking about I had Kevin there all along!

For the test in this review I did not use the Grace DAC.

 

[dhwilkin]

Are you planning on making additional comments, after the Gilmore amp has more burn-in time (say 80-100 hours)?

 

[88Sound]

Quote:

[size=xx-small]Originally posted by dhwilken[/size] Are you planning on making additional comments, after the Gilmore amp has more burn-in time (say 80-100 hours)?

If there is any change I will post. The Grace sounds quite a bit better now after a few hundred hours than when it was new. The kit was so much fun to build I might try selling it and building another one! or maybe even a balanced bridge version....it would be a shame to see those new tools go to waste.

 

[kelly]

88Sound
Thanks for posting your review.

I'm honestly surprised the Grace beat it but you're right, maybe with some breakin things will change. I don't agree that it's not a fair fight. The Grace costs more but is also a commercial product (overhead, customer service, labor, etc.) and the Grace is also a DAC. I'd be very surprised if the amplifier section of the Grace had a more expensive parts total than the Gilmore.

Of course, there is that stepped attenuator.

 

[BoyElroy]

Quote:

Of course, there is that stepped attenuator

A stepped attenuator would definitely result in a significant improvement over a standard pot. It is not a small difference, either.

A bit OT, but I actually wonder how a maxed Meta42 would sound with a stepped attenuator.

 

[ServinginEcuador]

Very well done review and comments on your DIY exploits and the amp you undertook to build!! I thoroughly enjoyed your humor, especially this particular quote:
Quote:

I am a meticulous trained monkey solder slinger...

Makes one want to go and buy the parts and start this project for themself!!! Great job!!

 

[Hirsch]

Quote:

Originally posted by kelly . The Grace costs more but is also a commercial product (overhead, customer service, labor, etc.) and the Grace is also a DAC. I'd be very surprised if the amplifier section of the Grace had a more expensive parts total than the Gilmore.

Tim de Paravicini of EAR has made some quite controversial statements about "audiophile parts". While I don't remember the exact quote, it's something along the lines of" the parts themselves don't matter as much as what you do with them". In other words, a good design using relatively cheap parts will sound better than a lesser design using "audiophile approved" parts. Then again, I disagree with much of which he says, as changing tubes in my EAR has dramatically improved the amp, despite his recommendations. Back on track, arguments about what should sound better because of parts used may be a dead end. It may well be that the part that works best in a specific design is not the one that has the "audiophile stamp of goodness". Sometimes a cheap part is the right one to use in the design.

 

[88Sound]

Quote:

[size=xx-small]Originally posted by Kelly[/size] I'm honestly surprised the Grace beat it but you're right, maybe with some breakin things will change. I don't agree that it's not a fair fight.

I think this is a fair fight now. The references to the fight not being fair were in another thread when I had the Grace using the VD power cord and it's internal DAC vs. the freshly built Gilmore with the supplied AC cord and analog out from the DV47A. That comparison would never be fair because of the DAC alone. The cost comparison is more informational rather than suggesting a mismatch.

The Gilmore is still burning in, it has about 28 hours on it now and sounds better. The burn in process is still a mystery to me, at one point yesterday I picked up the phones and that ragged sound actually sounded increased. I resisted the temptation to open it up and take more measurements. This morning It's starting to lose that ragged sound altogether, best it's ever been. The Grace sounds very musically rounded in comparison still, some people might call what I'm labeling as ragged ' high end sparkle' but the instruments sound more realistic to me without it.

I suspect that although the Grace and Gilmore will never sound the same it will come down to personal preference. the Grace has capabilities the Gilmore doesn't have (built in DAC with optical & coax in, balanced and unbalanced inputs, sensitivity switch which sets up the amp optimally for what ever phone you have). The Gilmore has capabilities the Grace does'nt have ( two sets of analog in's that can be instantly switched, and the ability to use as a preamp).

It is clear to me now that I will update my review after the Gilmore completely settles down which I expect will be in the 100 hour plus range.

Quote:

[size=xx-small]Originally posted by BoyElroy[/size] A stepped attenuator would definitely result in a significant improvement over a standard pot. It is not a small difference, either.

I was looking at the Elma stepped metal film resistor attenuators on the Elma site (the same one in the Grace). I would love to put one of these in the Gilmore if it would make that big of a difference. It looks like the minimum order is 10, there is no cost listed, and I suspect they aren't cheap.

I would be very interested in any suggestions you might have regarding this.

Quote:

[size=xx-small]Originally posted by ServinginEcuador[/size] Makes one want to go and buy the parts and start this project for themself!!! Great job!!

Thanks, it was great fun and even though I'm picking at nits I am very satisfied with the outcome so far and it seems like it's only getting better.

Quote:

[size=xx-small]Originally posted by Hirsch[/size] It may well be that the part that works best in a specific design is not the one that has the "audiophile stamp of goodness". Sometimes a cheap part is the right one to use in the design.

Absolutely true.

 

[kelly]

Tim is a businessman so I think what he says is in his interest to say. He's also a good designer, so I'll not reply further to that. If he shows himself on Head-Fi to speak for himself we can debate.

Meanwhile, my belief is and will remain that the potential for good design is increased with a greater budget. Does this mean every more expensive part is better than every cheaper part? Of course not. Is every expensive component better than every less expensive one? Of course not. However, it seems obvious to me that on an unlimited budget, one has more options--the cheap parts AND expensive ones are both available and the best overall decisions can be made. This philosophy cannot exist in a for-profit business.

Kevin Gilmore does not run a for profit business AND he is a good designer. It is beyond irritation to me that someone who contributes his work freely is given so little respect.

And that's all I have to say about that.

88Sound
I had read somewhere that the Grace uses the Dact stepped attenuator and the steps given in one review matched the Dact's. Are you sure you aren't thinking of the other switches being Elnas?

Upon reflection, I realized the tone of my replies may have been off from my intent. The actual thought in my head when you say the Grace and Gilmore are close is, "Wow, the Grace must be really good," since after all the Grace is the one I haven't heard. And I agree, if you're getting a competent DAC in a box with something that sounds that similar to the Gilmore--I do think the Grace sounds like an awesome product. Sure you can't make it to the next Dallas meet?

I don't understand burn-in either... but I've witnessed it repeatedly, to my dismay.

 

[Hirsch]

Quote:

Originally posted by kelly Kevin Gilmore does not run a for profit business AND he is a good designer. It is beyond irritation to me that someone who contributes his work freely is given so little respect.

I haven't seen anything in this thread, or in fact in any thread that I've read, in which Kevin Gilmore's work is treated with "little respect", so I have no idea where this comment came from. I have only heard one of his designs once, and, to refresh your memory, I liked it a lot and have repeatedly said so. If you're implying that respect means that everything he does should be treated as the greatest thing since the invention of two-channel audio simply because he designed it, rather than evaluated honestly against other designs, sorry. That's where I get off the bandwagon.

Di Paravicini's position, whether you agree with it or not, has an interesting implication that bears further consideration. In the end, it's not the electrical parts so much as the reproduction of music that is the goal of a product...and that part selection is subservient to that goal. While I disagree with much of what he says, that part rings true.

 

[kelly]

Quote:

Originally posted by Hirsch I haven't seen anything in this thread, or in fact in any thread that I've read, in which Kevin Gilmore's work is treated with "little respect", so I have no idea where this comment came from. I have only heard one of his designs once, and, to refresh your memory, I liked it a lot and have repeatedly said so. If you're implying that respect means that everything he does should be treated as the greatest thing since the invention of two-channel audio simply because he designed it, rather than evaluated honestly against other designs, sorry. That's where I get off the bandwagon. Di Paravicini's position, whether you agree with it or not, has an interesting implication that bears further consideration. In the end, it's not the electrical parts so much as the reproduction of music that is the goal of a product...and that part selection is subservient to that goal. While I disagree with much of what he says, that part rings true.

I wrote a lengthy and bitchy reply and deleted it. This thread is about the Gilmore kit by HeadAmp.com and 88Sound's impressions of it. Hirsch and I disagree on a great number of things that are better argued elsewhere (or perhaps not at all). I don't think Tim's quotes had any relevance in this thread and I've already said too much on the subject here.

 

[BoyElroy]

Hi 88Sound,

You should be able to fit a DACT CT2 stepped attenuator in Antness' enclosure without too much trouble. I think www.diycable.com has them for around $125-$130 US.

 

[88Sound]

Quote:

[size=xx-small]Originally posted by kelly[/size] I had read somewhere that the Grace uses the Dact stepped attenuator and the steps given in one review matched the Dact's. Are you sure you aren't thinking of the other switches being Elnas? Kevin Gilmore does not run a for profit business AND he is a good designer. It is beyond irritation to me that someone who contributes his work freely is given so little respect.

I am sure that my Grace 901 has an Elma (that's Elma with an 'm') I had always thought it was Elna until I looked it up today. Michael Grace specifically mentioned it to me when I spoke with him. I also looked on the Elma web site and they have pictures of the attenuator that's in my unit. This does not mean that Grace did not change this at some point. I believe I have a very early model.

With all this comparison to the Grace I don't know how well it's come across that IMO the Gilmore is an awesome amp, but to my ear the Grace is the most utterly unflinchingly accurate and musical sounding at the same time amp I have ever heard. The Gilmore continues to change and get better with burn in so where this will all end up I won't know for a few days.

Those thank you's I put at the end of my review to Kevin, Justin, and Jude are Heartfelt. For the record I am in awe of Kevin's abilities (insert five Wayne's World "I am not worthy" 's here) and the fact that he shares these gifts freely is amazing.

Quote:

[size=xx-small]Originally posted by BoyElroy[/size] You should be able to fit a DACT CT2 stepped attenuator in Antness' enclosure without too much trouble.

Thanks for the info! What sonic improvements might I expect from the DACT CT2 over the Alps Blue and are you familiar with the Elma? Here is the place on their website that shows the
attenuator in my 901 http://www.elma.com/us/products/rota...%20Switches/24