QUAD VINTAGE Genalex Gold Monarch KT88 Vacuum Tubes - SOLD
I have these listed elsewhere, so I thought I would try here as well.
Yes – these are ORIGINAL vintage Genalex Gold Monarch KT88 vacuum tubes. These are extremely desirable and very difficult to come by. I picked up a group of these a while back, sold most off, but did keep 4 for myself.
I have come to the realization that I do not need such prime tubes, and could use the value (cash/trade) for other things, so here they are for sale.
As you will see from the test results below, by almost all measures these 4 tubes can be considered a matched QUAD. Different testers, however, can give vastly different test results. This ad is SOLELY based on my testers and my test results (see the TERMS AND CONDITIONS below).
As you can see from the photos, these are clearly USED tubes, and are NOT pristine in any way, shape or form. The bases are generally weathered (but stable), and there is old tape residue and writing on all of the tubes. The printing is faded but still discernable. Flashing is very good on these tubes, but there clearly is some wear. One tube (#10) is missing the center guide, plus the pins are not entirely straight, plus it is missing the Genalex sticker (but does have printing on the glass); however, these issues do not affect performance in any way (I have actually tried this tube in an amp, see below). Other than trying to get some of the tape off, and cleaning some of the pins a tiny bit, I have not modified these tubes in any way from the condition as received. I would at least recommend giving the pins a good cleaning prior to use.
As you will see below, these tubes test nicely and reasonably close. If you track these on Ebay, you will see that REJECT Gold Monarch/Gold Lion KT88s are going for over $100 each. On that basis, my asking price seems pretty reasonable, especially when considering that these are a decently-matched quad. If, however, you can find a comparable testing QUAD of these at a lower price (from someone with a decent history of selling tubes), then I will be happy to discuss my asking price.
When I originally acquired these tubes, I tested them in three different ways:
(1) Weston 981 III – I tested these as 6550s using the comparable settings from a Heathkit TT-1 (KT88s are tested as 6550s on the Heathkit). The Weston does have its own setting for a 6550, but it does not make sense (tests at a plate voltage of 90V versus 225V for the Heathkit setting). The Weston and Heathkit are in many respects based on the same circuitry, and most of the octal settings for the Heathkit can be directly used on the Weston (and vice versa).
The reject point (65%) for this setting is 1430, making about 2200 “theoretical” 100%. In my general experience with the Weston, a new tube ON AVERAGE will test higher than this “theoretical” 100% level (say about 10%).
(2) Precision 660 emissions tester – These were also tested as 6550s. Once again, the Precision does have its own setting for a KT88, but it does not make sense (tests at a filament voltage of 5V as opposed to 6.3V).
According to the Precision manual, an average new tube should read 84 (65+ is good). My experience is that this varies from tube to tube, so it is good to compare to a reference.
(3) A custom rig to measure plate current (Ia) – I used a custom rig to apply 250V plate voltage (Va) and -14 to -16 V grid voltage (Vg) to measure plate current (Ia) and derive transconductance (delta Ia/delta Vg) under these conditions. I am not entirely confident about the absolute numbers, but the numbers relative to one another and compared to the reference do provide useful information. The results are provided in the following format:
Ia (Vg = -14V)/Ia (Vg = -15V)/Ia (Vg = -16V)/derived Gm (mmhos)
All the results are provided below. On the Gold Monarchs, each tube has a number written on the top (from a previous owner). I will be using those numbers for identification in the results.
All tubes were clean for shorts and leakage.
I have also provided results for two lightly used new production KT88s (Shuguang) for comparison (not included).
Whether you use these results as absolute values or not is up to you, but the comparison (both against the Shuguang tubes and against one another) clearly seems to be of relevance.
Reference Tubes
Shuguang KT88 #1
Weston 981 III 2450
Precision 660 95
Test Rig 121/132/144/11500
Shuguang KT88 #2
Weston 981 III 2300
Precision 660 96
Test Rig 112/123/134/11000
Gold Monarchs
#2
Weston 981 III 2150
Precision 660 95
Test Rig 101/111/122/10500
#10
Weston 981 III 2150
Precision 660 94
Test Rig 100/110/121/10750
#14
Weston 981 III 2200
Precision 660 94
Test Rig 100/110/121/10500
#16
Weston 981 III 2050
Precision 660 95
Test Rig 106/116/126/10000
More recently, I also tested the four Gold Monarchs on a reasonably calibrated B&K 700. The results were 90 (#2), 92 (#10), 92 (#14) and 91 (#16). All passed the life test as well. These results seem very consistent with the ones earlier taken.
I also ran tubes #10 and #14 for a very short time (less than 10 hours) in a custom SE KT88 amp that I have. They performed as expected. I would expect the other two tubes to perform exactly the same. Should the purchaser desire, I will be happy to run the other two tubes for a few hours to confirm performance.
I can provide additional information or pictures upon request.
GENERAL TERMS AND CONDITIONS – PLEASE READ CAREFULLYPlease note that these tubes are being sold 'AS IS', but I will guarantee against a DOA tube (does not work at all). In such event, I will refund purchase price less shipping upon return of the tubes in the same condition as sent.
I ONLY describe what I know about the tubes, and what I have tested for. Although my tube testers tend to be reliable, YOUR TUBE TESTER MAY GIVE A DIFFERENT RESULT THAN MINE, so please take that into account. If the information is not there, DO NOT ASSUME, and do not rely on any of YOUR assumptions. If you need more information than provided in the listing, ASK IN ADVANCE. If I happen to have the information, I will provide it. If I can get the information in a reasonable way, I will get it. I do the best I can with very limited time and capabilities. I am an honest seller, but I am NOT a tube professional, and I am NOT in the tube business.
AS SUCH, PLEASE NOTE THAT I CANNOT GUARANTEE (OR EVEN REMOTELY PREDICT) HOW THESE TUBES WILL SOUND OR PERFORM IN YOUR EQUIPMENT. THE TEST RESULTS ARE ONLY PROVIDED AS AN INDICATION OF TUBE PERFORMANCE IN A VERY LIMITED (AND NON-IDEAL) ENVIRONMENT. OTHER THAN AS SET FORTH ABOVE, I EXPRESSLY DISCLAIM ANY LIABILITY WITH RESPECT TO THESE TUBES OR RESPONSIBILITY FOR YOUR USE OF THEM.
Shipping in the USA via US Postal Priority Mail is included, although insurance if desired will be extra. If you are outside the USA, or wish to use a different shipping method, contact me for a shipping quote.
Money order/cashiers check/personal check preferred, but all (other than US Postal money orders) must clear my bank first.
I also accept Paypal for convenience (but add 3% to the total for USA, and 4% to the total everywhere else). IF YOU PAY VIA PAYPAL, HOWEVER, A CONDITION OF YOUR PAYMENT IS THAT YOU EXPRESSLY WAIVE THE RIGHT TO FILE A PAYPAL CLAIM OR CHARGE BACK (but do retain the right to sue me in court should you so desire).
IF YOU ARE NOT WILLING TO ACCEPT EACH AND EVERY ONE OF THE ABOVE TERMS AND CONDITIONS, DO NOT CONTACT ME AND DO NOT PURCHASE THESE TUBES. NO EXCEPTIONS!
Almost all audio and tube-related trade value will be considered. I don’t have any specific needs, but possibly something will catch my interest (even things like SACD/DVD-A/DAD or other high resolution discs). The only items I am not interested in at all are tuners, turntables and CD/DVD players (although a dedicated SACD player would be of interest). I will even consider equipment repair services. In any event, feel free to propose something (tubes or audio equipment) and I will at least consider it and respond.
Please check my feedback on Audiogon, Videogon and Ebay (ID=baileyler) and buy with confidence.
